Characterizing the vaginal microbiome in a sexually fluid primate (Pan paniscus).

While there have been recent breakthroughs in human vaginal microbiome research, very few non-human primate (NHP) vaginal microbiome studies exist due to difficulty in obtaining samples. In this study, we sought to: (1) characterize the bonobo vaginal microbiota for the first time, and (2) determine the relationship between vaginal pH and swelling size. During a 21-day study period, we collected observational data and 71 vaginal swabs from three cohoused adult females at the Ape Cognition and Conservation Initiative. After filtering and classification, a total of 3452 amplicon sequence variants were recruited from 12 vaginal samples. The most dominant phylum represented was Actinobacteria, and the most abundant genera were Gardnerella, Atopobium, and Prevotella. The mean pH score was 6.1 (range: 5.1-7.0), and pH levels varied with relative swelling size. This is the first study to examine the vaginal microbial composition in this species, and it conforms to previous NHP studies in that there was not the same bacterial dominance of Lactobacillus spp. often highlighted in human vaginal microbiota studies. Our findings suggest there may be other factors contributing to the protection of the bonobo vaginal environment, but future analysis of a larger sample is needed to fully understand how sociality and sexuality shape vaginal microbiota and host health.