ORCID Profile
0000-0002-1351-3740
Current Organisation
Edith Cowan University
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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)
Chemical Engineering | Functional Materials | Nanotechnology | Catalytic Process Engineering | Colloid And Surface Chemistry | Condensed Matter Physics | Microbiology | Membrane and Separation Technologies | Animal Production | Microbiology (Excl. Virology) | Infectious Agents | Veterinary Microbiology (excl. Virology) | Nanotechnology | Bacteriology | Metals and Alloy Materials | Animal Protection (Pests and Pathogens) | Microbial Genetics | Electronic and Magnetic Properties of Condensed Matter; Superconductivity | Optics And Opto-Electronic Physics
ANZSRC Socio-Economic Objective (SEO)
Energy Conservation and Efficiency not elsewhere classified | Pigs | Management of Greenhouse Gas Emissions from Energy Activities (excl. Electricity Generation) | Management of Greenhouse Gas Emissions from Information and Communication Services | Infectious diseases | Manufacturing not elsewhere classified | Biological sciences | Chemical sciences | Physical sciences | Solar-Photovoltaic Energy | Digestive system and disorders | Pigs | Expanding Knowledge in the Agricultural and Veterinary Sciences | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Global evolutionary dynamics and resistome analysis of Clostridioides difficile ribotype 017
Publisher: Microbiology Society
Date: 22-03-2022
Abstract: Clostridioides difficile PCR ribotype (RT) 017 ranks among the most successful strains of C. difficile in the world. In the past three decades, it has caused outbreaks on four continents, more than other ‘epidemic’ strains, but our understanding of the genomic epidemiology underpinning the spread of C. difficile RT 017 is limited. Here, we performed high-resolution phylogenomic and Bayesian evolutionary analyses on an updated and more representative dataset of 282 non-clonal C. difficile RT 017 isolates collected worldwide between 1981 and 2019. These analyses place an estimated time of global dissemination between 1953 and 1983 and identified the acquisition of the ermB -positive transposon Tn 6194 as a key factor behind global emergence. This coincided with the introduction of clindamycin, a key inciter of C. difficile infection, into clinical practice in the 1960s. Based on the genomic data alone, the origin of C. difficile RT 017 could not be determined however, geographical data and records of population movement suggest that C. difficile RT 017 had been moving between Asia and Europe since the Middle Ages and was later transported to North America around 1860 (95 % confidence interval: 1622–1954). A focused epidemiological study of 45 clinical C. difficile RT 017 genomes from a cluster in a tertiary hospital in Thailand revealed that the population consisted of two groups of multidrug-resistant (MDR) C. difficile RT 017 and a group of early, non-MDR C. difficile RT 017. The significant genomic ersity within each MDR group suggests that although they were all isolated from hospitalized patients, there was probably a reservoir of C. difficile RT 017 in the community that contributed to the spread of this pathogen.
Prevalence of binary toxin positive Clostridium difficile in diarrhoeal humans in the absence of epidemic ribotype 027
Publisher: Public Library of Science (PLoS)
Date: 08-11-2017
Efficient delivery of oxygen via magnetic framework composites
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TA07739H
Abstract: Metal–organic frameworks (MOFs), with their intriguing network structures, large internal surface areas, and tunable pore properties offer the perfect yet largely unexplored alternative for selective adsorption of oxygen.
Can sequencing improve the diagnosis and management of Clostridioides difficile infection?
Publisher: Informa UK Limited
Date: 21-04-2021
Soft magnetic properties of Ge-doped nanocrystalline Fe–Zr–B alloys
Publisher: Elsevier BV
Date: 2003
Clostridioides (Clostridium) difficile in children with diarrhoea in Vietnam
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.ANAEROBE.2022.102550
Abstract: Clostridioides (Clostridium) difficile commonly causes hospital-acquired infection which can range from mild diarrhoea to life-threatening toxic megacolon and even death. Reports on C. difficile infection (CDI) in Vietnam are limited, so this study was designed to evaluate the prevalence, molecular epidemiology and antimicrobial susceptibility of C. difficile isolated from children with diarrhoea in Vietnam. Infants are often colonised with C. difficile and it was hypothesised that those colonising strains would represent strains of C. difficile circulating in the hospital/region at the time, however, this was not an attempt to determine if C. difficile was the cause of the diarrhoea. Diarrhoeal stool s les collected at two children's hospitals in northern Vietnam from October 1, 2020 to February 28, 2021 were transported to Perth, Western Australia, for culture of C. difficile and further investigations on isolates PCR ribotyping, toxin gene profiling and antimicrobial susceptibility testing. From these hospitals, 370 diarrhoeal stool s les were collected, most from children aged 1-15 months (71.9% 266/370). The overall prevalence of C. difficile in stool s les from children aged ≤16 years was 37.8% (140/370) and the highest prevalence was in the 2-12 months age group (52.9% 74/140). In total, 151 isolates of C. difficile were recovered the proportion of toxigenic isolates was 16.6% (25/151). Of the 25 toxigenic C. difficile isolates, the toxin gene profiles A The prevalence of C. difficile in children with diarrhoea was high (37.8%) although the proportion of toxigenic strains was comparatively low. The clinical significance of any isolate needs to be determined.
The Clostridioides difficile species problem: global phylogenomic analysis uncovers three ancient, toxigenic, genomospecies
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2020
DOI: 10.1101/2020.09.21.307223
Abstract: Clostridioides difficile infection (CDI) remains an urgent global One Health threat. The genetic heterogeneity seen across C. difficile underscores its wide ecological versatility and has driven the significant changes in CDI epidemiology seen in the last 20 years. We analysed an international collection of over 12,000 C. difficile genomes spanning the eight currently defined phylogenetic clades. Through whole-genome average nucleotide identity, pangenomic and Bayesian analyses, we identified major taxonomic incoherence with clear species boundaries for each of the recently described cryptic clades CI-III. The emergence of these three novel genomospecies predates clades C1-5 by millions of years, rewriting the global population structure of C. difficile specifically and taxonomy of the Peptostreptococcaceae in general. These genomospecies all show unique and highly ergent toxin gene architecture, advancing our understanding of the evolution of C. difficile and close relatives. Beyond the taxonomic ramifications, this work impacts the diagnosis of CDI worldwide.
