(36e) Microdroplet Cocultivation and Characterization of Vaginal Bacteria in Vaginal Fluid

The human vaginal microbiome (HVM) plays a fundamental role in women’s health and susceptibility to sexually transmitted infections (STIs). For instance, bacterial vaginosis (BV) is characterized by the depletion of lactobacilli and an overgrowth of strict anaerobes. BV is associated with an increased risk of infertility, preterm birth, and acquiring STIs like HIV. Despite the importance of the HVM, the ecological roles of many vaginal species and their interactions within the microbiome as well as with the host remain unclear. In this work, we employ a microfluidic technology platform to encapsulate vaginal bacteria and cultivate them in nano-liter microdroplets. The small volume of these microdroplets lead to minimum requirement on reagents and enables us to make use of cervicovaginal fluid (CVF), a very limited resource that is used for cultivation. By incorporating CVF, our objective is to dissect bacterial inter-species interactions in the HVM under conditions closely mimicking the in vivo environment. We collect CVF from a cohort of donors of reproductive age and pool them for the droplet cultivation experiments. The CVF is used to cultivate several vaginal bacterial species, including Lactobacillus iners, the most frequently detected bacterium in the HVM, and Gardnerella vaginalis, a BV-associated bacterium. Monocultures and co-cultures are generated and characterized with cellular and molecular assays. From these experiments, we observe growth phenotypes that are different from those using laboratory media and reveal mechanisms that are relevant in vivo.