A new study estimates that nearly one in five urinary tract infections in Southern California may be caused by E. coli strains transmitted by contaminated meat, posing a hidden foodborne risk to millions of people not only in California but across the United States. The study, published in mBio, also found that people living in low-income areas are most at risk.
“Urinary tract infections have long been considered a personal health problem, but our findings suggest they are also a food safety problem,” said Lance B. Price, senior author of the study and professor of environmental and occupational health at George Washington University.
“This opens up new opportunities for prevention, especially for vulnerable communities that bear a disproportionate burden. That's why we must invest more, not less, in research on the social determinants of health. Your risk of infection should not depend on your zip code.” Price is also the founding director of the Center for Action on Antibiotic Resistance at the G.W. Institute School of Public Health. Milkena.
UTIs are one of the most common infections worldwide, disproportionately affecting women and the elderly. They cost billions of dollars in health care costs and lost productivity each year. E. coli, a leading cause of UTIs, is also a common contaminant in raw poultry and meat, but until now it has been difficult to estimate how often foodborne strains cause infections in humans.
To fill this gap, researchers from GW and Kaiser Permanente in Southern California collected more than 5,700 E. coli isolates from UTI patients and retail meat samples from the same areas. They used a new genomic modeling approach to assess whether each bacterial strain was likely to have a human or animal origin.
Key Findings:
- 18% of UTIs in the study population were associated with E. coli strains of animal origin, which are known as foodborne UTIs.
- The highest-risk strains were most often found in chickens and turkeys.
- People living in low-income areas had a 60% higher risk of developing a foodborne UTI compared to those living in more affluent areas.
- Women and older men were especially vulnerable.
The authors caution that more research is needed to distinguish foodborne transmission from other possible exposures, improve models that can accurately identify specific meat sources, and generalize these findings to other regions and types of infections. Although the study was conducted in Southern California, there is evidence that the problem occurs throughout the U.S., Price said.
The researchers plan to refine their host origin prediction model and apply it to bloodstream infections and other serious diseases caused by E. coli. They are also exploring the possibility of developing measures that could reduce the risk of foodborne infections. Such research may take years, but the results suggest buyers should act now.
What can consumers do?
People can protect themselves by practicing safe food handling:
- Buy meat and poultry in secure packaging to prevent contamination with other products.
- Cook all meats and poultry thoroughly.
- Avoid cross contamination in the kitchen.
- Wash your hands and surfaces after preparing raw meat.
- Advocate for food safety policies that eliminate inequities in retail and public settings.
Studying, “Zoonotic Escherichia coli and urinary tract infections in Southern California“, was published in mBio on October 23, 2025.
The research was supported by the Wellcome Trust, the National Institute of Allergy and Infectious Diseases and the Johns Hopkins Sherrilyn and Ken Fisher Center's Environmental Infectious Disease Discovery Program.
(To sign up for a free subscription to Safety News, click Here)
