Vaginal lactobacilli, microbial flora, and risk of human immunodeficiency virus type 1 and sexually transmitted disease acquisition

A prospective cohort study was conducted to examine the relationship betwee n vaginal colonization with lactobacilli, bacterial vaginosis (BV), and acq uisition of human immunodeficiency virus type 1 (HIV-1) and sexually transm itted diseases in a population of sex workers in Mombasa, Kenya, In total, 657 HIV-l-seronegative women were enrolled and followed at monthly interval s. At baseline, only 26% of women were colonized with Lactobacillus species . During follow-up, absence of vaginal lactobacilli on culture was associat ed with an increased risk of acquiring HIV-1 infection (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.2-3.5) and gonorrhea (HR, 1.7; 95% CI, 1.1-2.6), after controlling for other identified risk factors in separate multivariate models. Presence of abnormal vaginal flora on Gram's stain was associated with increased risk of both HIV-1 acquisition (HR, 1.9; 95% CI, 1.1-3.1) and Trichomonas infection (HR, 1.8; 95% CI, 1.3-2.4), Treatment o f BV and promotion of vaginal colonization with lactobacilli should be eval uated as potential interventions to reduce a woman's risk. of acquiring HIV -1, gonorrhea, and trichomoniasis.