ORCID Profile
0000-0002-1682-0025
Current Organisation
University of the Sunshine Coast
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Microbiology | Biotechnology Not Elsewhere Classified | Infectious Agents | Veterinary Immunology | Veterinary Sciences | Veterinary Microbiology (excl. Virology) | Biochemistry and Cell Biology | Protein Targeting And Signal Transduction | Bacteriology | Genetics Not Elsewhere Classified | Medicinal and Biomolecular Chemistry | Biologically Active Molecules | Immunology | Computer Software Not Elsewhere Classified | Immunology Not Elsewhere Classified | Computer Software | Genetics | Characterisation Of Macromolecules | Medical Biotechnology | Systems Biology | Biological Sciences Not Elsewhere Classified | Analytical Biochemistry | Membrane Biology | Infectious Agents | Virology | Medical Bacteriology | Conservation And Biodiversity | Data Security | Neurosciences Not Elsewhere Classified | Characterisation of Biological Macromolecules | Separation Science | Cheminformatics and Quantitative Structure-Activity Relationships | Biomedical Engineering | Biomechanical Engineering | Infectious Diseases | Proteins and Peptides | Pathology | Immunology | Other Biological Sciences | Veterinary Diagnosis and Diagnostics | Veterinary Epidemiology | Infectious Diseases | Bioinformatics | Numerical Analysis | Bacteriology
ANZSRC Socio-Economic Objective (SEO)
Infectious diseases | Biological sciences | Control of Animal Pests, Diseases and Exotic Species in Forest and Woodlands Environments | Flora, Fauna and Biodiversity of environments not elsewhere classified | Forest and Woodlands Flora, Fauna and Biodiversity | Animal Welfare | Veterinary Biological Preventatives (e.g. Vaccines) | Cancer and related disorders | Prevention—biologicals (e.g. vaccines) | Control of Pests, Diseases and Exotic Species at Regional or Larger Scales | Information processing services | Control of Animal Pests, Diseases and Exotic Species in Farmland, Arable Cropland and Permanent Cropland Environments | Application packages | Beef Cattle | Human Biological Preventatives (e.g. Vaccines) | Human Diagnostics | Mathematical sciences | Information services not elsewhere classified | Diagnostics | Other environmental aspects | Computer hardware and electronic equipment not elsewhere classified | Immune system and allergy | Living resources (flora and fauna) | Computer software and services not elsewhere classified | Human Pharmaceutical Treatments (e.g. Antibiotics) | Sheep - Meat | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Agricultural and Veterinary Sciences | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Babesia bovis: Proteins of virulent and avirulent parasites passaged through ticks and splenectomized or intact calves
Publisher: Elsevier BV
Date: 10-1983
DOI: 10.1016/0014-4894(83)90066-8
Abstract: Passage of the avirulent vaccine (K) strain of Babesia bovis (KA) through either Boophilus microplus ticks, intact calves, or intact calves and then ticks, resulted in two distinct protein and protein antigen profiles as analyzed by two-dimensional gel electrophoresis of biosynthetically labeled proteins and immunoprecipitates. Different degrees of expression of two major acidic antigens of KA designated Ka1 (Mr 47,500) and Ka2 (Mr 43,000) were observed. Ka1 was apparently lost following passage of KA B. bovis through intact calves but was strongly represented in the parasite population following a single tick passage. In contrast, passage through ticks of the virulent KV B. bovis (from which KA was derived by passage in splenectomized calves) did not lead to strong representation of the Ka1 protein although there was increased representation of another major acidic protein antigen, designated KV (Mr 35,000). These data suggest that the previously recognized reversion to a strain-dependent basal antigenic type in the tick vector depends also on intrastrain characteristics such as virulence and strain heterogeneity. The data suggest that KA is a more heterogeneous population than KV although cloned isolates are required to establish this point. Comparable syringe passage of another strain of B. bovis, designated C strain, through splenectomized calves resulted in less marked differences between the putative CA and CV B. bovis. This may explain the less stable avirulence of CA compared to KA B. bovis. Various selection pressures must act, in either the tick or the vertebrate host, on subpopulations in heterogeneous isolates to produce the changes described in protein antigen profiles of B. bovis. The possible relevance of changes in representation of proteins to biological characteristics of B. bovis (such as virulence and tick transmissibility) is discussed.
Elucidating the host–pathogen interaction between human colorectal cells and invading Enterovirus 71 using transcriptomics profiling
Publisher: Wiley
Date: 2014
Treatment efficacy of azithromycin 1 g single dose versus doxycycline 100 mg twice daily for 7 days for the treatment of rectal chlamydia among men who have sex with men - a double-blind randomised controlled trial protocol
Publisher: Springer Science and Business Media LLC
Date: 06-01-2017
In silico identification and in vivo analysis of a novel T-cell antigen from Chlamydia, NrdB
Publisher: Elsevier BV
Date: 03-2008
DOI: 10.1016/J.VACCINE.2007.12.048
Abstract: Chlamydial infections are a serious economic burden and health threat to developed and developing countries. Development of an efficacious vaccine is thought to be the most convenient, potentially reliable and cost effective option to control chlamydial infection and disease complications. Currently there are very few efficacious vaccine candidates that have been identified and characterized. In this study we have identified a number of unique vaccine candidates using a novel in silico approach. The chlamydial genome was screened for proteins containing epitopes predicted to bind multiple HLA class II molecules (i.e. 'promiscuous' epitopes). A selection of target proteins were cloned, expressed, and purified. Recombinant proteins were screened against sera s les from patients with Chlamydia trachomatis genital tract infections. Two proteins, hypothetical protein CT425 and ribonucleotide reductase small chain protein (NrdB) were identified as being immunoreactive. Using a mouse model, we found that intranasal immunization with NrdB conferred a CD4+ T-cell driven degree of protection similar to that seen with CD4+ T-cells primed from a whole organism, live challenge. In addition, serum from immunized mice was found to neutralize chlamydial infection of a cell monolayer in vitro. NrdB is a highly conserved chlamydial protein with an essential role in the replication of chlamydiae and could be a useful component of a multi-subunit vaccine against chlamydial genital tract infections.
Long-read genome sequence assembly provides insight into ongoing retroviral invasion of the koala germline
Publisher: Springer Science and Business Media LLC
Date: 20-11-2017
DOI: 10.1038/S41598-017-16171-1
Abstract: The koala retrovirus (KoRV) is implicated in several diseases affecting the koala (Phascolarctos cinereus) . KoRV provirus can be present in the genome of koalas as an endogenous retrovirus (present in all cells via germline integration) or as exogenous retrovirus responsible for somatic integrations of proviral KoRV (present in a limited number of cells). This ongoing invasion of the koala germline by KoRV provides a powerful opportunity to assess the viral strategies used by KoRV in an in idual. Analysis of a high-quality genome sequence of a single koala revealed 133 KoRV integration sites. Most integrations contain full-length, endogenous provirus KoRV-A subtype. The second most frequent integrations contain an endogenous recombinant element (recKoRV) in which most of the KoRV protein-coding region has been replaced with an ancient, endogenous retroelement. A third set of integrations, with very low sequence coverage, may represent somatic cell integrations of KoRV-A, KoRV-B and two recently designated additional subgroups, KoRV-D and KoRV-E. KoRV-D and KoRV-E are missing several genes required for viral processing, suggesting they have been transmitted as defective viruses. Our results represent the first comprehensive analyses of KoRV integration and variation in a single animal and provide further insights into the process of retroviral-host species interactions.
Protein Expression Profiles of Chlamydia pneumoniae in Models of Persistence versus Those of Heat Shock Stress Response
Publisher: American Society for Microbiology
Date: 07-2006
DOI: 10.1128/IAI.02104-05
Abstract: Chlamydia pneumoniae is an obligate intracellular pathogen that causes both acute and chronic human disease. Several in vitro models of chlamydial persistence have been established to mimic chlamydial persistence in vivo. We determined the expression patterns of 52 C. pneumoniae proteins, representing nine functional subgroups, from the gamma interferon (IFN-γ) treatment (primarily tryptophan limitation) and iron limitation (IL) models of persistence compared to those following heat shock (HS) at 42°C. Protein expression patterns of C. pneumoniae persistence indicates a strong stress component, as evidenced by the upregulation of proteins involved in protein folding, assembly, and modification. However, it is clearly more than just a stress response. In IFN persistence, but not IL or HS, amino acid and/or nucleotide biosynthesis proteins were found to be significantly upregulated. In contrast, proteins involved in the biosynthesis of cofactors, cellular processes, energy metabolism, transcription, and translation showed an increased in expression in only the IL model of persistence. These data represent the most extensive protein expression study of C. pneumoniae comparing the chlamydial heat shock stress response to two models of persistence and identifying the common and unique protein level responses during persistence.
Vaccination of koalas (Phascolarctos cinereus) against Chlamydia pecorum using synthetic peptides derived from the major outer membrane protein
Publisher: Public Library of Science (PLoS)
Date: 28-06-2018
Chlamydial Persistence: beyond the Biphasic Paradigm
Publisher: American Society for Microbiology
Date: 04-2004
HtrA, RseP, and Tsp proteins do not elicit a pathology-related serum IgG response during sexually transmitted infection with Chlamydia trachomatis.
Publisher: Elsevier BV
Date: 06-2010
DOI: 10.1016/J.JRI.2010.02.007
Abstract: Chlamydia trachomatis sexually transmitted infection can cause serious reproductive morbidities. This study determined the prevalence of a serum IgG response to C. trachomatis putative stress response proteins in women, to test for an association with genital tract pathology. There was no significant association of serum IgG reactive with C. trachomatis HtrA, Tsp, or RseP with infection or pathology. cHSP60 serum IgG prevalence was significantly associated with infection compared to IgG negative infertile controls, but not with upper genital tract pathology. Serum IgG(1-4) antibody subclasses reactive with these antigens was not significantly different between cohorts, although different responses to each antigen were detected.
Human Chlamydia pneumoniae isolates demonstrate ability to recover infectivity following penicillin treatment whereas animal isolates do not.
Publisher: Oxford University Press (OUP)
Date: 06-02-2015
Abstract: Chlamydia pneumoniae strains have recently been demonstrated to have substantially different capacities to enter and recover from IFN-γ-induced persistence, depending on whether they are from human or animal host sources. Here, we examined the ability of two human and two animal strains to enter and be rescued from penicillin-induced persistence. The ability to form inclusions after the addition of penicillin was much reduced in the two animal isolates (koala LPCoLN, bandicoot B21) compared to the two human isolates (respiratory AR39 and heart A03). The penicillin treatment resulted in a dose-dependent loss of infectious progeny for all isolates, with the human strains failing to produce infectious progeny at lower doses of penicillin than the animal strains. The most remarkable finding however was the contrasting ability of the isolates to recover infectious progeny production after rescue by removal of the penicillin (at 72 h) and continued culture. The animal isolates both showed virtually no recovery from the penicillin treatment conditions. In contrast, the human isolates showed a significant ability to recovery infectivity, with the heart isolate (A03) showing the most marked recovery. Combined, these data further support the hypothesis that the ability to establish and recover from persistence appears to be enhanced in human C. pneumoniae strains compared to animal strains.
Genetic diversity and gene flow among southeastern Queensland koalas (Phascolarctos cinereus)
Publisher: Wiley
Date: 02-2000
DOI: 10.1046/J.1365-294X.2000.00844.X
Abstract: Habitat fragmentation and destruction associated with the rapid urban and rural development of southeast Queensland presents an immediate threat to the survival of koala populations within this region. A sensitive method combining heteroduplex analysis (HDA) with temperature gradient gel electrophoresis (TGGE) was optimized to detect within-species variation in a mitochondrial DNA (mtDNA) control-region fragment, approximately 670 bp in length, from the koala. Eight different haplotypes were characterized in koalas, of which four were novel. Analysis of mtDNA ersity in 96 koalas from five populations in southeast Queensland revealed that the number of haplotypes in a single population ranged from one to five, with an average within-population haplotype ersity of 0.379 +/- 0.016, and nucleotide ersity of 0.22 +/- 0.001%. Nucleotide ergence between populations averaged 0.09 +/- 0.001% and ranged from 0.00 to 0.14%. Significant genetic heterogeneity was observed among most populations, suggesting that koala populations may be spatially structured along matrilines, although this may not be universal. The limited distribution of the central phylogenetic haplotype suggested the possibility of historical population bottlenecks north of the Gold Coast, while the presence of two highly ergent haplotypes at the Moreton site may indicate the occurrence of one or more undocumented translocation events into this area.
In silico characterisation of the two-component system regulators of Streptococcus pyogenes
Publisher: Public Library of Science (PLoS)
Date: 21-06-2018
Adaptation and conservation insights from the koala genome
Publisher: Springer Science and Business Media LLC
Date: 02-07-2018
CtHtrA: the lynchpin of the chlamydial surface and a promising therapeutic target.
Publisher: Future Medicine Ltd
Date: 07-2017
Abstract: Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection worldwide and the leading cause of preventable blindness. Reports have emerged of treatment failure, suggesting a need to develop new antibiotics to battle Chlamydia infection. One possible candidate for a new treatment is the protease inhibitor JO146, which is an effective anti-Chlamydia agent that targets the CtHtrA protein. CtHtrA is a lynchpin on the chlamydial cell surface due to its essential and multifunctional roles in the bacteria's stress response, replicative phase of development, virulence and outer-membrane protein assembly. This review summarizes the current understanding of CtHtrA function and presents a mechanistic model that highlights CtHtrA as an effective target for anti-Chlamydia drug development.
Kinematics of Intracellular Chlamydiae Provide Evidence for Contact-Dependent Development
Publisher: American Society for Microbiology
Date: 15-09-2009
DOI: 10.1128/JB.00293-09
Abstract: A crucial process of chlamydial development involves differentiation of the replicative reticulate body (RB) into the infectious elementary body (EB). We present experimental evidence to provide support for a contact-dependent hypothesis for explaining the trigger involved in differentiation. We recorded live-imaging of Chlamydia trachomatis -infected McCoy cells at key times during development and tracked the temporospatial trajectories of in idual chlamydial particles. We found that movement of the particles is related to development. Early to mid-developmental stages involved slight wobbling of RBs. The average speed of particles increased sharply at 24 h postinfection (after the estimated onset of RB to EB differentiation). We also investigated a penicillin-supplemented culture containing EBs, RBs, and aberrantly enlarged, stressed chlamydiae. Near-immobile enlarged particles are consistent with their continued tethering to the chlamydial inclusion membrane (CIM). We found a significantly negative, nonlinear association between speed and size/type of particles, providing further support for the hypothesis that particles become untethered near the onset of RB to EB differentiation. This study establishes the relationship between the motion properties of the chlamydiae and developmental stages, whereby wobbling RBs gradually lose contact with the CIM, and RB detachment from the CIM is coincidental with the onset of late differentiation.
The Duration of Chlamydia muridarum Genital Tract Infection and Associated Chronic Pathological Changes Are Reduced in IL-17 Knockout Mice but Protection Is Not Increased Further by Immunization
Publisher: Public Library of Science (PLoS)
Date: 20-09-2013
Vaccination of koalas with a prototype chlamydial vaccine is safe, does not increase the incidence of lymphoma-related disease and maybe associated with increased lifespan in captive koalas
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.VACCINE.2015.07.029
Abstract: To assess the impact of Chlamydia vaccination on survival of captive koalas, and to compare the incidence of lymphomas and neoplasias between vaccinated and unvaccinated koalas. Survival analysis using Cox and Weibull regressions on 54 vaccinated and 52 matched unvaccinated koalas, and chi-square contingency table for incidence of lymphomas/neoplasias. Vaccination was found to have a significant positive effect on koala lifespan (P=0.03), with vaccinated koalas having a median lifespan of 12.25 years compared to 8.8 years for unvaccinated ones. The effect of sex on lifespan was not significant (P=0.31). The risk ratio of unvaccinated over vaccinated koalas was 2.2 with both Cox and Weibull regressions. There was no association between the incidence of lymphoma/neoplasias and vaccination status (P=0.33). Koalas vaccinated with a prototype Chlamydia vaccine may live longer than unvaccinated ones. There was no known Chlamydia infection among koalas, so our interpretation is that vaccination may have boosted the innate and adaptive immune systems to protect against a wide spectrum of bacteria, fungi and parasites. Vaccinated koalas did not show negative physiological effects of the vaccine, for ex le, the frequency of deaths due to lymphomas/neoplasias was the same in both vaccinated and unvaccinated animals.
Antibiotic treatment of Chlamydia-induced cystitis in the koala is linked to expression of key inflammatory genes in reactive oxygen pathways
Publisher: Public Library of Science (PLoS)
Date: 15-08-2019
Comparison of subcutaneous versus intranasal immunization of male koalas (Phascolarctos cinereus) for induction of mucosal and systemic immunity against Chlamydia pecorum
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.VACCINE.2014.12.052
Abstract: Chlamydia pecorum infections are debilitating in the koala, contributing significantly to morbidity and mortality, with current antibiotic treatments having minimal success and adversely affecting gut microflora. This, combined with the sometimes-asymptomatic nature of the infection, suggests that an efficacious anti-chlamydial vaccine is required to control chlamydial infections in the koala. To date vaccination studies have focused primarily on female koalas, however, given the physiological differences between male and female reproductive tracts, we tested the efficacy of a vaccine in 12 captive male koalas. We evaluated the potential of both subcutaneous and intranasal vaccine delivery to elicit mucosal immunity in male koalas. Our results showed that both intranasal and subcutaneous delivery of a vaccine consisting of C. pecorum major outer membrane protein (MOMP) and the adjuvant immunostimulating complex (ISC) induced significant immune responses in male koalas. Subcutaneous immunization elicited stronger cell-mediated responses in peripheral blood lymphocytes (PBL), and greater plasma antibody levels whereas the intranasal immunization elicited stronger humoral responses in urogenital tract (UGT) secretions. This is the first time a Chlamydia vaccine has been tested in the male koala and the first assessment of a mucosal vaccination route in this species. Our results suggest that vaccination of male koalas can elicit mucosal immunity and could contribute to the long-term survivability of wild populations of the koala.
Evaluation of intra- and extra-epithelial secretory IgA in chlamydial infections
Publisher: Wiley
Date: 10-11-2014
DOI: 10.1111/IMM.12317
Genetic variation in captive koalas (Phascolarctos cinereus): Parentage determination and individual identification
Publisher: Springer Science and Business Media LLC
Date: 1998
Abstract: Highly repeatable randomly lified polymorphic DNA (RAPD) markers were developed for parentage studies in the koala (Phascolarctos cinereus). Of the 25 RAPD primers screened, 5 (20.0%) produced 32 repeatable polymorphic RAPD bands (average rimer = 6.4 +/- 4.2). A high level of polymorphism was observed for each group of koalas (Featherdale, 71.9% Lone Pine, 84.4%). All 25 koalas could be uniquely identified using either RAPD or microsatellite markers. Of the 32 RAPD markers generated in koalas, 25 were informative for parentage analyses. These RAPD markers successfully determined both parents to three offspring and a male parent to a fourth offspring. Paternity analysis (where the female parent is known) succeeded in assigning the correct male parent to seven offspring. Our RAPD-PCR method generates informative genetic markers that are useful for parentage determination and in idual identification of captive koalas. This would provide genetic analysis to zoos and wildlife parks as a low-cost alternative to the more expensive microsatellite markers.
Is Chlamydia to Blame for Koala Reproductive Cysts?
Publisher: MDPI AG
Date: 04-09-2021
DOI: 10.3390/PATHOGENS10091140
Abstract: A significant threat to koala populations is infection from Chlamydia, which results in disease and death. Wild koalas with Chlamydia infections are admitted to wildlife hospitals and treated with antibiotics however, up to 50% of koalas that present to wildlife hospitals do not survive. A major contributor to high mortality is the development of reproductive cysts, resulting in female infertility and euthanasia. However, the diagnosis of reproductive disease is limited to ultrasound with no further investigations. This communication highlights reports of histological and microbiological findings, the accuracy of ultrasound to necropsy reports and other possible causes for reproductive cyst development previously reported in other hosts. Our conclusions identify a significant knowledge gap in the aetiology of koala reproductive cysts and highlight the urgent need for future investigations.
