Re-assessing microbiomes in the low-biomass reproductive niche.

The female reproductive tract represents a continuum between the vagina and the upper genital tract. New evidence from cultivation-independent studies suggests that the female upper genital tract is not sterile; however, the significance of this for reproductive health and disease remains to be elucidated fully. Further, diagnosis and treatment of infectious reproductive tract pathologies using cultivation-independent technologies represents a largely unchartered area of modern medical science. The challenge now is to design well-controlled experiments to account for the ease of contamination known to confound molecular-based studies of low-biomass niches, including the uterus and placenta. This will support robust assessment of the potential function of microorganisms, microbial metabolites, and cell-free bacterial DNA on reproductive function in health and disease. TWEETABLE ABSTRACT: Molecular microbial studies of low-biomass niches require stringent experimental controls to reveal causal relations in reproductive health and disease.