Urine and vaginal microbiota compositions of postmenopausal and premenopausal women differ regardless of recurrent urinary tract infection and renal transplant status

Abstract

Postmenopausal women and renal transplant recipients are at increased risk of recurrent urinary tract infections (RUTI). Urine and vaginal microbiota of premenopausal controls (N = 18) and RUTI cases (18), and of postmenopausal controls (30) and RUTI cases (20) with and without a renal transplant, were characterized using 16S rRNA sequencing. Participants did not have UTI symptoms at the time of sampling. Gram-negative uropathobionts (predominantly Escherichia/Shigella, Pseudomonas, Klebsiella, and Acinetobacter) had a much higher mean relative abundance in urine than vaginal samples, especially in premenopausal women. No statistically significant differences in mean relative abundances of bacterial groups were found within the premenopausal group or within the postmenopausal group by RUTI or renal transplant status without chronic antibiotic use. Comparing postmenopausal to premenopausal women, mean relative abundances of lactobacilli (especially L. crispatus) in urine and vaginal samples and of Gram-negative uropathobionts in urine were lower, and of BV-anaerobes and Gram-positive uropathobionts in urine and vaginal samples were higher. While RUTI in premenopausal women is predominantly caused by Escherichia, the causative organisms in postmenopausal women are likely more diverse. The relative importance of individual organisms is currently unknown. We recommend that future studies, including intervention studies, include longitudinal microbiota assessments.

Figure 1

Shannon alpha diversity of urine and vaginal samples by study group. Abbreviations: AB on antibiotic prophylaxis, RTR renal transplant recipient, RUTI recurrent urinary tract infection (defined as at least three UTIs in the past year). The figure shows the mean Shannon alpha diversity index for each group with 95% confidence intervals. p Values are by Wilcoxon rank-sum tests. Data for Chao1 indexes and richness values are shown in Supplement-1.

Figure 2

Mean relative abundances of bacterial groups in urine and vaginal samples by study group. Abbreviations: AB on antibiotic prophylaxis, BV bacterial vaginosis, RTR renal transplant recipient, RUTI recurrent urinary tract infection (defined as at least three UTIs in the past year). Sample sizes: premenopausal urine controls (18) and RUTI (18); premenopausal vaginal samples controls (15) and RUTI (17); postmenopausal controls (20), RUTI (10), RTR controls (10), RTR RUTI (6), and RTR using antibiotic prophylaxis (4) for both urine and vaginal samples.

Figure 3

Relative abundances of bacterial subgroups in urine and vaginal samples by study group. Abbreviations: AB on antibiotic prophylaxis, BV bacterial vaginosis, RTR renal transplant recipient, RUTI recurrent urinary tract infection (defined as at least three UTIs in the past year). Each bar represents one unique sample. Sample sizes: premenopausal urine controls (18) and RUTI (18); premenopausal vaginal samples controls (15) and RUTI (17); postmenopausal controls (20), RUTI (10), RTR controls (10), RTR RUTI (6), and RTR using antibiotic prophylaxis (4) for both urine and vaginal samples.

Figure 4

Mean relative abundances of Lactobacillus species by urine and vaginal samples by study group. Abbreviations: AB on antibiotic prophylaxis, RTR renal transplant recipient, RUTI recurrent urinary tract infection (defined as at least three UTIs in the past year). Unresolved lactobacilli could only be identified at genus level, not at species level. Sample sizes: premenopausal urine controls (18) and RUTI (18); premenopausal vaginal samples controls (15) and RUTI (17); postmenopausal controls (20), RUTI (10), RTR controls (10), RTR RUTI (6), and RTR using antibiotic prophylaxis (4) for both urine and vaginal samples.