A proposed roadmap for the control of infections in wildlife using Chlamydia vaccine development in koalas Phascolarctos cinereus as a template
Publisher: Wiley
Date: 03-02-2020
DOI: 10.2981/WLB.00627
Molecular dynamics and mode of transmission of koala retrovirus as it invades and spreads through a wild Queensland koala population
Publisher: American Society for Microbiology
Date: 03-2018
DOI: 10.1128/JVI.01871-17
Abstract: The recent acquisition of a novel retrovirus (KoRV) by koalas ( Phascolarctos cinereus ) has created new opportunities for retroviral research and new challenges for koala conservation. There are currently two major subtypes of KoRV: KoRV-A, which is believed to be endogenous only in koalas from the northern part of Australia, and KoRV-B, which appears to be exogenous. Understanding and management of these subtypes require population level studies of their prevalence and ersity, especially when coinfected in the same population, and investigations of their modes of transmission in the wild. Toward this end, we studied a wild Queensland koala population of 290 animals over a 5-year period and investigated the prevalence, ersity and mode of transmission of KoRV-A and KoRV-B. We found KoRV-A to have an infection level of 100% in the population, with all animals sharing the same dominant envelope protein sequence. In contrast, the KoRV-B infection prevalence was only 24%, with 21 different envelope protein sequence variants found in the 83 KoRV-B-positive animals. Linked to severe disease outcomes, a significant association between KoRV-B positivity and both chlamydial disease and neoplasia was found in the population. Transmission of KoRV-B was found at a rate of 3% via adult-to-adult contact per year, while there was a 100% rate of KoRV-B-positive mothers transmitting the virus to their joeys. Collectively, these findings demonstrate KoRV-B as the pathogenic subtype in this wild koala population and inform future intervention strategies with subtype variation and transmission data. IMPORTANCE KoRV represents a unique opportunity to study a relatively young retrovirus as it goes through its molecular evolution in both an endogenous form and a more recently evolved exogenous form. The endogenous form, KoRV-A, now appears to have stably and completely established itself in Northern Australian koala populations and is progressing south. Conversely, the exogenous form, KoRV-B, is undergoing continuous mutation and spread in the north and, as yet, has not reached all southern koala populations. We can now link KoRV-B to neoplasia and chlamydial disease in both wild and captive koalas, making it an imminent threat to this already vulnerable species. This work represents the largest study of koalas in a wild population with respect to KoRV-A/KoRV-B-infected/coinfected animals and the linkage of this infection to chlamydial disease, neoplasia, viral evolution, and spread.
A mathematical model for the investigation of the Th1 immune response to Chlamydia trachomatis
Publisher: Elsevier BV
Date: 03-2003
DOI: 10.1016/S0025-5564(02)00180-3
Abstract: Chlamydia are bacterial pathogens of humans and animals causing the important human diseases trachoma, sexually transmitted chlamydial disease and pneumonia. Of the human chlamydial diseases, sexually transmitted disease caused by Chlamydia trachomatis is a major public health concern. Chlamydia trachomatis replicates intracellularly and is characterised by a complex developmental cycle. Chlamydia is susceptible to humoral and cell-mediated immunity. Here we investigate the Th1 cell-mediated immune response against Chlamydia-infected cells as the response changes over the chlamydial developmental cycle. We suggest a form for the immune response over one developmental cycle by modelling the change in the number of intracellular chlamydial particles and assume peptides are presented in proportion to the number of replicating forms of chlamydial particles. We predict, perhaps non-intuitively, that persistent Chlamydia should be induced and forced not to return to the lytic cycle. We also suggest that extending the length of the time of the lytic cycle will effectively decrease the required efficacy of the Th1 response to eliminate the pathogen. We produce plots of active disease progression, control and clearance for varying levels of Th1 effectiveness.
Use of gene sequences as type for naming prokaryotes: Recommendations of the international committee on the taxonomy of chlamydiae
Publisher: Elsevier BV
Date: 09-2023
PCR detection and differentiation of Chlamydia pneumoniae, Chlamydia psittaci and Chlamydia trachomatis
Publisher: Elsevier BV
Date: 10-1992
DOI: 10.1016/0890-8508(92)90032-S
Abstract: A PCR-based system was developed for the detection and differentiation of Chlamydia trachomatis, Chlamydia psittaci and Chlamydia pneumoniae. A conserved 145 bp fragment of the chlamydial omp1 gene was lified from all three species. The three species were then differentiated from each other by digestion of this PCR product with restriction enzymes Eco RI and either Hind III or Pst I. The system was shown to work for two strains of C. pneumoniae, 11 strains of C. psittaci and 10 serovars of C. trachomatis, and had a sensitivity of less than 10 chlamydial elementary bodies. This method was also applicable to the detection of C. trachomatis in conjunctival and nasopharyngeal swabs.
Identification and Mapping of Sigma-54 Promoters in Chlamydia trachomatis
Publisher: American Society for Microbiology
Date: 11-2000
DOI: 10.1128/JB.182.21.6239-6242.2000
Abstract: The first ς 54 promoters in Chlamydia trachomatis L2 were mapped upstream of hypothetical proteins CT652.1 and CT683. Comparative genomics indicated that these ς 54 promoters and potential upstream activation binding sites are conserved in orthologous C. trachomatis D, C. trachomatis mouse pneumonitis strain, and Chlamydia pneumoniae (CWL029 and AR39) genes.
In vitro characterisation of koala Chlamydia pneumoniae: Morphology, inclusion development and doubling time
Publisher: Elsevier BV
Date: 04-2009
DOI: 10.1016/J.VETMIC.2008.10.008
Abstract: Chlamydia pneumoniae is a common human and animal pathogen associated with upper and lower respiratory tract infections. Of the animal C. pneumoniae isolates, the koala nasal isolate (LPCoLN) is by far the best genetically characterised. This current study was designed to characterise the morphology and developmental events for the LPCoLN isolate, and our results showed several striking in vitro growth differences when compared to the human isolate, AR39. The LPCoLN inclusion size and morphology was distinct from AR39, and a much faster doubling time (3.4-4.9h versus 5.9-8.7h doubling time) was observed when grown in HEp-2 cell monolayers. Confocal and electron microscopy of LPCoLN confirmed large (9-30 microm in diameter) inclusions, that were heterogeneously shaped, compared to the small (5-9 microm in diameter), uniformly shaped inclusions of AR39. The morphology of the LPCoLN elementary body was round, and had a narrow or nonexistent periplasmic space, compared to the 'pear-shaped' morphology of AR39 EBs. While both isolates showed evidence of inclusion fusion, the level of fusion was much higher for LPCoLN (100%) compared to AR39 (30-40%). Our findings have provided new insights and identified key differences in the in vitro doubling time, size and morphology of an animal C. pneumoniae isolate.
Molecular vaccines against parasites
Publisher: Elsevier BV
Date: 07-1986
DOI: 10.1016/0169-4758(86)90203-6
Abstract: Prophylactic vaccines can be expected to be one of the major practical outputs of parasitology research. Various groups within Australia have pursued the vaccine objective for several years, with particular emphasis on blood-stage falciparum malaria in man, intestinal helminths of sheep and cattle, cutaneous myiasis (blowfly strike) in sheep, cysticercosis in sheep and cattle, bovine babesiosis, and cattle ticks. Other vaccine programmes are concerned with giardiasis, filariasis, toxoplasmosis, fascioliasis, coccidiosis in poultry, cutaneous leishmaniasis and schistosomiasis japonica. For many years, the only available vaccine against a parasite in Australia has been the attenuated Babesia bovis vaccine produced by the Tick Fever Research Centre of the Queensland Department of Primary Industries. Strategies for achieving molecular vaccines are generally similar within the various research groups. They involve analysis of the immunology and immunochemistry of a model or in-vitro system development of functional monoclonal antibodies analysis of antibody specificities in clinically and/or functionally defined polyclonal sera screening of cDNA or genomic expression libraries peptide synthesis identification of an appropriate vaccination schedule involving adjuvants or new recombinant DNA-based antigen delivery systems. Outlined below are five of the major vaccine programmes.
Antibody response against koala retrovirus (KoRV) in koalas harboring KoRV-A in the presence or absence of KoRV-B
Publisher: Springer Science and Business Media LLC
Date: 27-08-2019
DOI: 10.1038/S41598-019-48880-0
Abstract: Koala retrovirus (KoRV) is in the process of endogenization into the koala ( Phascolarctos cinereus ) genome and is currently spreading through the Australian koala population. Understanding how the koala’s immune system responds to KoRV infection is critical for developing an efficacious vaccine to protect koalas. To this end, we analyzed the antibody response of 235 wild koalas, s led longitudinally over a four-year period, that harbored KoRV-A, and with or without KoRV-B. We found that the majority of the s led koalas were able to make anti-KoRV antibodies, and that there was a linear increase in anti-KoRV IgG levels in koalas up to approximately seven years of age and then a gradual decrease thereafter. Koalas infected with both KoRV-A and KoRV-B were found to have slightly higher anti-KoRV IgG titers than koalas with KoRV-A alone and there was an inverse relationship between anti-KoRV IgG levels and circulating KoRV viral load. Finally, we identified distinct epitopes on the KoRV envelope protein that were recognized by antibodies. Together, these findings provide insight into the koala’s immune response to KoRV and may be useful in the development of a therapeutic KoRV vaccine.
The Genetic Transformation of Chlamydia pneumoniae
Publisher: American Society for Microbiology
Date: 31-10-2018
Abstract: The absence of tools for the genetic manipulation of C. pneumoniae has h ered research into all aspects of its biology. In this study, we established a novel reproducible method for C. pneumoniae transformation based on a plasmid shuttle vector system. We constructed a C. pneumoniae plasmid backbone shuttle vector, pRSGFPCAT-Cpn. The construct expresses the red-shifted green fluorescent protein (RSGFP) fused to chlor henicol acetyltransferase in C. pneumoniae . C. pneumoniae transformants stably retained pRSGFPCAT-Cpn and expressed RSGFP in epithelial cells, even in the absence of chlor henicol. The successful transformation in C. pneumoniae using pRSGFPCAT-Cpn will advance the field of chlamydial genetics and is a promising new approach to investigate gene functions in C. pneumoniae biology. In addition, we demonstrated that pRSGFPCAT-Cpn overcame the plasmid species barrier without the need for recombination with an endogenous plasmid, indicating the potential probability of horizontal chlamydial pathogenic gene transfer by plasmids between chlamydial species.
CTA1-DD is an effective adjuvant for targeting anti-chlamydial immunity to the murine genital mucosa
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.JRI.2009.04.002
Abstract: Chlamydia trachomatis is a significant human pathogen with potentially severe disease sequelae in the genital tract, including infertility. A successful vaccine will need to effectively target immunity to the genital mucosa. Intranasal immunisation with cholera toxin (CT) can target immunity to the genital tract, but has the potential to cause neurological side effects. CTA1-DD is a non-toxic potent mucosal adjuvant which combines the enzymatic properties of CT, with a B cell targeting moiety. Here, we demonstrate that intranasal immunisation with CTA1-DD and chlamydial Major Outer Membrane Protein (MOMP) results in the induction of neutralising systemic and mucosal antibodies, and reduces the level of chlamydial shedding following intravaginal challenge with Chlamydia muridarum. Thus, CTA1-DD is an effective adjuvant for vaccine development against Chlamydia trachomatis, and possibly also a range of other genital pathogens.
A targeted approach to investigating immune genes of an iconic Australian marsupial
Publisher: Wiley
Date: 17-05-2022
DOI: 10.1111/MEC.16493
Abstract: Disease is a contributing factor to the decline of wildlife populations across the globe. Koalas, iconic yet declining Australian marsupials, are predominantly impacted by two pathogens, Chlamydia and koala retrovirus. Chlamydia is an obligate intracellular bacterium and one of the most widespread sexually transmitted infections in humans worldwide. In koalas, Chlamydia infections can present as asymptomatic or can cause a range of ocular and urogenital disease signs, such as conjunctivitis, cystitis and infertility. In this study, we looked at differences in response to Chlamydia in two northern populations of koalas using a targeted gene sequencing of 1209 immune genes in addition to genome‐wide reduced representation data. We identified two MHC Class I genes associated with Chlamydia disease progression as well as 25 single nucleotide polymorphisms across 17 genes that were associated with resolution of Chlamydia infection. These genes are involved in the innate immune response (TLR5) and defence (TLR5, IFNγ, SERPINE1, STAT2 and STX4). This study deepens our understanding of the role that genetics plays in disease progression in koalas and leads into future work that will use whole genome resequencing of a larger s le set to investigate in greater detail regions identified in this study. Elucidation of the role of host genetics in disease progression and resolution in koalas will directly contribute to better design of Chlamydia vaccines and management of koala populations which have recently been listed as “endangered.”
Anti-P. gingivalis Response Correlates with Atherosclerosis
Publisher: SAGE Publications
Date: 2007
DOI: 10.1177/154405910708600105
Abstract: Significant associations between atherosclerosis and both Porphyromonas gingivalis, a major periodontopathogen, and the respiratory pathogen, Chlamydia pneumoniae, have been shown. Many in iduals with evidence of atherosclerosis demonstrate seropositivity to these pathogens. The aim of the present study was to examine the atherogenic effect of repeated immunizations with either or both of these agents, and to determine if molecular mimicry of bacterial heat-shock protein (HSP), termed GroEL, and host (h) HSP60 was involved. Atherogenesis was examined in apolipoprotein-E-deficient (−/−) mice following intraperitoneal immunizations with P. gingivalis, C. pneumoniae, P. gingivalis, and C. pneumoniae or vehicle. Lesion area in the proximal aorta and levels of serum antibodies to P. gingivalis, C. pneumoniae, and GroEL were measured. The increased pathogen burden of P. gingivalis, but not of C. pneumoniae, enhanced atherosclerosis. hHSP60 was detected in lesions, and in P. gingivalis-immunized mice, lesion development was correlated with anti-GroEL antibody levels, supporting the involvement of molecular mimicry between GroEL and hHSP60.
The cross-species prediction of bacterial promoters using a support vector machine
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.COMPBIOLCHEM.2008.07.009
Abstract: Due to degeneracy of the observed binding sites, the in silico prediction of bacterial sigma(70)-like promoters remains a challenging problem. A large number of sigma(70)-like promoters has been biologically identified in only two species, Escherichia coli and Bacillus subtilis. In this paper we investigate the issues that arise when searching for promoters in other species using an ensemble of SVM classifiers trained on E. coli promoters. DNA sequences are represented using a tagged mismatch string kernel. The major benefit of our approach is that it does not require a prior definition of the typical -35 and -10 hexamers. This gives the SVM classifiers the freedom to discover other features relevant to the prediction of promoters. We use our approach to predict sigma(A) promoters in B. subtilis and sigma(66) promoters in Chlamydia trachomatis. We extended the analysis to identify specific regulatory features of gene sets in C. trachomatis having different expression profiles. We found a strong -35 hexamer and TGN/-10 associated with a set of early expressed genes. Our analysis highlights the advantage of using TSS-PREDICT as a starting point for predicting promoters in species where few are known.
Chlamydial clinical isolates show subtle differences in persistence phenotypes and growth in vitro
Publisher: Microbiology Society
Date: 03-2021
Abstract: Urogenital Chlamydia trachomatis infection is the most common sexually transmitted bacterial infection throughout the world. While progress has been made to better understand how type strains develop and respond to environmental stress in vitro , very few studies have examined how clinical isolates behave under similar conditions. Here, we examined the development and persistence phenotypes of several clinical isolates, to determine how similar they are to each other, and the type strain C. trachomatis D/UW-3/Cx. The type strain was shown to produce infectious progeny at a higher magnitude than each of the clinical isolates, in each of the six tested cell lines. All chlamydial strains produced the highest number of infectious progeny at 44 h post-infection in the McCoy B murine fibroblast cell line, yet showed higher levels of infectivity in the MCF-7 human epithelial cell line. The clinical isolates were shown to be more susceptible than the type strain to the effects of penicillin and iron deprivation persistence models in the MCF-7 cell line. While subtle differences between clinical isolates were observed throughout the experiments conducted, no significant differences were identified. This study reinforces the importance of examining clinical isolates when trying to relate in vitro data to clinical outcomes, as well as the importance of considering the adaptations many type strains have to being cultured in vitro .
Genotyping of Urogenital Chlamydia trachomatis in Regional New South Wales, Australia
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2008
Chlamydia trachomatis responds to heat shock, penicillin induced persistence, and IFN-gamma persistence by altering levels of the extracytoplasmic stress response protease HtrA
Publisher: Springer Science and Business Media LLC
Date: 2008
A 5-year Chlamydia vaccination programme could reverse disease-related koala population decline: Predictions from a mathematical model using field data
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.VACCINE.2014.05.049
Abstract: Many koala populations around Australia are in serious decline, with a substantial component of this decline in some Southeast Queensland populations attributed to the impact of Chlamydia. A Chlamydia vaccine for koalas is in development and has shown promise in early trials. This study contributes to implementation preparedness by simulating vaccination strategies designed to reverse population decline and by identifying which age and sex category it would be most effective to target. We used field data to inform the development and parameterisation of an in idual-based stochastic simulation model of a koala population endemic with Chlamydia. The model took into account transmission, morbidity and mortality caused by Chlamydia infections. We calibrated the model to characteristics of typical Southeast Queensland koala populations. As there is uncertainty about the effectiveness of the vaccine in real-world settings, a variety of potential vaccine efficacies, half-lives and dosing schedules were simulated. Assuming other threats remain constant, it is expected that current population declines could be reversed in around 5-6 years if female koalas aged 1-2 years are targeted, average vaccine protective efficacy is 75%, and vaccine coverage is around 10% per year. At lower vaccine efficacies the immunological effects of boosting become important: at 45% vaccine efficacy population decline is predicted to reverse in 6 years under optimistic boosting assumptions but in 9 years under pessimistic boosting assumptions. Terminating a successful vaccination programme at 5 years would lead to a rise in Chlamydia prevalence towards pre-vaccination levels. For a range of vaccine efficacy levels it is projected that population decline due to endemic Chlamydia can be reversed under realistic dosing schedules, potentially in just 5 years. However, a vaccination programme might need to continue indefinitely in order to maintain Chlamydia prevalence at a sufficiently low level for population growth to continue.
Chlamydia trachomatis Serovars among Strains Isolated from Members of Rural Indigenous Communities and Urban Populations in Australia
Publisher: American Society for Microbiology
Date: 2008
DOI: 10.1128/JCM.01493-07
Abstract: We genotyped Chlamydia trachomatis strains from 45 women or men living in either a rural indigenous community or in urban heterosexual communities. We found six different C. trachomatis serovars: E ( n = 22 48.9%), F ( n = 10 22.2%), J/Ja ( n = 5 11.1%), D/Da ( n = 4 8.9%), G ( n = 3 6.7%), and K ( n = 1 2.2%). The distribution of C. trachomatis serovars among members of the indigenous rural and the urban Australian communities appears similar to that in other Western countries.
Conserved DNA sequences in Chlamydial plasmids
Publisher: Elsevier BV
Date: 09-1989
DOI: 10.1016/0147-619X(89)90018-8
Abstract: Two 7.4-kb plasmids from Chlamydia psittaci have been cloned and characterized. These plasmids are quite distinct from the 6.2-kb C. psittaci and the C. trachomatis plasmids when compared by restriction endonuclease analysis. The plasmids show considerable cross-hybridization, with only a small region highly conserved and identified as a 4 X 22-bp tandemly repeated region. This sequence is identical in the two size categories of C. psittaci plasmids and differs from C. trachomatis plasmids by only 2 bp in the 22-bp motif. AT-rich clusters 5' to the repeat region which are present in C. trachomatis and Escherichia coli plasmids were absent from both classes of C. psittaci plasmids. Extensive regions are less highly conserved but show a sufficient degree of cross-hybridization to suggest that the plasmids are homologous.
