title: Analysis of genetic lineages and their correlation with virulence genes in Enterococcus faecalis clinical isolates from root canal and systemic infections.
abstract: BACKGROUND
  Enterococcus faecalis is a member of the mammalian gastrointestinal microbiota but has been considered a leading cause of hospital-acquired infections. In the oral cavity, it is commonly detected from root canals of teeth with failed endodontic treatment. However, little is known about the virulence and genetic relatedness among E. faecalis isolates from different clinical sources. This study compared the presence of enterococcal virulence factors among root canal strains and clinical isolates from hospitalized patients to identify virulent clusters of E. faecalis.
  
  
  METHODS
  Multilocus sequence typing analysis was used to determine genetic lineages of 40 E. faecalis clinical isolates from different sources. Virulence clusters were determined by evaluating capsule (cps) locus polymorphisms, pathogenicity island gene content, and antibiotic resistance genes by polymerase chain reaction.
  
  
  RESULTS
  The clinical isolates from hospitalized patients formed a phylogenetically separate group and were mostly grouped in the clonal complex 2, which is a known virulent cluster of E. faecalis that has caused infection outbreaks globally. The clonal complex 2 group comprised capsule-producing strains harboring multiple antibiotic resistance and pathogenicity island genes. On the other hand, the endodontic isolates were more diverse and harbored few virulence and antibiotic resistance genes. In particular, although more closely related to isolates from hospitalized patients, capsule-producing E. faecalis strains from root canals did not carry more virulence/antibiotic genes than other endodontic isolates.
  
  
  CONCLUSIONS
  E. faecalis isolates from endodontic infections have a genetic and virulence profile different from pathogenic clusters of hospitalized patients' isolates, which is most likely due to niche specialization conferred mainly by variable regions in the genome.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Brazil.
authors.forename: Pâmela P
authors.initials: PP
authors.lastname: Penas
authors.forename: Marcia P A
authors.initials: MP
authors.lastname: Mayer
authors.forename: Brenda P F A
authors.initials: BP
authors.lastname: Gomes
authors.forename: Marcos
authors.initials: M
authors.lastname: Endo
authors.forename: Antonio C C
authors.initials: AC
authors.lastname: Pignatari
authors.forename: Karen C
authors.initials: KC
authors.lastname: Bauab
authors.forename: Ericka T
authors.initials: ET
authors.lastname: Pinheiro
mesh_terms: D016667:Bacterial Capsules / Q000235:genetics; D015373:Bacterial Typing Techniques; D002874:Chromosome Mapping; D003428:Cross Infection / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D013293:Enterococcus faecalis / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D044404:Genomic Islands / Q000235:genetics; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006801:Humans; D005810:Multigene Family / Q000235:genetics; D058885:Multilocus Sequence Typing; D011110:Polymorphism, Genetic / Q000235:genetics; D013753:Tetracycline Resistance / Q000235:genetics; D019553:Tooth, Nonvital / Q000382:microbiology*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D037521:Virulence Factors