Urine microbes and predictive metagenomic profiles associate with abnormalities in sperm parameters: implications for male subfertility

Objective: To explore the taxonomic and predicted functional relationship between the urine microbiome and alterations of semen analysis (SA) parameters.

Design: Cross-sectional study.

Setting: Academic medical center.

Patient(s): Men presenting for fertility evaluation or men presenting for vasectomy consultation with proven biological paternity were recruited and stratified on the basis of alterations, or lack thereof, in SA parameters.

Main outcome measure: Changes in the functional and taxonomic urine microbiome profiles of participants with or without alterations in SA parameters.

Results: Seventy-three participants were included in our study. Men with abnormal sperm motility (N = 27) showed a nearly 50-fold higher abundance of Dialister micraerophilus compared with those with normal sperm motility (N = 46). This relationship persisted on canonical correlational analysis (r = 0.439). Men with abnormal sperm concentration (N = 20) showed a lower abundance of Enterococcus faecalis and Staphylococcus aureus, compared with those with normal sperm concentration (N = 53). The urine of participants with impaired sperm motility demonstrated dramatic differences in predictive functional profiles in pathways involved in oxidation-reduction balance and cell longevity.

Conclusions: Our findings underscore differences in the urinary microbiome and abnormalities in semen parameters, especially sperm motility. By incorporating predictive functional profiling, we also highlight possible mechanisms that may drive the observed differences in sperm parameters.