Dynamic vaginal microbiota in pigtail macaques is associated with menstrual cycle and inflammation

A challenge in prevention of mucosal HIV transmission is incomplete understanding of correlates of vaginal transmission, including mucosal inflammation. Vaginal SIV/SHIV transmission in pigtail macaques ( Macaca nemestrina ) is an excellent model for HIV transmission, however little is known about how genital microbes may influence inflammation and transmission. Broad-range 16S rRNA gene PCR and pyrosequencing was performed on vaginal swabs to assess vaginal microbiome in healthy pigtail macaques. Bacteria were identified to the species or genus level. Luminex was used to measure cytokine and chemokine levels in vaginal swabs. Pigtail macaques had diverse bacterial communities at all phases of the menstrual cycle, with a range of dominant bacteria. Several species were identified that are commonly found in bacterial vaginosis (BV) in humans, and three animals exhibitied Lactobacillus- dominance . Longitudinal sampling demonstrated that the vaginal microbiome is dynamic and possibly influenced by the menstrual cycle. Animals with Lactobacillus -dominant vaginal microbiota had decreased IL-8 ( p =0.009) and IL-1Ra ( p =0.044). In conclusion, the macaque vaginal microbiota is diverse, dynamic, and can resemble the human vaginal microbiota, including BV-associated bacteria as well as Lactobacillus spp, which is associated with decreased innate inflammation. These data provide a foundation for understanding how the vaginal microbiome may impact risk of HIV/SIV transmission.