The role of the microbiome continues to provide more insights on why and how certain health conditions can affect certain patients and why some patients are resistant to certain health diseases. The microbiome considers the entire micro flora and microbial community on a specific surface or organ. The urogenital tract, prostate, and seminal vesicles seem to possess a very unique microbiome.
Over the last couple of years we have seen more research establish the presence of specific groups of bacteria in patients who have optimal fertility and it appears to differ from patients that have low fertility, particularly poor sperm health and fertility parameters. It is important to recognize that while this only establishes correlation and not causation, the trend seems to be pointing to specific changes in the urogenital microbiome in patients struggling with poor sperm health.
Previously, the urogenital tract was thought to be sterile, free from any microbes. We have since learned that this is not the case. Certain microbes are present as commensal bacteria, meaning they are present but are not causing an infection. However, it is possible that these bacterial strains, even though they may not create symptoms of an infection, may impact the quality of the sperm cells, either through direct on indirect effects.
In general, various studies have found three different microbial communities in the urogenital tract of patients assigned as males at birth: lactobacillus-enriched, prevotell-enriched, and/or polymicrobial or pseudomonas-enriched communities. Lactobacillus-enriched microbiomes seem to be associated with healthy sperm function and health. This may be due to decreased inflammation, reduced production of reactive oxygen species, and a careful control over the pH (which sperm cells are very sensitive to). Prevotella, polymicrobial, and pseudomonas enriched communities are associated with poor sperm health and occur more frequently in patients that have sperm-factor infertility.
It is important to note that the microbiome in the urogenital tract may be impacted from the gut microbiome, bacteria or microbes present on the foreskin, prostate, and seminal vesicles. Often the microbial community is shared among sexual partners and when working with patients undergoing fertility treatments, the reproductive microbiomes of both partners should ideally be evaluated. While the research is still in very early stages for sperm health and its connection to the microbiome, it provides an exciting avenue to consider for patients with poor sperm health where no causative factor is identified based on traditional diagnostic tests.
Reference:
Osadchiy, V., Mills, J. N., Mayer, E. A., & Eleswarapu, S. V. (2020). The seminal microbiome and male factor infertility. Current Sexual Health Reports, 12(3), 202-207.