Nearly $11 million grant supports study of gut bacteria
St. Louis American staff
Antibiotics can treat an infection while also wiping out helpful gut bacteria, allowing harmful bacteria to multiply. Researchers at Washington University School of Medicine in St. Louis want to understand how microbes that live harmlessly in the gut begin causing illness — and how to stop them.
A nearly $11 million federal grant will support research at WashU Medicine and Northwestern University into C. diff, which can cause severe diarrhea and intestinal damage, and E. coli strains that cause urinary tract infections.
Both can live in the gut without causing illness. But C. diff can produce damaging toxins, while some E. coli can travel to the bladder and cause an infection.
Researchers want to identify what allows those changes to happen. Their eventual goal is to help doctors recognize patients at risk and prevent infections before symptoms begin, according to WashU’s announcement.
Dr. Gautam Dantas, a WashU professor of laboratory and genomic medicine, leads the project, funded by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. medicine.washu.edu
Other research has documented differences in C. diff testing between Black and White patients and the difficulties Black women face with recurring urinary tract infections, or UTIs. Those studies were conducted outside St. Louis and are not part of the newly funded project. www.cambridge.org
One part of the WashU research focuses on why some people carry C. diff without becoming sick while others develop infections that can cause life-threatening intestinal damage.
Researchers will draw from a collection of more than 30,000 stool samples gathered over 15 years to investigate why. They will compare samples from patients with infections, people carrying C. diff without detectable toxins and other hospital patients.
The team will look for microbes and chemical signals that may keep C. diff from producing toxins. Researchers will also examine whether viruses that infect the bacterium affect toxin production, then test their findings in mice.
The other part of the project examines E. coli and recurring UTIs. Researchers will study stool and urine samples collected over six months from patients, mostly women, who experience repeated infections.
Antibiotics can treat a UTI while also disrupting beneficial gut microbes. Surviving E. coli may then multiply and cause another bladder infection. Researchers hope to find ways to interrupt that process.
For patients, repeated infections can carry an emotional burden as well as a physical one.
A University of Pennsylvania study published in March in the journal Urogynecology interviewed 12 Black women with recurring UTIs. Researchers found themes of shame and isolation linked to participants’ perceptions of UTIs as sexually transmitted infections.
Participants tended to focus on treating infections rather than preventing them and recommended earlier education for younger women. The authors called for care that better addresses patients’ experiences and puts more emphasis on prevention.
The study was too small to establish how widely those experiences are shared among Black women. pubmed.ncbi.nlm.nih.gov
A separate study at three Duke University Health System hospitals found Black patients received fewer C. diff tests relative to their time in the hospital than White patients. About 15% of tests were positive in both groups.
The researchers said the difference could reflect inequity in testing or differences in disease incidence. They did not establish the cause. www.cambridge.org
In areas monitored by the Centers for Disease Control and Prevention’s Emerging Infections Program, C. diff incidence was highest among White people in 2024. www.cdc.gov
Other research offers clues about how people’s surroundings may shape their gut microbes.
A 2023 study in PLOS Biology, co-authored by WashU biologist Dr. Elizabeth Mallott, analyzed 2,756 samples from 729 children. Small but statistically significant differences associated with race and ethnicity appeared around 3 months of age.
The authors emphasized that race and ethnicity are not biological explanations for those differences. The patterns likely reflect social and environmental conditions, such as diet, stress and access to care. The study did not establish that those differences cause C. diff infections or UTIs. journals.plos.org
Dr. Seth Bordenstein, a Penn State researcher who co-authored that study, pointed to changes in infants’ daily lives as possible influences on gut bacteria.
“Many changes occur in a child’s life between 3 and 9 months of age,” he said in a university account, citing solid foods, increased mobility and contact with more people. science.psu.edu
The newly funded research could eventually lead to screening tools and treatments that protect patients without further disrupting beneficial bacteria. For now, the team must determine which changes signal an approaching infection — and whether intervening can prevent it.