Clinical Implications of Biofilm Formation by Enterococcus Faecalis in the Urinary Tract

Acta Med Okayama. 2005 Jun;59(3):79-87. doi: 10.18926/AMO/31979.


The potential relationships between biofilm formation and pathogenicity of Enterococcus faecalis in urinary tract infections (UTI) were investigated. Over a 12-year period from 1991 through 2002, a total of 352 E.faecalis isolates were collected from patients with complicated UTI (one isolate per patient) at the urology ward of Okayama University Hospital. We analyzed the prevalence and transferability of genes encoding virulence factors(asa1, esp, cylA, gelE /sprE )and antimicrobial resistance(aac(6') /aph(2'')). The production of biofilm, hemolysin and gelatinase by these isolates was also examined and the associated medical records of patients were retrospectively reviewed. Of 352 E. faecalis isolates, 315 possessed and/or genes. Of the 63 hemolysin- and 167 gelatinase-producing isolates, 59 and 94 isolates, respectively, possessed both asa1 and esp genes. E. faecalis isolates with both asa1 and esp genes formed biofilms at significantly higher rates than those with neither gene (P=0.038). The genes encoding asa1, cylA , and aac(6') /(aph(2'') were transferable and appeared to have accumulated in these isolates. The E. faecalis isolates possessing asa1 and/or esp genes were found from both catheter-related or -unrelated UTI. Our study indicates that E. faecalis isolates that have accumulated virulence genes are apt to form persistent biofilms in the urinary tracts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Bacterial Proteins / genetics
  • Biofilms / growth & development*
  • Child
  • Child, Preschool
  • Enterococcus faecalis / genetics
  • Enterococcus faecalis / growth & development*
  • Enterococcus faecalis / pathogenicity
  • Female
  • Gelatinases / genetics
  • Gene Expression Regulation, Bacterial
  • Gene Transfer, Horizontal
  • Gram-Positive Bacterial Infections / microbiology*
  • Hemolysin Proteins / genetics
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Membrane Proteins / genetics
  • Middle Aged
  • Retrospective Studies
  • Urinary Tract Infections / microbiology*
  • Virulence
  • Virulence Factors / genetics


  • Bacterial Proteins
  • Hemolysin Proteins
  • Membrane Proteins
  • Virulence Factors
  • aggregation substance, Enterococcus faecalis
  • enterococcal surface protein, esp
  • Gelatinases