Antimicrobial resistance in Clostridium difficile ribotype 017
Publisher: Informa UK Limited
Date: 06-12-2019
Genetically related Clostridium difficile from water sources and human CDI cases revealed by whole‐genome sequencing
Publisher: Wiley
Date: 24-10-2021
Abstract: Clostridium difficile isolates from the environment are closely related to those from humans, indicating a possible environmental transmission route for C. difficile infection (CDI). In this study, C. difficile was isolated from 47.3% (53/112) of lake ond, 23.0% (14/61) of river, 20.0% (3/15) of estuary and 0.0% (0/89) of seawater s les. The most common toxigenic strain isolated was C. difficile PCR ribotype (RT) 014/020 (10.5%, 8/76). All water isolates were susceptible to fidaxomicin, metronidazole, rifaximin, amoxicillin/clavulanic acid, moxifloxacin and tetracycline. Resistance to vancomycin, clindamycin, erythromycin and meropenem was detected in 5.3% (4/76), 26.3% (20/76), 1.3% (1/76) and 6.6% (5/76) of isolates, respectively. High‐resolution core‐genome analysis was performed on RT 014/020 isolates of water origin and 26 clinical RT 014/020 isolates from the same year and geographical location. Notably, both human and water strains were intermixed across three sequence types (STs), 2, 13 and 49. Six closely related groups with ≤10 core‐genome single nucleotide polymorphisms were identified, five of which comprised human and water strains. Overall, 19.2% (5/26) of human strains shared a recent genomic relationship with one or more water strains. This study supports the growing hypothesis that environmental contamination by C. difficile plays a role in CDI transmission.
Effect of Processing Parameters on the Magnetic Properties and Macrotexture of a Nd13.5Fe73.8Co6.7B5.6Ga0.4Alloy Processed by Equal Channel Angul
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2016
Performance evaluation of CuBTC composites for room temperature oxygen storage
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0RA07068H
Abstract: Oxygen is commonly separated from air using cryogenic liquefaction.
Clostridium difficile in soil conditioners, mulches and garden mixes with evidence of a clonal relationship with historical food and clinical isolates
Publisher: Wiley
Date: 07-10-2020
Spectrum of antibacterial activity and mode of action of a novel tris-stilbene bacteriostatic compound
Publisher: Springer Science and Business Media LLC
Date: 02-05-2018
DOI: 10.1038/S41598-018-25080-W
Abstract: The spectrum of activity and mode of action of a novel antibacterial agent, 135C , was investigated using a range of microbiological and genomic approaches. Compound 135C was active against Gram-positive bacteria with MICs for Staphylococcus aureus ranging from 0.12–0.5 μg/ml. It was largely inactive against Gram-negative bacteria. The compound showed bacteriostatic activity in time-kill studies and did not elicit bacterial cell leakage or cell lysis. Checkerboard assays showed no synergy or antagonism when 135C was combined with a range of other antibacterials. Multi-step serial passage of four S. aureus isolates with increasing concentrations of 135C showed that resistance developed rapidly and was stable after drug-free passages. Minor differences in the fitness of 135C -resistant strains and parent wildtypes were evident by growth curves, but 135C -resistant strains did not show cross-resistance to other antibacterial agents. Genomic comparison of resistant and wildtype parent strains showed changes in genes encoding cell wall teichoic acids. 135C shows promising activity against Gram-positive bacteria but is currently limited by the rapid resistance development. Further studies are required to investigate the effects on cell wall teichoic acids and to determine whether the issue of resistance development can be overcome.
Confinement-Induced Giant Spin–Orbit-Coupled Magnetic Moment of Co Nanoclusters in TiO2 Films
Publisher: American Chemical Society (ACS)
Date: 29-10-2019
Abstract: High magnetization materials are in great demand for the fabrication of advanced multifunctional magnetic devices. Notwithstanding this demand, the development of new materials with these attributes has been relatively slow. In this work, we propose a new strategy to achieve high magnetic moments above room temperature. Our material engineering approach invoked the embedding of magnetic nanoclusters in an oxide matrix. By precisely controlling pulsed laser deposition parameters, Co nanoclusters are formed in a 5 at % Co-TiO
Antimicrobial-resistant Bacteroides fragilis in Thailand and their inhibitory effect in vitro on the growth of Clostridioides difficile
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.ANAEROBE.2021.102505
Abstract: The aim of this study was to investigate antimicrobial-resistant Bacteroides fragilis in Thailand and possible effects of such strains on human health and disease. Phenotypic antimicrobial susceptibility testing was performed on 17 clinical B. fragilis isolates. The genome of one isolate was sequenced and analysed to explore its resistance genotype. An in vitro growth assay was conducted to evaluate the inhibitory effect of B. fragilis on Clostridioides difficile. There was a high prevalence of clindamycin (71%), meropenem (47%) and moxifloxacin (29%) resistance. Most strains remained susceptible to metronidazole, but one had high-level metronidazole resistance conferred by a nimD-containing plasmid. B. fragilis displayed an in vitro inhibitory effect on the growth of C. difficile and a drug-resistant strain retained this inhibition in the presence of clindamycin. Antimicrobial resistance was seen in Thai B. fragils isolates, which may help protect the host against C. difficile infection.
Major genetic discontinuity and novel toxigenic species in Clostridioides difficile taxonomy
Publisher: eLife Sciences Publications, Ltd
Date: 11-06-2021
DOI: 10.7554/ELIFE.64325
Abstract: Clostridioides difficile infection (CDI) remains an urgent global One Health threat. The genetic heterogeneity seen across C. difficile underscores its wide ecological versatility and has driven the significant changes in CDI epidemiology seen in the last 20 years. We analysed an international collection of over 12,000 C. difficile genomes spanning the eight currently defined phylogenetic clades. Through whole-genome average nucleotide identity, and pangenomic and Bayesian analyses, we identified major taxonomic incoherence with clear species boundaries for each of the recently described cryptic clades CI–III. The emergence of these three novel genomospecies predates clades C1–5 by millions of years, rewriting the global population structure of C. difficile specifically and taxonomy of the Peptostreptococcaceae in general. These genomospecies all show unique and highly ergent toxin gene architecture, advancing our understanding of the evolution of C. difficile and close relatives. Beyond the taxonomic ramifications, this work may impact the diagnosis of CDI.
