Researchers have linked approximately 1 in 5 urinary tract infections (UTIs) in Southern California to E. coli strains found in contaminated meat, publishing their findings in mBio.1
The data indicated the greatest risk is in patients residing in low-income neighborhoods. Additional vulnerability was reported in women, with the greatest-risk strains most often found in chicken and turkey. Investigators recommended additional research to separate foodborne transmission from other exposures.
Key takeaways:
- About 1 in 5 UTIs in Southern California were linked to E. coli strains originating from contaminated meat, particularly chicken and turkey.
- Women and residents of low-income neighborhoods faced the highest risk of infection from zoonotic E. coli strains.
- Turkey showed the highest contamination rate (82%), followed by chicken (58%), pork (54%), and beef (47%).
- Zoonotic E. coli isolates shared similar antimicrobial resistance patterns with meat samples, suggesting foodborne transmission.
- Researchers emphasized preventive interventions in meat processing and noted gepotidacin as a promising new treatment option for uncomplicated UTIs.
“This opens up new avenues for prevention, especially for vulnerable communities that bear a disproportionate burden. This is why we should be investing more, not less, in research about the social determinants of health,” said Lance B. Price, PhD, senior author and professor at George Washington University.
Testing methods
The study was conducted to evaluate rates of zoonotic extraintestinal pathogenic Escherichia coli(ExPEC) strains linked to UTIs, and how these proportions differed by sociodemographic factors.2 Urine culture was obtained from Kaiser Permanente Southern California patients between February 2017 and May 2021.
Standard techniques were used to collect and recover E. coli isolates from urine samples. Investigators also obtained retail meat samples in the same catchment area from major grocery chains on a weekly basis, including raw chicken, turkey, pork, and beef samples.
Disk diffusion was utilized to determine the antimicrobial susceptibility of meat isolates. Meat information included USDA establishment code, brand, grocery or retail location, date of collection, meat processor, organic or conventional production, and raised without antibiotics labeling.
Patient data was obtained from electronic health data and included age, sex, residence 3-digit ZIP code, and date of isolate collection. Investigators evaluated a total of 5,728 E. coli genomes, 2349 of which were human clinical isolates and 3379 were from retail meat samples.
Contamination and socioeconomic disparities
Patients were aged a median 50 years, with 42.2% residing in areas with low family poverty rates and 44.5% with median rates. Rates of E. coli contamination included:
- 82% for turkey
- 58% for chicken
- 54% for pork
- 47% from beef
Each 10% increase in the regional family poverty rate was linked to a 12% increase in contamination, highlighting greater contamination from areas with increased poverty. Increased contamination was also reported in samples from value packs, with an adjusted odds ratio (aOR) of 1.18.
Food animals were linked to 17.7% of human clinical urine E. coli isolates among the study population, indicating these as zoonotic ExPEC strains. However, only 0.6% of meat isolates were identified as having a human origin.
Of sequence types, 13% were shared between non-zoonotic ExPEC, zoonotic ExPEC, and meat isolates, though distinct distribution across E. coli groups was reported. The B2 and D phylogroups, significantly linked to extraintestinal pathogenesis, most often presented with non-zoonotic ExPEC isolates.
Antimicrobial resistance profiles and overall conclusions
Significantly varied antimicrobial resistance gene profiles were reported between non-zoonotic ExPEC, zoonotic ExPEC, and meat isolates. While non-zoonotic ExPEC isolates presented with significantly greater multidrug resistance, similar resistance was reported between zoonotic ExPEC and meat isolates.
Isolates from retail chicken had the greatest rate of zoonotic ExPEC-associated sequence types at 38%, followed by turkey at 36%, beef at 14%, and pork at 12%. Clinical isolates often had B2 and D phylogroups, which were rare among meat isolates.
Zoonotic ExPEC strains were more often reported in women than men, at 19.7% and 8.5%, respectively. Overall, the data highlighted zoonotic ExPEC strains as a significant cause of UTIs in Southern California. Investigators concluded interventions are needed to reduce rates of zoonotic ExPEC in processed meet.
“Until such measures are widely adopted, individuals at heightened risk of bacterial infections—including immunocompromised individuals, older adults, and those with chronic conditions—should exercise caution when handling raw meat (including frozen),” wrote investigators.
Emerging treatment options for UTIs
Fortunately, new treatment methods for uncomplicated UTIs are emerging, such as gepotidacin, which was discussed by Ryan Haumschild, PharmD, MS, MBA, CPEL, vice president of pharmacy at Emory Healthcare and Winship Cancer Institute, in a discussion with Contemporary OB/GYN.3
Gepotidacin received FDA approval following positive results from the phase 3 trials EAGLE-2 and EAGLE-3. The data indicated a significant therapeutic success rate of 58.5% vs 43.6% for nitrofurantoin. This provides patients with an alternative option to antibiotics commonly used to manage UTIs.
"Now, when we look at the clinical trial data, it was non-inferior to current available treatment options, which isn't a bad thing... because now it shows that there is equitable data that gives another option," said Haumschild.
