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Uncoupling between core genome and virulome in extraintestinal pathogenicEscherichia coli
- Source :
- Canadian Journal of Microbiology. 61:647-652
- Publication Year :
- 2015
- Publisher :
- Canadian Science Publishing, 2015.
-
Abstract
- Extraintestinal pathogenic Escherichia coli (ExPEC) are among the most frequently isolated bacterial pathogens in hospitals. They are considered opportunistic pathogens and are found mostly in urinary and bloodstream infections. They are genetically diverse, and many studies have sought associations between genotypes or virulence genes and infection site, severity, or outcome, with varied, often contradictory, results. To understand these difficulties, we have analyzed the diversity patterns in the core genomes and virulomes of more than 500 ExPEC isolates from 5 different collections. The core genome was analyzed using a multilocus sequence type-based single-nucleotide polymorphism (SNP) pyrosequencing approach, while the virulence gene content (the virulome) was studied by polymerase chain reaction detection of 25 representative genes. SNP typing showed a similar population structure in the different collections: half of the isolates belong to a few sequence types (5 to 8), while the other half is composed of a large diversity of sequence types that are found once or twice. Sampling analysis by rarefaction plots of SNP profiles showed saturation curves indicative of a limited diversity. Contrary to this, the virulome shows an extremely high diversity, with almost as many gene profiles as isolates, and linear, nonsaturating, rarefaction plots, even within sequence types. These data show that genetic exchange rates are very heterogeneous along the chromosome, being much higher in the virulome fraction of the genome than in the core genome.
- Subjects :
- Genotype
Immunology
medicine.disease_cause
Polymorphism, Single Nucleotide
Applied Microbiology and Biotechnology
Microbiology
Genome
Escherichia
Escherichia coli
Genetics
medicine
Humans
Molecular Biology
Escherichia coli Infections
Extraintestinal Pathogenic Escherichia coli
Virulence
biology
Escherichia coli Proteins
Genetic Variation
General Medicine
biology.organism_classification
Genome, Bacterial
Multilocus Sequence Typing
Subjects
Details
- ISSN :
- 14803275 and 00084166
- Volume :
- 61
- Database :
- OpenAIRE
- Journal :
- Canadian Journal of Microbiology
- Accession number :
- edsair.doi.dedup.....2199497379dab577cbc4e0f993cace21