Ridinilazole: a novel, narrow-spectrum antimicrobial agent targeting Clostridium (Clostridioides) difficile
Publisher: Oxford University Press (OUP)
Date: 09-2022
DOI: 10.1111/LAM.13664
Abstract: Clostridium (Clostridioides) difficile infection (CDI) remains an urgent threat to patients in health systems worldwide. Recurrent CDI occurs in up to 30% of cases due to sustained dysbiosis of the gut microbiota which normally protects against CDI. Associated costs of initial and recurrent episodes of CDI impose heavy financial burdens on health systems. Vancomycin and metronidazole have been the mainstay of therapy for CDI for many years however, these agents continue to cause significant disruption to the gut microbiota and thus carry a high risk of recurrence for CDI patients. Treatment regimens are now turning towards novel narrow spectrum antimicrobial agents which target C. difficile while conserving the commensal gut microbiota, thus significantly reducing risk of recurrence. One such agent, fidaxomicin, has been in therapeutic use for several years and is now recommended as a first-line treatment for CDI, as it is superior to vancomycin in reducing risk of recurrence. Another narrow spectrum agent, ridnilazole, was recently developed and is undergoing evaluation of its potential clinical utility. This review aimed to summarize experimental reports of ridinilazole and assess its potential as a first-line agent for treatment of CDI. Reported results from in vitro assessments, and from hamster models of CDI, show potent activity against C. difficile, non-inferiority to vancomycin for clinical cure and non-susceptibility among most gut commensal bacteria. Phase I and II clinical trials have been completed with ridinilazole showing high tolerability and efficacy in treatment of CDI, and superiority over vancomycin in reducing recurrence of CDI within 30 days of treatment completion. Phase III trials are currently underway, the results of which may prove its potential to reduce recurrent CDI and lessen the heavy health and financial burden C. difficile imposes on patients and healthcare systems.
Persistence of spore-formingClostridium(Clostridioides)difficilethrough wastewater treatment plants in Western Australia
Publisher: Cold Spring Harbor Laboratory
Date: 20-10-2022
DOI: 10.1101/2022.10.19.512806
Abstract: There is growing evidence that shows Clostridium ( Clostridioides ) difficile is a pathogen of One Health importance with a complex dissemination pathway involving animals, humans and the environment. Thus, environmental discharge and agricultural recycling of human and animal waste have been suspected as factors behind the dissemination of C. difficile in the community. Here, the presence of C. difficile in 12 wastewater treatment plants (WWTPs) in Western Australia was investigated. Overall, C. difficile was found in 90.5% (114/126) of raw sewage influent, 48.1% (50/104) of treated effluent, 40% (2/5) of reclaimed irrigation water, 100% (38/38) of untreated biosolids, 95.2% (20/21) of anaerobically digested biosolids and 72.7% (8/11) of lime-amended biosolids. Over half the isolates (55.3%, 157/284) were toxigenic and 97 C. difficile ribotypes (RTs) were identified with RT014/020 the most common (14.8%, 42/284). Thirteen C. difficile isolates with the toxin profile A+B+CDT+ were found, including the hypervirulent RT078 strain. Resistance to the antimicrobials fidaxomicin, vancomycin, metronidazole, rifaximin, amoxicillin/clavulanate, meropenem and moxifloxacin was uncommon, however, resistance to clindamycin, erythromycin and tetracycline was relatively frequent at 56.7% (161/284), 14.4% (41/284) and 13.7% (39/284), respectively. This study revealed that toxigenic C. difficile was commonly encountered in WWTPs and being released into the environment. This raises concern about the possible spill-over of C. difficile into animal and/or human populations via land receiving the treated waste. In Western Australia, stringent measures are in place to mitigate the health and environmental risk of recycling human waste, however, further studies are needed to elucidate the public health significance of C. difficile surviving the treatment processes at WWTPs. Clostridium difficile infection (CDI) is a leading cause of antimicrobial-associated diarrhoea in healthcare facilities. Extended hospital stays and recurrences increase the cost of treatment, and morbidity and mortality. Community-associated CDI (CA-CDI) cases, with no history of antimicrobial use or exposure to healthcare settings, are increasing. The isolation of clinically important C. difficile strains from animals, rivers, soil, meat, vegetables, compost, treated wastewater and biosolids has been reported. The objective of this study was to characterise C. difficile in wastewater treatment plants (WWTPs) in Australia. We found that C. difficile can persist through the treatment processes of WWTPs and toxigenic C. difficile was being released into the environment becoming a potential source/reservoir for CA-CDI.
Clostridium difficile in Asia: Opportunities for One Health Management
Publisher: MDPI AG
Date: 28-12-2018
DOI: 10.3390/TROPICALMED4010007
Abstract: Clostridium difficile is a ubiquitous spore-forming bacterium which causes toxin-mediated diarrhoea and colitis in people whose gut microflora has been depleted by antimicrobial use, so it is a predominantly healthcare-associated disease. However, there are many One Health implications to C. difficile, given high colonisation rates in food production animals, contamination of outdoor environments by use of contaminated animal manure, increasing incidence of community-associated C. difficile infection (CDI), and demonstration of clonal groups of C. difficile shared between human clinical cases and food animals. In Asia, the epidemiology of CDI is not well understood given poor testing practices in many countries. The growing middle-class populations of Asia are presenting increasing demands for meat, thus production farming, particularly of pigs, chicken and cattle, is rapidly expanding in Asian countries. Few reports on C. difficile colonisation among production animals in Asia exist, but those that do show high prevalence rates, and possible importation of European strains of C. difficile like ribotype 078. This review summarises our current understanding of the One Health aspects of the epidemiology of CDI in Asia.
Polyethylenimine–Silica–Magnetic Nanoparticle Composites for Efficient Extraction of Dissolved Copper from Aqueous Solutions and Multiphase Mixtures
Publisher: American Chemical Society (ACS)
Date: 23-02-2023
Clostridioides (Clostridium) difficile in adults with diarrhoea in Vietnam
Publisher: Elsevier BV
Date: 06-2023
Global evolutionary dynamics and resistome analysis of Clostridioides difficile ribotype 017
Publisher: Cold Spring Harbor Laboratory
Date: 05-07-2021
DOI: 10.1101/2021.07.04.451084
Abstract: Clostridioides difficile PCR ribotype (RT) 017 ranks among the most successful strains of C. difficile in the world. In the past three decades, it has caused outbreaks on four continents, more than other “epidemic” strains, however, our understanding of the genomic epidemiology underpinning the spread of C. difficile RT 017 is limited. Here, we performed high-resolution phylogenomic and Bayesian evolutionary analyses on an updated and more representative dataset of 282 non-clonal C. difficile RT 017 isolates collected worldwide between 1981 and 2019. These analyses place an estimated time of global dissemination between 1953 and 1983 and identified the acquisition of the ermB -positive transposon Tn6194 as a key factor behind global emergence. This coincided with the introduction of clindamycin, a key inciter of C. difficile infection, into clinical practice in the 1960s. Based on the genomic data alone, the origin of C. difficile RT 017 could not be determined, however, geographical data and records of population movement suggest that C. difficile RT 017 had been moving between Asia and Europe since the Middle Ages and was later transported to North America around 1860 (95% CI: 1622 – 1954). A focused epidemiological study of 45 clinical C. difficile RT 017 genomes from a cluster in a tertiary hospital in Thailand revealed that the population consisted of two groups of multidrug-resistant (MDR) C. difficile RT 017 and a group of early, non-MDR C. difficile RT 017. The significant genomic ersity within each MDR group suggests that although they were all isolated from hospitalised patients, there was likely a reservoir of C. difficile RT 017 in the community that contributed to the spread of this pathogen. This study utilises genomic sequence data from 282 non-clonal C. difficile ribotype (RT) 017 isolates collected from around the world to delineate the origin and spread of this epidemic lineage, as well as explore possible factors that have driven its success. It also reports a focused epidemiological investigation of a cluster of C. difficile RT 017 in a tertiary hospital in Thailand to identify possible sources of transmission in this specific setting. All new WGS data generated in this study has been submitted to the European Nucleotide Archive under the BioProject PRJEB44406 (s le accession ERS6268756 – ERS6268798). The complete genome of C. difficile MAR286 was submitted to GenBank under BioProject PRJNA679085 (accession CP072118 ). Details of all genomes included in the final analyses are available in the Supplementary Document , available at 10.6084/m9.figshare.14544792 .
