Urinary tract infections are common conditions that occur when bacteria from the intestines enter the urinary tract. New research, however, suggests that the bacteria causing these infections may come from contaminated food — especially chickens. While it sounds bizarre, studies from Canadian researchers show that stricter chicken-farm ani-contamination practices may help curb cases of urinary tract infections. Urinary tract infections (UTIs) are the second most common type of infection in the body, accounting for 8.1 million visits to health care providers in the United States each year and around $1-2 billion per year in health care costs. In 2010, researchers showed that the most common cause of the infections — E. coli bacteria — can originate in food. In a study published Wednesday February 29, 2012 the authors show that chicken is the likely culprit.
Scientists have long believed that urinary tract infections are typically caused by a person’s own E. coli bacteria, but a new Canadian study suggests the bacteria may more often than not come from chickens. Yes, chickens.
As many as 85 percent of urinary tract infections are caused by E. coli, according to the report in the March issue of Emerging Infectious Diseases, a publication of the U.S. Centers for Disease Control and Prevention.
Researchers compared the genetic fingerprints of E. coli from these infections to that of E. coli from chicken, beef and pork. And they found a match: chicken. What’s more, they report that the infections probably came directly from the chickens, not from human contamination during food processing.
“Chicken may be a reservoir for the E. coli that cause infections like urinary tract infections,” said study author Amee Manges, who is with the department of epidemiology, biostatistics and occupational health at McGill University in Montreal.
Manges has been researching strains of E. coli for years, and in particular, bacteria called extraintestinal pathogenic Escherichia coli, a form of the bacterium that lives in your intestines and is the most common strain of the bacteria responsible for UTIs. It’s milder than the deadlier strainE. coli O157, which is often implicated in food recalls.
For the study, Manges and her coauthors collected urine samples from women in Canada and California who had been diagnosed with UTIs and compared the E. coli bacteria in those samples with E. coli found in samples of beef, pork, and chicken purchased at grocery stores in those same regions. They also collected E. coli samples from animals killed at commercial slaughterhouses.
In 71 percent of the cases, the E. coli bacteria collected from women with UTIs matched that of theE. coli found in the supermarket chicken, while just 29 percent matched those found in beef and pork. Similarly, the E. coli bacteria collected from factory-farm slaughterhouse chickens matched UTI bacteria 79 percent of the time, compared to just 3 percent of those from cattle and 17 percent of those from pigs.
“We are also concerned about the selection and amplification of drug-resistant E. coli on the farms because of improper or overuse of antimicrobials during food animal production. It may be possible to reduce the level of drug-resistant infections in humans by encouraging rational and judicious use of antimicrobials on farms,” Manges said.
“We just want to emphasize that it isn’t just inappropriate use of antibiotics in human medicine that matters, but also the use of antibiotics in veterinary medicine and food production that leads to greater drug-resistant bugs,” the study author added.
“When you eat the meat, these bacteria live in your gut,” Manges says, adding that the bacteria can cause a UTI as much as six months after you’ve eaten contaminated chicken.
In the second half of the study, Manges analyzed the strains of E. coli found in women suffering UTIs and the supermarket chicken for its resistance to the antibiotics commonly used to treat UTIs, and she found that some of the bacteria had developed, or were developing, resistance to the medications.
“Drug-resistant UTIs are more difficult to treat,” Manges says. “Most of what we found could be treated with antibiotics, but it’s still concerning because that just means we have fewer drugs to treat them.”
The U.S. Food and Drug Administration already advises against the overuse of antibiotics in livestock, because it can lead to resistant strains of bacteria.
Dr. Philip Tierno, director of clinical microbiology and immunology at NYU Langone Medical Center in New York City, said it is not surprising that the food supply, especially chicken, may play a role in causing urinary tract and other infections. He said the best protection begins with proper hygiene.
“If you practice good personal hygiene, good food hygiene and good home hygiene, we can reduce the number of infections,” he suggested. Proper hand washing should last for 20 seconds. “Wash in between your [fingers] and under your nails,” Tierno said. “When dealing with counter surfaces, use a product that can disinfect surfaces and prevent cross-contamination.”
Cooking also helps kill disease-causing bugs. “Eat nothing raw. Cook it well, and if you are eating vegetables, make sure to soak them and wash them well,” he said.
The solution is definitely not to throw more antibiotics at livestock, Tierno agreed. As far as preventing E. coli in chicken coops, “we need a better system developed to raise chickens so they are not raised in crowded conditions and prone to diseases like E. coli,” he explained.