Characteristics of women and their male sex partners predict Bacterial vaginosis among a prospective cohort of Kenyan women with non-optimal vaginal microbiota

BACKGROUND Up to 50% of women with non-optimal vaginal microbial community state type (CST) have Bacterial vaginosis (BV). Little is known about what distinguishes women with and without BV diagnosis within non-optimal CST. We identified features of women and their male sex partners associated with BV among women with non-optimal vaginal CST. METHODS In this prospective study, 252 heterosexual couples were observed at 1-, 6-, and 12- months following baseline. Microbiomes were characterized in cervicovaginal lavage and penile meatal swabs through high-throughput 16s ribosomal RNA gene amplicon sequencing. Non-optimal CST was defined as CST-IV. BV was defined as Nugent score 7-10. Generalized estimating equation (GEE) analysis estimated adjusted odds ratios (aOR) for BV among women with non-optimal CST. RESULTS At baseline, women with non-optimal CST were median age 22 years, 44% with BV, 16% with HIV, and 66% with HSV-2. Male partners were median age 27 years, 12% with HIV, 48% with HSV-2, and 55% circumcised. Within non-optimal CST, S. sanguinegens, Prevotella spp., P. amnii, and Clostridiales BV-associated bacteria-2 (BVAB-2) were statistically significantly enriched in observations with BV. In multivariable GEE controlling for CST, HIV and HSV-2, BV was increased among women with CST-IVA (aOR=1.91; p=0.087), HIV (aOR=2.30; p=0.051), HSV-2 (aOR=1.75; p=0.065), and enrichment of male partner penile taxa: Dialister (aOR=1.16; p=0.034), Megasphaera (aOR=1.22; p=0.001), Brevibacterium (aOR=1.13; p=0.019). CONCLUSIONS These results provide insight on factors differentiating women with BV among those with non-optimal vaginal CST. Interrupting the sexual exchange of penile and vaginal taxa may be beneficial for preventing pathologic state of vaginal microbiome.