Background: Little is known about the relationship of proximal urogenital microbiomes in the bladder and the vagina and how this contributes to bladder health. In this study, we use a microbial ecology and network framework to understand the dynamics of interactions/co-occurrences of bacteria in the bladder and vagina in women with and without urgency urinary incontinence (UUI). Methods: We collected vaginal swabs and catheterized urine specimens from 20 women with UUI (cases) and 30 women without UUI (controls). We sequenced the V4 region of the bacterial 16S rRNA gene and evaluated using alpha and beta diversity metrics. We used microbial network analysis to detect interactions in the microbiome and the betweenness centrality measure to identify central bacteria in the microbial network. Bacteria exhibiting maximum betweenness centrality are considered central to the microbe-wide networks and likely maintain the overall microbial network structure. Results: There were no significant differences in the vaginal or bladder microbiomes between cases and controls using alpha and beta diversity. Silhouette metric analysis identified two distinct microbiome clusters in both the bladder and vagina. One cluster was dominated by Lactobacillus genus while the other was more diverse. Network-based analyses demonstrated that vaginal and bladder microbial networks were different between cases and controls. In the vagina, there were similar numbers of genera and subgroup clusters in each network for cases and controls. However, cases tend to have more unique bacterial co-occurrences. While Bacteroides and Lactobacillus were the central bacteria with the highest betweenness centrality in controls, Aerococcus had the highest centrality in cases and correlated with bacteria commonly associated with bacterial vaginosis. In the bladder, cases have less than half as many network clusters compared to controls. Lactobacillus was the central bacteria in both groups but associated with several known uropathogens in cases. The number of shared bacterial genera between the bladder and the vagina differed between cases and controls, with cases having larger overlap (43%) compared to controls (29%). Conclusion: Our study shows overlaps in microbial communities of bladder and vagina, with higher overlap in cases. We also identified differences in the bacteria that are central to the overall community structure.
Bibliographical noteFunding Information:
This project was supported by the Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction Foundation – OAB Urgency Incontinence Grant 2015 (RN); the National Institutes of Health (NIH) funded Oregon BIRCWH K12 award number K12HD043488 made possible through the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Office of Research on Women's Health (LK); the NIH National Institute of Diabetes and Digestive and Kidney Diseases K01 award number K01DK116706 (LK) and the NIH National Library of Medicine training award T15LM007088 (EL). The content is solely the responsibility of the authors and does not necessarily represent the official views of the any of the funders or National Institutes of Health.
The authors would like to acknowledge and thank the OHSU Women?s Health Research Unit and research participants that contributed samples and data to this research project. The authors also thank Guanming Wu, Ph.D., Tim Nice, Ph.D., and Eilis Boudreau M.D., Ph.D. for helpful feedback and discussions on the data analysis.
Copyright © 2022 Nardos, Leung, Dahl, Davin, Asquith, Gregory and Karstens.
- network analysis
- urgency urinary incontinence
- urinary microbiome
- vaginal microbiome
PubMed: MeSH publication types
- Journal Article
- Research Support, N.I.H., Extramural