We know well the intestinal bacterial flora, but we know much less that there is a urinary microbiota. Yet that bacteria play an important role in our health.

Contrary to popular belief, urine is not “naturally” sterile. Advanced analyzes (genetic sequencing) indeed show the presence of bacteria in more than 90% of urine where they are not detected by traditional tests. “Characteristic imprint of each individual, this urinary microbiota varies between sexes and according to age,” explains a French researcher. “It is very diverse in bacteria originating from the faecal, skin and vaginal flora”.

In humans, it is rich in Corynebacterium from the skin microbiota. In women, it contains particularly large quantities of lactobacilli, characteristic of the vaginal microbiota where they play a protective role against bacterial vaginosis, urinary tract infections and sexually transmitted diseases (STDs).

Director of the clinical microbiology laboratory of the University Hospital of Nîmes (France), Prof. Jean-Philippe Lavigne indicates: “The urinary microbiota seems to have a role of both protection against urinary tract infections, stimulation of immune defenses, and degradation of certain toxic compounds. “.

It will be important to better understand the interactions between pathogenic and commensal bacteria, and to examine the evolution of the urinary microbiota during life, whether naturally, in the presence of a disease and when taking medication. At the same time, one has to wonder about the influence of the urinary flora in the development of diseases such as bladder cancer or prostate cancer, even if at this stage no link has been established.