Magnetic Induction Framework Synthesis: A General Route to the Controlled Growth of Metal-Organic Frameworks
Publisher: American Chemical Society (ACS)
Date: 14-06-2017
Effect of direct-current magnetic field on the specific absorption rate of metamagnetic CoMnSi: A potential approach to switchable hyperthermia therapy
Publisher: AIP Publishing
Date: 2020
DOI: 10.1063/1.5130398
Abstract: Materials with 1st order antiferromagnetic (AFM) to high-magnetization (MM) phase transition known for their inverse magnetocaloric effect, abrupt rise in magnetization and magnetoelastic coupling, are promising for application in combined simultaneous diagnosis and targeted cancer therapy. A therapy that combines alternating-current (ac) and direct-current (dc) magnetic fields for simultaneous magnetic hyperthermia therapy (MHT) and magnetic resonance imaging (MRI), using same magnetic particles for heating and as contrast agents. We report a proof-of-concept study on the induction heating ability of 1st order metamagnetic material with moderate specific absorption rates (SAR) and no tendency for agglomeration, for potential MHT and MRI cancer therapy. CoMnSi, a metamagnetic antiferromagnet (MM) was used in this study because of its desirable ability to rapidly switch from a low to high magnetization state in an applied dc bias field condition without particle agglomeration on field removal. The results showed that the magnetization switched from & 20 Am2kg-1 at 0.75 T to about 53.31 Am2kg-1 at 1.0 T applied dc field, a field large enough for magnetic resonance imaging. An SAR value of 10.7 Wg-1 was obtained under an ac field of 31.0 kAm-1 at 212.0 kHz. When combined with a dc bias field of 1.0 T, SAR values of 9.83 Wg-1 and 6.65 Wg-1 were obtained in the directions 45° and 90° away from the dc bias field direction respectively. These SAR values obtained from CoMnSi particles in the presence of simultaneous ac and dc magnetic field bias are in comparison, at least 25 times greater than those obtained from 2nd order magnetic phase transition Fe3O4 suspension. It is observed that Fe3O4 particles showed large suppression of SAR, and agglomeration under the same experimental conditions. This study shows the great potential of 1st order phase transition metamagnets for simultaneous MHT and MRI cancer therapy using MRI equipment.
Lead(ii ) uptake by aluminium based magnetic framework composites (MFCs) in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TA04154F
Abstract: MIL-53(Al) based magnetic framework composites with iron oxide nanoparticles exhibit high uptake of lead( ii ) from aqueous solution.
Towards energy efficient separations with metal organic frameworks
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CC00331A
Abstract: The huge energy requirement for industrial separations of chemical mixtures has necessitated the need for the development of energy efficient and alternative separation techniques in order to mitigate the negative environmental impacts associated with greenhouse gas emissions from fossil fuel combustions for energy generation.
Complete Genome Sequences of Evolutionary Clade C-III Strains of Clostridioides ( Clostridium ) difficile Isolated from the Environment in Western Australia
Publisher: American Society for Microbiology
Date: 17-05-2023
DOI: 10.1128/MRA.00239-23
Abstract: Clostridioides ( Clostridium ) difficile in the environment is thought to contribute to C. difficile infection in community settings. Here, we provide complete genome assemblies for two esculin hydrolysis-negative strains of C. difficile that were isolated from soils in Western Australia the strains produce white colonies on chromogenic media and belong to evolutionarily ergent clade C-III.
High Prevalence of Clostridium difficile in Home Gardens in Western Australia
Publisher: American Society for Microbiology
Date: 17-12-2020
DOI: 10.1128/AEM.01572-20
Abstract: Recently, community-associated Clostridium difficile infection (CA-CDI) has emerged as a significant problem, accounting for ∼50% of all CDI cases and reported to affect a younger population without traditional risk factors. Possible sources of CA-CDI are soil, food, and water contaminated by animal feces, and recent reports show overlapping ribotypes of C. difficile in animals, humans, and the environment however, the epidemiology of CA-CDI and related risk factors need to be better understood. Our research aimed to determine the prevalence of C. difficile in home gardens and on the shoe soles of homeowners in Perth, Western Australia. There were high rates of contamination with C. difficile in gardens, and some of the ribotypes identified had been isolated from human cases of CDI in Western Australia. This study shows that home gardens and shoes may be a source of C. difficile in CA-CDI.
Phase reduction of coated maghemite (γ-Fe 2 O 3 ) nanoparticles under microwave-induced plasma heating for rapid heat treatment
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1JM12524A
A species-wide genetic atlas of antimicrobial resistance in Clostridioides difficile
Publisher: Microbiology Society
Date: 18-11-2021
Abstract: Antimicrobial resistance (AMR) plays an important role in the pathogenesis and spread of Clostridioides difficile infection (CDI), the leading healthcare-related gastrointestinal infection in the world. An association between AMR and CDI outbreaks is well documented, however, data is limited to a few ‘epidemic’ strains in specific geographical regions. Here, through detailed analysis of 10 330 publicly-available C. difficile genomes from strains isolated worldwide (spanning 270 multilocus sequence types (STs) across all known evolutionary clades), this study provides the first species-wide snapshot of AMR genomic epidemiology in C. difficile . Of the 10 330 C . difficile genomes, 4532 (43.9 %) in 89 STs across clades 1–5 carried at least one genotypic AMR determinant, with 901 genomes (8.7 %) carrying AMR determinants for three or more antimicrobial classes (multidrug-resistant, MDR). No AMR genotype was identified in any strains belonging to the cryptic clades. C. difficile from Australia/New Zealand had the lowest AMR prevalence compared to strains from Asia, Europe and North America ( P .0001). Based on the phylogenetic clade, AMR prevalence was higher in clades 2 (84.3 %), 4 (81.5 %) and 5 (64.8 %) compared to other clades (collectively 26.9 %) ( P .0001). MDR prevalence was highest in clade 4 (61.6 %) which was over three times higher than in clade 2, the clade with the second-highest MDR prevalence (18.3 %). There was a strong association between specific AMR determinants and three major epidemic C. difficile STs: ST1 (clade 2) with fluoroquinolone resistance (mainly T82I substitution in GyrA) ( P .0001), ST11 (clade 5) with tetracycline resistance (various tet -family genes) ( P .0001) and ST37 (clade 4) with macrolide-lincosamide-streptogramin B (MLS B ) resistance (mainly ermB ) ( P .0001) and MDR ( P .0001). A novel and previously overlooked tetM -positive transposon designated Tn 6944 was identified, predominantly among clade 2 strains. This study provides a comprehensive review of AMR in the global C. difficile population which may aid in the early detection of drug-resistant C. difficile strains, and prevention of their dissemination worldwide.
