Resistance to antimicrobial agents is rising for a specific type of foodborne bacteria that can cause anything from mild diarrhea to very serious illness. Shiga toxin–producing E. coli infects about100,000 people in the U.S each year, with some developing serious enough symptoms to end up in the hospital. The biggest concern is for children under five years of age, who are more likely to develop serious complications, such as kidney failure.
“Most previous studies have looked at snapshots in time, not how resistance changes year by year,” said study leader Csaba Varga, professor of epidemiology at the University of Illinois Urbana-Champaign. “We didn’t have a clear picture of long-term trends, whether resistance was increasing, decreasing or staying the same. Resistance doesn’t stay in one place; it moves through people, animals and the environment. Our study helps fill those gaps by looking at when, where and in whom resistance is emerging over time.”
In their study, published in Future Microbiology, Varga and team focused on the E. coli strain O157, which produces the Shiga toxin responsible for the majority of severe illnesses.
Analyzing 1,995 samples collected between 2010 and 2021, the researchers found that, while overall resistance remains low, it has steadily increased over time—especially for the common antibiotics tetracycline and sulfisoxazole. They also found that resistance varied by geographical region and by age group, with younger adults in their 20s and 30s most likely to have infections resistant to some antibiotics.
Surprisingly, antibiotics are not typically recommended for Shiga-producing E. coli infections as the drugs can actually trigger the release of more Shiga toxin.
“Even though we don’t usually treat this infection with antibiotics, we’re still seeing resistance emerging and spreading, which tells us these bacteria are being exposed to antibiotics somewhere along the way,” Varga said.
The researchers propose a “One Health” approach to the issue, taking into account not only human health and antibiotic use, but animals and environment as well—particularly because the illness is foodborne.
Data from University of Illinois at Urbana-Champaign