The effects of calcitriol treatment in glucocorticoid-resistant asthma
Publisher: Elsevier BV
Date: 06-2014
Retroviral integrations contribute to elevated host cancer rates during germline invasion
Publisher: Springer Science and Business Media LLC
Date: 26-02-2021
DOI: 10.1038/S41467-021-21612-7
Abstract: Repeated retroviral infections of vertebrate germlines have made endogenous retroviruses ubiquitous features of mammalian genomes. However, millions of years of evolution obscure many of the immediate repercussions of retroviral endogenisation on host health. Here we examine retroviral endogenisation during its earliest stages in the koala ( Phascolarctos cinereus ), a species undergoing germline invasion by koala retrovirus (KoRV) and affected by high cancer prevalence. We characterise KoRV integration sites (IS) in tumour and healthy tissues from 10 koalas, detecting 1002 unique IS, with hotspots of integration occurring in the vicinity of known cancer genes. We find that tumours accumulate novel IS, with proximate genes over-represented for cancer associations. We detect dysregulation of genes containing IS and identify a highly-expressed transduced oncogene. Our data provide insights into the tremendous mutational load suffered by the host during active retroviral germline invasion, a process repeatedly experienced and overcome during the evolution of vertebrate lineages.
Development of a quantitative gene expression assay for Chlamydia trachomatis identified temporal expression of σ factors
Publisher: Wiley
Date: 21-09-1999
DOI: 10.1016/S0014-5793(99)01182-5
Abstract: Chlamydia trachomatis is an important human pathogen which possesses a unique bi-phasic developmental cycle. We used lightcycler methodology to quantitatively measure gene transcript levels in C. trachomatis strain L2. By measuring 16S rRNA transcript levels, we determined C. trachomatis L2 to have a generation time of approximately 3 h and an inclusion burst size of 200-300 particles. The three chlamydial sigma factor genes rpoD (sigma66), rpsD (sigma28) and rpoN (sigma54) exhibited different patterns of temporal expression. rpoD was central to early chlamydial development, whereas rpsD and rpoN were temporally expressed, coinciding with elementary body (EB) to reticulate body (RB) conversion and RB to EB conversion, respectively.
Epizootiology of Chlamydia infections in two free-range koala populations
Publisher: Elsevier BV
Date: 03-1999
DOI: 10.1016/S0378-1135(98)00302-2
Abstract: The prevalence of Chlamydia pecorum and Chlamydia pneumoniae infections in two free-range koala populations was assessed using genus-specific PCR combined with species-specific DNA probe hybridisation. Population A had a very high overall level of chlamydial infection (85%) with significantly more of these infections being due to C. pecorum (73%) compared to C. pneumoniae (24%). The second population had a much lower prevalence of infection (10%) with equal levels of both species. An important finding of this study was that. while five of 24 C. pecorum-infected koalas had clinical signs of the disease (both ocular and urogenital sites), none out of seven C. pneumoniae-infected koalas had signs of clinical disease. This suggests that C. pecorum may be the more pathogenic of the two chlamydial species infecting this host. The level of infection (assessed by intensity of the specific hybridisation signal) also differed between chlamydial species, with C. pecorum infections ranging from low to high grade whereas C. pneumoniae infections were always low grade. When the age of infected koalas was examined, 58% of young, sexually immature koalas were found to have C. pecorum infections, increasing to 100% of koalas in the older age groups. This suggests that, in this population at least, young koalas are readily infected with C. pecorum from their mothers. While the infection levels with C. pneumoniae were too low to be statistically significant, again, sexually immature koalas were found to be infected. The recent separation of chlamydial infections in koalas into two species is beginning to indicate different epizootiologies for koala C. pecorum compared to koala C. pneumoniae.
THE PARADOX OF EUTHANIZING KOALAS (PHASCOLARCTOS CINEREUS) TO SAVE POPULATIONS FROM ELIMINATION
Publisher: Wildlife Disease Association
Date: 10-2015
DOI: 10.7589/2014-12-278
Abstract: Koala (Phascolarctos cinereus) populations in the wild are in sharp decline in Australia due to deforestation, road accidents, dog attacks, and disease from infection with sexually transmitted Chlamydia spp. Severely diseased koalas that are captured are euthanized for humane reasons because antibiotics are not effective. Paradoxically, we propose that euthanizing more koalas could help to increase koala population numbers. We investigated the potential impact of systematically euthanizing diseased koalas. Using data from a well-studied koala population, and an in idual-based computer simulation model, we predict that such a program would result in a larger population of koalas after 7 yr than would exist without the program. If terminally diseased and sterile koalas are euthanized and other infected captured koalas are given antibiotics, chlamydial infection could be eliminated and population growth observed after 4 yr. The practical implementation of such a program would be facilitated with further development of tools to diagnose infection and internal disease in the field.
Protein A as a fusion partner for the expression of heterologous proteins in Lactobacillus
Publisher: Springer Science and Business Media LLC
Date: 28-05-1997
Abstract: An expression system based on the Staphylococcus aureus protein A gene (spa) was developed to allow the production and export of proteins in Lactobacillus. Plasmid shuttle vectors were constructed that carried the eZZ gene, a synthetic gene based on the Protein A gene (spa) but lacking the carboxy-terminal membrane-anchoring region. A gene fusion was created between the eZZ gene and the VD4 region of a chlamydial major outer-membrane protein gene. Expression studies demonstrated the recognition of the spa regulatory signals by several Lactobacillus, with the recombinant protein being expressed (from 0.1 microgram of EZZVD4 fusion protein per ml in L. plantarum up to 10 micrograms of EZZ protein per ml in L. fermentum) and exported (levels up to 20% in L. fermentum) in several Lactobacillus strains.
Completing the Genome Sequence of Chlamydia pecorum Strains MC/MarsBar and DBDeUG: New Insights into This Enigmatic Koala (Phascolarctos cinereus) Pathogen
Publisher: MDPI AG
Date: 25-11-2021
DOI: 10.3390/PATHOGENS10121543
Abstract: Chlamydia pecorum, an obligate intracellular pathogen, causes significant morbidity and mortality in livestock and the koala (Phascolarctos cinereus). A variety of C. pecorum gene-centric molecular studies have revealed important observations about infection dynamics and genetic ersity in both koala and livestock hosts. In contrast to a variety of C. pecorum molecular studies, to date, only four complete and 16 draft genomes have been published. Of those, only five draft genomes are from koalas. Here, using whole-genome sequencing and a comparative genomics approach, we describe the first two complete C. pecorum genomes collected from diseased koalas. A de novo assembly of DBDeUG_2018 and MC/MarsBar_2018 resolved the chromosomes and chlamydial plasmids each as single, circular contigs. Robust phylogenomic analyses indicate biogeographical separation between strains from northern and southern koala populations, and between strains infecting koala and livestock hosts. Comparative genomics between koala strains identified new, unique, and shared loci that accumulate single-nucleotide polymorphisms and separate between northern and southern, and within northern koala strains. Furthermore, we predicted novel type III secretion system effectors. This investigation constitutes a comprehensive genome-wide comparison between C. pecorum from koalas and provides improvements to annotations of a C. pecorum reference genome. These findings lay the foundations for identifying and understanding host specificity and adaptation behind chlamydial infections affecting koalas.
Babesia bovis: Evidence for selection of subpopulations during attenuation
Publisher: Elsevier BV
Date: 05-1990
DOI: 10.1016/0014-4894(90)90124-U
Abstract: DNA probes were used to detect variation in subpopulations of virulent and serially passaged Babesia bovis. Two distinct patterns were evident after hybridization to genomic DNA the first was a basic profile typical of virulent B. bovis and the second, a more variable array, was characteristic of B. bovis after various stages of attenuation. Tick transmission of avirulent B. bovis causes reversion to the virulent genomic pattern, suggesting that selective enrichment of a small residual subpopulation caused reversion to a virulent profile of subpopulations. Certain genomic fragments, predominant in either virulent or avirulent parasite forms, are putative "markers" or actual elements responsible for these biological characteristics.
Wide range of Chlamydiales types detected in native Australian mammals
Publisher: Elsevier BV
Date: 10-2003
DOI: 10.1016/S0378-1135(03)00211-6
Abstract: The Chlamydiales are a unique order of intracellular bacterial pathogens that cause significant disease of birds and animals, including humans. The recent development of a Chlamydiales-specific 16S rDNA polymerase chain reaction (PCR) assay has enabled the identification of Chlamydiales DNA from an increasing range of hosts and environmental sources. Whereas the Australian marsupial, the koala, has previously been shown to harbour several Chlamydiales types, no other Australian marsupials have been analysed. We therefore used a 16S rDNA PCR assay combined with direct sequencing to determine the presence and genotype of Chlamydiales in five wild Australian mammals (gliders, possums, bilbies, bandicoots, potoroos). We detected eight previously observed Chlamydiales genotypes as well as 10 new Chlamydiales sequences from these five Australian mammals. In addition to PCR analysis we used antigen specific staining and in vitro culture in HEp-2 cell monolayers to confirm some of the identifications. A strong association between ocular PCR positivity and the presence of clinical disease (conjunctivitis, proliferation of the eyelid) was observed in two of the species studied, gliders and bandicoots, whereas little clinical disease was observed in the other animals studied. These findings provide further evidence that novel Chlamydiales infections occur in a wide range of hosts and that, in some of these, the chlamydial infections may contribute to clinical disease.
Immunization with a MOMP-Based Vaccine Pfrotects Mice against a Pulmonary Chlamydia Challenge and Identifies a Disconnection between Infection and Pathology
Publisher: Public Library of Science (PLoS)
Date: 16-04-2013
Navigating to the most promising directions amid complex fields of vaccine development: a chlamydial case study
Publisher: Informa UK Limited
Date: 02-12-2019
Spatial constraints within the chlamydial host cell inclusion predict interrupted development and persistence
Publisher: Springer Science and Business Media LLC
Date: 09-01-2008
Abstract: The chlamydial developmental cycle involves the alternation between the metabolically inert elementary body (EB) and the replicating reticulate body (RB). The triggers that mediate the interchange between these particle types are unknown and yet this is crucial for understanding basic Chlamydia biology. We have proposed a hypothesis to explain key chlamydial developmental events whereby RBs are replicating strictly whilst in contact with the host cell membrane-derived inclusion via type three secretion (T3S) injectisomes. As the inclusion expands, the contact between each RB and the inclusion membrane decreases, eventually reaching a threshold, beyond which T3S is inactivated upon detachment and this is the signal for RB-to-EB differentiation. We explore this hypothesis through the development of a detailed mathematical model. The model uses knowledge and data of the biological system wherever available and simulates the chlamydial developmental cycle under the assumptions of the hypothesis in order to predict various outcomes and implications under a number of scenarios. We show that the concept of in vitro persistent infection is not only consistent with the hypothesis but in fact an implication of it. We show that increasing the RB radius, and/or the maximum length of T3S needles mediating contact between RBs and the inclusion membrane, and/or the number of inclusions per infected cell, will contribute to the development of persistent infection. The RB radius is the most important determinant of whether persistent infection would ensue, and subsequently, the magnitude of the EB yield. We determine relationships between the length of the T3S needle and the RB radius within an inclusion, and between the RB radius and the number of inclusions per host cell to predict whether persistent infection or normal development would occur within a host cell. These results are all testable experimentally and could lead to significantly greater understanding of one of the most crucial steps in chlamydial development.
Peptide immunization of guinea pigs against Chlamydia psittaci (GPIC agent) infection induces good vaginal secretion antibody response, in vitro neutralization and partial protection aga
Publisher: Wiley
Date: 06-2001
DOI: 10.1046/J.1440-1711.2001.01005.X
Abstract: Immunization of female guinea pigs with a chimeric peptide consisting of variable domain IV (VDIV) and a region known as GP8 from the major outer membrane protein of Chlamydophila caviae, formerly Chlamydia psittaci guinea pig inclusion conjunctivitis strain, was performed to assess whether humoral immune responses could be elicited in the reproductive tracts of immunized animals. The C. caviae strain is able to cause a sexually transmitted infection in the guinea pig that closely parallels C. trachomatis infections in humans. The best anti-VDIV antibody response in vaginal secretions was achieved by intraperitoneal priming with subsequent intravaginal boosting (P < 0.001). Dot-blot analyses of vaginal secretions confirmed that these anti-VDIV antibodies, produced against a linear peptide, were able to recognize and bind to whole conformational C. caviae elementary bodies. Following live intravaginal challenge with C. caviae, a significant reduction in the intensity (P = 0.01) and an apparent reduction in the duration of the infection was evident between the guinea pigs immunized with VDIV-GP8 and non-immunized controls.
Novel PCR-EIA method for the detection of Chlamydia pneumoniae in respiratory specimens
Publisher: Elsevier BV
Date: 02-2002
Tissue MicroArray (TMA) analysis of normal and persistent Chlamydophila pneumoniae infection
Publisher: Springer Science and Business Media LLC
Date: 19-10-2006
Enterovirus71 (EV71) Utilise Host microRNAs to Mediate Host Immune System Enhancing Survival during Infection
Publisher: Public Library of Science (PLoS)
Date: 21-07-2014
CD4+ T cells reduce the tissue burden of Chlamydia muridarum in male BALB/c mice
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.VACCINE.2010.05.050
Abstract: Male chlamydial infections are becoming more recognised as an aetiological agent in infertility. An IFN-gamma response is required for protection against Chlamydia in females, but may have the potential to induce pathology in the immune-privileged male reproductive tract. We examined the induction of immunity following intranasal immunisation with major outer membrane protein (MOMP) of Chlamydia muridarum in male BALB/c mice, and the role of MOMP-specific CD4+ T cells in clearance of an intrapenile infection. Here we report that adoptive transfer of MOMP-specific CD4+ T cells into naïve mice confers partial protective immunity, which significantly reduces the tissue burden of Chlamydia.
Immune responses of cattle following vaccination with living and non-living Babesia bovis antigens
Publisher: Elsevier BV
Date: 11-1984
DOI: 10.1016/0304-4017(84)90042-6
Abstract: Twenty-four yearling Hereford (Bos taurus) cattle were vaccinated against Babesia bovis using either live parasites or non-living antigens obtained from the supernatant of in vitro cultures. A single dose of live parasites was given subcutaneously, while the non-living supernatant antigen (NLSA) was combined with saponin and 2 doses given, 2 weeks apart. Following vaccination with live parasites, serum antibodies remained at high levels for 6 months, but the lymphocyte transformation response was low and lasted only 10-18 days. In contrast, NLSA vaccination was followed, after 21-28 days, by a peak of serum antibodies which then slowly declined. The lymphocyte transformation response in these animals was much higher and persisted for 6 months. Following heterologous challenge all unvaccinated cattle had severe reactions and required treatment to prevent death. Cattle vaccinated with live parasites had mild reactions with only 1 of the 12 requiring treatment. Cattle vaccinated with NLSA were only partially protected and 6 of the 12 required treatment.
In vitro susceptibility of recent Chlamydia trachomatis clinical isolates to the CtHtrA inhibitor JO146
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.MICINF.2015.09.004
Abstract: The present study aimed to establish if a previously identified Chlamydia trachomatis HtrA (CtHtrA) inhibitor, JO146, is effective against currently circulating clinical isolates to validate if CtHtrA is a clinically relevant target for future therapeutic development. Inhibition of CtHtrA during the middle of the chlamydial replicative cycle until the completion of the cycle resulted in loss of infectious progeny for six unique clinical isolates representing different serovars. This supports the potential for CtHtrA to be a clinically relevant target for development of new therapeutics and suggests the importance of further investigation of JO146 as a lead compound.
Degradation and remobilization of endogenous retroviruses by recombination during the earliest stages of a germ-line invasion
Publisher: Proceedings of the National Academy of Sciences
Date: 06-08-2018
Abstract: Endogenous retroviruses (ERVs) are proviral sequences that result from host germ-line invasion by exogenous retroviruses. The majority of ERVs are degraded. Using the koala retrovirus (KoRV) as a model system, we demonstrate that recombination with an ancient koala retroelement disables KoRV, and that recombination occurs frequently and early in the invasion process. Recombinant KoRVs (recKoRVs) are then able to proliferate in the koala germ line. This may in part explain the generally degraded nature of ERVs in vertebrate genomes and suggests that degradation via recombination is one of the earliest processes shaping retroviral genomic invasions.
Evolution to a chronic disease niche correlates with increased sensitivity to tryptophan availability for the obligate intracellular bacterium Chlamydia pneumoniae.
Publisher: American Society for Microbiology
Date: 28-03-2014
DOI: 10.1128/JB.01476-14
Development and evaluation of a multi-antigen peptide ELISA for the diagnosis of Chlamydia trachomatis-related infertility in women.
Publisher: Microbiology Society
Date: 09-2016
DOI: 10.1099/JMM.0.000311
The temperature activated HtrA protease from pathogen Chlamydia trachomatis acts as both a chaperone and protease at 37 °C
Publisher: Wiley
Date: 26-06-2007
DOI: 10.1016/J.FEBSLET.2007.06.039
Abstract: Characterization of the protease, HtrA, from pathogen Chlamydia trachomatis is presented. The purified recombinant protein was a serine endoprotease, specific for unfolded proteins, and temperature activated above 34 degrees C. Chaperone activity was observed, although this appeared target-dependent. Inactive protease (S247A) was able to chaperone insulin B-chain, irrespective of temperature, but at 30 degrees C only HtrA and not S247A displayed significant chaperone activity for alpha-lactalbumin. These data demonstrate that chaperone activity may involve functional protease domain and that C. trachomatis HtrA functions as both a chaperone and protease at 37 degrees C. These properties are consistent with the developmental cycle of this obligate intracellular bacterium.
Molecular characterization of Chlamydophila pneumoniae isolates from Western barred bandicoots
Publisher: Microbiology Society
Date: 03-2007
Abstract: Chlamydophila pneumoniae is an obligate intracellular respiratory pathogen that has been associated with pneumonia and chronic bronchitis, atherosclerosis, asthma and other chronic diseases in humans. However, C. pneumoniae is not restricted to humans, as originally thought, and can cause infections in several animal hosts. C. pneumoniae was isolated in cell culture from nine Western barred bandicoots (Perameles bougainville) from Australia. The sequences of five genomic regions were determined, including full-length sequences of the 16S rRNA and ompA genes and the ygeD-urk intergenic spacer, and partial sequences of the 23S rRNA and rpoB genes. Sequence analysis of the entire 16S rRNA and ompA genes from bandicoot isolates demonstrated that they were 98.2-98.3% similar to human isolates, 94.6-99.3% similar to the equine biovar and almost identical, with 99.5-99.9% similarity, to the koala biovar. Comparative genotyping of the variable domain 4 region of the ompA gene demonstrated that bandicoot isolates seemed to be identical to the animal genotype that has been recently identified in human carotid plaque specimens. Minor sequence polymorphism observed in ompA, 16S rRNA and rpoB genes of animal isolates, indicating genomic ersity within C. pneumoniae, may have important implications for diagnostic PCR assays leading to false negative results. Forty percent of selected published species-specific PCR assays were found to have sequence variability in primer and/or probe that might affect their performance in detecting bandicoot isolates of C. pneumoniae, or possibly other animal and human strains where minor sequence polymorphisms may be present. The data from this study support the previous observations that C. pneumoniae is not restricted to humans and may be widespread in an animal reservoir with a potential risk of transmission to humans.
