The urinary microbiome in patients with refractory urge incontinence and recurrent urinary tract infection

Urinary urge incontinence is a chronic, debilitating condition that is difficult to treat. Patients refractory to standard antimuscarinic therapy often experience recurrent urinary tract infections (rUTIs). The microbiota of these refractory patients with rUTI remains unexplored. A midstream urine (MSU) sample was collected from patients with refractory urge incontinence and coexistent rUTI during acute symptomatic episodes. Culture-based diagnosis was performed using routine microbiological methods. Culture-independent profiling was performed using bacterial 16S RNA profiling. E. coli strain typing was performed by amplicon pyrosequencing of the fimH gene. Over 2 years, 39 patients with refractory urge incontinence and coexistent rUTI were studied, yielding 9 severely affected cases. These 9 patients were carefully monitored for a further 2 years, resulting in the collection of 102 MSU samples, 70 of which were diagnosed as UTI (median of 8 UTIs/woman). Culture-independent analysis of 38 of these samples revealed the existence of a diverse urinary microbiota. Strain typing of E. coli identified instances of rUTI caused by the same persisting strain and by new infecting strains. Patients with refractory urge incontinence and coexistent rUTI possess a diverse urinary microbiota, suggesting that persistent bladder colonisation might augment the pathology of their chronic condition.