Urinary microbiota and prostatic diseases: the key for the lock? A systematic review

Background Urinary microbiota is implicated in many diseases of the urinary tract. The aim of this study was to perform a systematic review of the role of urinary microbiota in prostatic diseases. Methods A PubMed/Medline search was undergone from inception through June 2022 for studies investigating urinary microbiota alterations in prostatic diseases, subdivided into benign prostatic hyperplasia (BPH), prostate cancer (PCa), and chronic prostatitis (CP). Study selection followed the PRISMA statement. Phylum, family, genus and species of each bacterium in cancer patients and controls were recorded. Quality of included studies was evaluated using the Critical Appraisal Skills Program (CASP) checklist for non-randomized studies. Results A total of 16 studies (4 studies on BPH, 9 studies on PCa and 3 studies on CP) comprising 1486 patients were included in our final analysis. Patients with BPH had a different urinary microbial composition, with a certain pattern proven to be associated with a higher lower urinary tract symptoms severity. Regarding PCa, some bacterial phyla/genera/classes/species were more abundant in PCa and others predicted a higher grade disease. In patients with CP, a different microbiota composition and a higher diversity were found, with the symptom severity being influenced mainly by microbiota composition, favoring aerobic microorganisms. Conclusion Urinary microbiota is implicated in prostatic diseases, especially in BPH, PCa and CP. However, given the relative heterogeneity among published studies, this implication suggests better delineation is needed. Further studies are needed to confirm these findings.