Hydrogen Peroxide--Producing Lactobacilli and Acquisition of Vaginal Infections

TLDR

The study tested whether colonization by lactobacilli reduces acquisition of vaginal infections. It was a 2‑year cohort study of 182 women at an STD clinic, following them for incident infections. Over two years, 50 women developed bacterial vaginosis, 25 candidiasis, and 7 trichomoniasis; Cox analysis found that absence of H₂O₂‑producing lactobacilli quadrupled BV risk (HR 4.0), non‑producing strains doubled it (HR 2.2), and new partners and douching also increased BV risk, while lactobacilli status did not affect candidiasis and trichomoniasis was linked only to new partners, supporting that H₂O₂‑producing lactobacilli protect against BV but not other infections.

Abstract

This cohort study of 182 women attending a sexually transmitted disease clinic evaluated the hypothesis that women colonized by lactobacilli have decreased acquisition of vaginal infections. During a 2-year follow-up, 50 women acquired bacterial vaginosis (BV), 25 acquired symptomatic vulvovaginal candidiasis (YYC), and 7 acquired vaginal trichomoniasis. By multivariate analysis, utilizing Cox proportional hazards modeling with time-dependent covariates, acquisition of BV was independently associated with lack of vaginal H202-producing lactobacilli (hazard ratio [HR] = 4.0, P < .001) or presence of only non–H202-producing lactobacilli (HR = 2.2, P = .02). Acquisition of BV was associated with having a new sex partner (HR = 2.5, P = .004) and with douching for hygiene (HR = 2.1, P = .05). Absence of lactobacilli did not increase acquisition of VVC. Trichomoniasis was associated only with having a new sex partner (HR = 4.7, P = .05). These results support the hypothesis that H202-producing vaginal lactobacilli protect against acquisition of BV but do not protect against VVC or vaginal trichomoniasis.