The recent discovery of the urinary microbiome has sparked research into the connection between this microbiome and urological symptoms and diseases, among which overactive bladder (OAB). Most studies demonstrate an increase in Lactobacillus. However, further results vary heavily between studies. To our knowledge, this is the first study that aims to clarify the differences in urinary microbiota between patient with OAB and detrusor overactivity shown on urodynamics (OAB DO+) and patients with OAB without detrusor overactivity (OAB DO-).
We obtained midstream urine of 12 patient with OAB DO+, 9 patients with OAB DO- and 12 healthy controls. The microbiome of the urine samples were analyzed with 16S rRNA gene sequence analysis.
In the OAB DO+ group 11 of the 12 samples (92%) are dominated by one genus (relative proportion of >50%), compared to 44% (OAB DO-) and 42% (control). The median Shannon numerics of 1.76 (OAB DO+), 3.34 (OAB DO-) and 3.39 (control) showed a significantly lower diversity in the OAB DO+ group. The portion of the bacteria are summarized in figure 1. Overall, Lactobacillus was the dominant bacteria, followed by Gardnerella and Prevotella. Lactobacillus was dominant in 58% of the OAB DO+ group. The median proportion of Lactobacillus in the OAB DO+ group (57.33) was significantly higher than in the OAB DO- (0.04) and control group (0.03). 70% of the Lactobacillus containing samples from the OAB DO+ group showed a dominance of Lactobacillus Iners. Gardnerella proportions did not differ significantly between groups. Median Prevotella proportions were significantly smaller in OAB DO+ (5.14) than in OAB DO- (12.58) and control (23.48). Moreover, Propionimicrobium, Dialister, Anaerococcus and Peptoniphilus made up significantly smaller proportions of the microbiome in the OAB DO+ group compared to one or both of the other patient groups.
The microbiome of patients with OAB DO+ was significantly less diverse and showed a higher proportion of Lactobacillus, particularly Lactobacillus Iners than the OAB DO- and healthy controls. These data suggest that bacterial flora could play a role in OAB pathophysiology. The microbiome could be a new starting point to study causes and treatments of OAB.