Tests from the nonprofit Consumers Union have found that grocery store shelves are littered with contaminated meat. Their tests regularly show that as much as two-thirds of grocery-store chicken contains bacteria resistant to some of the most common classes of antibiotics.
While those tests have an obvious ick factor, they also prove that dirty factory farms are filling our guts with bacteria that can cause all sorts of infections. And for women, that could mean more uncomfortable urinary tract infections (UTIs).
"In 80 to 90 percent of routine urinary tract infections, E. coli is the most common cause," says Amy Manges, PhD, associate professor in the department of epidemiology, biostatistics and occupational health at McGill University in Montreal. As lead author of a new study, published in the Centers for Disease Control and Prevention's journal Emerging Infections Diseases, Manges has found that supermarket chicken could be where all that E. coli is coming from.
"People are eating a lot more chicken because it's often perceived as healthier," she says. "But what people don't realize is that chicken is pretty heavily contaminated with bacteria in general, and those bacteria tend to be drug resistant."
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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 strain E. 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 the E. 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.
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"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."
Manges and her fellow researchers are joining the chorus of food activists and physicians who would like the Food and Drug Administration (FDA) to tighten restrictions on the levels and types of antibiotics that feedlot operators are permitted to add to feed and inject into animals. "Anytime you use antibiotics, we're just more concerned with these E. coli ending up in people at some point," she says.
The FDA took baby steps towards antibiotic overuse in January, when they restricted the use of cephalosporins in animals raised for food. Those same antibiotics are one of four types commonly used to treat UTIs. But that announcement came weeks after the FDA withdrew a petition that would have allowed it to regulate the use of the two most commonly used antibiotics, penicillin and tetracycline. So the risk of antibiotic resistance is still dire.
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The bottom line? If you're prone to UTIs, buy organic chicken. Research published in the journal Environmental Health Perspectives found that turkeys and chickens raised on organic poultry farms had almost four times lower levels of drug-resistant bacteria in their systems than those raised on cramped, dirty feedlots.
Better still, get your organic chicken from a local farmer. On both organic and feedlot farms, the amount of bacteria, studies have found, is directly related to the size of the flock. Local farmers with small flocks of chickens that roam on pasture and eat a healthy diet of bugs, grass, and organic grain will have the lowest levels of bacteria, drug resistant or otherwise.
Published on: February 24, 2012