title: Prevalence, phenotype, and genotype of Enterococcus faecalis isolated from saliva and root canals in patients with persistent apical periodontitis.
abstract: BACKGROUND
  The aim of this study was to investigate the prevalence, phenotype, and genotype of Enterococcus faecalis isolated from saliva and root canals in patients with endodontic treatment failure.
  
  
  METHODS
  Samples were collected from 32 adults undergoing retreatment for periapical lesions after endodontic treatment performed at least 2 years previously. Isolates that were presumed to be E. faecalis were identified by both API20 Strep kits and 16S rRNA sequencing. Phenotypic tests for hemolysin and gelatinase production and antibiotic susceptibility were performed. Genotype analysis comprised virulence gene detection and pulsed field gel electrophoresis (PFGE).
  
  
  RESULTS
  The prevalence of E. faecalis was 18.8% in saliva and 40.6% in root canals (P = .666, Fisher exact test). Of the 19 isolates of E. faecalis, 6 were from saliva and 13 were from root canals. In 3 patients, E. faecalis isolates from saliva were more resistant to gentamicin than those from root canals. The genes ace, asa, gelE, cylA, and efaA were detected from all isolates. PFGE after SmaI digestion showed a genetic correlation among all isolates of 62%-100%.
  
  
  CONCLUSIONS
  Phenotype and genotype evidence of potential virulence factors was identified in E. faecalis from both saliva and root canals. A single patient might carry different E. faecalis strains in saliva and root canals.
authors.affiliation: Special Department, School and Hospital of Stomatology, Peking University, Beijing, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Zhu
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Wang
authors.forename: Chengfei
authors.initials: C
authors.lastname: Zhang
authors.forename: Gary S P
authors.initials: GS
authors.lastname: Cheung
authors.forename: Ya
authors.initials: Y
authors.lastname: Shen
mesh_terms: D000328:Adult; D055113:Chronic Periodontitis / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology*; D019232:Dental Restoration Failure; D004352:Drug Resistance, Microbial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D013293:Enterococcus faecalis / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D018093:Gelatinases / Q000096:biosynthesis; D005798:Genes, Bacterial; D005838:Genotype; D006460:Hemolysin Proteins / Q000096:biosynthesis; D006801:Humans; D010485:Periapical Periodontitis / Q000382:microbiology*; D010641:Phenotype; D012390:Root Canal Therapy / Q000009:adverse effects; D012463:Saliva / Q000382:microbiology*; D017211:Treatment Failure; D037521:Virulence Factors / Q000235:genetics
chemical_list: D006460:Hemolysin Proteins; D037521:Virulence Factors; D018093:Gelatinases