Interaction between lactobacilli, bacterial vaginosis-associated bacteria, and HIV Type 1 RNA and DNA Genital shedding in U.S. and Kenyan women

Abstract

Bacterial vaginosis has been associated with genital HIV-1 shedding; however, the effect of specific vaginal bacterial species has not been assessed. We tested cervicovaginal lavage from HIV-1-seropositive women for common Lactobacillus species: L. crispatus, L. jensenii, and seven BV-associated species: BVAB1, BVAB2, BVAB3, Leptotrichia, Sneathia, Megasphaera, and Atopobium spp. using quantitative PCR. We used linear and Poisson regression to evaluate associations between vaginal bacteria and genital HIV-1 RNA and DNA. Specimens from 54 U.S. (310 visits) and 50 Kenyan women (137 visits) were evaluated. Controlling for plasma viral load, U.S. and Kenyan women had similar rates of HIV-1 RNA (19% of visits vs. 24%; IRR=0.95; 95% CI 0.61, 1.49) and DNA shedding (79% vs. 76%; IRR=0.90; 0.78, 1.05). At visits during antiretroviral therapy (ART), the likelihood of detection of HIV-1 RNA shedding was greater with BVAB3 (IRR=3.16; 95% CI 1.36, 7.32), Leptotrichia, or Sneathia (IRR=2.13; 1.02, 4.72), and less with L. jensenii (IRR=0.39; 0.18, 0.84). At visits without ART, only L. crispatus was associated with a lower likelihood of HIV-1 RNA detection (IRR=0.6; 0.40, 0.91). Vaginal Lactobacillus species were associated with lower risk of genital HIV-1 shedding, while the presence of certain BV-associated species may increase that risk.

FIG. 1.

Comparison of quantity of HIV-1 RNA (copies/ml cervicovaginal lavage) and HIV-1 DNA (copies/10⁶ cells) between U.S. and Kenyan women with detectable virus in genital tract samples. No significant differences were seen in quantity of genital tract RNA (p=0.16) or DNA (p=0.32) between U.S. and Kenyan women with virus detected.

FIG. 2.

Comparison of vaginal bacterial colonization between U.S. and Kenyan women. Rates (A) of bacterial colonization were overall similar between U.S. and Kenyan women, although L. jensenii was more prevalent in U.S. women. Log₁₀ quantity of bacteria in those with the bacterium detected (B) was similar for most species, but higher levels of Megasphaera were found in U.S. women.