Meat contaminated by E. coli may be cause of one in five UTIs in California

A large genomic study has estimated that 18% of urinary tract infections in Southern California arise from foodborne Escherichia coli strains in poultry and meat, with residents of low-income neighbourhoods facing about more than double the risk when compared to wealthier areas so raising concerns about food safety, antimicrobial resistance and health inequalities across the United States

People in low-income neighbourhoods face the highest risk of foodborne infections, according to a large genomic study conducted in Southern California that has raised fresh concerns about food safety and health inequalities across the United States.

Researchers have estimated that nearly one in five urinary tract infections (UTIs) in Southern California may be resulting from Escherichia coli (E. coli) strains that originate in food animals and have reached people through contaminated meat. The work has also indicated that residents of low-income neighbourhoods have faced substantially higher risk than those in wealthier areas.

“Urinary tract infections have long been considered a personal health issue, but our findings suggest that they are also a food safety problem,” said Dr. Lance B. Price, senior author of the study and professor of environmental and occupational health at George Washington University, Washington, D.C.

“This opens up new avenues for prevention, especially for vulnerable communities that bear a disproportionate burden.

“This is why we should be investing more in research about the social determinants of health. Your infection risk should not depend on your ZIP code,” he said.

Price is also the founding director of the Antibiotic Resistance Action Center at the George Washington University Milken Institute School of Public Health.

Urinary tract infections are among the most common bacterial infections worldwide and affect women and older adults in particular. They impose substantial costs on healthcare systems through clinic visits, antimicrobial prescriptions, diagnostic tests and hospital admissions, as well as loss of productivity due to pain and recurrent illness.

E. coli is the leading cause of UTIs and is also a frequent contaminant of raw poultry and meat. However, it has been difficult to quantify how often E. coli strains that circulate in animals reared in food production move into people and then cause clinical infections.

The research team at George Washington University and the for-profit medical group provider, Kaiser Permanente Southern California, has attempted to close this gap by combining large-scale microbiological surveillance with whole-genome sequencing. The investigators collected E. coli samples from more than 5,700 patients with UTIs who had received care in Southern California, along with isolates from retail meat purchased in the same neighbourhoods. By comparison of genetic signatures from human and meat isolates, they used a novel genomic modelling approach to predict whether each strain most likely originated in a human host or in an animal host that entered the food chain.

The analyses suggested that about 18% of UTIs in the study population had arisen from E. coli strains which were of animal origin. The team referred to these as foodborne UTIs. The highest-risk lineages appeared most often in chicken and turkey products, which supports long-standing concerns about poultry as a reservoir for pathogenic, drug-resistant E. coli.

The study also indicated that residents of low-income areas had a roughly 60% higher risk of foodborne UTIs than residents of wealthier neighbourhoods. Women and older men were especially vulnerable which reflects the known epidemiology of UTIs but places it in a clearer food safety context.

According to the authors, the findings have strengthened the case for a ‘one health’ perspective, which treats human, animal and environmental health as interdependent. If foodborne E. coli strains contribute a large fraction of community-acquired UTIs, then interventions at abattoirs, processing plants and retail outlets, as well as in domestic kitchens, could reduce disease burden.

The work has also highlighted how structural disadvantages in housing, access to high-quality food retail, healthcare and transport can translate into measurable differences in exposure to foodborne pathogens.

The researchers have stressed that further work is required to refine these estimates and to separate foodborne transmission from other routes, such as contact with animals or environmental contamination. They aim to improve their host-origin prediction model so that it can attribute particular infections to specific types of meat or production systems.

The team also plans to extend the approach to bloodstream infections and other more severe forms of E. coli disease which arise following initial infection by UTIs but can have life-threatening complications. Price said there is evidence that similar patterns exist in other parts of the US suggesting a broader problem across the nation.

Alongside long-term research, the authors have argued that consumers and policymakers can already take practical action. Food retailers and regulators can strengthen controls that limit faecal contamination of meat during slaughter and processing, increase surveillance for high-risk E. coli lineages and address inequalities in the quality and safety of food sold in low-income communities.

At the household level, individuals can reduce their risk if they follow strict food hygiene measures for meat and poultry. The study team noted that consumers should:

• Buy meat and poultry that is securely sealed to prevent leakage onto other groceries.
• Cook all meat and poultry thoroughly, with particular care for chicken and turkey.
• Avoid cross-contamination by use of separate utensils and surfaces for raw and ready-to-eat foods.
• Wash hands and kitchen surfaces carefully after contact with raw meat.
• Support food safety policies that aim to reduce disparities in retail and community environments.

Although such steps may appear routine, they become increasingly important if a substantial proportion of UTIs have a foodborne origin. The authors warned that, because foodborne UTIs start in the community, they often involve strains that already carry resistance to multiple antibiotics used in human medicine, which adds to the global burden of the antimicrobial resistance crisis.

For further reading please visit: 10.1128/mbio.01428-25