Adaptation of host transmission cycle during Clostridium difficile speciation
Publisher: Springer Science and Business Media LLC
Date: 12-08-2019
DOI: 10.1038/S41588-019-0478-8
Abstract: Bacterial speciation is a fundamental evolutionary process characterized by erging genotypic and phenotypic properties. However, the selective forces that affect genetic adaptations and how they relate to the biological changes that underpin the formation of a new bacterial species remain poorly understood. Here, we show that the spore-forming, healthcare-associated enteropathogen Clostridium difficile is actively undergoing speciation. Through large-scale genomic analysis of 906 strains, we demonstrate that the ongoing speciation process is linked to positive selection on core genes in the newly forming species that are involved in sporulation and the metabolism of simple dietary sugars. Functional validation shows that the new C. difficile produces spores that are more resistant and have increased sporulation and host colonization capacity when glucose or fructose is available for metabolism. Thus, we report the formation of an emerging C. difficile species, selected for metabolizing simple dietary sugars and producing high levels of resistant spores, that is adapted for healthcare-mediated transmission.
Magnetic Metal-Organic Frameworks for Efficient Carbon Dioxide Capture and Remote Trigger Release
Publisher: Wiley
Date: 03-01-2016
Abstract: Magnetic metal-organic framework (MOF) composites show highly efficient CO2 desorption capacities upon their exposure to an alternating magnetic field, demonstrating a magnetic induction swing strategy for potentially low-energy regeneration of MOF adsorbents.
Comparative Study of the Magnetic Behavior of Spherical and Cubic Superparamagnetic Iron Oxide Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 20-12-2010
DOI: 10.1021/JP104953Z
The Brief Case: a White-Colony-Producing Clostridioides difficile Ribotype 020 Strain
Publisher: American Society for Microbiology
Date: 20-06-2023
DOI: 10.1128/JCM.00893-22
Effect of natural products on the production and activity of Clostridium difficile toxins in vitro
Publisher: Springer Science and Business Media LLC
Date: 24-10-2018
DOI: 10.1038/S41598-018-33954-2
Abstract: Clostridium difficile infection is a toxin-mediated disease of the colon. C . difficile virulence is primarily attributed to the production of toxin A and toxin B thus this study was aimed to investigate the effect of a range of natural products on the production and activity of C . difficile toxins in vitro . Twenty-two natural products were investigated against four C . difficile strains. The activity of products against toxins was determined using Vero and HT-29 cells cytotoxicity and neutral red uptake assays. The indirect effect of products on toxin-mediated cytotoxicity was determined using the same cell lines. The effect of seven products on toxin production by C . difficile was determined using ELISA. Zingerone (0.3 mg/ml) protected both cell lines from C . difficile cytopathic effects, confirmed by the neutral red uptake assay ( P 0.05). Three Leptospermum honeys (4% w/v), fresh onion bulb extract (12.5% v/v) and trans -cinnamaldehyde (0.005% v/v) all reduced toxin production and activity significantly ( P ≤ 0.023). Garlic clove powder (4.7 mg/ml) only reduced toxin activity ( P ≤ 0.047). Overall, several natural products had activity against C . difficile toxins in vitro encouraging further investigation against C . difficile toxins in vivo .
Genomic Analysis of Clostridioides difficile Recovered from Horses in Western Australia
Publisher: MDPI AG
Date: 03-07-2023
DOI: 10.3390/MICROORGANISMS11071743
Abstract: Clostridioides difficile poses an ongoing threat as a cause of gastrointestinal disease in humans and animals. Traditionally considered a human healthcare-related disease, increases in community-associated C. difficile infection (CDI) and growing evidence of inter-species transmission suggest a wider perspective is required for CDI control. In horses, C. difficile is a major cause of diarrhoea and life-threatening colitis. This study aimed to better understand the epidemiology of CDI in Australian horses and provide insights into the relationships between horse, human and environmental strains. A total of 752 faecal s les from 387 Western Australian horses were collected. C. difficile was isolated from 104 (30.9%) horses without gastrointestinal signs and 19 (37.8%) with gastrointestinal signs. Of these, 68 (55.3%) harboured one or more toxigenic strains, including C. difficile PCR ribotypes (RTs) 012 (n = 14), 014/020 (n = 10) and 087 (n = 7), all prominent in human infection. Whole-genome analysis of 45 strains identified a phylogenetic cluster of 10 closely related C. difficile RT 012 strains of equine, human and environmental origin (0–62 SNP differences average 23), indicating recent shared ancestry. Evidence of possible clonal inter-species transmission or common-source exposure was identified for a subgroup of three horse and one human isolates, highlighting the need for a One Health approach to C. difficile surveillance.
Cationic Peptidomimetic Amphiphiles Having a N-Aryl- or N-Naphthyl-1,2,3-Triazole Core Structure Targeting Clostridioides (Clostridium) difficile: Synthesis, Antibacterial Evaluation, and an In Vivo C. difficile Infection Model
Publisher: MDPI AG
Date: 26-07-2021
DOI: 10.3390/ANTIBIOTICS10080913
Abstract: Clostridioides (also known as Clostridium) difficile is a Gram-positive anaerobic, spore producing bacterial pathogen that causes severe gastrointestinal infection in humans. The current chemotherapeutic options are inadequate, expensive, and limited, and thus inexpensive drug treatments for C. difficile infection (CDI) with improved efficacy and specificity are urgently needed. To improve the solubility of our cationic hiphilic 1,1′-binaphthylpeptidomimetics developed earlier that showed promise in an in vivo murine CDI model we have synthesized related compounds with an N-arytriazole or N-naphthyltriazole moiety instead of the 1,1′-biphenyl or 1,1′-binaphthyl moiety. This modification was made to increase the polarity and thus water solubility of the overall peptidomimetics, while maintaining the aromatic character. The dicationic N-naphthyltriazole derivative 40 was identified as a C. difficile-selective antibacterial with MIC values of 8 µg/mL against C. difficile strains ATCC 700057 and 132 (both ribotype 027). This compound displayed increased water solubility and reduced hemolytic activity (32 µg/mL) in an in vitro hemolysis assay and reduced cytotoxicity (CC50 32 µg/mL against HEK293 cells) relative to lead compound 2. Compound 40 exhibited mild efficacy (with 80% survival observed after 24 h compared to the DMSO control of 40%) in an in vivo murine model of C. difficile infection by reducing the severity and slowing the onset of disease.
