Defense factors of vaginal lactobacilli

Alla Aroutcheva, Dominique Gariti, Melissa Simon, Susan Shott, Jonathan Faro, Jose A. Simoes, Alfred Gurguis, Sebastian Faro

Research output: Contribution to journalArticlepeer-review

330 Scopus citations


OBJECTIVE: To determine the antagonistic relationship between vaginal lactobacilli and endogenous vaginal microflora. STUDY DESIGN: Twenty-two Lactobacillus strains were studied for the production of lactic acid, hydrogen peroxide, and bacteriocin. RESULTS: Under standardized growth conditions, most strains increased their biomass by more than 4 times. Lactobacillus species grew best at a pH ≥ 4.5, and growth was retarded at a pH < 4.5. Lactic acid levels were 0.68 to 2.518 mg/mL and were not related to the number of cells or the pH of media. The pH of the media was caused by the secretion of lactic and other organic acids. Approximately 80% of the strains produced H2O2 and were graded as 2+ in one third of the strains and 1+ in others. No statistical correlation was found between H2O2 lactic acid and bacteriocin production. Bacteriocin activity was tested on 4 strains of Gardnerella vaginalis. Approximately 80% of the lactobacilli tested produced bacteriocin that inhibited growth of G vaginalis. Six of the strains did not produce bacteriocin. Thirteen strains produced all 3 defense factors, whereas the others lacked 1 or 2 properties. CONCLUSIONS: Lactobacillus species grow best at a pH > 4.5. The pH of the media is dependent on the cell mass and on all organic acids produced by Lactobacillus species. Although all species produce organic acids, not all produce H2O2 and bacteriocin. Not all strains of G vaginalis can be inhibited by lactobacilli-producing bacteriocin.

Original languageEnglish (US)
Pages (from-to)375-379
Number of pages5
JournalAmerican journal of obstetrics and gynecology
Issue number2
StatePublished - 2001


  • Bacterial vaginosis
  • Bacteriocin
  • Gardnerella vaginalis
  • Hydrogen peroxide
  • Lactic acid
  • Lactobacillus species

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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