It's estimated that over 80 billion animals are slaughtered every year for their meat, and the average person eats about 43 kilograms per year. The average American, however, eats about 100 kilograms (about 220 pounds) of meat annually. Researchers have now suggested that bacterial contamination in meat from Escherichia coli bacteria could cause between 480,000 and 640,000 urinary tract infections (UTIs) in the United States every year. The findings, which used a novel approach for tracking bacterial strains by their genomes, have been published in the journal One Health.
"We're used to the idea that foodborne E. coli can cause outbreaks of diarrhea, but the concept of foodborne E. coli causing urinary tract infections seems strange; that is, until you recognize that raw meat is often riddled with the E. coli strains that cause these infections," said George Washington University professor and study co-author Lance Price, formerly of Northern Arizona University. "Our study provides compelling evidence that dangerous E. coli strains are making their way from food animals to people through the food supply and making people sick, sometimes really sick."
E. coli is a known cause of over of 85% of UTIs. These infections tend to impact women at higher rates than men, and while some may seem like an annoyance, they can become life-threatening illnesses if they move to the bloodstream.
While many strains of E. coli live harmlessly in the guts of humans and animals, sometimes even performing beneficial functions, there are dangerous strains of E. coli that generate toxins and can cause gastrointestinal distress. Some strains, such as E. coli O157:H7, are under surveillance in the US and other countries because of the threat they pose to human health when they contaminate meat products.
In this study, the investigators obtained samples of raw chicken, pork, and turkey from grocery store chains in Flagstaff, Arizona. The researchers isolated E. coli from these samples as well as bacteria that was collected from patients who had been hospitalized in the local area for UTIs. This way, the researchers were able to compare the genomes of E. coli bacteria in the meat to the pathogens that had been causing illnesses in people.
This showed that there were sequences of E. coli DNA that were unique to strains that contaminated food compared to those that infected humans. With this data, the scientists created a predictive model that could differentiate between the E. coli that came from those two sources.
The researchers determined that about 8 percent of UTIs in the Flagstaff area could be attributed to meat contaminated with E coli.
When the researchers scaled from the Flagstaff area to the overall U.S. population the work suggested that foodborne E. coli might cause hundreds of thousands of UTIs every year in the US.
Foodborne strains of E. coli that the researchers found are also linked to serious infections in the kidneys and bloodstream. It's thought that as many as 40,000 Americans die from E. coli bloodstream infections every year.
The study authors noted that the FDA could improve monitoring and surveillance for foodborne pathogens. Consumers should also follow safe food handling practices, including using separate surfaces for the preparation of raw meat and other foods, and good hand-washing.
Sources: Northern Arizona University, One Health
