Practice Update, 04/21/2021 - The microbiome has been studied in a wide variety of illnesses and medical conditions, including urologic disorders. The microbiome refers to all bacteria, fungi, and algae, as well as associated agents such as viruses and phages in a specific region (eg, urine, gut, or semen.)
The authors of this article observed substantial overlap between seminal and urine microbiomes, and there was also substantial overlap between seminal microbiomes of fertile and infertile males.They did observe differences in specific agents, including Prevotella abundance, which was inversely associated with sperm concentration, and Pseudomonas, which was directly associated with total motile sperm count. As vasectomy altered the seminal microbiome, there is suggestion of a testicular or epididymal contribution. Anaerobes were highly overrepresented in the semen of infertile men with a varicocele. Genomic alterations in the S-adenosyl-L-methionine cycle, which is involved with DNA methylation, oxidative stress, and/or polyamine synthesis, were detected in microbiome changes, which provides a potential pathogenic mechanism for microbiome alterations.
Taken together, what does this mean for infertility patients? This is one of the more comprehensive studies of the “dysbiosis” of semen, urine, and gut microbiome in infertile men. But, despite nearly 10 years of study of microbiome changes in infertility,1 we have very little insight into whether the microbiome is an important area for further investigation or future treatment. Given that treatment with probiotics has not been demonstrated to be effective,2 it appears unlikely that study of the microbiome will be a high-priority target for identifying causes or future treatment for male infertility.