Different molecular characteristics and antimicrobial resistance profiles of Clostridium difficile in the Asia-Pacific region
Publisher: Informa UK Limited
Date: 2019
Complete Genome Assemblies of Three Highly Prevalent, Toxigenic Clostridioides difficile Strains Causing Health Care-Associated Infections in Australia
Publisher: American Society for Microbiology
Date: 05-08-2021
DOI: 10.1128/MRA.00599-21
Abstract: Clostridioides difficile infection (CDI) is the leading cause of life-threatening health care-related gastrointestinal illness worldwide. Phylogenetically appropriate closed reference genomes are essential for studies of C. difficile transmission and evolution. Here, we provide high-quality complete hybrid genome assemblies for the three most prevalent C. difficile strains causing CDI in Australia.
Synthesis and electromagnetic interference shielding properties of iron oxide/polypyrrole nanocomposites
Publisher: Wiley
Date: 20-09-2011
DOI: 10.1002/PEN.21813
Environmental contamination with Clostridioides (Clostridium) difficile in Vietnam
Publisher: Oxford University Press (OUP)
Date: 06-2023
Abstract: To investigate the prevalence, molecular type, and antimicrobial susceptibility of Clostridioides difficile in the environment in Vietnam, where little is known about C. difficile. S les of pig faeces, soils from pig farms, potatoes, and the hospital environment were cultured for C. difficile. Isolates were identified and typed by polymerase chain reaction (PCR) ribotyping. The overall prevalence of C. difficile contamination was 24.5% (68/278). Clostridioides difficile was detected mainly in soils from pig farms and hospital soils, with 70%–100% prevalence. Clostridioides difficile was isolated from 3.4% of pig faecal s les and 5% of potato surfaces. The four most prevalent ribotypes (RTs) were RTs 001, 009, 038, and QX574. All isolates were susceptible to metronidazole, fidaxomicin, vancomycin, and amoxicillin/clavulanate, while resistance to erythromycin, tetracycline, and moxifloxacin was common in toxigenic strains. Clostridioides difficile RTs 001A+B+CDT– and 038A–B–CDT– were predominantly multidrug resistant. Environmental sources of C. difficile are important to consider in the epidemiology of C. difficile infection in Vietnam, however, contaminated soils are likely to be the most important source of C. difficile. This poses additional challenges to controlling infections in healthcare settings.
Whole-genome sequencing links Clostridium (Clostridioides) difficile in a single hospital to diverse environmental sources in the community
Publisher: Oxford University Press (OUP)
Date: 09-2022
DOI: 10.1111/JAM.15408
Abstract: To investigate if Clostridium (Clostridioides) difficile infection (CDI), traditionally thought of as hospital-acquired, can be genomically linked to hospital or community environmental sources, and to define possible importation routes from the community to the hospital. In 2019, C. difficile was isolated from 89/300 (29.7%) floor and 96/300 (32.0%) shoe sole s les at a tertiary hospital in Western Australia. Non-toxigenic C. difficile ribotype (RT) 010 predominated among floor (96.6%) and shoe sole (73.2%) isolates, while toxigenic RT 014/020 was most prevalent among contemporaneous clinical cases (33.0%) at the hospital. Whole-genome sequencing and high-resolution core genome single nucleotide polymorphism (cgSNP) analysis on C. difficile strains from hospital and community sources showed no clinical C. difficile RT 014/020 strains were genetically related, and evidence of frequent long-distance, multi-directional spread between humans, animals and the environment. In addition, cgSNP analysis of environmental RT 010 strains suggested transportation of C. difficile via shoe soles. While C. difficile RT 014/020 appears to spread via routes outside the healthcare system, RT 010 displayed a pattern of possible importation from the community into the hospital. These findings suggest developing community-based infection prevention and control strategies could significantly lower rates of CDI in the hospital setting.
MaLISA - a cooperative method to release adsorbed gases from metal-organic frameworks
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA09826F
Abstract: A dual stimuli-responsive metal–organic framework exhibits a cooperatively enhanced gas desorption capacity upon simultaneously exposing it to both UV light and an alternating magnetic field, highlighting a low-energy yet highly efficient strategy to regenerate MOF adsorbents.
Clostridium difficile ribotype 017 – characterization, evolution and epidemiology of the dominant strain in Asia
Publisher: Informa UK Limited
Date: 2019
A Gallium-Based Magnetocaloric Liquid Metal Ferrofluid.
Publisher: American Chemical Society (ACS)
Date: 07-11-2017
DOI: 10.1021/ACS.NANOLETT.7B04050
Abstract: We demonstrate a magnetocaloric ferrofluid based on a gadolinium saturated liquid metal matrix, using a gallium-based liquid metal alloy as the solvent and suspension medium. The material is liquid at room temperature, while exhibiting spontaneous magnetization and a large magnetocaloric effect. The magnetic properties were attributed to the formation of gadolinium nanoparticles suspended within the liquid gallium alloy, which acts as a reaction solvent during the nanoparticle synthesis. High nanoparticle weight fractions exceeding 2% could be suspended within the liquid metal matrix. The liquid metal ferrofluid shows promise for magnetocaloric cooling due to its high thermal conductivity and its liquid nature. Magnetic and thermoanalytic characterizations reveal that the developed material remains liquid within the temperature window required for domestic refrigeration purposes, which enables future fluidic magnetocaloric devices. Additionally, the observed formation of nanometer-sized metallic particles within the supersaturated liquid metal solution has general implications for chemical synthesis and provides a new synthetic pathway toward metallic nanoparticles based on highly reactive rare earth metals.