Variation in koala microbiomes within and between individuals: effect of body region and captivity status
Publisher: Springer Science and Business Media LLC
Date: 11-05-2015
DOI: 10.1038/SREP10189
Abstract: Metagenomic analysis of 16S ribosomal RNA has been used to profile microbial communities at high resolution and to examine their association with host diet or diseases. We examined the oral and gut microbiome composition of two captive koalas to determine whether bacterial communities are unusual in this species, given that their diet consists almost exclusively of Eucalyptus leaves. Despite a highly specialized diet, koala oral and gut microbiomes were similar in composition to the microbiomes from the same body regions of other mammals. Rectal swabs contained all of the ersity present in faecal s les, along with additional taxa, suggesting that faecal bacterial communities may merely subs le the gut bacterial ersity. Furthermore, the faecal microbiomes of the captive koalas were similar to those reported for wild koalas, suggesting that captivity may not compromise koala microbial health. Since koalas frequently suffer from ocular diseases caused by Chlamydia infection, we also examined the eye microbiome composition of two captive koalas, establishing the healthy baseline for this body part. The eye microbial community was very erse, similar to other mammalian ocular microbiomes but with an unusually high representation of bacteria from the family Phyllobacteriaceae.
Type III secretion à la Chlamydia
Publisher: Elsevier BV
Date: 06-2007
DOI: 10.1016/J.TIM.2007.04.005
Abstract: Type III secretion (T3S) is a mechanism that is central to the biology of the Chlamydiaceae and many other pathogens whose virulence depends on the translocation of toxic effector proteins to cytosolic targets within infected eukaryotic cells. Biomathematical simulations, using a previously described model of contact-dependent, T3S-mediated chlamydial growth and late differentiation, suggest that chlamydiae contained in small non-fusogenic inclusions will persist. Here, we further discuss the model in the context of in vitro-persistent, stress-induced aberrantly enlarged forms and of recent studies using small molecule inhibitors of T3S. A general mechanism is emerging whereby both early- and mid-cycle T3S-mediated activities and late T3S inactivation upon detachment of chlamydiae from the inclusion membrane are crucial for chlamydial intracellular development.
Use of a commercial assay for detecting the 60 kDa chlamydial heat shock protein in a range of patient groups
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2006
Infection with koala retrovirus subgroup B (KoRV-B), but not KoRV-A, is associated with chlamydial disease in free-ranging koalas (Phascolarctos cinereus)
Publisher: Springer Science and Business Media LLC
Date: 09-03-0009
DOI: 10.1038/S41598-017-00137-4
Abstract: The virulence of chlamydial infection in wild koalas is highly variable between in iduals. Some koalas can be infected (PCR positive) with Chlamydia for long periods but remain asymptomatic, whereas others develop clinical disease. Chlamydia in the koala has traditionally been studied without regard to coinfection with other pathogens, although koalas are usually subject to infection with koala retrovirus (KoRV). Retroviruses can be immunosuppressive, and there is evidence of an immunosuppressive effect of KoRV in vitro . Originally thought to be a single endogenous strain, a new, potentially more virulent exogenous variant (KoRV-B) was recently reported. We hypothesized that KoRV-B might significantly alter chlamydial disease outcomes in koalas, presumably via immunosuppression. By studying sub-groups of Chlamydia and KoRV infected koalas in the wild, we found that neither total KoRV load (either viraemia or proviral copies per genome), nor chlamydial infection level or strain type, was significantly associated with chlamydial disease risk. However, PCR positivity with KoRV-B was significantly associated with chlamydial disease in koalas ( p = 0.02961). This represents an ex le of a recently evolved virus variant that may be predisposing its host (the koala) to overt clinical disease when co-infected with an otherwise asymptomatic bacterial pathogen ( Chlamydia ).
Analysis and Conservation Implications of Koala Genetics
Publisher: Wiley
Date: 06-2000
DOI: 10.1046/J.1523-1739.2000.99384.X
Abstract: Abstract: Koalas are the only living member of their family and therefore deserve serious conservation consideration. Koalas have low levels of genetic variation within and among populations in the southern part of their range, where they have experienced many relocations and population crashes since European colonization of Australia. The importance of this change in variation is underlined by preliminary indications that levels of genetic variation may affect fitness in koalas. Techniques have been developed to help identify and monitor genetic problems in koalas and to provide the information and tools to make genetic management an integral part of koala conservation. The koala is currently at an appropriate point for conservation intervention: there is clear evidence of decline in some populations, but the existence of other robust populations offers the possibility of a variety of creative solutions to their conservation problems. Managers should aim to maintain this species' current ecological litude (the range of environments in which populations are found) and minimize the loss, fragmentation, or decline of populations. There are no data to suggest that any population requires genetic supplementation. The concepts of evolutionarily significant unit ( ESU) and management unit (MU) can be useful in the genetic management of koalas, including monitoring and management regimes. But ESUs and MUs can also be misleading if they are not interpreted carefully in terms of population history and the ultimate goal of management. Translocations should not involve extensive use of stock from a single source, especially those with low genetic variation, and they require careful management to avoid possible problems when in iduals encounter novel strains of the pathogen Chlamydia pecorum , because several genetically distinct strains have been found in koalas, some of which may derive from introduced species. Genetic indicators can and must make considerable contributions to koala management, but they require careful interpretation.
Human and pathogen factors associated with chlamydia trachomatis-related infertility in women
Publisher: American Society for Microbiology
Date: 10-2015
DOI: 10.1128/CMR.00035-15
Abstract: Chlamydia trachomatis is the most common bacterial sexually transmitted pathogen worldwide. Infection can result in serious reproductive pathologies, including pelvic inflammatory disease, ectopic pregnancy, and infertility, in women. However, the processes that result in these reproductive pathologies have not been well defined. Here we review the evidence for the human disease burden of these chlamydial reproductive pathologies. We then review human-based evidence that links Chlamydia with reproductive pathologies in women. We present data supporting the idea that host, immunological, epidemiological, and pathogen factors may all contribute to the development of infertility. Specifically, we review the existing evidence that host and pathogen genotypes, host hormone status, age of sexual debut, sexual behavior, coinfections, and repeat infections are all likely to be contributory factors in development of infertility. Pathogen factors such as infectious burden, treatment failure, and tissue tropisms or ascension capacity are also potential contributory factors. We present four possible processes of pathology development and how these processes are supported by the published data. We highlight the limitations of the evidence and propose future studies that could improve our understanding of how chlamydial infertility in women occurs and possible future interventions to reduce this disease burden.
Proof of concept: A bioinformatic and serological screening method for identifying new peptide antigens for Chlamydia trachomatis related sequelae in women
Publisher: Elsevier BV
Date: 2013
Comprehensive profiling of retroviral integration sites using target enrichment methods from historical koala samples without an assembled reference genome
Publisher: PeerJ
Date: 28-03-2016
DOI: 10.7717/PEERJ.1847
Abstract: Background. Retroviral integration into the host germline results in permanent viral colonization of vertebrate genomes. The koala retrovirus (KoRV) is currently invading the germline of the koala (Phascolarctos cinereus) and provides a unique opportunity for studying retroviral endogenization. Previous analysis of KoRV integration patterns in modern koalas demonstrate that they share integration sites primarily if they are related, indicating that the process is currently driven by vertical transmission rather than infection. However, due to methodological challenges, KoRV integrations have not been comprehensively characterized. Results. To overcome these challenges, we applied and compared three target enrichment techniques coupled with next generation sequencing (NGS) and a newly customized sequence-clustering based computational pipeline to determine the integration sites for 10 museum Queensland and New South Wales (NSW) koala s les collected between the 1870s and late 1980s. A secondary aim of this study sought to identify common integration sites across modern and historical specimens by comparing our dataset to previously published studies. Several million sequences were processed, and the KoRV integration sites in each koala were characterized. Conclusions. Although the three enrichment methods each exhibited bias in integration site retrieval, a combination of two methods, Primer Extension Capture and hybridization capture is recommended for future studies on historical s les. Moreover, identification of integration sites shows that the proportion of integration sites shared between any two koalas is quite small.
Seventy years of Chlamydia vaccine research - Limitations of the past and directions for the future
Publisher: Frontiers Media SA
Date: 31-01-2019
CIDB: Chlamydia Interactive Database for cross-querying genomics, transcriptomics and proteomics data
Publisher: Elsevier BV
Date: 12-2007
DOI: 10.1016/J.BIOENG.2007.08.017
Abstract: Chlamydiae are important pathogens of humans, birds and a wide range of animals. They are a unique group of bacteria, characterized by their developmental cycle. Chlamydia has been difficult to study because of their obligate intracellular growth habit and lack of a genetic transformation system. However, the past 5 years has seen the full genome sequencing of seven strains of Chlamydia and a rapid expansion of genomic, transcriptomic (RT-PCR, microarray) and proteomic analysis of these pathogens. The Chlamydia Interactive Database (CIDB) described here is the first database of its type that holds genomic, RT-PCR, microarray and proteomics data sets that can be cross-queried by researchers for patterns in the data. Combining the data of many research groups into a single database and cross-querying from different perspectives should enhance our understanding of the complex cell biology of these pathogens. The database is available at: www3.it.deakin.edu.au:8080/CIDB/.
The active site residue V266 of chlamydial HtrA is critical for substrate binding during both in vitro and in vivo conditions
Publisher: S. Karger AG
Date: 2012
DOI: 10.1159/000336312
Abstract: HtrA is a complex, multimeric chaperone and serine protease important for the virulence and survival of many bacteria. i Chlamydia trachomatis /i is an obligate, intracellular bacterial pathogen that is responsible for severe disease pathology. i C. trachomatis /i HtrA (CtHtrA) has been shown to be highly expressed in laboratory models of disease. In this study, molecular modelling of CtHtrA protein active site structure identified putative S1–S3 subsite residues I242, I265, and V266. These residues were altered by site-directed mutagenesis, and these changes were shown to considerably reduce protease activity on known substrates and resulted in a narrower and distinct range of substrates compared to wild type. Bacterial two-hybrid analysis revealed that CtHtrA is able to interact in vivo with a broad range of protein sequences with high affinity. Notably, however, the interaction was significantly altered in 35 out of 69 clones when residue V266 was mutated, indicating that this residue has an important function during substrate binding.
Babesia bovis: Molecular and biological characteristics of cloned parasite lines
Publisher: Elsevier BV
Date: 04-1987
DOI: 10.1016/0014-4894(87)90160-3
Abstract: An in vivo limiting dilution technique was used to produce several Babesia bovis cloned lines with which to study the basis of virulence and immunogenicity in this parasite. DNA hybridization using a cloned DNA fragment from the BabR locus demonstrated that the cloned lines were a more restricted genetic population than the parent strain. Biosynthetic labeling and immunoprecipitation studies indicated that the cloned lines differed from each other and from the parentals in the expression of a small number of polypeptides and antigens. Animal trials with three of the lines demonstrated that the parental line contains both virulent and avirulent parasite populations, at least three of which are not tick transmissible, and that while the lines do provide significant protection against heterologous challenge, they may not give as effective protection as the parental line. These experiments demonstrated the existence of subpopulations with distinctive molecular and biological properties, providing evidence that the attenuation process is based on the selection of preexisting parasite subpopulations combined with the ability of these parasites to vary genetically.
CXCL10, CXCL11, HLA-A and IL-1β are induced in peripheral blood mononuclear cells from women with Chlamydia trachomatis related infertility.
Publisher: Oxford University Press (OUP)
Date: 27-10-2016
Abstract: Chlamydia trachomatis infections can result in the development of serious sequelae such as pelvic inflammatory disease and tubal infertility. In this study, peripheral blood mononuclear cells from women who were undergoing or had recently undergone IVF treatment were cultured ex vivo with C. trachomatis to identify the immune responses associated with women who had serological evidence of a history of Chlamydia infection. Cytokines secreted into the supernatant from the cultures were measured using ELISA, and the level of IL-1β was found to be significantly higher in Chlamydia positive women than Chlamydia negative women. qRT-PCR analysis of the expression of 88 immune-related genes showed trends towards an upregulation of CXCL10, CXCL11 and HLA-A in Chlamydia positive women compared with Chlamydia negative women. These findings support that some women launch a more marked proinflammatory response upon infection with C. trachomatis and this may be associated with why C. trachomatis induces infertility in some infected women.
Plasma tissue inhibitor of metalloproteinase-1 levels are elevated in essential hypertension and related to left ventricular hypertrophy
Publisher: Oxford University Press (OUP)
Date: 03-2002
DOI: 10.1016/S0895-7061(01)02316-0
Abstract: Essential hypertensive patients have an increased heart and arterial collagen concentration. Increased collagen synthesis can be assessed using procollagen III N peptide (PIIINP) and reduced collagen degradation measured using tissue inhibitor of metalloproteinase-1 (TIMP-1). Plasma TIMP-1 and PIIINP levels were measured in 31 patients with essential hypertension and in 17 normotensive control subjects. The hypertensive patients were either treatment naive (n = 18) or had been without treatment for 1 month (n = 13). Both groups of patients were screened to exclude other fibrotic diseases. In the hypertensive patients, TIMP-1 levels were significantly (P < .0002) elevated (median 380 ng/ mL, range 160 to 1,560 ng/mL) compared with those of the normotensive control subjects (median 178 ng/mL, range 99 to 330 ng/mL). In hypertensive subjects who had never received antihypertensive therapy there were significant correlations between TIMP-1 and left ventricular posterior wall thickness in diastole (LVPWd) (r = 0.58) (P < .02) and left ventricular mass index (r = 0.58) (P < .02). There was no difference in PIIINP levels (mean +/- 2 SD) between the hypertensive (0.56 U/mL +/- 0.3) and normotensive groups (0.52 U/mL +/- 0.2). The increased tissue collagen III levels found in the heart and vessels of hypertensive patients is due to a reduction in collagen degradation because of high TIMP-1 levels, rather than an increase in synthesis of collagen type III. The tissue source of this TIMP-1 is unclear.
Chlamydia Psittaci ST24: Clonal Strains of One Health Importance Dominate in Australian Horse, Bird and Human Infections
Publisher: MDPI AG
Date: 11-08-2021
DOI: 10.3390/PATHOGENS10081015
Abstract: Chlamydia psittaci is traditionally regarded as a globally distributed avian pathogen that can cause zoonotic spill-over. Molecular research has identified an extended global host range and significant genetic ersity. However, Australia has reported a reduced host range (avian, horse, and human) with a dominance of clonal strains, denoted ST24. To better understand the widespread of this strain type in Australia, multilocus sequence typing (MLST) and ompA genotyping were applied on s les from a range of hosts (avian, equine, marsupial, and bovine) from Australia. MLST confirms that clonal ST24 strains dominate infections of Australian psittacine and equine hosts (82/88 93.18%). However, this study also found novel hosts (Australian white ibis, King parrots, racing pigeon, bovine, and a wallaby) and demonstrated that strain ersity does exist in Australia. The discovery of a C. psittaci novel strain (ST306) in a novel host, the Western brush wallaby, is the first detection in a marsupial. Analysis of the results of this study applied a multidisciplinary approach regarding Chlamydia infections, equine infectious disease, ecology, and One Health. Recommendations include an update for the descriptive framework of C. psittaci disease and cell biology work to inform pathogenicity and complement molecular epidemiology.
Characterization of in vitro Chlamydia muridarum persistence and utilization in an in vivo mouse model of Chlamydia vaccine.
Publisher: Wiley
Date: 18-02-2013
DOI: 10.1111/AJI.12093
Abstract: Chlamydia trachomatis genital tract infections are easily treated with antibiotics however, the majority of infections are asymptomatic and therefore untreated, highlighting the need for a vaccine. Because most infections are asymptomatic, vaccination could potentially be administered to in iduals who may have an acute infection at that time. In such in iduals, the effect of vaccination on the existing infection is unknown however, one potential outcome could be the development of a persistent infection. In vitro chlamydial persistence has been well characterized in various strains however, there have been no reported studies in C. muridarum. We performed ultrastructural characterization and transcriptome analysis of selected genes. We then used the transcriptional profiles of the selected genes to examine whether intranasal immunization of mice during an active genital infection would induce persistence in the upper reproductive tract of female mice. We found that persistence developed in the oviducts of mice as a result of immunization. This is a significant finding, not only because it is the first time that C. muridarum persistence has been characterized in vitro, but also due to the fact that there is a minimal characterization of in vivo persistence of any chlamydial species. This highlights the importance of the timing of vaccination in in iduals.
The effects of vitamin D2 or D3supplementation on glycaemic control and related metabolic parameters in people at risk of type 2 diabetes: protocol of a randomised double-blind placebo-controlled tria
Publisher: Springer Science and Business Media LLC
Date: 23-10-2013
Abstract: The global prevalence of type 2 diabetes is increasing. Effective strategies to address this public health challenge are currently lacking. A number of epidemiological studies have reported associations between low concentrations of 25-hydroxy vitamin D and the incidence of diabetes, but a causal link has not been established. We investigate the effect of vitamin D supplementation on the metabolic status of in iduals at increased risk of developing type 2 diabetes. In a randomised double-blind placebo-controlled trial in iduals identified as having a high risk of type 2 diabetes (non-diabetic hyperglycaemia or positive diabetes risk score) are randomised into one of three groups and given 4 doses of either placebo, or 100,000 IU Vitamin D 2 (ergocalciferol) or 100,000 IU Vitamin D 3 (cholecalciferol) at monthly intervals. The primary outcome measure is the change in glycated haemoglobin level between baseline and 4 months. Secondary outcome measures include blood pressure, lipid levels, apolipoproteins, highly sensitive C-reactive protein, parathyroid hormone (PTH) and safety of supplementation. and C-reactive protein. The trial is being conducted at two sites (London and Cambridge, U.K.) and a total of 342 participants are being recruited. Trial data examining whether supplementation of vitamin D improves glycaemic status and other metabolic parameters in people at risk of developing type 2 diabetes are sparse. This trial will evaluate the causal role of vitamin D in hyperglycaemia and risk of type 2 diabetes. Specific features of this trial include recruitment of participants from different ethnic groups, investigation of the relative effectiveness and safety of vitamin D 2 and D 3 and an evidence based approach to determination of the dose of supplementation. EudraCT2009-011264-11 ISRCTN86515510
Evidence of a conserved role for Chlamydia HtrA in the replication phase of the chlamydial developmental cycle
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.MICINF.2014.07.003
Abstract: Identification of the HtrA inhibitor JO146 previously enabled us to demonstrate an essential function for HtrA during the mid-replicative phase of the Chlamydia trachomatis developmental cycle. Here we extend our investigations to other members of the Chlamydia genus. C. trachomatis isolates with distinct replicative phase growth kinetics showed significant loss of viable infectious progeny after HtrA was inhibited during the replicative phase. Mid-replicative phase addition of JO146 was also significantly detrimental to Chlamydia pecorum, Chlamydia suis and Chlamydia cavie. These data combined indicate that HtrA has a conserved critical role during the replicative phase of the chlamydial developmental cycle.
Distribution of Chlamydia pneumoniae DNA in Atherosclerotic Carotid Arteries: Significance for Sampling Procedures
Publisher: American Society for Microbiology
Date: 04-2003
DOI: 10.1128/JCM.41.4.1454-1457.2003
Abstract: Despite extensive efforts to confirm a direct association between Chlamydia pneumoniae and atherosclerosis, different laboratories continue to report a large variability in detection rates. In this study, we analyzed multiple sections from atherosclerotic carotid arteries from 10 endartectomy patients to determine the location of C. pneumoniae DNA and the number of sections of the plaque required for analysis to obtain a 95% confidence of detecting the bacterium. A sensitive nested PCR assay detected C. pneumoniae DNA in all patients at one or more locations within the plaque. On average, 42% (ranging from 5 to 91%) of the sections from any single patient had C. pneumoniae DNA present. A patchy distribution of C. pneumoniae in the atherosclerotic lesions was observed, with no area of the carotid having significantly more C. pneumoniae DNA present. If a single random 30-μm-thick section was tested, there was only a 35.6 to 41.6% (95% confidence interval) chance of detecting C. pneumoniae DNA in a patient with carotid artery disease. A minimum of 15 sections would therefore be required to obtain a 95% chance of detecting all true positives. The low concentration and patchy distribution of C. pneumoniae DNA in atherosclerotic plaque appear to be among the reasons for inconsistency between laboratories in the results reported.
