ORCID Profile
0000-0002-6492-6983
Current Organisations
Sheffield Hallam University
,
University of Melbourne
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Publisher: Elsevier BV
Date: 11-2018
Publisher: Elsevier BV
Date: 08-2021
Publisher: Springer Science and Business Media LLC
Date: 27-05-2019
Publisher: Frontiers Media SA
Date: 05-02-2019
Publisher: American Society of Tropical Medicine and Hygiene
Date: 05-2019
Publisher: Elsevier BV
Date: 07-2021
Publisher: Public Library of Science (PLoS)
Date: 05-06-2020
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.VETMIC.2018.10.022
Abstract: Clostridium perfringens is the etiological agent of necrotic enteritis in chickens. As necrotic enteritis is a gastrointestinal disease, the interactions of pathogenic C. perfringens strains with the complex microbiota of the gastrointestinal tract may influence disease development and severity of disease. In this study the interactions of a pathogenic strain of C. perfringens, WER-NE36, with the microbiota of broilers was investigated to determine whether the pre-existing microbiota could influence disease outcomes in the necrotic enteritis challenge model. Methods and approach: Faecal microbiota compositions were measured before and after C. perfringens challenge and caecal microbiota was also characterised at necropsy. The microbiota profiles from in idual birds were related back to the degree of necrotic enteritis that each bird developed. Under the experimental conditions used the pre-existing microbiota did not have an effect on disease outcomes. However, C. perfringens challenge was shown to have a significant effect on the microbiota of broilers, regardless of disease status, by displacement of commensal clostridia. The microbiota signature after challenge resembled that of lower productivity birds, supporting the finding that physically obvious disease (necrotic lesions), as well as dysbiosis, are associated with shifts in gut microbiota and affect broiler performance, increasing costs to the poultry industry.
Publisher: Springer Science and Business Media LLC
Date: 22-05-2018
Publisher: Springer Science and Business Media LLC
Date: 30-11-2022
DOI: 10.1038/S41467-022-34243-3
Abstract: Described antimicrobial resistance mechanisms enable bacteria to avoid the direct effects of antibiotics and can be monitored by in vitro susceptibility testing and genetic methods. Here we describe a mechanism of sulfamethoxazole resistance that requires a host metabolite for activity. Using a combination of in vitro evolution and metabolic rescue experiments, we identify an energy-coupling factor (ECF) transporter S component gene ( thfT ) that enables Group A Streptococcus to acquire extracellular reduced folate compounds. ThfT likely expands the substrate specificity of an endogenous ECF transporter to acquire reduced folate compounds directly from the host, thereby bypassing the inhibition of folate biosynthesis by sulfamethoxazole. As such, ThfT is a functional equivalent of eukaryotic folate uptake pathways that confers very high levels of resistance to sulfamethoxazole, yet remains undetectable when Group A Streptococcus is grown in the absence of reduced folates. Our study highlights the need to understand how antibiotic susceptibility of pathogens might function during infections to identify additional mechanisms of resistance and reduce ineffective antibiotic use and treatment failures, which in turn further contribute to the spread of antimicrobial resistance genes amongst bacterial pathogens.
