Reproductive microbiota in humans: characterization and role in infertility.

Advancements in next generation sequencing technologies, including 16S rRNA amplicon sequencing, have vastly expanded our understanding of reproductive microbiota and its role in fertility. For example, in humans, the bacterial genus of Lactobacillus is the overwhelmingly dominant commensal bacterium within reproductive tissues and fluids, such as the vagina, and is an indicator of fertility in women. Shifts away from Lactobacillus allow for opportunistic pathogenic bacteria to inhabit the reproductive tract and result in dysbiosis and infertility. The goal of this review is to explore human reproductive microbiota including bacteria that commensally inhabit reproductive tissues and fluids as well as opportunistic pathogenic bacteria that can result in dysbiosis, infertility, and disease. Continued exploration of the microbiome and its association with reproductive health will aid in the development of targeted therapeutic strategies to positively modulate bacteria and improve fertility.