Immunopathogenesis of chlamydia trachomatis infections in women
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S0015-0282(03)00396-0
Abstract: To develop a model of pathogenesis by which Chlamydia trachomatis progresses from acute to chronic infection, and finally serious disease (salpingitis, tubal occlusion). Review of current literature located through web-based Medline searches using key words: Chlamydia trachomatis, immunology, cytokines, heat shock protein, infertility. Cell-mediated immune mechanisms appear to be critical in determining whether acute infection is resolved or progresses into chronicity with pathological outcome. What determines the particular immune pathway depends on a range of determinants-HLA subtype and human genetics, cytokine profile, infectious load, route of infection, and endocrinology. A clearer picture of the natural history of chlamydial pathology may assist in providing better predictors of those women who may go on to develop significant sequelae after infection. Predicting those who may develop serious disease, including infertility, may contribute to improved management of such persons during earlier stages of infection and assist in prevention.
The epidemiology of chlamydia trachomatis organism load during genital infection: A systematic review
Publisher: Oxford University Press (OUP)
Date: 09-12-2015
Abstract: The role of organism load in Chlamydia trachomatis infection is not well understood. We conducted a systematic review to investigate the epidemiology of C. trachomatis organism load in human genital chlamydia infection. Embase, PubMed, and Medline databases were searched for literature published through August 2014. English-language publications that quantified load in humans were eligible. Participant characteristics and laboratory data were extracted. A total of 737 records were identified, and 29 publications involving 40 883 participants were included. In women, load was highest for cervical swabs and lowest for urine specimens. In men, load was highest for rectal swabs and similar for urethral swabs and urine specimens. Evidence of any association between load and age, serovar, risk of transmission, hormone levels, and concurrent sexually transmitted infections was inconsistent. Eight of 9 culture-based studies found an association between load and signs and symptoms, in contrast with only 3 of 8 nucleic acid lification test (NAAT)-based studies (P = .03). Chlamydia organism load varies by specimen type and site of s ling, and viable chlamydia organism load may be a more important indicator of severity of infection than total load measured by NAAT.
Increased sensitivity to tryptophan bioavailability is a positive adaptation by the human strains of Chlamydia pneumoniae.
Publisher: Wiley
Date: 22-07-2014
DOI: 10.1111/MMI.12701
Abstract: One of the most significant activities induced by interferon-gamma against intracellular pathogens is the induction of IDO (indoleamine 2,3-dioxygenase) expression, which subsequently results in the depletion of tryptophan. We tested the hypothesis that human strains of Chlamydia pneumoniae are more sensitive to tryptophan limitation than animal C. pneumoniae strains. The human strains were significantly more sensitive to IFN-γ than the animal strains in a lung epithelia cell model (BEAS-2B), with exposure to 1 U ml(-1) IFN-γ resulting in complete loss of infectious yield of human strains, compared to the animal strains where reductions in infectious progeny were around 3.5-4.0 log. Strikingly, the IFN-γ induced loss of ability to form infectious progeny production was completely rescued by removal of the IFN-γ and addition of exogenous tryptophan for the human strains, but not the animal strains. In fact, a human heart strain was more capable of entering a non-infectious, viable persistent stage when exposed to IFN-γ and was also more effectively rescued, compared to a human respiratory strain. Exquisite susceptibility to IFN-γ, specifically due to tryptophan availability appears to be a core adaptation of the human C. pneumoniae strains, which may reflect the chronic nature of their infections in this host.
Vaccination to protect against infection of the female reproductive tract
Publisher: Informa UK Limited
Date: 2012
DOI: 10.1586/ECI.11.80
Abstract: Infection of the female genital tract can result in serious morbidities and mortalities from reproductive disability, pelvic inflammatory disease and cancer, to impacts on the fetus, such as infant blindness. While therapeutic agents are available, frequent testing and treatment is required to prevent the occurrence of the severe disease sequelae. Hence, sexually transmitted infections remain a major public health burden with ongoing social and economic barriers to prevention and treatment. Unfortunately, while there are two success stories in the development of vaccines to protect against HPV infection of the female reproductive tract, many serious infectious agents impacting on the female reproductive tract still have no vaccines available. Vaccination to prevent infection of the female reproductive tract is an inherently difficult target, with many impacting factors, such as appropriate vaccination strategies/mechanisms to induce a suitable protective response locally in the genital tract, variation in the local immune responses due to the hormonal cycle, selection of vaccine antigen(s) that confers effective protection against multiple variants of a single pathogen (e.g., the different serovars of Chlamydia trachomatis) and timing of the vaccine administration prior to infection exposure. Despite these difficulties, there are numerous ongoing efforts to develop effective vaccines against these infectious agents and it is likely that this important human health field will see further major developments in the next 5 years.
Identification of a serine protease inhibitor which causes inclusion vacuole reduction and is lethal to C hlamydia trachomatis
Publisher: Wiley
Date: 12-07-2013
DOI: 10.1111/MMI.12306
Abstract: The mechanistic details of the pathogenesis of Chlamydia, an obligate intracellular pathogen of global importance, have eluded scientists due to the scarcity of traditional molecular genetic tools to investigate this organism. Here we report a chemical biology strategy that has uncovered the first essential protease for this organism. Identification and application of a unique CtHtrA inhibitor (JO146) to cultures of Chlamydia resulted in a complete loss of viable elementary body formation. JO146 treatment during the replicative phase of development resulted in a loss of Chlamydia cell morphology, diminishing inclusion size, and ultimate loss of inclusions from the host cells. This completely prevented the formation of viable Chlamydia elementary bodies. In addition to its effect on the human Chlamydia trachomatis strain, JO146 inhibited the viability of the mouse strain, Chlamydia muridarum, both in vitro and in vivo. Thus, we report a chemical biology approach to establish an essential role for Chlamydia CtHtrA. The function of CtHtrA for Chlamydia appears to be essential for maintenance of cell morphology during replicative the phase and these findings provide proof of concept that proteases can be targeted for antimicrobial therapy for intracellular pathogens.
Chlamydia muridarum Major Outer Membrane Protein-Specific Antibodies Inhibit In Vitro Infection but Enhance Pathology In Vivo
Publisher: Wiley
Date: 06-01-2011
DOI: 10.1111/J.1600-0897.2010.00894.X
Abstract: Chlamydia trachomatis is a significant worldwide health problem, and the often-asymptomatic disease can result in infertility. To develop a successful vaccine, a complete understanding of the immune response to chlamydial infection and development of genital tract pathology is required. We utilized the murine genital model of chlamydial infection. Mice were immunized with chlamydial major outer membrane protein, and vaginal lavage was assessed for the presence of neutralizing antibodies. These s les were then pre-incubated with Chlamydia muridarum and administered to the vaginal vaults of immune-competent female BALB/c mice to determine the effect on infection. The administration of C. muridarum in conjunction with neutralizing antibodies reduced the numbers of mice infected, but a surprising finding was that this accelerated the development of severe oviduct pathology. Antibodies play an under-recognized role in chlamydial infection and pathology development, which possibly involves interaction with Th1 immunity.
Reduced levels of gamma-interferon secretion in response to chlamydial 60 kDa heat shock protein amongst women with pelvic inflammatory disease and a history of repeated Chlamydia trachomatis infectio
Publisher: Elsevier BV
Date: 05-2002
DOI: 10.1016/S0165-2478(02)00036-6
Abstract: Peripheral lymphocytes in uninfected fertile controls, women with various histories of Chlamydia trachomatis infection, pelvic inflammatory disease (PID) and infertility not due to C. trachomatis infection (endometriosis) were cultured overnight with PHA mitogen and the 60 kDa chlamydial heat shock protein. Plasma s les were then assayed for levels of gamma-interferon and IL-10 using a commercial ELISA system. Women with PID and those with a history of multiple C. trachomatis infections showed reduced gamma-interferon production in response to cHSP60, not seen in women infected only once and those with infertility due to other causes (endometriosis). Secretion of IL-10 in response to cHSP60 did not vary significantly across the various patient groups, though all patients showed elevated levels of total IL-10 compared with uninfected controls.
In vitro rescue of genital strains of Chlamydia trachomatis from interferon-γ and tryptophan depletion with indole-positive, but not indole-negative Prevotella spp.
Publisher: Springer Science and Business Media LLC
Date: 12-2016
Divergent outcomes following transcytosis of IgG targeting intracellular and extracellular chlamydial antigens
Publisher: Wiley
Date: 21-01-2014
DOI: 10.1038/ICB.2013.110
Time-delayed influence of urban landscape change on the susceptibility of koalas to chlamydiosis
Publisher: Springer Science and Business Media LLC
Date: 07-01-2017
The protease inhibitor JO146 demonstrates a critical role for CtHtrA for Chlamydia trachomatis reversion from penicillin persistence
Publisher: Frontiers Media SA
Date: 2013
Randomly amplified polymorphic DNA variation in populations of eastern Australian koalas, Phascolarctos cinereus
Publisher: Springer Science and Business Media LLC
Date: 1998
Abstract: Randomly lified polymorphic DNA (RAPD) variation in populations of the koala, Phascolarctos cinereus, was investigated, revealing significant differences in the level of ersity between southern and northern regions of eastern Australia. Of the 20 polymorphic RAPD markers identified in koalas, 4-7 were polymorphic in southern populations, while 12-17 were polymorphic in northern populations. Analysis of molecular variance revealed a significant difference in the estimated variance between koalas from northern and those from southern regions (P < 0.001), where populations from the north were greater than twice as variable as their southern cousins. The total genetic ersity observed was attributed to regional differences (30.91%), population differences within a region (11.77%), and differences among in iduals within a population (57.32%). For the within-region analyses, a large proportion of the genetic ersity was attributable to in idual differences within a population, 80.34% for the north and 91.23% for the south. These results demonstrate that RAPD markers are useful for determining population structure among koalas.
Detection of Chlamydia trachomatis mRNA using digital PCR as a more accurate marker of viable organism.
Publisher: Springer Science and Business Media LLC
Date: 14-08-2018
Evidence that HumanChlamydia pneumoniaeWas Zoonotically Acquired
Publisher: American Society for Microbiology
Date: 06-2009
DOI: 10.1128/JB.00746-09
Abstract: Zoonotic infections are a growing threat to global health. Chlamydia pneumoniae is a major human pathogen that is widespread in human populations, causing acute respiratory disease, and has been associated with chronic disease. C. pneumoniae was first identified solely in human populations however, its host range now includes other mammals, marsupials, hibians, and reptiles. Australian koalas ( Phascolarctos cinereus ) are widely infected with two species of Chlamydia , C. pecorum and C. pneumoniae . Transmission of C. pneumoniae between animals and humans has not been reported however, two other chlamydial species, C. psittaci and C. abortus , are known zoonotic pathogens. We have sequenced the 1,241,024-bp chromosome and a 7.5-kb cryptic chlamydial plasmid of the koala strain of C. pneumoniae (LPCoLN) using the whole-genome shotgun method. Comparative genomic analysis, including pseudogene and single-nucleotide polymorphism (SNP) distribution, and phylogenetic analysis of conserved genes and SNPs against the human isolates of C. pneumoniae show that the LPCoLN isolate is basal to human isolates. Thus, we propose based on compelling genomic and phylogenetic evidence that humans were originally infected zoonotically by an animal isolate(s) of C. pneumoniae which adapted to humans primarily through the processes of gene decay and plasmid loss, to the point where the animal reservoir is no longer required for transmission.
Identification of novel markers for uncomplicated lower genital tract infections and upper genital tract pathology due to Chlamydia trachomatis
Publisher: Elsevier BV
Date: 04-2011
DOI: 10.1016/J.IJID.2010.12.005
Abstract: Untreated Chlamydia trachomatis infections in women can result in disease sequelae such as salpingitis and pelvic inflammatory disease (PID), ultimately culminating in tubal occlusion and infertility. Whilst nucleic acid lification tests can effectively diagnose uncomplicated lower genital tract (LGT) infections, they are not suitable for diagnosing upper genital tract (UGT) pathological sequelae. As a consequence, this study aimed to identify serological markers that can, with a high degree of sensitivity and specificity, discriminate between LGT infections and UGT pathology. Plasma was collected from 73 women with a history of LGT infection, UGT pathology due to C. trachomatis, or no serological evidence of C. trachomatis infection. Western blotting was used to analyze antibody reactivity against extracted chlamydial proteins. Sensitivity and specificity of differential markers were also calculated. Four antigens (CT157, CT423, CT727 and CT396) were identified and found to be capable of discriminating between the infection and disease sequelae state. Sensitivity and specificity calculations showed that our assay for diagnosing LGT infection had a sensitivity of 75% and specificity of 76%, whilst the assay for identifying UGT pathology demonstrated 80% sensitivity and 86% specificity. The use of these assays could potentially facilitate earlier diagnoses in women suffering UGT pathology due to C. trachomatis.
Dysbiosis of the Vaginal Microbiota and Higher Vaginal Kynurenine/Tryptophan Ratio Reveals an Association with Chlamydia trachomatis Genital Infections.
Publisher: Frontiers Media SA
Date: 18-01-2018
A cohort study of Chlamydia trachomatis treatment failure in women: A study protocol
Publisher: Springer Science and Business Media LLC
Date: 17-08-2013
A Multi-subunit chlamydial vaccine induces antibody and cell-mediated immunity in immunized koalas (phascolarctos cinereus): Comparison of three different adjuvants
Publisher: Wiley
Date: 06-01-2010
DOI: 10.1111/J.1600-0897.2009.00776.X
Abstract: Chlamydial infections represent a major threat to the survival of the koala. Infections caused by Chlamydia pecorum cause blindness, infertility, pneumonia and urinary tract infections and represent a threat to the survival of the species. Little is known about the immune response in koalas, or the safety of commonly used adjuvants for induction of protective systemic and mucosal immunity. of study In the present study, we immunized 18 healthy female koalas subcutaneously with a combination of three chlamydial antigens [major outer membrane protein (MOMP), NrdB and TC0512 (Omp85)] mixed with one of three different adjuvants [Alhydrogel, Immunostimulating Complex (ISC) and TiterMax Gold]. All adjuvants induced strong neutralizing IgG responses in plasma against the three antigens with prolonged responses lasting more than 270 days seen in Alhydrogel and ISC immunized animals. Cloacal IgG responses lasting >270 days were also induced in ISC-immunized animals. Chlamydia-specific peripheral blood mononuclear cell proliferative responses were elicited by both Alhydrogel and ISC, and these lasted >270 days in the ISC group. The data show that a multi-subunit chlamydial vaccine, given subcutaneously, can elicit Chlamydia-specific cell-mediated and antibody responses in the koala demonstrating that the development of a protective vaccine is feasible.
Identification of Chlamydia pneumoniae Proteins in the Transition from Reticulate to Elementary Body Formation
Publisher: Elsevier BV
Date: 12-2006
Koala biovar of Chlamydia pneumoniae infects human and koala monocytes and induces increased uptake of lipids in vitro
Publisher: American Society for Microbiology
Date: 12-2001
DOI: 10.1128/IAI.69.12.7894-7897.2001
Abstract: We examined the ability of the koala biovar of Chlamydia pneumoniae to infect both Hep-2 cells and human monocytes and the effect of infection on the formation of foam cells. The koala biovar produced large inclusions in both human and koala monocytes and in Hep-2 cells. Koala C. pneumoniae induced foam cell formation with and without added low-density lipoprotein, in contrast to TW183, which produced increased foam cell formation only in the presence of low-density lipoprotein.
Comparison of koala LPCoLN and human strains of Chlamydia pneumoniae highlights extended genetic diversity in the species
Publisher: Springer Science and Business Media LLC
Date: 21-07-2010
Abstract: Chlamydia pneumoniae is a widespread pathogen causing upper and lower respiratory tract infections in addition to a range of other diseases in humans and animals. Previous whole genome analyses have focused on four essentially clonal ( 99% identity) C. pneumoniae human genomes (AR39, CWL029, J138 and TW183), providing relatively little insight into strain ersity and evolution of this species. We performed in idual gene-by-gene comparisons of the recently sequenced C. pneumoniae koala genome and four C. pneumoniae human genomes to identify species-specific genes, and more importantly, to gain an insight into the genetic ersity and evolution of the species. We selected genes dispersed throughout the chromosome, representing genes that were specific to C. pneumoniae , genes with a demonstrated role in chlamydial biology and/or pathogenicity (n = 49), genes encoding nucleotide salvage or amino acid biosynthesis proteins (n = 6), and extrachromosomal elements (9 plasmid and 2 bacteriophage genes). We have identified strain-specific differences and targets for detection of C. pneumoniae isolates from both human and animal origin. Such characterisation is necessary for an improved understanding of disease transmission and intervention.
Isolation and Antimicrobial Susceptibilities of Chlamydial Isolates from Western Barred Bandicoots
Publisher: American Society for Microbiology
Date: 02-2007
DOI: 10.1128/JCM.01726-06
Abstract: A range of species of Chlamydiales have previously been detected in a variety of Australian marsupials, including koalas and western barred bandicoots. Thirty-seven ocular, urogenital, or nasal swabs were obtained from 21 wild western barred bandicoots. Chlamydia culture and antibiotic susceptibility testing were performed for cycloheximide-treated HEp-2 cells in 96-well microtiter plates. Chlamydia spp. were isolated from 11 specimens from 9 (42.8%) bandicoots. All isolates were identified as Chlamydiales by conventional PCR with 16S and 23S rRNA gene primers specific to Chlamydiales and were confirmed to be Chlamydia pneumoniae by a C. pneumoniae -specific ompA -based real-time PCR assay and 16S rRNA and 23S rRNA gene signature sequence analyses. The MICs of azithromycin, doxycycline, ciprofloxacin, and enrofloxacin for 10 C. pneumoniae isolates from these bandicoots ranged from 0.015 to 1 μg/ml, 0.25 to 1 μg/ml, 0.25 to 2 μg/ml, and 0.25 to 0.5 μg/ml, respectively. The MICs at which 90% of isolates were inhibited and the minimal bactericidal concentrations were within the ranges reported previously for human isolates of C. pneumoniae.
Failure to detect Chlamydia pneumoniae in atherosclerotic plaques of Australian patients
Publisher: Elsevier BV
Date: 1998
DOI: 10.1080/00313029800169166
Abstract: Chlamydia pneumoniae is a recently reported, but common, respiratory tract pathogen. The organism has been detected by electron microscopy, immunocytochemistry, polymerase chain reaction (PCR) and recently culture within atherosclerotic plaques, suggesting a possible association between C. pneumoniae infection and atherosclerosis. Interestingly this association has not been found by all researchers. We examined 17 carotid endarterectomy specimens, 16 carotid arteries and 16 coronary arteries from autopsy specimens. They were examined by PCR for the presence of C. pneumoniae. In none of the 49 atherosclerotic s les examined was C. pneumoniae detected. The sensitivity of our PCR assay was rigorously tested and found to detect consistently fewer than ten elementary bodies. The association between C. pneumoniae and atherosclerosis is intriguing but has not yet been demonstrated in Australian patients.
Therapeutic effect of a Chlamydia pecorum recombinant major outer membrane protein vaccine on ocular disease in koalas (Phascolarctos cinereus)
Publisher: Public Library of Science (PLoS)
Date: 07-01-2019
Type III secretion, contact-dependent model for the intracellular development of Chlamydia
Publisher: Springer Science and Business Media LLC
Date: 2006
DOI: 10.1007/S11538-005-9024-1
Abstract: The medically significant genus Chlamydia is a class of obligate intracellular bacterial pathogens that replicate within vacuoles in host eukaryotic cells termed inclusions. Chlamydia's developmental cycle involves two forms an infectious extracellular form, known as an elementary body (EB), and a non-infectious form, known as the reticulate body (RB), that replicates inside the vacuoles of the host cells. The RB surface is covered in projections that are in intimate contact with the inclusion membrane. Late in the developmental cycle, these reticulate bodies differentiate into the elementary body form. In this paper, we present a hypothesis for the modulation of these developmental events involving the contact-dependent type III secretion (TTS) system. TTS surface projections mediate intimate contact between the RB and the inclusion membrane. Below a certain number of projections, detachment of the RB provides a signal for late differentiation of RB into EB. We use data and develop a mathematical model investigating this hypothesis. If the hypothesis proves to be accurate, then we have shown that increasing the number of inclusions per host cell will increase the number of infectious progeny EB until some optimal number of inclusions. For more inclusions than this optimum, the infectious yield is reduced because of spatial restrictions. We also predict that a reduction in the number of projections on the surface of the RB (and as early as possible during development) will significantly reduce the burst size of infectious EB particles. Many of the results predicted by the model can be tested experimentally and may lead to the identification of potential targets for drug design.
