Illinois Researchers Track Antimicrobial Resistance of E. Coli in Swine
Drug-resistant microbes are a global health concern that threatens our ability to treat infections. Antimicrobials help prevent and treat infections in humans and animals. According to the US Food and Drug Administration, 70% of all antibiotic sales in the U.S. are used for livestock production.
Unfortunately, microbes change over time to overcome these chemicals, eventually becoming resistant. The result? Infections become harder to treat. These resistant organisms can spread from farm animals to humans, creating a bigger health crisis. A recently published study tracked the antimicrobial resistance of Escherichia coli isolated from swine.
The researchers focused on E. coli since these bacteria are ubiquitous in the intestinal tract of humans and pigs, according to a University of Illinois release, and they are good indicators to test whether meat and meat products have been contaminated. E. coli can also acquire and transfer resistance genes to other bacteria in the intestinal tract, making them ideal for monitoring programs of livestock and humans.
“It is important to monitor the emergence of antimicrobial-resistant bacteria in the swine industry because in 2022 the U.S. was the third largest producer and consumer of swine meat and products, after the European Union and China,” Hamid Reza Sodagari, a postdoctoral research associate in the Varga lab, said in the release. “Although it is a big problem, to the best of our knowledge this paper is the first surveillance study in the US that looks at antimicrobial resistance in E. coli from swine at slaughter.”
Using publicly available surveillance data of cecal samples, which were collected from the intestine after slaughter, researchers focused on market swine and sows in the U.S. between 2013 and 2019. The data was collected by the USDA Food Safety Inspection Service under the National Antimicrobial Resistance Monitoring System for Enteric Bacteria program.
“Federal agencies often don’t have the manpower to carry out such long-term and detailed analyses. Alternatively, for most researchers such studies are challenging because usually they track samples on a smaller scale. In this paper, however, we were able to look at more than 3,000 samples across several years,” Csaba Varga (IGOH), an assistant professor of epidemiology, explained in the release.
Researchers found that since 2013, the number of antimicrobials to which E. coli is resistant has either remained steady or increased over the years. In particular, the resistance to ceftriaxone, an important antimicrobial drug in both human and veterinary medicine, increased from 0.8% in 2013 to 7.7% in 2019. Even though these numbers are not high compared to the resistance to other antimicrobials, the increasing trend is concerning, the release said.
Sodagari pointed out that they can't explain the increasing trend. Further research is required at the molecular level to understand the reason for the increase.
“We are not blaming anyone for this problem. Our study is meant to show that there is an issue and that surveillance systems are very important to show the changes in resistance,” Varga said. “By gathering this data, we hope that the public health authorities will be able to develop mitigation strategies.”
The study “Evaluating Antimicrobial Resistance Trends in Commensal Escherichia coli Isolated from Cecal Samples of Swine at Slaughter in the United States, 2013-2019” was published in Microorganisms.
