Characteristics of Women and Their Male Sex Partners Predict Bacterial Vaginosis Among a Prospective Cohort of Kenyan Women With Nonoptimal Vaginal Microbiota

Abstract

Background: Up to 50% of women with nonoptimal vaginal microbial community state type (CST) have bacterial vaginosis (BV). Little is known about what distinguishes women with and without BV diagnosis within nonoptimal CST. We identified features of women and their male sex partners associated with BV among women with nonoptimal vaginal CST.

Methods: In this prospective study, 252 heterosexual couples were observed at 1, 6, and 12 months after baseline. Microbiomes were characterized in cervicovaginal lavage and penile meatal swabs through high-throughput 16s ribosomal RNA gene amplicon sequencing. Nonoptimal CST was defined as CST-IV. Bacterial vaginosis was defined as a Nugent score of 7 to 10. Generalized estimating equation analysis estimated adjusted odds ratios (aORs) for BV among women with nonoptimal CST.

Results: At baseline, women with nonoptimal CST were a median age of 22 years, 44% had BV, 16% had HIV, and 66% had herpes simplex virus (HSV) type 2. Male partners were a median age of 27 years, 12% had HIV, 48% had HSV-2, and 55% were circumcised. Within nonoptimal CST, Sneathia sanguinegens, Prevotella species, Prevotella amnii, and Clostridiales, BV-associated bacteria-2 were statistically significantly enriched in observations with BV. In multivariable generalized estimating equation 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), and Brevibacterium (aOR, 1.13; P = 0.019).These results provide insights into factors differentiating women with BV among those with nonoptimal vaginal CST. Interrupting the sexual exchange of penile and vaginal taxa may be beneficial for preventing pathologic state of vaginal microbiome.

Figure 1

Heatmap summarizing relative abundance for the 10 most abundant vaginal taxa by CST and Nugent BV status. The heatmap represents the relative abundance of the 10 taxa with highest mean relative abundance, shown for each observation, clustered by CST and Nugent BV status. Greater relative abundance is shaded with increasing intensity of blue color. Observations with Nugent BV (Nugent score 7–10) are indicated with black coloring.

Figure 2

Nonmetric multidimensional scaling plot showing the similarity of vaginal microbiome community of women with and without BV (Nugent score 7–10 vs. 0–6), within CST IVB. The nonmetric multidimensional scaling plot (MDS) represents the pairwise Bray-Curtis dissimilarity between observations. Red triangles represent observations in which Nugent BV is detected (Nugent score 7–10), and blue triangles represent observations in which Nugent BV is absent (Nugent score 0–6).

Figure 3

Stacked bar charts summarizing the mean relative abundance of 10 meatal taxa with the highest relative abundance by circumcision status and female partner BV status. These stacked bar charts summarize the mean relative abundance (y axis) of 10 penile taxa with the highest mean relative abundance, stratified by Nugent BV status and man’s circumcision status.