Urinary microbiota: specificities in cases of prostate cancer


The urinary microbiota of people with prostate cancer harbors pathogens that may contribute to the onset and/or development of this type of cancer.


This is the conclusion of an American study, the most exhaustive to date about the connections between the urinary microbiota and prostate cancer. Recent studies have shown that bacterial infections and chronic prostate inflammation may contribute to the development of prostate cancer, raising interest in identifying the species that are likely to be involved in the pathophysiology of the disease. The existence of a urinary microbiota may increase the repeated exposure of the prostate to various opportunistic bacteria, considering the proximity of the urethra.

To explore this possibility, researchers analyzed the composition of the urinary microbiota in 129 people with prostate cancer before a prostate biopsy. Among them, 63 had a benign tumor, 61 had a malignant tumor, and 5 others had an initially benign tumor that developed into cancer. The results indicate that all of the participants’ urinary microbiotas were largely equivalent, composed of around sixty species dominated by the genera Corynebacterium, Staphylococcus, Streptococcus, Lactobacillus, and Gardnerella. However, the presence of a group of bacteria containing Streptococcus anginosus, Anaerococcus lactolyticus, Anaerococcus obesiensis, Actinobaculum schaalii, Varibaculum cambriense and Propionimicrobium lymphophilum was most often associated with cancer (70.8% of cases). All of these species are implicated in urogenital infections, including prostatitis. The researchers also detected more pathogens like Ureaplasma parvum and Ureaplasma urealyticum in patients with cancer and Gardnerella vaginalis in patients with moderate to severe chronic prostate inflammation. These data do not allow conclusions to be drawn about the specific role of certain bacteria in the cancer, but they do shed new light on the composition of the urinary microbiota in patients with prostate cancer. They also suggest the presence of pro-inflammatory and uropathogenic bacteria in patients with prostate cancer.


Shrestha E et al. Profiling the Urinary Microbiome in Men with Positive versus Negative Biopsies for Prostate Cancer. 5. J Urol. 2017 Aug 7. pii: S0022-5347(17)77253-9. doi: 10.1016/j.juro.2017.08.001.