Until recently, it was believed that healthy urine was sterile, but this dogma was later disproved: the community of microorganisms (microbiome) in the urinary tract of women was discovered and described. It was recently discovered* that, in addition to bacteria, it also includes numerous bacteriophages.

A wide variety of bacteriophages—viruses that infect and destroy bacteria—have been found in bacteria living in the human bladder. This provides further support for treating bacterial infections with phages, bacteria's natural enemies.

Scientists analyzed the genomes of 181 bacteria in the female urinary tract microbiome and discovered 457 phage DNA sequences. Bacteriophages are already known to normally inhabit the human intestine, skin, and oral and vaginal mucosa, but this is the first time such a diversity of bacterial viruses has been described in the bladder.

Phage DNA was found to be similar in different women, suggesting that there is a specific set of phages specific to the bladder (as well as, for example, the intestines). At the same time, certain differences in the phage composition were found between healthy women and patients with urinary tract infection symptoms. This may indicate a role for phages in maintaining the health of the urinary system and opens a new avenue for the search for treatments for urological infections, particularly cystitis.

*Miller-Ensminger T, Garretto A, Jonathon B, Thomas-White K, et al. Bacteriophages of the urinary microbiome // J ournal of Bacteriology, 29 January 2018 . JB.00738-17 DOI: 10.1128/JB.00738-17