Tests find drug-resistant bacteria in meat

LOS ANGELES — Meat in the United States may be widely contaminated with strains of drug-resistant bacteria, researchers reported Friday after testing 136 samples of beef, chicken, pork and turkey purchased at grocery stores.

Nearly half of the samples — 47 percent — contained strains of Staphylococcus aureus, the type of bacteria that most commonly causes staph infections. Of those bacteria, 52 percent were resistant to at least three classes of antibiotics, according to a study published in the journal Clinical Infectious Diseases.

DNA testing suggested the animals were the source of contamination. Environmental-health scientist Lance Price, the study's leader, said the animals most likely harbored these drug-resistant pathogens because they are fed to livestock to promote growth and prevent disease in crowded pens on large farms.

"These findings really point to serious problems with the way food animals are raised in the U.S. today," said Price, who directs the Center for Food Microbiology and Environmental Health at the Translational Genomics Research Institute, a nonprofit biomedical-research center in Phoenix.

Proper cooking kills the germs, as does thoroughly washing all foods and surfaces that come into contact with raw meat. And federal health officials estimate staph accounts for less than 3 percent of foodborne illnesses, far less than more common bugs such as salmonella and E. coli.

Last summer, the Food and Drug Administration (FDA) urged the meat industry to cut back on antibiotics out of concern that the practice breeds drug-resistant bacteria in stockyards that makes antibiotics less effective in humans.

But other scientists said it was premature to conclude that antibiotics in animal feed were to blame.

About half of all humans have staph bacteria in their nose or throat, and a food handler with poor hygiene could introduce the pathogen to the food supply, said Beilei Ge, a food scientist at Louisiana State University in Baton Rouge.

The meat and poultry samples tested in the study represented 80 brands and were purchased in Los Angeles, Chicago, Fort Lauderdale, Fla., Flagstaff, Ariz., and Washington, D.C.

The research was paid for by the Pew Campaign on Human Health and Industrial Farming, which advocates against the routine use of antibiotics in animal feed.

About 11,000 people die every year from S. aureus infections, according to the Centers for Disease Control and Prevention (CDC), and more than half of those deaths are from the hospital "superbug" methicillin-resistant S. aureus, or MRSA.

The American Meat Institute, which represents producers, said Friday that the country's meat and poultry supply is safe. And data from the CDC show that cases of food-borne illness in the U.S. have declined 20 percent in the past decade.

The bigger threat to public health is that widespread antibiotic use in livestock could make the drugs increasingly ineffective in humans, Price said.

The American Medical Association, the World Health Organization and other medical groups have warned that the misuse of antibiotics in food animal production may be creating a serious problem to human health by fostering development of drug-resistant bacteria.

Studies in Canada and Denmark show that taking antibiotics out of animal feed makes antibiotic-resistant bacteria less prevalent with no ill effects, Price said.

"Our lifesaving medications are being used as tools to make animals grow faster," Price said. "We must do everything we can to protect these antibiotics that protect our health."