Purple urine bag syndrome: rethinking the role of urinary and gut microbiome in the pathogenesis of urinary tract infections

Abstract

The effort of the Humane Microbiome Project has led to the awareness that many districts of the human organism, like the skin, gastrointestinal tract, and genitals harbor their normal resident microbes. For this reason, the scientific community overcame the dogma that urines are sterile. Instead, the urinary tract hosts many bacteria, the so-called urobiome, that contribute to its homeostasis and pathology. Urobiome seems to be involved in the pathogenesis of the urinary tract infections (UTIs) and its relationship with the gut microbiome is still far from being understood. We describe a case of an emergent urinary condition, the “purple urine bag syndrome” (PUBS) that displayed with a peculiar combination of pathogens: Corynebacterium urealitycum and Enterococcus faecium. Both bacteria have been described as components of the urobiome and the latter is a well-known member of the gut microbiome but also a possible uropathogen. This case report is the starting point to analyze what we know about urobiome, its role in UTIs, and its interactions with the gut microbiome in the socalled “gut-UTIs axis”.

Keywords

• urinary microbiome
• urobiome
• gut microbiome
• gut-utis axis
• urinary tract infections
• purple urine bag syndrome.