Sexual & Demographic Risks for Infection with Specific Bacteria Associated with Baterial Vaginosis (BV)

Background: Molecular methods have expanded the spectrum of BV associated bacteria (BVAB). Unprotected sex increases BV risk, but transmissible pathogens have not been identified.

Objectives: Among women with BV, characterize BVAB detected by PCR, with analysis of sexual risks.

Methods: Species-specific 16S rRNA PCRs for BVAB1, BVAB2, BVAB3, Megasphaera phylotypes 1 and 2, Mobiluncus curtisii, M. mulieris, Leptotrichia spp, TM7 division BVAB, G. vaginalis, A. vaginae, P. lacrimalis and L. crispatus were applied to vaginal fluid in women with BV. Recent behaviors (3 months) were ascertained.

Results: Of 171 women with BV (median 26 y.o.), 22% were Black; 47% reported recent vaginal intercourse with men, 43% sex only with women (WSW), 9.4% men and women and 7.6% no sex. Women reporting intercourse with men were more likely to have Megasphaera-2 (RR 4.6 (95% C.I. 2.0-10.7)) and L. crispatus (RR 3.2 (1.5-7.0)) relative to no intercourse with male; Megasphaera-2 detection increased with increasing number of male partners (RR 1.5 (1.0-2.2) for each partner). WSW were more likely to have Megasphaera-1 (RR 1.4 (1.2-1.6)), and Black women Megasphaera-1, -2, M. mulieris, TM7-BVAB and P. lacrimalis. No associations between BVAB and anal/oral sex, antibiotic use, or age were found. For Megasphaera-2, adjustment for sex with women attenuated associations with Black race (2.0 (0.7-6.0)); adjustment for race modified risks associated with sex with women (RR 0.16 (0.04-0.69)) and intercourse with male (2.46 (0.9-6.4)).

Conclusions: Vaginal communities of BVAB Megasphaera types 1 and 2, which are highly specific for BV, are associated with recent sexual behavior and host characteristics that track with race. This supports roles for exogenous (sexual acquisition) and endogenous (host) factors in determining BVAB communities.

Implications for Programs, Policy, and/or Research: Further research is needed to evaluate host factors and extragenital sites (urethra, oropharynx) as reservoirs for sexual BVAB transmission.