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1.
BMC Genomics ; 19(1): 379, 2018 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-29788909

RESUMO

BACKGROUND: Clostridium perfringens causes a range of diseases in animals and humans including necrotic enteritis in chickens and food poisoning and gas gangrene in humans. Necrotic enteritis is of concern in commercial chicken production due to the cost of the implementation of infection control measures and to productivity losses. This study has focused on the genomic analysis of a range of chicken-derived C. perfringens isolates, from around the world and from different years. The genomes were sequenced and compared with 20 genomes available from public databases, which were from a diverse collection of isolates from chickens, other animals, and humans. We used a distance based phylogeny that was constructed based on gene content rather than sequence identity. Similarity between strains was defined as the number of genes that they have in common divided by their total number of genes. In this type of phylogenetic analysis, evolutionary distance can be interpreted in terms of evolutionary events such as acquisition and loss of genes, whereas the underlying properties (the gene content) can be interpreted in terms of function. We also compared these methods to the sequence-based phylogeny of the core genome. RESULTS: Distinct pathogenic clades of necrotic enteritis-causing C. perfringens were identified. They were characterised by variable regions encoded on the chromosome, with predicted roles in capsule production, adhesion, inhibition of related strains, phage integration, and metabolism. Some strains have almost identical genomes, even though they were isolated from different geographic regions at various times, while other highly distant genomes appear to result in similar outcomes with regard to virulence and pathogenesis. CONCLUSIONS: The high level of diversity in chicken isolates suggests there is no reliable factor that defines a chicken strain of C. perfringens, however, disease-causing strains can be defined by the presence of netB-encoding plasmids. This study reveals that horizontal gene transfer appears to play a significant role in genetic variation of the C. perfringens chromosome as well as the plasmid content within strains.


Assuntos
Clostridium perfringens/genética , Clostridium perfringens/fisiologia , Enterite/microbiologia , Evolução Molecular , Variação Genética , Animais , Galinhas/microbiologia , Cromossomos/genética , Enterite/complicações , Necrose/complicações , Plasmídeos/genética
2.
Anaerobe ; 49: 58-62, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29274467

RESUMO

The aim of this study was to examine the incidence of Clostridioides (previously Clostridium) difficile and Clostridium perfringens in the feces of diarrheic and non-diarrheic dogs. Also, the presence of other common canine enteropathogens was examined. Toxigenic C. difficile and C. perfringens positive for the NetF-encoding gene (netF) were detected in 11 (11.9%) and seven (7.6%) diarrheic dogs, respectively. Three dogs were diagnosed simultaneously with toxigenic C. difficile and netF-positive C. perfringens. Among other enteropathogens, Giardia sp. was the most common agent detected in dogs positive for toxigenic C. difficile or netF-positive C. perfringens. The results suggest that C. difficile and C. perfringens occur more frequently as a primary cause of diarrhea.


Assuntos
Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/veterinária , Clostridium perfringens/isolamento & purificação , Diarreia/veterinária , Doenças do Cão/microbiologia , Enterotoxinas/metabolismo , Animais , Brasil/epidemiologia , Clostridioides difficile/genética , Clostridioides difficile/metabolismo , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Clostridium perfringens/genética , Clostridium perfringens/metabolismo , Diarreia/microbiologia , Doenças do Cão/epidemiologia , Cães , Enterotoxinas/genética , Fezes/microbiologia , Incidência
3.
FEMS Microbiol Lett ; 362(9)2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25837817

RESUMO

Bacterial Wzx flippases translocate (flip) short oligosaccharide repeat units (O units) across the inner membrane into the periplasm, which is a critical step in the assembly of many O antigens, capsules and other surface polysaccharides. There is enormous diversity in O antigens and capsules in particular, even within species. Wzx proteins are similarly diverse, but it has been widely accepted that they have significant specificity only for the first sugar of an O unit. In this study, we analysed the Wzx from the Salmonella enterica group C2 O antigen gene cluster, which is a unique and divergent member of a set of gene clusters that produce galactose-initiated O antigens. We demonstrate that this Wzx has a strong preference for the presence of an abequose side-branch, which manifests in a reduction of long-chain O antigen and a major growth defect. This contributes to a growing body of evidence that, contrary to earlier proposals, Wzx flippases commonly exhibit a strong preference for the structure of their native O unit.


Assuntos
Genes Bacterianos , Proteínas de Membrana Transportadoras/metabolismo , Antígenos O/biossíntese , Antígenos O/genética , Salmonella enterica/genética , Salmonella enterica/metabolismo , Proteínas de Bactérias/genética , Membrana Celular/genética , Membrana Celular/metabolismo , Técnicas de Inativação de Genes , Lipopolissacarídeos/metabolismo , Proteínas de Membrana Transportadoras/genética , Família Multigênica , Antígenos O/química , Salmonella enterica/crescimento & desenvolvimento
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