In this month's Did You Know? series, Chief Science Officer Beth DuPriest, PhD discusses the connection between the vaginal biome and urinary tract health. Have a question about vaginal biome science? Submit yours here and your answer may be featured in an upcoming newsletter.
Q: How does the vaginal microbiome affect urinary tract health?
A: Millions of women suffer from urinary tract infections (UTIs) each year – they account for 25% of ALL infections in the US!1 For younger women, UTIs are a nuisance and cause suffering and economic losses, but in the elderly, UTIs can turn deadly. Most people understand that women are more susceptible to UTIs than men are because of differences in anatomy. The shorter urethra and smaller distance from anus to urethral orifice allow easy access for UTI-causing bacteria, including uropathogenic E. coli and other species. But did you know that the vagina also serves as a reservoir of bacteria that can inhabit the urethra as well?
Contrary to popular belief, healthy urine, urethras, and bladders are not sterile, but host a variety of microbes. In individual women, the urinary microbiome is similar to the vaginal microbiome – women with high vaginal lactobacilli levels also had lots of lactobacilli in the urine, with a similar pattern for the various vaginal community state types2. Women with fewer vaginal lactobacilli are at higher risk for developing UTIs.
During menopause, falling estrogen levels cause the vaginal microbiome to shift from a lactobacillus-dominant community to a polymicrobial community like that seen in bacterial vaginosis. The loss of protective lactobacilli in the vagina is a primary driver of the increased rate of UTI after menopause.
Supporting the vaginal microbiome, whether before or after menopause, may reduce the frequency of UTI. Vaginal estrogen after menopause can improve the vaginal microbiome and reduce UTI. And in pre-menopausal women, a double-blind randomized placebo-controlled trial showed vaginal Lactobacillus crispatus probiotics were able to reduce the risk of UTI by half over the 10-week study3. All in all, better vaginal health means better urinary tract health, too.
1. Al-Badr A, Al-Shaikh G. Recurrent Urinary Tract Infections Management in Women: A review. Sultan Qaboos Univ Med J. 2013;13(3):359-367. doi:10.12816/0003256
2. Brown SE, Robinson CK, Shardell MD, et al. Assessing the Concordance Between Urogenital and Vaginal Microbiota: Can Urine Specimens Be Used as a Proxy for Vaginal Samples? Front Cell Infect Microbiol. 2021;11:671413. doi:10.3389/fcimb.2021.67141
3. Stapleton AE. The Vaginal Microbiota and Urinary Tract Infection. Microbiol Spectr. 2016;4(6). doi:10.1128/microbiolspec.UTI-0025-2016