Genome-Wide Mutagenesis Identifies Factors Involved in Enterococcus faecalis Vaginal Adherence and Persistence

Infect Immun. 2020 Sep 18;88(10):e00270-20. doi: 10.1128/IAI.00270-20. Print 2020 Sep 18.


Enterococcus faecalis is a Gram-positive commensal bacterium native to the gastrointestinal tract and an opportunistic pathogen of increasing clinical concern. E. faecalis also colonizes the female reproductive tract, and reports suggest vaginal colonization increases following antibiotic treatment or in patients with aerobic vaginitis. Currently, little is known about specific factors that promote E. faecalis vaginal colonization and subsequent infection. We modified an established mouse vaginal colonization model to explore E. faecalis vaginal carriage and demonstrate that both vancomycin-resistant and -sensitive strains colonize the murine vaginal tract. Following vaginal colonization, we observed E. faecalis in vaginal, cervical, and uterine tissue. A mutant lacking endocarditis- and biofilm-associated pili (Ebp) exhibited a decreased ability to associate with human vaginal and cervical cells in vitro but did not contribute to colonization in vivo Thus, we screened a low-complexity transposon (Tn) mutant library to identify novel genes important for E. faecalis colonization and persistence in the vaginal tract. This screen revealed 383 mutants that were underrepresented during vaginal colonization at 1, 5, and 8 days postinoculation compared to growth in culture medium. We confirmed that mutants deficient in ethanolamine catabolism or in the type VII secretion system were attenuated in persisting during vaginal colonization. These results reveal the complex nature of vaginal colonization and suggest that multiple factors contribute to E. faecalis persistence in the reproductive tract.

Keywords: E. faecalis; Enterococcus; T7SS; TnSeq; colonization; ethanolamine catabolism; vaginal tract.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Adhesion / genetics
  • Bacterial Adhesion / physiology*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cell Line
  • Enterococcus faecalis / genetics
  • Enterococcus faecalis / growth & development
  • Enterococcus faecalis / physiology*
  • Ethanolamine / metabolism
  • Female
  • Fimbriae, Bacterial / genetics
  • Fimbriae, Bacterial / metabolism
  • Genitalia, Female / microbiology
  • Genome, Bacterial / genetics
  • Gram-Positive Bacterial Infections / microbiology*
  • Humans
  • Mice
  • Mutagenesis
  • Mutation
  • Type VII Secretion Systems / genetics
  • Type VII Secretion Systems / metabolism
  • Vagina / microbiology*


  • Bacterial Proteins
  • Type VII Secretion Systems
  • Ethanolamine