Continuous Flow Synthesis of a Zr Magnetic Framework Composite for Post‐Combustion CO2 Capture
Publisher: Wiley
Date: 13-09-2019
Abstract: Metal-organic frameworks (MOFs) have an unprecedented ability to store gas molecules, however energy efficient regeneration remains challenging. Use of magnetic induction to aid this shows promise, but economical synthesis of the requisite composites is unresolved. Continuous flow chemistry has been reported as a rapid and reliable method of MOF synthesis, delivering step-change improvements in space time yields (STY). Here the scalable production of nanomaterials suitable for regeneration by magnetic induction is demonstrated. The zirconium MOF composite, MgFe
Decomposition behaviour of amorphous Fe89 xZr7B3Cu1Gexalloys
Publisher: IOP Publishing
Date: 11-02-2004
Spore-Forming Clostridium (Clostridioides) difficile in Wastewater Treatment Plants in Western Australia
Publisher: American Society for Microbiology
Date: 14-02-2023
DOI: 10.1128/SPECTRUM.03582-22
Abstract: Clostridium difficile infection (CDI) is a leading cause of antimicrobial-associated diarrhea in health care facilities. Extended hospital stays and recurrences increase the cost of treatment and morbidity and mortality.
Laboratory-Based Surveillance of Clostridium difficile Infection in Australian Health Care and Community Settings, 2013 to 2018
Publisher: American Society for Microbiology
Date: 21-10-2020
DOI: 10.1128/JCM.01552-20
Abstract: In the early 2000s, a binary toxin (CDT)-producing strain of Clostridium difficile , ribotype 027 (RT027), caused extensive outbreaks of diarrheal disease in North America and Europe. This strain has not become established in Australia, and there is a markedly different repertoire of circulating strains there compared to other regions of the world. The C. difficile Antimicrobial Resistance Surveillance (CDARS) study is a nationwide longitudinal surveillance study of C. difficile infection (CDI) in Australia.
Clostridioides difficile infection in Africa: A narrative review
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.ANAEROBE.2022.102549
Abstract: Clostridioides (Clostridium) difficile infection (CDI) places a burden on healthcare facilities worldwide. Most research studies have been concentrated in high-income countries in North America, Europe, Asia and Australia, where C. difficile is the leading cause of diarrhoea associated with antimicrobial use. This narrative review summarises African CDI studies, focussing on reports published in the last 20 years. Although relatively sparse, the data suggest that CDI is an important cause of diarrhoea on the continent. African CDI patient populations are often younger than in European and North American settings, probably due to the high prevalence of co-morbid conditions such as tuberculosis, particularly in sub-Saharan Africa. Strain typing data are rare and where reported generally limited to single sites and institutions. Despite challenges, including a lack of facilities and awareness, there is a need for further investigation to more accurately determine the true burden of disease caused by C. difficile in Africa.
Magnetic Framework Composites for Low Concentration Methane Capture
Publisher: American Chemical Society (ACS)
Date: 16-04-2018
Antibiotics and hospital-associatedClostridioides difficileinfection: systematic review and meta-analysis 2020 update
Publisher: Cold Spring Harbor Laboratory
Date: 23-02-2021
DOI: 10.1101/2021.02.21.21252172
Abstract: Clostridioides difficile infection (CDI) is the most common cause of healthcare facility-associated (HCFA) infectious diarrhoea in high-income countries. Antibiotic use is the most important modifiable risk factor for CDI. The most recent systematic review covered studies published until 31 st December 2012. To update the evidence for epidemiological associations between specific antibiotic classes and HCFA-CDI for the period 1 st January 2013 to 31 st December 2020. PubMed, Scopus, Web of Science Core Collection, WorldCat, and Proquest Dissertations and Theses. Eligible studies were those conducted among adult hospital inpatients, measured exposure to in idual antibiotics or antibiotic classes, included a comparison group, and measured the occurrence of HCFA-CDI as an outcome. The Newcastle–Ottawa Scale for the Assessment of Quality was used to appraise study quality. To assess the association between each antibiotic class and HA-CDI, a pooled random effects meta-analysis was undertaken. Metaregression and sub-group analysis was used to investigate study characteristics identified a priori as potential sources of heterogeneity. Carbapenems, and 3 rd and 4 th generation cephalosporin antibiotics remain most strongly associated with HCFA-CDI, with cases more than twice as likely to have recent exposure to these antibiotics prior to developing CDI. Modest associations were observed for fluoroquinolones clindamycin, and beta-lactamase inhibitor combination penicillin antibiotics. In idual study effect sizes were variable and heterogeneity was observed for most antibiotic classes. Availability of a single reviewer to select, extract and critically appraise the studies. This review provides the most up to date synthesis of evidence in relation to the risk of HCFA-CDI associated with exposure to specific antibiotic classes. Studies were predominantly conducted in North America or Europe and more studies outside of these settings are needed. Prospero CRD42020181817
Hepatitis C testing and re-testing among people attending sexual health services in Australia, and hepatitis C incidence among people with human immunodeficiency virus: analysis of national sentinel s
Publisher: Springer Science and Business Media LLC
Date: 12-2017
Colossal Magnetization and Giant Coercivity in Ion-Implanted (Nb and Co) MoS2 Crystals
Publisher: American Chemical Society (ACS)
Date: 16-12-2020
Bifunctional Fe3O4@AuNWs particle as wearable bending and strain sensor
Publisher: Elsevier BV
Date: 06-2019
The use of plasma treatment for simultaneous carbonization and reduction of iron oxide/polypyrrole core/shell nanoparticles
Publisher: Springer Science and Business Media LLC
Date: 19-09-2012
Esculin hydrolysis negative and TcdA-only producing strains of Clostridium (Clostridioides) difficile from the environment in Western Australia
Publisher: Oxford University Press (OUP)
Date: 09-2022
DOI: 10.1111/JAM.15500
Abstract: Clostridium (Clostridiodes) difficile clade 3 ribotype (RT) 023 strains that fail to produce black colonies on bioMérieux ChromID agar have been reported, as well as variant strains of C. difficile that produce only toxin A. We have recently isolated strains of C. difficile from the environment in Western Australia (WA) with similar characteristics. The objective of this study was to characterize these strains. It was hypothesized that a putative β-glucosidase gene was lacking in these strains of C. difficile, including RT 023, leading to white colonies. A total of 17 environmental isolates of C. difficile from garden soil and compost, and gardening shoe soles in Perth, WA, failed to produce black colonies on ChromID agar. MALDI-TOF MS analysis confirmed these strains as C. difficile. Four strains contained only a tcdA gene (A+B−CDT−) by PCR and were a novel RT (QX 597). All isolates were susceptible to all antimicrobials tested except one with low-level resistance to clindamycin (MIC = 8 mg/L). The four tcdA-positive strains were motile. All isolates contained neither bgl locus but only bgl K or a putative β-glucosidase gene by PCR. Whole-genome sequencing showed the 17 strains belonged to novel multi-locus sequence types 632, 848, 849, 850, 851, 852 and 853, part of the evolutionarily ergent clade C-III. Four isolates carried a full-length tcdA but not tcdB nor binary toxin genes. ChromID C. difficile agar is used for the specific detection of C. difficile in the s les. To date, all strains except RT 023 strains from clinical s les hydrolyse esculin. This is the first report to provide insights into the identification of esculin hydrolysis negative and TcdA-only producing (A+B−CDT−) strains of C. difficile from environmental s les. White colonies of C. difficile from environmental s les could be overlooked when using ChromID C. difficile agar, leading to false-negative results, however, whether these strains are truly pathogenic remains to be proven.
