Longitudinal urinary microbiome characteristics in women with urgency urinary incontinence undergoing sacral neuromodulation

Introduction and hypothesis: The objective was to evaluate the stability of the urinary microbiome communities in women undergoing sacral neuromodulation (SNM) for urgency urinary incontinence (UUI). We hypothesized that clinical response to SNM therapy would be associated with changes in the urinary microbiome.

Methods: Women completed the Overactive Bladder Questionnaire Short-Form, the International Consultation on Incontinence Questionnaire Short Form, and the Female Sexual Function Index at baseline and 3 months post-SNM implantation. Transurethral urinary specimens were obtained for microbiome analysis at baseline and 3 months postoperatively. The V4 region of the 16S rRNA gene (515F-806R) was amplified with region-specific primers, and Amplicon Sequence Variants (ASVs) were identified with a closed-reference approach of taxonomic classification. Alpha-diversity was calculated using the phylogenetic (i.e., Faith's phylogenetic diversity) and nonphylogenetic metrics (i.e., Shannon diversity, and Pielou's evenness) using the QIIME2 plugin. Longitudinal paired volatility analysis was performed using the DEICODE and Gemelli plugin to account for host specificity across both time and space.

Results: Nineteen women who underwent SNM and provided both baseline and 3-month urine samples were included in this analysis. Women reported improvement in objective (number of UUI episodes) and subjective (symptom severity and health-related quality of life) measures. Ninety percent of the bacteria were classified as Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. No significant differences were observed in each subject's beta-diversity at 3 months compared with their baseline microbiome.

Conclusions: Our descriptive pilot study of a cohort of women who had achieved objective and subjective improvements in UUI following SNM therapy demonstrates that the urinary microbiome remains relatively stable, despite variability amongst the cohort.