Tough-to-Kill Germs Found in Chicken and Hog Farms

Drug-resistant germs are turning up on our farms, and maybe in your food.

March 27, 2009

Big chicken farms may be growing antibiotic-resistant bacteria along with poultry.

RODALE NEWS, EMMAUS, PA—Flies can do more than annoy you at a summer picnic. A new study in press at the journal Science and the Total Environment has revealed that they can carry antibiotic-resistant bacteria, increasing our exposure to germs that are hard to kill.


THE DETAILS: Researchers from Johns Hopkins Bloomberg School of Public Health set up traps to collect flies near 8 poultry farms and then collected samples of poultry litter (a mix of manure and bedding materials) from 3 large-scale, conventional poultry operations in that same area. Both the poultry litter and the flies were found to harbor antibiotic-resistant strains of bacteria—“superbugs” that don’t respond to medicines commonly used to treat them. This isn’t the first study linking large-scale farms, often referred to as CAFOs, or "concentrated animal feeding operations," to drug-resistant bacteria. A small study of 20 Iowa hog farms, published in February in the online journal PLoS One, found that nearly 50 percent of the animals carried methicillin-resistant Staphylococcus aureus, or MRSA. That study is in line with others from Canada and Europe that have found similar relationships between MRSA in hog farmers and their animals. MRSA, one of the most widely publicized forms of antibiotic-resistant bacteria, can cause a severe skin infection that does not respond to standard antibiotics and can be fatal.

WHAT IT MEANS: If our farms are harboring MRSA and other medicine-resisting germs, it’s a threat to all of us. There’s potential for the microbes to spread to people who don’t live within a fly’s distance of a poultry farm, or anywhere near a hog farm, says Hopkins study coauthor Ellen Silbergeld, PhD, professor of environmental health sciences and epidemiology at the Johns Hopkins School of Public Health. In fact, a recent Johns Hopkins study found that cars traveling behind poultry-transport trucks were contaminated with drug-resistant bacteria. “This study points to a general breakdown in food safety and oversight of how we grow, produce, ship, and store food that humans consume,” says Silbergeld. Finding the bacteria in flies may be a particularly ominous sign, says Stuart Levy, MD, professor of medicine at Tufts University and author of The Antibiotic Paradox: How the Misuse of Antibiotics Destroys Their Curative Powers. “This just indicates that you have no control over where bacteria will go, ” he says. Fortunately, there’s no evidence of flies directly transmitting resistant bacteria to humans, though research by Dr. Levy and others has found flies to be important vectors for transmitting bacteria between farms.

Here are a few ways to minimize your exposure to antibacterial-resistant germs, and help eliminate them:

• Follow basic food-safety rules. With these extra-tough germs around, it’s more important than ever to practice good food safety. Testing in the Netherlands, for instance, has found some samples of raw pork to be contaminated with MRSA, and Consumer Reports has detected high levels of antibiotic-resistant salmonella and campylobacter in raw broiler chickens. Use separate cutting boards for vegetables and raw meat, and cook meat products to the appropriate internal temperature. The U.S. Department of Agriculture’s Food Safety and Inspection Service offers handy meat and poultry preparation guides.

• Buy antibiotic-free, organic meat. The way animals are raised really can lead to healthier food: Another Johns Hopkins study found that organically raised chickens had much lower levels of antibiotic-resistant bacteria than conventionally raised birds. And by supporting organic animal husbandry, you’re also encouraging a farming system that doesn’t contribute to the spread of antibiotic-resistant diseases. Find organic meat near you at Eat Well Guide or, if you can’t access it locally, order online from Heritage Foods USA.

• Purge your cabinets. You can also stop the rise of drug-resistant germs by choosing personal-care and cleaning products that are free of antibiotics. The chemical triclosan and its relative triclocarban appear in everything from toothpaste and towels to hand soaps, cleaning products, and cutting boards. Both chemicals are suspected of contributing to our growing resistance to antibiotics. Simple hand-washing and proper hygiene are just as effective at killing germs.

• Call your congressman. The “Preservation of Antibiotics for Medical Treatment Act” was just reintroduced last week and, if enacted, would limit the use of 7 classes of antibiotics on factory farms unless animals are sick. Currently, antibiotics are also fed to healthy animals to promote growth, and this overuse is contributing the rise of drug-resistant superbugs. Write a letter to your congressmen using the online form at the Pew Charitable Trust’s