Publisher: Elsevier BV
Date: 10-2018
Publisher: MDPI AG
Date: 18-11-2022
DOI: 10.3390/HEALTHCARE10112310
Abstract: Representative epidemiologic data on the average volume of the parotid gland in a large population-based MRI survey is non-existent. Within the Study of Health in Pomerania (SHIP), we examined the parotid gland in 1725 non-contrast MRI-scans in T1 weighted sequence of axial layers. Thus, a reliable standard operating procedure (Intraclass Correlation Coefficient 0.8) could be established. In this study, we found an average, single sided parotid gland volume of 27.82 cm3 (95% confidence interval (CI) 27.15 to 28.50) in male and 21.60 cm3 (95% CI 21.16 to 22.05) in female subjects. We observed positive associations for age, body mass index (BMI), as well as male sex with parotid gland size in a multivariate model. The prevalence of incidental tumors within the parotid gland regardless of dignity was 3.94% in the Northeast German population, slightly higher than assumed. Further epidemiologic investigations regarding primary salivary gland diseases are necessary.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Informa UK Limited
Date: 03-05-2016
DOI: 10.1080/03079457.2016.1153799
Abstract: The investigation of genomic variation between Clostridium perfringens isolates from poultry has been an important tool to enhance our understanding of the genetic basis of strain pathogenicity and the epidemiology of virulent and avirulent strains within the context of necrotic enteritis (NE). The earliest studies used whole genome profiling techniques such as pulsed-field gel electrophoresis to differentiate isolates and determine their relative levels of relatedness. DNA sequencing has been used to investigate genetic variation in (a) in idual genes, such as those encoding the alpha and NetB toxins (b) panels of housekeeping genes for multi-locus sequence typing and (c) most recently whole genome sequencing to build a more complete picture of genomic differences between isolates. Conclusions drawn from these studies include: differential carriage of large conjugative plasmids accounts for a large proportion of inter-strain differences plasmid-encoded genes are more highly conserved than chromosomal genes, perhaps indicating a relatively recent origin for the plasmids isolates from NE-affected birds fall into three distinct sequence-based clades while non-pathogenic isolates from healthy birds tend to be more genomically erse. Overall, the NE causing strains are closely related to C. perfringens isolates from other birds and other diseases whereas the non-pathogenic poultry strains are generally more remotely related to either the pathogenic strains or the strains from other birds. Genomic analysis has indicated that genes in addition to netB are associated with NE pathogenic isolates. Collectively, this work has resulted in a deeper understanding of the pathogenesis of this important poultry disease.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-11-2020
DOI: 10.1126/SCITRANSLMED.ABB3791
Abstract: The hydroxyquinoline analog PBT2 breaks resistance to polymyxin class antibiotics in polymyxin-resistant Gram-negative bacteria.
Publisher: MDPI AG
Date: 29-01-2019
Abstract: Clostridium perfringens causes a wide range of diseases in a variety of hosts, due to the production of a erse set of toxins and extracellular enzymes. The C. perfringens toxins play an important role in pathogenesis, such that the presence and absence of the toxins is used as a typing scheme for the species. In recent years, several new toxins have been discovered that have been shown to be essential or highly correlated to diseases these include binary enterotoxin (BecAB), NetB and NetF. In the current study, genome sequence analysis of C. perfringens isolates from erse sources revealed several putative novel toxin homologs, some of which appeared to be associated with potential mobile genetic elements, including transposons and plasmids. Four novel toxin homologs encoding proteins related to the pore-forming Leukocidin/Hemolysin family were found in type A and G isolates. Two novel toxin homologs encoding proteins related to the epsilon aerolysin-like toxin family were identified in Type A and F isolates from humans, contaminated food and turkeys. A novel set of proteins related to clostridial binary toxins was also identified. While phenotypic characterisation is required before any of these homologs can be established as functional toxins, the in silico identification of these novel homologs on mobile genetic elements suggests the potential toxin reservoir of C. perfringens may be much larger than previously thought.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Elsevier BV
Date: 08-2023
Publisher: Springer Science and Business Media LLC
Date: 19-09-2020
Publisher: Springer Science and Business Media LLC
Date: 24-02-2023
DOI: 10.1038/S41467-023-36717-4
Abstract: A new variant of Streptococcus pyogenes serotype M1 (designated ‘M1 UK ’) has been reported in the United Kingdom, linked with seasonal scarlet fever surges, marked increase in invasive infections, and exhibiting enhanced expression of the superantigen SpeA. The progenitor S. pyogenes ‘M1 global ’ and M1 UK clones can be differentiated by 27 SNPs and 4 indels, yet the mechanism for speA upregulation is unknown. Here we investigate the previously unappreciated expansion of M1 UK in Australia, now isolated from the majority of serious infections caused by serotype M1 S. pyogenes . M1 UK sub-lineages circulating in Australia also contain a novel toxin repertoire associated with epidemic scarlet fever causing S. pyogenes in Asia. A single SNP in the 5’ transcriptional leader sequence of the transfer-messenger RNA gene ssrA drives enhanced SpeA superantigen expression as a result of ssrA terminator read-through in the M1 UK lineage. This represents a previously unappreciated mechanism of toxin expression and urges enhanced international surveillance.