Partial protection against chlamydial reproductive tract infection by a recombinant major outer membrane protein/CpG/cholera toxin intranasal vaccine in the guinea pig Chlamydia caviae model
Publisher: Elsevier BV
Date: 09-2011
DOI: 10.1016/J.JRI.2011.06.100
Abstract: Chlamydia trachomatis is a major cause of sexually transmitted diseases worldwide. There is currently no vaccine to protect against chlamydial infection of the female reproductive tract. Vaccine development has predominantly utilised the murine model however, infection of female guinea pigs with Chlamydia caviae more closely resembles chlamydial infection of the human female reproductive tract, and presents a better model to assess potential human chlamydial vaccines. We immunised female guinea pigs intranasally with recombinant major outer membrane protein (r-MOMP) combined with CpG-10109 and cholera toxin adjuvants. Both systemic and mucosal immune responses were elicited in immunised animals, with MOMP-specific IgG and IgA present in the vaginal mucosae, and high levels of MOMP-specific IgG detected in the serum. Antibodies from the vaginal mucosae were also capable of neutralising C. caviae in vitro. Following immunisation, animals were challenged intravaginally with 10(2) inclusion forming units of live C. caviae. We observed a decrease in the duration of infection and a significant (p<0.025) reduction in infection load in r-MOMP-immunised animals, compared with animals immunised with adjuvant only. Importantly, we also observed a marked reduction in upper reproductive tract pathology in r-MOMP-immunised animals. Intranasal immunisation of female guinea pigs with r-MOMP was able to provide partial protection against C. caviae infection, by reducing not only chlamydial burden, but also upper reproductive tract pathology. This data demonstrates the value of using the guinea pig model to evaluate potential chlamydial vaccines for protection against infection and disease pathology caused by C. trachomatis in the female reproductive tract.
Prevalence of Chlamydia pecorum in Juvenile Koalas (Phascolarctos cinereus) and Evidence for Protection from Infection via Maternal Immunization
Publisher: Wildlife Disease Association
Date: 10-2018
DOI: 10.7589/2017-07-183
Abstract: Chlamydia pecorum in koalas ( Phascolarctos cinereus) is considered a sexually transmitted infection. Analysis of s les from koala joeys (<1 yr) suggested that mother-to-young direct transmission was also occurring. Further, evidence suggested that joeys from vaccinated mothers were less likely to contract infections than joeys with unvaccinated mothers.
Lack of antiviral antibody response in koalas infected with koala retroviruses (KoRV)
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.VIRUSRES.2015.01.002
Abstract: Many wild koalas are infected with the koala retrovirus, KoRV, some of which suffer from lymphoma and chlamydial disease. Three subgroups, KoRV-A, KoRV-B and KoRV-J, have so far been described. It is well known that other closely related gammaretroviruses can induce tumours and severe immunodeficiencies in their respective hosts and a possible role for KoRV infection in lymphoma and chlamydial disease in koalas has been suggested. In many wild koalas, KoRV-A has become endogenised, i.e., it is integrated in the germ-line and is passed on with normal cellular genes. In this study, sera from koalas in European zoos and from wild animals in Australia were screened for antibodies against KoRV-A. These naturally infected animals all carry endogenous KoRV-A and two zoo animals are also infected with KoRV-B. The antibody response is generally an important diagnostic tool for detecting retrovirus infections. However, when Western blot analyses were performed using purified virus or recombinant proteins corresponding to KoRV-A, none of the koalas tested positive for specific antibodies, suggesting a state of tolerance. These results have implications for koala vaccination, as they suggest that therapeutic immunisation of animals carrying and expressing endogenous KoRV-A will not be successful. However, it remains unclear whether these animals can be immunised against KoRV-B and immunisation of uninfected koalas could still be worthwhile.
Chlamydia trachomatis Genital Tract Infections: When Host Immune Response and the Microbiome Collide.
Publisher: Elsevier BV
Date: 09-2016
Ethnic Variation in Inflammatory Profile in Tuberculosis
Publisher: Public Library of Science (PLoS)
Date: 04-07-2013
An improved method for the transformation of Lactobacillus strains using electroporation
Publisher: Elsevier BV
Date: 1995
Longitudinal study of vitamin D metabolites after long bone fracture
Publisher: Wiley
Date: 21-05-2013
DOI: 10.1002/JBMR.1855
Abstract: Animal models suggest a key role for dihydroxylated vitamin D metabolites in fracture healing, as evidenced by increases in serum concentration of 24R,25-dihydroxyvitamin D (24R,25[OH]₂D) after long bone fracture. Human studies investigating the kinetics of serum concentrations of 24R,25[OH]₂D, 1,25-dihydroxyvitamin D (1,25[OH]₂D) and their parent metabolite 25-hydroxyvitamin D (25[OH]D) are lacking. We, therefore, conducted a longitudinal study to determine whether total, free, or bioavailable concentrations of these vitamin D metabolites fluctuate in humans after long bone fracture. Twenty-eight patients with cross-shaft (diaphyseal) long bone fracture presenting to an emergency department in London, UK, were studied. Serum concentrations of 25(OH)D, 24R,25(OH)₂D, 1,25(OH)₂D, vitamin D binding protein, albumin, and calcium were determined within 48 hours of fracture and again at 1 and 6 weeks postfracture. Concentrations of free and bioavailable vitamin D metabolites were calculated using standard equations. No changes in mean serum concentrations of 25(OH)D or 24R,25(OH)₂D were seen at either follow-up time point versus baseline. In contrast, mean serum 1,25(OH)2 D concentration declined by 21% over the course of the study, from 68.5 pmol/L at baseline to 54.1 pmol/L at 6 weeks (p < 0.05). This decline was associated with an increase in mean serum corrected calcium concentration, from 2.32 mmol/L at baseline to 2.40 mmol/L at 1 week (p < 0.001) that was maintained at 6 weeks. No changes in free or bioavailable concentrations of any vitamin D metabolite investigated were seen over the course of the study. We conclude that serum 1,25(OH)₂D concentration declines after long bone fracture in humans but that the serum 24R,25(OH)₂D concentration does not fluctuate. The latter finding contrasts with those of animal models reporting increases in serum 24R,25(OH)₂D concentration after long bone fracture.
cDNA clone encoding a high molecular weight antigen of Babesia bovis
Publisher: Elsevier BV
Date: 1987
DOI: 10.1016/0166-6851(87)90050-8
Abstract: An expression library was constructed by inserting cDNA copied from mRNA of the blood stages of Babesia bovis isolate KA into bacteriophage lambda gt11- 3. An antigen-positive cDNA clone detected by screening the library with antibodies from cattle vaccinated with the KA isolate was shown to encode part of a high-molecular weight polypeptide antigen of B. bovis. This molecule was a dominant immunogen and was found by immunofluorescence to be within the parasite in infected erythrocytes.
Sero-epidemiological assessment of Chlamydia trachomatis infection and sub-fertility in Samoan women.
Publisher: Springer Science and Business Media LLC
Date: 21-04-2016
Unexpected Pathogen Diversity Detected in Australian Avifauna Highlights Potential Biosecurity Challenges
Publisher: MDPI AG
Date: 02-01-2023
DOI: 10.3390/V15010143
Abstract: Birds may act as hosts for numerous pathogens, including members of the family Chlamydiaceae, beak and feather disease virus (BFDV), avipoxviruses, Columbid alphaherpesvirus 1 (CoAHV1) and Psittacid alphaherpesvirus 1 (PsAHV1), all of which are a significant biosecurity concern in Australia. While Chlamydiaceae and BFDV have previously been detected in Australian avian taxa, the prevalence and host range of avipoxviruses, CoAHV1 and PsAHV1 in Australian birds remain undetermined. To better understand the occurrence of these pathogens, we screened 486 wild birds (kingfisher, parrot, pigeon and raptor species) presented to two wildlife hospitals between May 2019 and December 2021. Utilising various qPCR assays, we detected PsAHV1 for the first time in wild Australian birds (37/486 7.61%), in addition to BFDV (163/468 33.54%), Chlamydiaceae (98/468 20.16%), avipoxviruses (46/486 9.47%) and CoAHV1 (43/486 8.85%). Phylogenetic analysis revealed that BFDV sequences detected from birds in this study cluster within two predominant superclades, infecting both psittacine and non-psittacine species. However, BFDV disease manifestation was only observed in psittacine species. All Avipoxvirus sequences clustered together and were identical to other global reference strains. Similarly, PsAHV1 sequences from this study were detected from a series of novel hosts (apart from psittacine species) and identical to sequences detected from Brazilian psittacine species, raising significant biosecurity concerns, particularly for endangered parrot recovery programs. Overall, these results highlight the high pathogen ersity in wild Australian birds, the ecology of these pathogens in potential natural reservoirs, and the spillover potential of these pathogens into novel host species in which these agents cause disease.
Multiple genotypes of Chlamydia pneumoniae identified in human carotid plaque
Publisher: Microbiology Society
Date: 07-2005
Abstract: Chlamydia pneumoniae is an obligate intracellular respiratory pathogen that causes 10 % of community-acquired pneumonia and has been associated with cardiovascular disease. Both whole-genome sequencing and specific gene typing suggest that there is relatively little genetic variation in human isolates of C. pneumoniae . To date, there has been little genomic analysis of strains from human cardiovascular sites. The genotypes of C. pneumoniae present in human atherosclerotic carotid plaque were analysed and several polymorphisms in the variable domain 4 (VD4) region of the outer-membrane protein-A ( ompA ) gene and the intergenic region between the ygeD and uridine kinase ( ygeD – urk ) genes were found. While one genotype was identified that was the same as one reported previously in humans (respiratory and cardiovascular), another genotype was found that was identical to a genotype from non-human sources (frog/koala).
Systemic Antibody Response to Chlamydia Trachomatis Infection in Patients Either Infected or Reinfected with Different Chlamydia Serovars
Publisher: Elsevier BV
Date: 07-2017
The relative contribution of causal factors in the transition from infection to clinical chlamydial disease
Publisher: Springer Science and Business Media LLC
Date: 11-06-2018
DOI: 10.1038/S41598-018-27253-Z
Abstract: Chlamydia is a major bacterial pathogen in humans and animals globally. Yet 80% of infections never progress to clinical disease. Decades of research have generated an interconnected network linking pathogen, host, and environmental factors to disease expression, but the relative importance of these and whether they account for disease progression remains unknown. To address this, we used structural equation modeling to evaluate putative factors likely to contribute to urogenital and ocular chlamydial disease in the koala ( Phascolarctos cinereus ). These factors include Chlamydia detection, load, and ompA genotype urogenital and ocular microbiomes host sex, age, weight, body condition breading season, time of year location retrovirus co-infection and major histocompatibility complex class II (MHCII) alleles. We show different microbiological processes underpin disease progression at urogenital and ocular sites. From each category of factors, urogenital disease was most strongly predicted by chlamydial PCR detection and load, koala body condition and environmental location. In contrast, ocular disease was most strongly predicted by phylum-level Chlamydiae microbiome proportions, s ling during breeding season and co-infection with koala retrovirus subtype B. Host MHCII alleles also contributed predictive power to both disease models. Our results also show considerable uncertainty remains, suggesting major causal mechanisms are yet to be discovered.
Differential expression of genes encoding membrane proteins between acute and continuous Chlamydia pneumoniae infections
Publisher: Elsevier BV
Date: 2003
DOI: 10.1016/S0882-4010(02)00187-0
Abstract: Chlamydia pneumoniae is associated with several chronic human diseases, including chronic obstructive pulmonary disease and atherosclerotic cardiovascular disease. During chronic disease, organisms are believed to exist in a persistent phase that is not well understood at the genetic level. Long-term in vitro continuous infections are spontaneously persistent and are less susceptible than in vitro acute infections to treatment with antibiotics, and are therefore particularly relevant as an in vitro model of in vivo chronic disease. Real-time reverse transcriptase-PCR (r-t RT-PCR) was used to quantitate transcript copy numbers of 13 genes in continuous and acute infections with C. pneumoniae. The set of genes studied encodes proteins with known or predicted functions in the cell membrane, the inclusion membrane, cell ision, metabolism, and immunopathology. Significant upregulation was seen for five genes (CPn0483, nlpD, ompA, pmp1 and porB) in continuous cultures. The genes omcB, pmp1, and porB, all of which encode membrane proteins, shared similar patterns of expression over both acute and continuous profiles. These results show that Chlamydia in the long-term continuous model of persistence have a unique transcription profile, adding to our knowledge of regulation of this important stage of chlamydial growth.
A retrospective pilot study to determine whether the reproductive tract microbiota differs between women with a history of infertility and fertile women.
Publisher: Wiley
Date: 26-12-2018
DOI: 10.1111/AJO.12754
DNA polymorphisms and subpopulations in Babesia bovis
Publisher: Elsevier BV
Date: 04-1984
DOI: 10.1016/0166-6851(84)90057-4
Abstract: Independent isolates of Babesia bovis differ by only a limited number of polypeptides, some of which may be important as host protective antigens. Avirulent derivatives of these parasites also differ from their virulent counterparts in only a few polypeptides. To identify genes encoding such polypeptides we have isolated cDNA clones corresponding to poly(A)+ RNAs that are expressed only in certain isolates. For this purpose a cDNA clone library was constructed from poly(A)+ RNA of the K-avirulent isolate (KA). These clones were screened by colony hybridization using [32P]cDNA complementary to poly(A)+ RNA from KA and from virulent isolates, in order to identify clones that selectively hybridize to one cDNA probe. Hybridization of DNA from three clones, designated pK4, pK5 and pK6 to poly(A)+ RNA from various isolates revealed different and complex patterns. The gene represented by clone pK5 appeared to be transcribed predominantly in avirulent parasites. Analysis of genomic DNA by the Southern procedure enabled each isolate to be distinguished and suggested that most isolates are comprised of a heterogeneous mixture of subpopulations. Analysis of genomic DNA from parasites obtained after passage of KA through the tick vector (Boophilus microplus) suggested that a subpopulation was being selected that more closely resembled KV than KA.
Characterisation of CD4 T cells in healthy and diseased koalas (Phascolarctos cinereus) using cell-type-specific monoclonal antibodies
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.DCI.2016.02.018
Abstract: The koala (Phascolarctos cinereus) is an arboreal herbivorous marsupial that is an Australian icon. Koalas in many parts of Australia are under multiple threats including habitat destruction, dog attacks, vehicular accidents, and infectious diseases such as Chlamydia spp. and the koala retrovirus (KoRV), which may contribute to the incidence of lymphoma and leukaemia in this species. Due to a lack of koala-specific immune reagents and assays there is currently no way to adequately analyse the immune response in healthy, diseased or vaccinated animals. This paper reports the production and characterisation of the first anti-koala CD4 monoclonal antibody (mAb). The koala CD4 gene was identified and used to develop recombinant proteins for mAb production. Fluorochrome-conjugated anti-CD4 mAb was used to measure the levels of CD4(+) lymphocytes collected from koala spleens (41.1%, range 20-45.1%) lymph nodes (36.3%, range 19-55.9%) and peripheral blood (23.8%, range 17.3-35%) by flow cytometry. Biotin-conjugated anti-CD4 mAb was used for western blot to determine an approximate size of 52 kDa for the koala CD4 molecule and used in immunohistochemistry to identify CD4(+) cells in the paracortical region and germinal centres of spleen and lymph nodes. Using the anti-CD4 mab we showed that CD4 cells from vaccinated, but not control, koalas proliferated following in vitro stimulation with UV-inactivated Chlamydia pecorum and recombinant chlamydial antigens. Since CD4(+) T cells have been shown to play a pivotal role in clearing chlamydial infection in both human and mouse infections, using this novel antibody will help determine the role CD4(+) T cells play in protection against chlamydial infection in koalas and also enhance our knowledge of how KoRV affects the koala immune system.
Identification, characterisation and expression analysis of natural killer receptor genes in Chlamydia pecorum infected koalas (Phascolarctos cinereus)
Publisher: Springer Science and Business Media LLC
Date: 15-10-2015
Vitamin D3 supplementation in patients with chronic obstructive pulmonary disease (ViDiCO): a multicentre, double-blind, randomised controlled trial
Publisher: Elsevier BV
Date: 02-2015
Comparison of DNA-spot hybridization, cell culture and direct immunofluorescence staining for the diagnosis of avian chlamydiae
Publisher: Elsevier BV
Date: 09-1988
DOI: 10.1016/0378-1135(88)90112-5
Abstract: DNA-spot hybridization, cell culture and direct immunofluorescence staining were compared for the detection of avian Chlamydia psittaci strains in cell culture dilutions and in routine s les submitted for diagnosis. With dilutions of infected cell culture material, growth in BGM cells was by far the most sensitive technique, detecting 0.01 infected cells (20 elementary bodies) ml-1. DNA-spot hybridization and direct immunofluorescence staining were of approximately equal sensitivity, both detecting 16 infected cells (3.2 x 10(4) elementary bodies) per ml-1. When 27 avian liver and spleen s les were assayed, all 3 tests performed similarly (13 positive and 12 negative by all 3 tests). This suggests that in most avian s les presented for diagnosis, sufficient numbers of chlamydiae are present to allow any of the test to the be used. Thus, the direct immunofluorescence staining method is currently the test of choice for routine diagnosis since it is available in kit form, is relatively simple and quick to perform, and like DNA-spot hybridization, detects non-viable as well as viable organisms. However, if low levels of chlamydiae are to be effectively detected, such as in carrier birds or birds with recently acquired infections, then cell culture should be used.
Microbiota composition of the koala (Phascolarctos cinereus) ocular and urogenital sites, and their association with Chlamydia infection and disease
Publisher: Springer Science and Business Media LLC
Date: 12-07-2017
DOI: 10.1038/S41598-017-05454-2
Abstract: Disease caused by Chlamydia pecorum is characterised by ocular and urogenital infections that can lead to blindness and infertility in koalas. However, koalas that are infected with C . pecorum do not always progress to disease. In other host systems, the influence of the microbiota has been implicated in either accelerating or preventing infections progressing to disease. This study investigates the contribution of koala urogenital and ocular microbiota to Chlamydia infection and disease in a free ranging koala population. Using univariate and multivariate analysis, it was found that reproductive status in females and sexual maturation in males, were defining features in the koala urogenital microbiota. Changes in the urogenital microbiota of koalas is correlated with infection by the common pathogen, C . pecorum . The correlation of microbiota composition and C . pecorum infection is suggestive of members of the microbiota being involved in the acceleration or prevention of infections progressing to disease. The analysis also suggests that multiple microbes are likely to be associated with this process of disease progression, rather than a single organism. While other Chlamydia -like organisms were also detected, they are unlikely to contribute to chlamydial disease as they are rare members of the urogenital and ocular microbiota communities.
