Microorganisms in the human vagina, collectively referred to as the human vaginal microbiome (HVM), play fundamental roles in women’s health and their susceptibility to various urogenital diseases. For instance, bacterial vaginosis (BV), a common genital tract disorder in women, is characterized by an overgrowth of strict anaerobes over Lactobacilli, and is associated with an increased risk of acquiring sexually transmitted diseases (e.g. HIV), infertility, preterm birth and other adverse pregnancy outcomes. Despite the HVM's significance, the ecological roles of many vaginal species remain unclear and current approaches for investigating them have severe limitations. We are developing a new technology, based on microfluidic droplet co-cultivation, to dissect inter-species interactions in microbial communities in a highly parallel manner. In our initial work, we tested and validated this new technology using pairwise model systems consisting of Lactobacillus jensenii, a favored lactic acid producing vaginal bacterium, and one of two uropathogens, Gardnerella vaginalis or Enterococcus faecalis. Several analytical assays were adapted for downstream characterization of pooled droplets or individual ones to detect inter-species interactions. Our results showed severe inhibition of G. vaginalis ATCC 49145 growth by L. jensenii JV-V16 based on flask experiments, qPCR on pooled droplets, and CFU estimates of individual droplets. Similarly, E. faecalis ATCC 19433 growth was also inhibited when co-cultured with L. jensenii JV-V16 both in flasks and in micro-droplets. Building on this demonstration, our ongoing work is aimed at elucidating key ecological interactions in the HVM, by examining vaginal samples containing both bacteria and vaginal secretions.
Sponsored by the Host Microbiome Initiative