Research fellow University of Miami, Miller School of Medicine
Introduction: Some observational studies have implied a link between vasectomy and an elevated risk of prostatitis and prostate cancer. Because inflammation within the semen could be a possible explanation, we hypothesized that vasectomy is a cause of dysbiosis in the seminal microbiota. We investigated the impact of vasectomy on semen microbiome, mainly using semen samples obtained from men before and after vasectomy.
Methods: Semen samples were obtained from men before and 3 months after vasectomy. To control external variables, vasectomies were performed by the same urologist. Microbial diagnosis (MicroGenDX laboratory in Lubbock, TX, USA) consisted of a rapid screening quantitative and qualitative real-time polymerase chain reaction test, followed by DNA pyrosequencing using 16S ribosomal RNA. Microorganism's specie, relative abundances and antimicrobial resistance were documented. Quantitative variables were analyzed with t-test. Beta-diversity among groups and paired-samples was calculated by Bray-Curtis dissimilarity. Relative abundance of 4 microorganism associated with prostatitis and prostate cancer was compared between groups.
Results: A total of 26 patients were included in the study and 119 bacteria were identified. The mean age at collection of the semen sample was 37 years old. No statistically significant differences were observed between the microbiota of semen samples obtained before and after vasectomy.
The most frequent organisms and with the highest relative abundances by before and after vasectomy were Enterococcus faecalis, Corynebacterium tuberculostearicum and Staphylococcus epidermidis, respectively.
Beta-diversity among groups and between paired sample was 0.29 and 0.22, respectively. The relative abundance of 4 bacteria that have been associated with prostatitis and prostate cancer was characterized (figure). Overall, 27% of the samples displayed antibiotic resistance, most commonly to aminoglycosides, and none of the groups exhibited a significant higher resistance (p=.4).
Conclusions: Our data suggests that seminal microbiome does not change after vasectomy. The relative abundance of bacteria that have been associated to prostatitis and prostate cancer do not appear to be increased after vasectomy, suggesting that it remains a safe procedure and does not promote semen microbiota dysbiosis.
Source of Funding: This work was supported by National Institutes of Health Grant R01 DK130991 and Clinician Scientist Development Grant from the American Cancer Society to RR.