Women suffering from overactive bladder syndrome exhibit a higher urethral viral abundance compared to healthy controls: a pilot study

The interactions between the human bacterial microbiome and essential bodily functions are well established for organ systems such as the oral cavity, gut, and female reproductive tract. However, the urinary microbiome, particularly its viral component, remains largely unexplored. Emerging evidence suggests that the urinary microbiome may play a significant role in the development of overactive bladder syndrome (OAB). This study aims to fill this knowledge gap by investigating the potential link between the urethral virome and female overactive bladder syndrome, and by aligning these findings with the bacterial microbiome. Prospective pilot study including 15 patients with overactive bladder syndrome and five controls. Current urinary tract infection and antibiotic therapy within the last two months were ruled out and controls were matched to cases by age and body mass index. Urethral swabs (Copan eSwab^® urethra) were taken from each participant at one single time point. Subsequent viral isolation, purification, and enrichment were conducted using the ViPEP method. Next-generation sequencing was performed on pooled samples, followed by bioinformatic analysis to identify and classify viral contigs. Phylogenetic analysis was conducted to assess genetic relationships among identified viral sequences. The bacterial microbiome was analyzed by sequencing of the variable V3-4 region of the eubacterial 16 S rDNA gene on the Illumina MiSeq platform. We identified twenty-one viruses and bacteriophages only in pooled urethral swab samples of the OAB group, but no valid detections were retained in the control group after analysis. The most abundant human virus in urethral swab samples was human papilloma virus, whereas the most abundant bacteriophages belong to the family of Siphoviridae. In the bacterial microbiome analysis, we identified statistically higher levels of Veillonella and Bacteroides in OAB samples. Results of this pilot study suggest a difference in the urethral virome between women with OAB and healthy controls. When looking deeper into the detected virus families and species, we might postulate a unique microbial pattern of OAB patients. This pattern suggests an interplay of immunosuppression, autoimmune processes and a larger diversity of bacterial and viral microbes. Current evidence strongly suggests a disturbance of the healthy microbiome of the urogenital tract in patients with OAB, leading to subclinical chronic inflammation and thus typical OAB symptoms. Further research should focus on interventions aimed at restoring a healthy microbiome in OAB patients to mitigate inflammation and improve symptom control.