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 10-2019
Publisher: American Society for Microbiology
Date: 31-05-2019
DOI: 10.1128/MICROBIOLSPEC.GPP3-0033-2018
Abstract: Whole-genome sequences are now available for all the clinically important clostridia and many of the lesser or opportunistically pathogenic clostridia. The complex clade structures of C. difficile , C. perfringens , and the species that produce botulinum toxins have been delineated by whole-genome sequence analysis. The true clostridia of cluster I show relatively low levels of gross genomic rearrangements within species, in contrast to the species of cluster XI, notably C. difficile , which have been found to have very plastic genomes with significant levels of chromosomal rearrangement. Throughout the clostridial phylotypes, a large proportion of the strain ersity is driven by the acquisition and loss of mobile elements, including phages, plasmids, insertion sequences, and transposons. Genomic analysis has been used to investigate the ersity and spread of C. difficile within hospital settings, the zoonotic transfer of isolates, and the emergence, origins, and geographic spread of epidemic ribotypes. In C. perfringens the clades defined by chromosomal sequence analysis show no indications of clustering based on host species or geographical location. Whole-genome sequence analysis helps to define the different survival and pathogenesis strategies that the clostridia use. Some, such as C. botulinum , produce toxins which rapidly act to kill the host, whereas others, such as C. perfringens and C. difficile , produce less lethal toxins which can damage tissue but do not rapidly kill the host. The genomes provide a resource that can be mined to identify potential vaccine antigens and targets for other forms of therapeutic intervention.
Publisher: American Society for Microbiology
Date: 15-12-2017
DOI: 10.1128/AEM.01814-17
Abstract: Clostridium perfringens is a gastrointestinal pathogen capable of causing disease in a variety of hosts. Necrotic enteritis in chickens is caused by C. perfringens strains that produce the pore-forming toxin NetB, the major virulence factor for this disease. Like many other C. perfringens toxins and antibiotic resistance genes, NetB is encoded on a conjugative plasmid. Conjugative transfer of the netB -containing plasmid pJIR3535 has been demonstrated in vitro with a netB -null mutant. This study has investigated the effect of plasmid transfer on disease pathogenesis, with two genetically distinct transconjugants constructed under in vitro conditions, within the intestinal tract of chickens. This study also demonstrates that plasmid transfer can occur naturally in the host gut environment without the need for antibiotic selective pressure to be applied. The demonstration of plasmid transfer within the chicken host may have implications for the progression and pathogenesis of C. perfringens -mediated disease. Such horizontal gene transfer events are likely to be common in the clostridia and may be a key factor in strain evolution, both within animals and in the wider environment. IMPORTANCE Clostridium perfringens is a major gastrointestinal pathogen of poultry. C. perfringens strains that express the NetB pore-forming toxin, which is encoded on a conjugative plasmid, cause necrotic enteritis. This study demonstrated that the conjugative transfer of the netB -containing plasmid to two different nonpathogenic strains converted them into disease-causing strains with disease-causing capability similar to that of the donor strain. Plasmid transfer of netB and antibiotic resistance was also demonstrated to occur within the gastrointestinal tract of chickens, with approximately 14% of the isolates recovered comprising three distinct, in vivo -derived, transconjugant types. The demonstration of in vivo plasmid transfer indicates the potential importance of strain plasticity and the contribution of plasmids to strain virulence.
Publisher: Springer Science and Business Media LLC
Date: 16-08-2019
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.SCITOTENV.2019.134742
Abstract: Fungal spore resuspension on the surfaces of the heating, ventilation and air-conditioning (HVAC) ducts have been verified as one of the most important factors causing indoor biological pollution. To effectively control indoor bioaerosols pollution, it is essential to understand the resuspension characteristics of fungal spores in HVAC ducts. Therefore, this study aims to investigate the movement behavior of particles and further the variation of particle resuspension with HVAC operation mode. Based on the experimental and numerical study, this study specifically investigated the micro-movement behavior of particles and impact of particle size (1, 4, 7 and 10 μm), air temperature (9, 15 and 30 °C), relative humidity (20, 50 and 80%), duct surface roughness (0.5 and 50 μm) and air velocity (0.3, 0.9, 1.5 and 2.5 m/s) on the short-term resuspension of particle in horizontal HVAC ducts. Results indicate that spore particles were dominantly rolling off rather than sliding or being lifted into the air. Compared with larger particles, smaller ones were more sensitive to the wall roughness. The resuspension rate of spores was mainly affected by airflow velocity and particle size, where the resuspension rate of particles increased by up to six times with the increase of airflow velocity from 0.9 to 2.5 m/s. In comparison, either air temperature or relative humidity made negligible difference to particle resuspension rate. Overall, this study provides the knowledge of fungal spore resuspension in HVAC ducts, laying the foundation for effectively controlling the indoor biological pollution.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Jake Lacey.