Immunity against a Chlamydia infection and disease may be determined by a balance of IL‐17 signaling
Publisher: Wiley
Date: 24-12-2014
DOI: 10.1038/ICB.2013.92
Abstract: Most vaccines developed against Chlamydia using animal models provide partial protection against a genital tract infection. However, protection against the oviduct pathology associated with infertility is highly variable and often has no defining immunological correlate. When comparing two adjuvants (CTA1-DD and a combination of Cholera toxin plus CpG-oligodeoxynucleotide-CT/CpG) combined with the chlamydial major outer membrane protein (MOMP) antigen and delivered via the intranasal (IN), sublingual (SL) or transcutaneous (TC) routes, we identified two vaccine groups with contrasting outcomes following infection. SL immunization with MOMP/CTA1-DD induced a 70% reduction in the incidence of oviduct pathology, without significantly altering the course of infection. Conversely, IN immunization with MOMP/CT/CpG prevented an ascending infection, but not the oviduct pathology. This anomaly presented a unique opportunity to study the mechanisms by which vaccines can prevent oviduct pathology, other than by controlling the infection. The IL-17 signaling in the oviducts was found to associate with both the enhancement of immunity to infection and the development of oviduct pathology. This conflicting role of IL-17 may provide some explanation for the discordance in protection between infection and disease and suggests that controlling immunopathology, as opposed to the rapid eradication of the infection, may be essential for an effective human chlamydial vaccine that prevents infertility.
Therapeutic vaccination of koalas harbouring endogenous koala retrovirus (KoRV) improves antibody responses and reduces circulating viral load
Publisher: Springer Science and Business Media LLC
Date: 16-07-2020
DOI: 10.1038/S41541-020-0210-9
Abstract: The long-term survival of the koala is under serious threat from multiple factors, including infectious disease agents such as Chlamydia and koala retrovirus (KoRV). KoRV is present in both exogenous and endogenous forms, depending on the geographical location of the population. In the northern half of Australia, it is present as an endogenous infection in all koalas, making a case for an urgent need to develop a therapeutic vaccine that might prevent KoRV-associated pathologies in these koalas. To this end, we determined the therapeutic effects of vaccinating koalas harbouring endogenous KoRV with a recombinant KoRV Env protein combined with a Tri-adjuvant. We found that vaccination led to a significant increase in circulating anti-KoRV IgG levels, as well as increase in neutralising antibodies. Our study also showed that post-vaccination antibodies were able to recognize epitopes on the Env protein that were unrecognised pre-vaccination, as well as resulting in an increase in the recognition of the previously recognised epitopes. The vaccine also induced antibodies that were cross-reactive against multiple KoRV-subtypes. Finally, we found a complete clearance of KoRV-A in plasma from koalas that had detectable levels of KoRV-A pre-vaccination. Similarly, there was a significant reduction in the expression of KoRV-B viral RNA levels post-vaccination. Collectively, this study showed that koalas harbouring endogenous KoRV can benefit from prophylactic vaccination against KoRV using a recombinant KoRV-A Env protein and that the mechanism of this protection might be through the boosting of natural anti-KoRV antibodies and expanding the breadth of the recognised epitopes.
The global roadmap for advancing development of vaccines against sexually transmitted infections: Update and next steps
Publisher: Elsevier BV
Date: 06-2016
Effects of inoculating dose on the kinetics of Chlamydia muridarum genital infection in female mice
Publisher: Wiley
Date: 10-02-2009
DOI: 10.1038/ICB.2009.3
Abstract: Chlamydia trachomatis infections have been implicated in problems such as pelvic inflammatory disease and infertility in females. Although there are some studies examining the kinetics of ascending infection, there is limited information on the kinetics of pathology development and cellular infiltrate into the reproductive tissues in relation to the effects of inoculating dose, and a better understanding of these is needed. The murine model of female genital tract Chlamydia muridarum infection is frequently used as a model of human C. trachomatis reproductive tract infection. To investigate the kinetics of ascending genital infection and associated pathology development, female BALB/c mice were intravaginally infected with C. muridarum at doses ranging from 5 x 10(2) to 2.6 x 10(6) inclusion forming units. We found that the inoculating dose affects the course of infection and the ascension of bacteria, with the highest dose ascending rapidly to the oviducts. By comparison, the lowest dose resulted in the greatest bacterial load in the lower reproductive tract. Interestingly, we found that the dose did not significantly affect inflammatory cell infiltrate in the various regions. Overall, this data show the effects of infectious dose on the kinetics of ascending chlamydial infection and associated inflammatory infiltration in BALB/c mice.
Induction of neutralizing antibody response against koala retrovirus (KoRV) and reduction in viral load in koalas following vaccination with recombinant KoRV envelope protein
Publisher: Springer Science and Business Media LLC
Date: 02-08-2018
DOI: 10.1038/S41541-018-0066-4
Abstract: Koala retrovirus (KoRV) infects the majority of Australia’s koalas ( Phascolarctos cinereus ) and has been linked to several life-threatening diseases such as lymphoma and leukemia, as well as Chlamydia and thus poses a threat to the continued survival of this species. While quarantine and antiretroviral drug treatment are possible control measures, they are impractical, leaving vaccination as the only realistic option. In this study, we examined the effect of a recombinant envelope protein-based anti-KoRV vaccine in two groups of South Australian koalas: KoRV infected or KoRV free. We report a successful vaccination response in the koalas with no vaccine-associated side effects. The vaccine induced a significant humoral immune response as well as the production of neutralizing antibodies in both groups of koalas. We also identified B-cell epitopes that were differentially recognized in KoRV-infected versus KoRV-free koalas following vaccination. Importantly, we also showed that vaccination had a therapeutic effect on koalas infected exogenously with KoRV by reducing their circulating viral load. Together, this study highlights the possibility of successfully developing a vaccine against KoRV infection in koalas.
Chlamydia pneumoniae is genetically diverse in animals and appears to have crossed the host barrier to humans on (at least) two occasions
Publisher: Public Library of Science (PLoS)
Date: 20-05-2010
Chlamydia-infected macrophages are resistant to azithromycin treatment and are associated with chronic oviduct inflammation and hydrosalpinx development
Publisher: Wiley
Date: 11-09-2019
DOI: 10.1111/IMCB.12285
Abstract: Chlamydia infection remains the leading sexually-transmitted bacterial infection worldwide, causing damaging sequelae such as tubal scarring, infertility and ectopic pregnancy. As infection is often asymptomatic, prevention via vaccination is the optimal strategy for disease control. Vaccination strategies aimed at preventing bacterial infection have shown some promise, although these strategies often fail to prevent damaging inflammatory pathology when Chlamydia is encountered. Using a murine model of Chlamydia muridarum genital infection, we employed two established independent models to compare immune responses underpinning pathologic development of genital Chlamydia infection. Model one uses antibiotic treatment during infection, with only early treatment preventing pathology. Model two uses a plasmid-cured variant strain of C. muridarum that does not cause pathologic outcomes like the plasmid-containing wild-type counterpart. Using these infection models, contrasted by the development of pathology, we identified an unexpected role for macrophages. We observed that mice showing signs of pathology had greater numbers of activated macrophages present in the oviducts. This may have been due to early differences in macrophage activation and proinflammatory signaling leading to persistent or enhanced infection. These results provide valuable insight into the cellular mechanisms driving pathology in Chlamydia infection and contribute to the design and development of more effective vaccine strategies for protection against the deleterious sequelae of Chlamydia infection of the female reproductive tract.
Development of aChlamydia trachomatisvaccine for urogenital infections: novel tools and new strategies point to bright future prospects
Publisher: Informa UK Limited
Date: 21-12-2017
DOI: 10.1080/14760584.2018.1417044
Abstract: The "cloaked" bacterial pathogen that is Chlamydia trachomatis continues to cause sexually transmitted infections (STIs) that adversely affect the health and well-being of children, adolescents and adults globally. The reproductive disease sequelae follow unresolved or untreated chronic or recurrent asymptomatic C.trachomatis infections of the lower female genital tract (FGT) and can include pelvic pain, pelvic inflammatory disease (PID) and ectopic pregnancy. Tubal Factor Infertility (TFI) can also occur since protective and long-term natural immunity to chlamydial infection is incomplete, allowing for ascension of the organism to the upper FGT. Developing countries including the WHO African (8.3 million cases) and South-East Asian regions (7.2 million cases) bear the highest burden of chlamydial STIs. Genetic advances for Chlamydia have provided tools for transformation (including dendrimer-enabled transformation), lateral gene transfer and chemical mutagenesis. Recent progress in these areas is reviewed with a focus on vaccine development for Chlamydia infections of the female genital tract. A vaccine that can elicit immuno-protective responses whilst avoiding adverse immuno-pathologic host responses is required. The current technological advances in chlamydial genetics and proteomics, as well as novel and improved adjuvants and delivery systems, provide new hope that the elusive chlamydial vaccine is an imminent and realistic goal.
Editorial: Novel strategies for developing vaccines bring encouraging progress
Publisher: Oxford University Press (OUP)
Date: 29-07-2017
Evaluation of a PGP3 ELISA for surveillance of the burden of Chlamydia infection in women from Australia and Samoa.
Publisher: Oxford University Press (OUP)
Date: 04-2019
Abstract: Serological assays can be used to investigate the population burden of infection and potentially sequelae from Chlamydia. We investigated the PGP3 ELISA as a sero-epidemiological tool for infection or sub-fertility in Australian and Samoan women. The PGP3 ELISA absorbance levels were compared between groups of women with infertility, fertile, and current chlamydial infections. In the Australian groups, women with chlamydial tubal factor infertility had significantly higher absorbance levels in the PGP3 ELISA compared to fertile women (P & 0.0001), but not when compared to women with current chlamydial infection (P = 0.44). In the Samoan study, where the prevalence of chlamydial infections is much higher there were significant differences in the PGP3 ELISA absorbance levels between chlamydial sub-fertile women and fertile women (P = 0.003). There was no difference between chlamydial sub-fertile women and women with a current infection (P = 0.829). The results support that the PGP3 assay is effective for sero-epidemiological analysis of burden of infection, but not for evaluation of chlamydial pathological sequelae such as infertility.
A comparison of the effects of a chlamydial vaccine administered during or after a C. muridarum urogenital infection of female mice
Publisher: Elsevier BV
Date: 09-2011
DOI: 10.1016/J.VACCINE.2011.07.012
Abstract: Research into an efficacious Chlamydia trachomatis vaccine is ongoing, however, there has been no examination into the timing of vaccine administration to either asymptomatically or previously infected in iduals. Using the female Chlamydia muridarum genital tract mouse model, we examined this aspect of vaccine development. Our results show timing of vaccination affected the production of systemic antibodies, but had minimal effects on mucosal antibody production. Vaccination during an active infection or after a resolved infection did not provide protection against re-exposure to Chlamydia, and did not exacerbate the development of pathological sequelae in infected mice. This demonstrates that vaccination may not be protective in in iduals who are seropositive for an acute or previous chlamydial infection.
High expression of IDO1 and TGF-β1 during recurrence and post infection clearance with Chlamydia trachomatis, are independent of host IFN-γ response.
Publisher: Springer Science and Business Media LLC
Date: 04-03-2019
The Koala Immune Response to Chlamydial Infection and Vaccine Development—Advancing Our Immunological Understanding
Publisher: MDPI AG
Date: 03-02-2021
DOI: 10.3390/ANI11020380
Abstract: Chlamydia is a significant pathogen for many species, including the much-loved Australian marsupial, the koala (Phascolarctos cinereus). To combat this situation, focused research has gone into the development and refinement of a chlamydial vaccine for koalas. The foundation of this process has involved characterising the immune response of koalas to both natural chlamydial infection as well as vaccination. From parallels in human and mouse research, it is well-established that an effective anti-chlamydial response will involve a balance of cell-mediated Th1 responses involving interferon-gamma (IFN-γ), humoral Th2 responses involving systemic IgG and mucosal IgA, and inflammatory Th17 responses involving interleukin 17 (IL-17) and neutrophils. Characterisation of koalas with chlamydial disease has shown increased expression within all three of these major immunological pathways and monitoring of koalas’ post-vaccination has detected further enhancements to these key pathways. These findings offer optimism that a chlamydial vaccine for wider distribution to koalas is not far off. Recent advances in marsupial genetic knowledge and general nucleic acid assay technology have moved koala immunological research a step closer to other mammalian research systems. However, koala-specific reagents to directly assay cytokine levels and cell-surface markers are still needed to progress our understanding of koala immunology.
Ultrastructural Study ofChlamydia pneumoniaeIn a Continuous-Infection Model
Publisher: American Society for Microbiology
Date: 10-2001
DOI: 10.1128/JCM.39.10.3721-3723.2001
Abstract: We have established an in vitro model of long-term continuous Chlamydia pneumoniae infection in HEp-2 cells. Using transmission electron microscopy, we demonstrated the presence of spontaneous abnormal chlamydial inclusions similar in appearance to the persistent chlamydial forms induced in vitro by treatment with cytokines or antibiotics or by nutrient deprivation.
Genome-wide analysis of chlamydiae for promoters that phylogenetically footprint
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.RESMIC.2007.08.005
Abstract: Currently, there is a lack of phylogenetic footprinting programmes that can take advantage of multiple whole genome sequences of different species within the same bacterial genus. Therefore, we have developed and tested a position weight matrix-based programme called Footy, that performs genome-wide analysis of bacterial genomes for promoters that phylogenetically footprint. When Footy was used to analyse the non-coding regions upstream of genes from three chlamyidal species for promoters that phylogenetically footprint, it predicted a total of 42 promoters, of which 41 were new. Ten of the 41 new promoters predicted by Footy were biologically assayed in Chlamydia trachomatis by mapping the 5' end of the transcripts for the associated genes. The primer extension assay validated seven of the 10 promoters. When Footy was compared to two other accepted methods for genome-wide prediction of promoters in bacteria (the standard PWM method and MITRA), Footy performed equally as well or better than these programmes. This paper, therefore, shows the value of a bioinformatics programme able to perform genome-wide analysis of bacteria for promoters that phylogenetically footprint.
Chlamydia trachomatis infection: Host immune responses and potential vaccines
Publisher: Elsevier BV
Date: 03-2008
DOI: 10.1038/MI.2007.19
Abstract: Chlamydia trachomatis causes genital tract infections that affect men, women, and children on a global scale. This review focuses on innate and adaptive immune responses in the female reproductive tract (FRT) to genital tract infections with C. trachomatis. It covers C. trachomatis infections and highlights our current knowledge of genital tract infections, serovar distribution, infectious load, and clinical manifestations of these infections in women. The unique features of the immune system of the FRT will be discussed and will include a review of our current knowledge of innate and adaptive immunity to chlamydial infections at this mucosal site. The use of animal models to study the pathogenesis of, and immunity to, Chlamydia infection of the female genital tract will also be discussed and a review of recent immunization and challenge experiments in the murine model of chlamydial FRT infection will be presented.
Characterisation of enterovirus 71 replication kinetics in human colorectal cell line, HT29
Publisher: Springer Science and Business Media LLC
Date: 18-06-2013
Abstract: Hand, Foot and Mouth Disease (HFMD), a contagious viral disease that commonly affects infants and children with blisters and flu like symptoms, is caused by a group of enteroviruses such as Enterovirus 71 (EV71) and coxsackievirus A16 (CA16 ) . However some HFMD caused by EV71 may further develop into severe neurological complications such as encephalitis and meningitis. The route of transmission was postulated that the virus transmit from one person to another through direct contact of vesicular fluid or droplet from the infected or via faecal-oral route. To this end, this study utilised a human colorectal adenocarcinoma cell line (HT29) with epithelioid morphology as an in vitro model for the investigation of EV71 replication kinetics. Using qPCR, viral RNA was first detected in HT29 cells as early as 12 h post infection (hpi) while viral protein was first detected at 48 hpi. A significant change in HT29 cells’ morphology was also observed after 48 hpi. Furthermore HT29 cell viability also significantly decreased at 72 hpi. Together, data from this study demonstrated that co-culture of HT29 with EV71 is a useful in vitro model to study the pathogenesis of EV71.
Reduction of fensulfothion and accumulation of the product, fensulfothion sulfide, by selected microbes
Publisher: Springer Science and Business Media LLC
Date: 07-1983
DOI: 10.1007/BF01608775
Abstract: Intrauterine growth restriction (IUGR) is a pregnancy complication due to placental dysfunction that prevents the fetus from obtaining enough oxygen and nutrients, leading to serious mortality and morbidity risks. There is no treatment for IUGR despite having a prevalence of 3% in developed countries, giving rise to an urgency to improve our understanding of the disease. Applying biomechanics investigation on IUGR placental tissues can give important new insights. We performed pressure-diameter mechanical testing of placental chorionic arteries and found that in severe IUGR cases (RI > 90
Phylogenetic comparison of the known Chlamydia trachomatis σ66 promoters across to Chlamydia pneumoniae and Chlamydia caviae identifies seven poorly conserved promoters
Publisher: Elsevier BV
Date: 09-2008
DOI: 10.1016/J.RESMIC.2008.07.002
Abstract: We used four different phylogenetic footprinting programs and the six chlamydial species with publicly available whole genome sequences to analyze the 12 known sigma(66) promoters of Chlamydia trachomatis that phylogenetically footprinted negative in our previous paper. The analysis showed that 7 of the 12 promoters were poorly conserved across C. trachomatis, Chlamydia pneumoniae and Chlamydia caviae. Interestingly, the associated gene sets for these seven promoters were homologs and the gene orders were well conserved across these three species. Additional phylogenetic footprinting, across different subsets from that used above, of the six publicly available whole chlamydial genome sequences and transcription initiation site mapping of chlamydial promoters was also performed. This analysis showed that two of the seven poorly conserved promoters, the promoters in the upstream regions of C. caviae ltuA and ltuB, were like Escherichia coli sigma(70) promoters. Therefore, these promoters are similar to the promoters of C. trachomatis ltuA and ltuB, as they are sigma(70)-like. Given the fact that 7 out of the 22 known sigma(66) promoters in C. trachomatis are poorly conserved across C. trachomatis, C. pneumoniae and C. caviae, we would like to suggest that many other chlamydial promoters are poorly conserved across these species.
Development status and future prospects for a vaccine against Chlamydia trachomatis infection
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.VACCINE.2013.08.020
Abstract: Chlamydia trachomatis continues to be the most commonly reported sexually transmitted bacterial infection in many countries with more than 100 million new cases estimated annually. These acute infections translate into significant downstream health care costs, particularly for women, where complications can include pelvic inflammatory disease and other disease sequelae such as tubal factor infertility. Despite years of research, the immunological mechanisms responsible for protective immunity versus immunopathology are still not well understood, although it is widely accepted that T cell driven IFN-g and Th17 responses are critical for clearing infection. While antibodies are able to neutralize infections in vitro, alone they are not protective, indicating that any successful vaccine will need to elicit both arms of the immune response. In recent years, there has been an expansion in the number and types of antigens that have been evaluated as vaccines, and combined with the new array of mucosal adjuvants, this aspect of chlamydial vaccinology is showing promise. Most recently, the opportunities to develop successful vaccines have been given a significant boost with the development of a genetic transformation system for Chlamydia, as well as the identification of the key role of the chlamydial plasmid in virulence. While still remaining a major challenge, the development of a successful C. trachomatis vaccine is starting to look more likely.
Chlamydia trachomatis infection: Incidence, health costs and prospects for vaccine development
Publisher: Elsevier BV
Date: 08-2000
DOI: 10.1016/S0165-0378(00)00069-3
Abstract: Chlamydia trachomatis infection is now the most common sexually transmitted disease worldwide. World Health Organisation figures estimated that 89 million new cases of genital Chlamydia infections occurred in 1995, highlighting the worldwide prevalence of infections and the economic burden on healthcare delivery. A number of methods have been developed for detection of chlamydial infection, which vary in sensitivity and specificity. No single method has yet gained general acceptance and in many countries Chlamydia infections are not reported, suggesting that the above figures may be an underestimate of the problem. As yet there is no consensus as to what constitutes a protective immune response against genital Chlamydia infection. Studies in animal models have shown that cell-mediated immunity, both Th1-driven macrophage activation and cytotoxic T cell responses, as well as antibody can mediate protection at different stages of the chlamydial life cycle. A successful vaccine would probably need to elicit both a systemic cell-mediated immune response to limit/resolve established infections and a mucosal IgA response to reduce bacterial shedding and the resulting spread of infection to partners of infected in iduals. The immune response to Chlamydia, either through natural infection or following immunisation, also has the potential to enhance inflammation and to act as a driving force for constant mutation in the variable regions of the major outer membrane protein. As a result a constant prevalence of infection is maintained even in an immune population through the emergence of new allelic variants. Immune responses against antigens such as the 60 kDa heat shock protein can exacerbate inflammation through molecular mimicry and must not be elicited as a result of vaccination. Thus there are many challenges for the development of a successful vaccine which must elicit immunity against multiple serovars while at the same time minimising damaging pro-inflammatory immune responses.
