Urinary microbiomes in postmenopausal women with or without urinary symptoms of the genitourinary syndrome of menopause: a cross-sectional study

Some postmenopausal women suffer from genital and urinary symptoms, while others do not. Therefore, the hypoestrogenic status cannot entirely explain the occurrence of the genitourinary syndrome in menopause (GSM). Differences in the urinary microbiome might play a role in bladder function and vulnerability to urinary symptoms. This study aimed to compare characterization urinary microbiome in postmenopausal women who experienced GSM with urinary symptoms with that in those without urinary symptoms. Forty participants were screened for genital symptoms of GSM and then divided into the urinary symptoms group and the non-urinary symptoms group on the basis of a validated questionnaire. 16 S rRNA gene sequencing was performed to investigate microbial diversity. The alpha diversity was used to evaluate the species richness and evenness, while the beta diversity was used to estimate the differences in the urinary microbiome between the groups. Differential abundance analysis was used to investigate biomarkers in the groups by linear discriminant analysis effect size. The relationship between the urinary microbiome and urinary symptoms was assessed using Spearman's correlation analysis. The characteristics of the participants were not different between the groups. Gardnerella was found in 22.2% (4/18) and 11.1% (2/18) of participants in the urinary symptoms group and in the non-urinary symptoms group, respectively (p > 0.05). Alpha diversity was less in the urinary symptoms group than in the non-urinary symptoms group, but this was not significant. Beta diversity of the urinary microbiome was not significantly different between the two groups. A differential abundance analysis showed that the genus Prevotella was significantly dominant in postmenopausal women with GSM who reported urinary symptoms. Prevotella was marginally correlated with voiding symptoms (r² = 0.44; p = 0.01). The bladder or urinary microbiome is closely related to urinary symptoms of GSM. Species richness and diversity are not significantly different between postmenopausal women with GSM with and without urinary symptoms. Prevotella is dominant in symptomatic women and slightly correlated with voiding symptoms.