Researchers at the University of Texas at Dallas have identified specific bacteria in the bladder that may indicate which postmenopausal women are more susceptible to recurrent urinary tract infections (UTIs), and found that estrogen may play a role in reducing that susceptibility.
We found a very strong association between beneficial bladder bacteria and the use of estrogen hormone therapy in postmenopausal women. Estrogen is important not only for regulating reproductive processes, but also for setting up the chemical environment of the entire body. When you lose this hormone, you lose all the benefits it offers.”
Dr. Nicole De Nisco, Assistant Professor of Biological Sciences, School of Natural Sciences and Mathematics
De Nisco is the corresponding author of a study published online Sept. 30 and in the Oct. 18 print edition of Cell Reports Medicine. The researchers found strong correlations between so-called “good” bacteria and urinary estrogen in postmenopausal women with no history of UTIs.
Urinary tract infections are among the most common adult bacterial infections and place a particularly significant medical burden on women, with more than 50% of women experiencing a UTI in their lifetime. Age is one of the strongest associated risk factors for UTIs.
Working with Dr. Philippe Zimmern, professor of urology at UT Southwestern Medical Center, the UTD research team tested 75 postmenopausal women who were divided into three groups:
- Those who had no history of UTI.
- Those who have recurrent UTIs and had one at the time of testing.
- Those who have recurrent UTIs but did not have one at the time of testing.
Michael Neugent BS’13, MS’19, PhD’20, a postdoctoral fellow in De Nisco’s lab and first author of the paper, said the research suggests that UTIs and estrogen make up the pool of all microbes; called microbiome -; it is found in the urinary and genital tracts of postmenopausal women.
“What we found is that those women who are between infections – those with a history of recurrent UTI but currently UTI negative – had a microbiome full of microorganisms capable of causing urinary tract disease while they had less good bacteria.” He he said.
In contrast, many of the women who were taking estrogen therapy did not have the “bad” bacteria in their bladders. The researchers said that the higher amount of estrogen found in urine correlates with a predominance of good bacteria, such as lactobacilli, in the microbiome.
The researchers also found that the microbiomes of women with recurrent UTIs contained more antibiotic resistance genes than those of women without a history of UTIs. Antibiotic resistance genes can be exchanged between cells, allowing resistance to spread rapidly through a population of bacteria and thus making infections more difficult to treat.
While antibiotics have been somewhat effective in fighting disease-causing bacteria, De Nisco said the prescription of antibiotics when they are not necessary -; that is accelerating antibiotic resistance -; is one of the biggest obstacles in the treatment of UTIs.
“We just can’t throw antibiotics at this problem or else we’ll never break the cycle of recurring infections,” De Nisco said. “We need to start thinking about outside-the-box therapies that don’t rely so much on antibiotics. Rather, we can use things like estrogen or maybe give a combination therapy of estrogen and a probiotic.”
De Nisco said the new information can perhaps guide the development of new detection and prevention tools. He is studying whole-cell vaccines and believes other solutions may be developed.
Dr. Kelli Palmer, associate professor of biological sciences at UTD, is an expert on antibiotic resistance and one of the authors of the article. He said the study is important because it addresses a demographic that is often overlooked.
“This research is meeting an important unmet need, which is the health of postmenopausal women, who have not typically been the focus of research,” Palmer said. “We need more research, new treatments, and generally more public attention on this issue of chronic infections, chronic UTI, and older women.”
De Nisco and his team have begun a five-year longitudinal study that tracks the microbiomes of postmenopausal women over time -; some with recurrent UTIs and others with no history of UTIs.
“No one has done this kind of longitudinal work in the urinary microbiome field,” De Nisco said. “This research is more difficult because you have to get a patient to come back multiple times and give you samples.”
Source:
University of Texas at Dallas
Journal reference:
Neugent, ML, et al. (2022) Recurrent urinary tract infection and estrogen shape the taxonomic ecology and functional potential of the postmenopausal urogenital microbiome. Cell Reports Medicine. doi.org/10.1016/j.xcrm.2022.100753.