Defining the Relationship Between Vaginal and Urinary Microbiomes.

Document Type

Article

Publication Date

8-14-2019

Abstract

BACKGROUND: Although the vaginal and urinary microbiomes have been increasingly well-characterized in health and disease, few have described the relationship between these neighboring environments. Elucidating this relationship has implications for understanding how manipulation of the vaginal microbiome may affect the urinary microbiome and treatment of common urinary conditions.

OBJECTIVE: To describe the relationship between urinary and vaginal microbiomes using 16S rRNA gene sequencing. We hypothesized that the composition of the urinary and vaginal microbiomes would be significantly associated, with similarities in predominant taxa.

STUDY DESIGN: This multicenter study collected vaginal swabs and catheterized urine samples from 186 women with mixed urinary incontinence (MUI) enrolled in a parent study and 84 similarly aged controls. Investigators decided a priori that if vaginal and/or urinary microbiomes differed between continent and incontinent women, the groups would be analyzed separately; if similar, samples from continent and incontinent women would be pooled and analyzed together. A central laboratory sequenced variable regions 1-3 (v1-3) and characterized bacteria to the genus level. Operational taxonomic unit (OTU) abundance was described for paired vaginal and urine samples. Pearson's correlation characterized the relationship between individual OTUs of paired samples. Canonical Correlation Analysis (CCA) evaluated the association between clinical variables (including MUI and control status) and vaginal and urinary OTUs, using the CCA function in the Vegan package (R version 3.5). Linear discriminant analysis effect size (LEfSe) was used to find taxa that discriminated between vaginal and urinary samples.

RESULTS: Urinary and vaginal samples were collected from 212 women [mean age 53 (±11 years)] and results from 197-paired samples were available for analysis. As OTUs in MUI and control samples were related in CCA and since taxa did not discriminate between MUI or controls in either vagina or urine, MUI and control samples were pooled for further analysis. CCA of vaginal and urinary samples indicated that that 60 of the 100 most abundant OTUs in the samples largely overlapped. Lactobacillus was the most abundant genus in both urine and vagina (contributing on average 53% to an individual's urine sample and 64% to an individual's vaginal sample) (Pearson correlation r=0.53). Though less abundant than Lactobacillus, other bacteria with high Pearson correlation coefficients also commonly found in vagina and urine included: Gardnerella (r=0.70), Prevotella (r=0.64), and Ureaplasma (r=0.50). LEfSe analysis identified Tepidomonas and Flavobacterium as bacteria that distinguished the urinary environment for both MUI and controls as these bacteria were absent in the vagina (Tepidimonas effect size 2.38, p

CONCLUSIONS: Significant associations between vaginal and urinary microbiomes were demonstrated with Lactobacillus being predominant in both urine and vagina. Abundance of other bacteria also correlated highly between the vagina and urine. This inter-relatedness has implications for studying manipulation of the urogenital microbiome in treating conditions such as urgency urinary incontinence and urinary tract infections.

Publisher

Elsevier

Publication Title

American journal of obstetrics and gynecology

ISSN

1097-6868

DOI

10.1016/j.ajog.2019.08.011

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