Pre- and postmenopausal women have different core urinary microbiota

Abstract

Recent studies suggest that alterations in the female urinary microbiota is associated to development of bladder disease. However, the normal microbiota composition and variation in healthy women are poorly described. Moreover, the effects of hormonal changes on microbiota during menopause is not well understood. The aim of our study was to investigate the urinary microbiota in healthy pre- and postmenopausal women without urinary tract symptoms. Microbiota composition in catheterized urine samples was mapped using 16S rRNA gene sequencing. In total, 41 premenopausal and 42 postmenopausal women were initially included. Samples with first PCR amplification concentration below level of the negative control were excluded, resulting in 34 premenopausal and 20 postmenopausal women included in data analysis. Urine from postmenopausal women showed significantly higher alpha diversity compared to premenopausal women. Lactobacillus was the most abundant bacteria in both groups, however the relative abundance of Lactobacillus accounted for 77.8% in premenopausal versus 42.0% in postmenopausal women. In conclusion, urine from premenopausal mostly presented with Lactobacillus dominated urotypes, whereas urine from postmenopausal women presented a more diverse urinary microbiota with higher abundance of the genera Gardnerella and Prevotella. The clinical and pathophysiological implications of this difference remain to be elucidated.

Figure 1

Alpha-diversity of the urinary microbiota in pre- and postmenopausal women depicted using (a) Number of observed OTUs, (b) Pielou’s evenness index, and (c) Shannon diversity index.

Figure 2

The bacterial composition in urine samples from pre- and postmenopausal women. (a) PCoA plot using Bray Curtis dissimilarity. Three urotypes were identified, as indicated with green, purple and orange circles. (b) Heatmap, indicating the 20 most abundant bacterial genera in the urine, as well as percentage of total OTUs. Red and blue respectively indicates high and low relative abundance. *Benjamin Hochberg adjusted p value < 0.01. (c) Dendrogram obtained with hierarchical clustering of OTU diversity in samples, based on the PCoA plot. Branch colors represent urotype, while label color represent menopausal state: red indicate premenopausal women, whereas blue represent postmenopausal women.

Figure 3

The bacterial composition in urine samples from premenopausal women. (a) Dendrogram obtained with hierarchical clustering of OTU diversity in samples. Three urotypes were identified, with green, purple and orange branches representing urotype I, II, and III respectively. (b–d) Heatmaps showing the 20 most abundant bacterial genera in the three urotypes, I, II and III. The premenopausal donors 2, 4, and 6 were not placed in any clusters by the unsupervised clustering algorithm used.

Figure 4

The bacterial composition in urine samples from postmenopausal women. (a) Dendrogram obtained with hierarchical clustering of OTU diversity in samples. Two urotypes were identified, with grey and mangenta colored branches representing urotype IV and V respectively. (b,c) Heatmaps showing the 20 most abundant bacterial genera in the two urotypes.

Figure 5

Demographics of the urotypes from pre- and postmenopausal women. (a) Age of the different urotypes in pre- and postmenopausal women. (b) Months since last menstruation for postmenopausal women. * p = 0.041.