Optimising the short and long-term clinical outcomes for koalas (Phascolarctos cinereus) during treatment for chlamydial infection and disease
Publisher: Public Library of Science (PLoS)
Date: 27-12-2018
Poly-Immunoglobulin receptor-mediated transport of IgA into the male genital tract is important for clearance of chlamydia muridarum infection
Publisher: Wiley
Date: 13-10-2008
DOI: 10.1111/J.1600-0897.2008.00637.X
Abstract: Chlamydia trachomatis is the most common sexually transmitted infection worldwide. While infection in females requires a Th1 response for clearance, such a response in males may disrupt the immune privileged nature of the male reproductive tract, potentially contributing to infertility. We investigated the role of IgA in protection against an intrapenile Chlamydia muridarum infection of C57BL/6 and pIgR-/- mice. Here, we show that the poly immunoglobulin receptor is the main pathway for IgA transport into the male reproductive tract. The high levels of IgA seen in prostatic fluid of wild-type mice correlate with reduction in chlamydial infection both in vitro and in vivo. These findings indicate that a Chlamydia vaccine that induces neutralizing IgA in the prostate will aid in the protection against infection in males.
Development of babesial vaccines
Publisher: Oxford University Press (OUP)
Date: 1989
DOI: 10.1016/0035-9203(89)90608-1
Abstract: The most widely used vaccine against cattle babesiosis was blood from a carrier animal. The development of a calf passage attenuated strain in Australia was a great improvement in vaccine safety and efficacy. The degree of immunity generated by this vaccine remains a standard against which to compare other vaccines. Vaccines derived from culture supernatants have also been developed. These have considerable value. To date no efficacious recombinant vaccine exists. A variety of antigens will probably be required in any synthetic vaccine. Study of clones derived from calf passage attenuated vaccines indicate that the vaccine contains a variety of parasites of differing virulence. The attenuation process enriches for the less virulent clones. The clones may also vary in their antigenic characteristics. To date no single clone gives immunity equal to the original uncloned preparation. An ideal vaccine should not be a living agent. It will probably contain a variety of antigens and may induce less strong immunity than the living vaccine but its greater safety, stability and ease of handling will more than compensate for this.
Treatment of rectal chlamydia infection may be more complicated than we originally thought
Publisher: Oxford University Press (OUP)
Date: 04-12-2014
DOI: 10.1093/JAC/DKU493
Abstract: Rectal chlamydia diagnoses have been increasing among MSM and may also rise among women as anal sex rates increase among heterosexuals. However, there is growing concern about treatment for rectal chlamydia with treatment failures of up to 22% being reported. This article addresses factors that may be contributing to treatment failure for rectal chlamydia, including the pharmacokinetic properties of azithromycin and doxycycline in rectal tissue, the ability of chlamydia to transform into a persistent state that is less responsive to antimicrobial therapy, the impact of the rectal microbiome on chlamydia, heterotypic resistance, failure to detect cases of lymphogranuloma venereum and the performance of screening tests. If we are to reduce the burden of genital chlamydia, treatment for rectal chlamydia must be efficacious. This highlights the need for randomized controlled trial evidence comparing azithromycin with doxycycline for the treatment of rectal chlamydia.
Longitudinal study of wild koalas (Phascolarctos cinereus) reveals chlamydial disease progression in two thirds of infected animals
Publisher: Springer Science and Business Media LLC
Date: 13-09-2019
DOI: 10.1038/S41598-019-49382-9
Abstract: Chlamydial disease threatens many of Australia’s koala populations, and yet our understanding of chlamydial epidemiology and disease dynamics in koalas is limited by a lack of comprehensive, longitudinal population studies. To address this, we utilised longitudinal s les from a large-scale population study of wild koalas in south-east Queensland, to follow chlamydial infections over time and to investigate some of the drivers of disease progression. Our findings show, firstly, that almost two thirds of chlamydial infections progressed to disease, challenging the notion that chlamydial infections in koalas commonly remain chronic and asymptomatic. Secondly, disease progression at the urogenital tract site was associated with infection load, and urogenital tract shedding was significantly higher when koalas acquired a new infection. Thirdly, chronic chlamydial exposure was not necessary for pathogenic sequelae to develop, such as infertility and mortality. Fourthly, omp A-characterised strain sub-types may reflect tissue tropisms and pathogenicity, and the chlamydial status of some chronically infected koalas may be explained by reinfections with novel genotypes. Finally, successful antimicrobial treatment provided only short-term protection against reinfection and disease progression in susceptible koalas. These findings highlight the importance of identifying and preventing chlamydial infections in koalas, informing new population management strategies and research priorities.
Changes in endogenous and exogenous koala retrovirus subtype expression over time reflect koala health outcomes
Publisher: American Society for Microbiology
Date: 15-09-2019
DOI: 10.1128/JVI.00849-19
Abstract: The long-term survival of the koala is under serious threat, with this iconic marsupial being declared “vulnerable” by the Australian Government and officially listed as a threatened species. KoRV is clearly contributing to the overall health status of koalas, and research into this virus has been lacking detailed study of the multiple subtypes at both the proviral and expressed viral levels over time. By designing new subtype-specific assays and following well-defined koala cohorts over time, this study has generated a new more complete picture of KoRV and its relationship to koala health outcomes in the wild. Only by building a comprehensive picture of KoRV during both koala health and disease can we bring meaningful koala health interventions into better focus.
Differential expression of ompA, ompB, pyk, nlpD and Cpn0585 genes between normal and interferon-γ treated cultures of Chlamydia pneumoniae
Publisher: Elsevier BV
Date: 06-2001
Improved prediction of bacterial transcription start sites
Publisher: Oxford University Press (OUP)
Date: 15-11-2006
DOI: 10.1093/BIOINFORMATICS/BTI771
Abstract: Motivation: Identifying bacterial promoters is an important step towards understanding gene regulation. In this paper, we address the problem of predicting the location of promoters and their transcription start sites (TSSs) in Escherichia coli. The accepted method for this problem is to use position weight matrices (PWMs), which define conserved motifs at the sigma-factor binding site. However this method is known to result in large numbers of false positive predictions. Results: Our approaches to TSS prediction are based upon an ensemble of support vector machines (SVMs) employing a variant of the mismatch string kernel. This classifier is subsequently combined with a PWM and a model based on distribution of distances from TSS to gene start. We investigate the effect of different scoring techniques and quantify performance using area under a detection-error tradeoff curve. When tested on a biologically realistic task, our method provides performance comparable with or superior to the best reported for this task. False positives are significantly reduced, an improvement of great significance to biologists. Availability: The trained ensemble-SVM model with instructions on usage can be downloaded from Contact: m.towsey@qut.edu.au
Endogenous and exogenous koala retrovirus patterns in wild koalas across Australia. In Proceedings of the Second Koala Retrovirus Workshop, ed. D. E. Alquezar-Planas, D. P. Higgins, C. L. Singleton, and A. D. Greenwood
Publisher: Australian Museum
Date: 21-06-2023
DOI: 10.3853/J.1835-4211.38.2023.1832
Abstract: Our understanding of koala retrovirus (KoRV) has advanced dramatically in recent years. Cross-sectional studies examining hundreds of wild koalas (Phascolarctos cinereus) from populations across their natural Australian range (Queensland–New South Wales–Victoria) have shed new light on KoRV abundance and ersity in the wild. A single strain of KoRV (the originally characterized Hanger strain from 2000) appears to be the dominant KoRV strain within koalas, endogenous in northern populations and the predominant exogenous strain in southern populations. Alongside this strain are potentially exogenous variants representing both intact and defective versions of some of the many recognized KoRV subtypes (KoRV-A to KoRV-M). The patterns of these may suggest a transition from endogenous KoRV in the north to exogenous KoRV in the south, occurring in southern New South Wales. They also highlight how actively the hypervariable region of the envelope gene of KoRV is ersifying, with fragmented koala populations across the country containing unique and distinctive KoRV proviral profiles. As more koala populations are examined with increasingly sensitive and specific genetic tools, our understanding of KoRV is poised to continue to evolve as quickly as the virus itself.
Detection of Chlamydia trachomatis in urine using enzyme immunoassay and DNA amplification
Publisher: Elsevier BV
Date: 12-1993
Abstract: The suitability of urine specimens for the detection of Chlamydia trachomatis infections in men was assessed. Urethral swabs from 301 patients were cultured for C. trachomatis, and the results were compared with results obtained from Chlamydiazyme. The results of 298 specimens were also compared with results obtained from PCR analysis of first-void urine specimens. The sensitivity of confirmed Chlamydiazyme analysis was 93% and the specificity was greater than 99% compared with culture. The sensitivity of the PCR method was 100% compared with culture. Chlamydia trachomatis was detected by PCR in an additional three specimens from which C. trachomatis could not be cultured. Urine appears to be an appropriate specimen for the detection of C. trachomatis antigens and nucleic acids.
Analysis of promoter sequences from Lactobacillus and Lactococcus and their activity in several Lactobacillus species
Publisher: Springer Science and Business Media LLC
Date: 06-04-2000
Abstract: Promoter-active fragments were isolated from the genome of the probiotic organism Lactobacillus rhamnosus strain GG using the promoter-probe vector pNZ272. These promoter elements, together with a promoter fragment isolated from the vaginal strain Lactobacillus fermentum BR11 and two previously defined promoters (Lactococcus lactis and Lactobacillus acidophilus ATCC 4356 slpA), were introduced into three strains of Lactobacillus. Primer-extension analysis was used to map the transcriptional start site for each promoter. All promoter fragments tested were functional in each of the three lactobacilli and a purine residue was used to initiate transcription in most cases. The promoter elements encompassed a 52- to 1,140-fold range in promoter activity depending on the host strain. Lactobacillus promoters were further examined by surveying previously mapped sequences for conserved base positions. The Lactobacillus hexamer regions (-35: TTgaca and -10: TAtAAT) closely resembled those of Escherichia coli and Bacillus subtilis, with the highest degree of agreement at the -10 hexamer. The TG dinucleotide upstream of the -10 hexamer was conserved in 26% of Lactobacillus promoters studied, but conservation rates differed between species. The region upstream of the -35 hexamer of Lactobacillus promoters showed conservation with the bacterial UP element.
Detection of Chlamydia pneumoniae DNA and Antigen in the Circulating Mononuclear Cell Fractions of Humans and Koalas
Publisher: American Society for Microbiology
Date: 05-2000
DOI: 10.1128/IAI.68.5.2744-2747.2000
Abstract: Chlamydia pneumoniae is a common respiratory pathogen of humans which, in addition to causing disease at the respiratory site, has recently been linked to disease at other body sites. If C. pneumoniae does contribute to disease at nonrespiratory sites, then it must have a mechanism by which it reaches these sites. We analyzed the peripheral blood mononuclear cell (PBMC) fractions from 60 healthy human blood donors for the presence of C. pneumoniae DNA (by ompA PCR) and chlamydial antigens (by genus- and species-specific monoclonal antibody staining). Ten of the sixty (16.7%) blood donors were C. pneumoniae positive by PCR, and all 10 of these PCR-positive in iduals' s les demonstrated specific staining with anti- C. pneumoniae monoclonal antibodies. The only other host naturally infected with C. pneumoniae is the koala, in which the bacterium also causes respiratory infections. We demonstrated the presence of C. pneumoniae DNA and antigens in the PBMC fractions of 30% of 20 koalas tested. Our finding of C. pneumoniae -infected PBMCs in koalas as well as humans suggests that the ability to infect PBMCs and to disseminate from the respiratory site is not restricted to the human biovar of C. pneumoniae but is a general characteristic of this chlamydial species.
Modeling the impact of potential vaccines on epidemics of sexually transmitted Chlamydia trachomatis infection
Publisher: Oxford University Press (OUP)
Date: 06-2009
DOI: 10.1086/598983
Abstract: We investigated the likely impact of vaccines on the prevalence of and morbidity due to Chlamydia trachomatis (chlamydia) infections in heterosexual populations. An in idual-based mathematical model of chlamydia transmission was developed and linked to the infection course in chlamydia-infected in iduals. The model describes the impact of a vaccine through its effect on the chlamydial load required to infect susceptible in iduals (the "critical load"), the load in infected in iduals, and their subsequent infectiousness. The model was calibrated using behavioral, biological, and clinical data. A fully protective chlamydia vaccine administered before sexual debut can theoretically eliminate chlamydia epidemics within 20 years. Partially effective vaccines can still greatly reduce the incidence of chlamydia infection. Vaccines should aim primarily to increase the critical load in susceptible in iduals and secondarily to decrease the peak load and/or the duration of infection in vaccinated in iduals who become infected. Vaccinating both sexes has a beneficial impact on chlamydia-related morbidity, but targeting women is more effective than targeting men. Our findings can be used in laboratory settings to evaluate vaccine candidates in animal models, by regulatory bodies in the promotion of candidates for clinical trials, and by public health authorities in deciding on optimal intervention strategies.
Apoptosis is induced in Chlamydia trachomatis-infected HEp-2 cells by the addition of a combination innate immune activation compounds and the inhibitor wedelolactone.
Publisher: Wiley
Date: 27-12-2011
DOI: 10.1111/J.1600-0897.2010.00936.X
Abstract: Innate immune activation of human cells, for some intracellular pathogens, is advantageous for vacuole morphology and pathogenic viability. It is unknown whether innate immune activation is advantageous to Chlamydia trachomatis viability. Innate immune activation of HEp-2 cells during Chlamydia infection was conducted using lipopolysaccharide (LPS), polyI:C, and wedelolactone (innate immune inhibitor) to investigate the impact of these conditions on viability of Chlamydia. The addition of LPS and polyI:C to stimulate activation of the two distinct innate immune pathways (nuclear factor kappa beta and interferon regulatory factor) had no impact on the viability of Chlamydia. However, when compounds targeting either pathway were added in combination with the specific innate immune inhibitor (wedelolactone) a major impact on Chlamydia viability was observed. This impact was found to be due to the induction of apoptosis of the HEp-2 cells under these conditions. This is the first time that induction of apoptosis has been reported in C. trachomatis-infected cells when treated with a combination of innate immune activators and wedelolactone.
Use of quantitative real-time PCR to monitor the shedding and treatment of chlamydiae in the koala (Phascolarctos cinereus)
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1016/J.VETMIC.2006.11.022
Abstract: The aim of this study was to monitor chlamydial shedding patterns in clinically affected koalas before, during and following treatment using quantitative real-time PCR. Swab s les were obtained from 14 koalas presented for treatment at the Australian Wildlife Hospital. Four of these animals were followed over a period of 8-9 weeks. Primers were designed based on the consensus signature sequence of the 16S rRNA chlamydial gene. Additional primers were designed based on the sequence of the koala beta-actin gene and used to normalize chlamydial values when comparing results from different swab s les. Chlamydial 16S rRNA gene copy number was highest in swab s les from clinically affected sites. Daily injections of chlor henicol resulted in a marked and rapid reduction in the numbers of chlamydiae being shed from all sites. In general, chlamydial copy number was no longer detectable by the end of the 2nd week of treatment. No evidence of relapse of infection was detected at 2 weeks after the cessation of treatment. In contrast, topical chlor henicol treatment of the eyes required a longer treatment period and had little effect on the shedding of chlamydiae from other sites of the body. Further studies are required to confirm the efficacy of a shorter treatment period.
Discordant detection of Chlamydia pneumoniae in patients with carotid artery disease using polymerase chain reaction, immunofluorescence microscopy and serological methods
Publisher: Elsevier BV
Date: 02-2005
DOI: 10.1080/00313020400011284
Abstract: To determine the presence of Chlamydia pneumoniae in carotid plaque and peripheral blood mononuclear cells (PBMCs) using a combination of serology, direct antigen detection by immunofluorescence (IF) microscopy and polymerase chain reaction (PCR), and to compare the results obtained from each assay. A total of 54 atherosclerotic carotid plaques were tested for the presence of Chlamydia by PCR and IF methods. Of these 54 patients with carotid artery disease (CAD), 43 were also tested for the presence of C. pneumoniae DNA in PBMCs and for Chlamydia antibodies using two methods, the Medac Chlamydien rELISA and Focus Chlamydia microimmunofluorescence (MIF) methods. Eighteen of the 54 (33%) carotid specimens were positive for the presence of C. pneumoniae DNA, whereas only two of 43 (5%) patients had C. pneumoniae DNA present within their PBMC fraction. Chlamydial antibodies were detected by MIF and/or rELISA in 56% (24/43) of the patients tested. None of the 43 patients was C. pneumoniae positive in all of the test specimens (plaque, PBMCs and serum). Chlamydia pneumoniae is commonly found in Australian patients with CAD. Serology and PCR-based detection of C. pneumoniae in PBMCs and plaque give highly discordant results.
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End Date: 2014
Funder: National Health and Medical Research Council
View Funded ActivityUnderstanding The Origin, Epidemiology And Transmission Threat Of Chlamydial Infections Between Australian Native Animals And Livestock
Start Date: 2013
End Date: 2015
Funder: Australian Research Council
View Funded ActivityDevelopment Of A Safe And Immunogenic Anti-chlamydia Vaccine For The Koala
Start Date: 2012
End Date: 2015
Funder: Australian Research Council
View Funded Activity(Convergence Of Biomaterials And Immunology: A Technology Platform For Delayed Burst Release Of Vaccines)
Start Date: 2012
End Date: 2014
Funder: Australian Research Council
View Funded Activity(Chemi–biology Computational Platform For Lead Discovery In Infectious Disease)
Start Date: 2012
End Date: 2012
Funder: Australian Research Council
View Funded ActivityStress Response Proteases Role For Chlamydia Trachomatis
Start Date: 2009
End Date: 2011
Funder: National Health and Medical Research Council
View Funded ActivityLinkage Projects - Grant ID: LP0884020
Start Date: 05-2009
End Date: 12-2012
Amount: $90,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP0449555
Start Date: 07-2004
End Date: 07-2007
Amount: $240,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP120200051
Start Date: 07-2012
End Date: 12-2015
Amount: $465,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP130102066
Start Date: 2013
End Date: 06-2016
Amount: $360,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP0455050
Start Date: 02-2005
End Date: 12-2008
Amount: $165,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP0990147
Start Date: 07-2009
End Date: 12-2013
Amount: $290,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP150101485
Start Date: 2015
End Date: 02-2018
Amount: $458,600.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE0347727
Start Date: 2002
End Date: 12-2003
Amount: $400,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE0775726
Start Date: 02-2007
End Date: 02-2008
Amount: $306,270.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE0668502
Start Date: 2006
End Date: 12-2007
Amount: $500,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP140100315
Start Date: 07-2014
End Date: 07-2017
Amount: $509,100.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP150100046
Start Date: 06-2016
End Date: 06-2019
Amount: $488,235.00
Funder: Australian Research Council
View Funded ActivitySpecial Research Initiatives - Grant ID: SR0567493
Start Date: 09-2005
End Date: 06-2007
Amount: $99,146.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP160100138
Start Date: 12-2016
End Date: 12-2020
Amount: $339,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE170100192
Start Date: 05-2017
End Date: 12-2017
Amount: $450,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE120100071
Start Date: 03-2012
End Date: 03-2014
Amount: $290,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP0559750
Start Date: 03-2005
End Date: 12-2008
Amount: $233,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE0561169
Start Date: 11-2005
End Date: 12-2006
Amount: $188,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE0668526
Start Date: 2006
End Date: 12-2007
Amount: $542,000.00
Funder: Australian Research Council
View Funded Activity