Vaginal Lactobacilli, Microbial Flora, and Risk of Human Immunodeficiency Virus Type 1 and Sexually Transmitted Disease Acquisition

TLDR

The study investigates whether vaginal lactobacilli colonization and bacterial vaginosis influence HIV‑1 and sexually transmitted disease acquisition among Kenyan sex workers, and proposes that treating BV and promoting lactobacilli could reduce these risks. A prospective cohort of 657 HIV‑1–seronegative sex workers in Mombasa was followed monthly to assess vaginal flora and subsequent HIV‑1 and STD acquisition. Women without vaginal lactobacilli had a 2.0‑fold higher risk of HIV‑1 and a 1.7‑fold higher risk of gonorrhea, whereas abnormal flora increased HIV‑1 risk by 1.9‑fold and trichomoniasis risk by 1.8‑fold.

Abstract

A prospective cohort study was conducted to examine the relationship between vaginal colonization with lactobacilli, bacterial vaginosis (BV), and acquisition of human immunodeficiency virus type 1 (HIV-1) and sexually transmitted diseases in a population of sex workers in Mombasa, Kenya. In total, 657 HIV-1—seronegative women were enrolled and followed at monthly intervals. At baseline, only 26% of women were colonized with Lactobacillus species. During follow-up, absence of vaginal lactobacilli on culture was associated 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 of BV and promotion of vaginal colonization with lactobacilli should be evaluated as potential interventions to reduce a woman's risk of acquiring HIV-1, gonorrhea, and trichomoniasis.