Author response: Major genetic discontinuity and novel toxigenic species in Clostridioides difficile taxonomy
Publisher: eLife Sciences Publications, Ltd
Date: 15-02-2021
Molecular characterisation of, and antimicrobial resistance in, Clostridioides difficile from Thailand, 2017-2018
Publisher: Cold Spring Harbor Laboratory
Date: 12-11-2020
DOI: 10.1101/2020.11.12.379040
Abstract: Antimicrobial resistance (AMR) plays an important role in the pathogenesis and spread of Clostridioides difficile infection (CDI). Many antimicrobials, such as fluoroquinolones, have been associated with outbreaks of CDI globally. This study aimed to characterise AMR among clinical C. difficile strains in Thailand, a country where the use of antimicrobials remains inadequately regulated. Stool s les were screened for tcdB and positives were cultured. C. difficile isolates were characterised by toxin profiling and PCR ribotyping. Antimicrobial susceptibility testing was performed using an agar incorporation method, and whole-genome sequencing and AMR genotyping performed on a subset of strains. There were 321 C. difficile strains isolated from 326 stool s les. The most common toxigenic ribotype (RT) was RT 017 (18%), followed by RTs 014 (12%) and 020 (7%). There was a high resistance prevalence (≥ 10%) to clindamycin, erythromycin, moxifloxacin and rifaximin, and resistance prevalence was greatest among RT 017 strains. AMR genotyping revealed a strong correlation between resistance genotype and phenotype for moxifloxacin and rif icin. The presence of erm -class genes was associated with high-level clindamycin and erythromycin resistance. Point substitutions on the penicillin-binding proteins (PBP1 and PBP3) were not sufficient to confer meropenem resistance, however, a Y721S substitution in PBP3 was associated with a slight increase in meropenem MIC. No resistance to metronidazole, vancomycin or fidaxomicin was observed. There was a large proportion of C. difficile RT 017 in Thailand and a high AMR prevalence among these strains. The concordance between AMR phenotype and genotype was strong.
Magnetic Induction Swing Adsorption: An Energy Efficient Route to Porous Adsorbent Regeneration
Publisher: American Chemical Society (ACS)
Date: 17-08-2016
Biogeographic distribution and molecular epidemiology of Clostridioides ( Clostridium ) difficile in Western Australian soils
Publisher: American Society for Microbiology
Date: 31-10-2023
DOI: 10.1128/AEM.00379-23
Clostridioides difficile infection in the Asia-Pacific region
Publisher: Informa UK Limited
Date: 24-12-2019
Mild or Malign: Clinical Characteristics and Outcomes of Clostridium difficile Infection in Thailand
Publisher: American Society for Microbiology
Date: 24-08-2020
DOI: 10.1128/JCM.01217-20
Abstract: Little is known about the clinical characteristics of Clostridium difficile infection (CDI) in Asia in general, and Thailand specifically, with a few studies suggesting that the disease may be milder than elsewhere. This study aimed to describe CDI in Thailand, evaluate treatment options and their outcomes, and explore possible protective factors responsible for any unique disease characteristics. From 2015 to 2018, 469 patients were included in the study. All patients had their stools tested for the tcdB gene by direct PCR and detection of toxigenic C. difficile by culture.
A species-wide genetic atlas of antimicrobial resistance in Clostridioides difficile
Publisher: Cold Spring Harbor Laboratory
Date: 15-06-2021
DOI: 10.1101/2021.06.14.448453
Abstract: Antimicrobial resistance (AMR) plays an important role in the pathogenesis and spread of Clostridioides difficile infection (CDI), the leading healthcare-related gastrointestinal infection in the world. An association between AMR and CDI outbreaks is well documented, however, data is limited to a few ‘epidemic’ strains in specific geographical regions. Here, through detailed analysis of 10,330 publicly-available C. difficile genomes from strains isolated worldwide (spanning 270 multilocus sequence types (STs) across all known evolutionary clades), this study provides the first species-wide snapshot of AMR genomic epidemiology in C. difficile . Of the 10,330 C. difficile genomes, 4,532 (43.9%) in 89 STs across clades 1 – 5 carried at least one genotypic AMR determinant, with 901 genomes (8.7%) carrying AMR determinants for three or more antimicrobial classes (multidrug-resistant, MDR). No AMR genotype was identified in any strains belonging to the cryptic clades. C. difficile from Australia/New Zealand had the lowest AMR prevalence compared to strains from Asia, Europe and North America (p .0001). Based on the phylogenetic clade, AMR prevalence was higher in clades 2 (84.3%), 4 (81.5%) and 5 (64.8%) compared to other clades (collectively 26.9%) (p .0001). MDR prevalence was highest in clade 4 (61.6%) which was over three times higher than in clade 2, the clade with the second-highest MDR prevalence (18.3%). There was a strong association between specific AMR determinants and three major epidemic C. difficile STs: ST1 (clade 2) with fluoroquinolone resistance (mainly T82I substitution in GyrA) (p .0001), ST11 (clade 5) with tetracycline resistance (various tet -family genes) (p .0001) and ST37 (clade 4) with macrolide-lincosamide-streptogramin B (MLS B ) resistance (mainly ermB ) (p .0001) and MDR (p .0001). A novel and previously overlooked tetM -positive transposon designated Tn 6944 was identified, predominantly among clade 2 strains. This study provides a comprehensive review of AMR in the global C. difficile population which may aid in the early detection of drug-resistant C. difficile strains, and prevention of their dissemination world-wide. Utilising a publicly-available database of 10,330 sequence reads, this study provides the first species-wide evaluation of genotypic AMR in C. difficile . It reports the most common AMR determinants and their genomic neighbourhood, associations between important genotypes and specific strains or geographical regions, and rare AMR genotypes that may have been missed in earlier studies. This study utilises publicly available raw sequence reads available at the NCBI Sequence Read Archive (SRA) as of January 2020. The details of all genomes are available in the Supplementary Data ( 10.6084/m9.figshare.14623533 ).
A genomic survey of Clostridioides difficile isolates from hospitalized patients in Melbourne, Australia
Publisher: American Society for Microbiology
Date: 10-10-2023
Engineered Porous Nanocomposites That Deliver Remarkably Low Carbon Capture Energy Costs
Publisher: Elsevier BV
Date: 06-2020
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