Abstract
BackgroundEnterococci rank among the leading causes of nosocomial infections. The failure to identify pathogen-specific genes in Enterococcus faecalis has led to a hypothesis where the virulence of different strains may be linked to strain-specific genes, and where the combined endeavor of the different gene-sets result in the ability to cause infection. Population structure studies by multilocus sequence typing have defined distinct clonal complexes (CC) of E. faecalis enriched in hospitalized patients (CC2, CC9, CC28 and CC40).ResultsIn the present study, we have used a comparative genomic approach to investigate gene content in 63 E. faecalis strains, with a special focus on CC2. Statistical analysis using Fisher's exact test revealed 252 significantly enriched genes among CC2-strains. The majority of these genes were located within the previously defined mobile elements phage03 (n = 51), efaB5 (n = 34) and a vanB associated genomic island (n = 55). Moreover, a CC2-enriched genomic islet (EF3217 to -27), encoding a putative phage related element within the V583 genome, was identified. From the draft genomes of CC2-strains HH22 and TX0104, we also identified a CC2-enriched non-V583 locus associated with the E. faecalis pathogenicity island (PAI). Interestingly, surface related structures (including MSCRAMMs, internalin-like and WxL protein-coding genes) implicated in virulence were significantly overrepresented (9.1%; p = 0.036, Fisher's exact test) among the CC2-enriched genes.ConclusionIn conclusion, we have identified a set of genes with potential roles in adaptation or persistence in the hospital environment, and that might contribute to the ability of CC2 E. faecalis isolates to cause disease.
Highlights
Enterococci rank among the leading causes of nosocomial infections
Overall genomic diversity To explore the genetic diversity among E. faecalis, BLAST comparison was performed with 24 publicly available sequenced draft genomes, including the two CC2-strains TX0104 (ST2), which is an endocarditis isolate, and HH22 (ST6; mentioned above) against the genome of strain V583, which is a ST6 isolate
We used comparative genomic hybridization (CGH) to investigate variation in gene content within 15 E. faecalis isolated in European hospital environments, with a special focus on a hospitaladapted subpopulation identified by multilocus sequence typing (MLST) (CC2)
Summary
Enterococci rank among the leading causes of nosocomial infections. The failure to identify pathogen-specific genes in Enterococcus faecalis has led to a hypothesis where the virulence of different strains may be linked to strain-specific genes, and where the combined endeavor of the different gene-sets result in the ability to cause infection. The ability of E. faecalis to cause infection has been putative virulence traits are present in infectious isolates and in animal and environmental isolates [18,19,20,21,22,23]. This widespread distribution of putative virulence determinants in enterococcal isolates strongly suggest that enterococcal pathogenicity is not a result of any single virulence factor, but rather a more intricate process. Bourgogne et al [24] proposed a scenario where the virulence of V583 and OG1RF may be linked to genes that are unique to each of the two strains, but where the combined endeavor of the different genesets result in the ability to cause infection
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
