Almost half of meat in stores may have drug-resistant bacteria



47% of samples tested had the type of bacteria that most commonly
causes staph infections. Food animals routinely fed antibiotics are a
possible source.


By Marissa Cevallos and P.J. Huffstutter, Special to the Los Angeles
Times

April 15, 2011, 4:32 p.m.

Meat in the U.S. 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% — contained strains of Staphylococcus
aureus, the type of bacteria that most commonly causes staph
infections. Of those bacteria, 52% 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 antibiotics routinely 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.

Last summer, the Food and Drug Administration urged the meat industry
to cut back on antibiotic use out of concern that the practice breeds
drug-resistant bacteria in stockyards and 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 noses or throats, 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.

Scientists incubated the samples for up to 24 hours in a broth that
was kept at human body temperature and used genetic tests to determine
whether they contained the staph bacteria. Then they treated them with
vancomycin, oxacillin, tetracycline and other antibiotics to determine
whether they were resistant to the drugs.

The research was funded by the Pew Campaign on Human Health and
Industrial Farming, which opposes 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, and more
than half of those deaths are from the hospital "superbug" methicillin-
resistant S. aureus, or MRSA.

The direct risk that consumers may acquire a staph infection from meat
can be reduced by cooking meat thoroughly and washing all foods and
surfaces that come into contact with raw meat, whether or not it is
resistant to antibiotics.

However, Caroline DeWaal, director of food safety at the Center for
Science in the Public Interest in Washington, D.C., said the study
results suggest that consumers might benefit by wearing gloves when
they handle raw meat. "It's making us rethink our advice to the
public," she said.

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

William Marler, a leading food safety attorney, said it was helpful to
test meat samples available in stores because the U.S. Department of
Agriculture's Food Safety and Inspection Service focused its testing
on meat production facilities.

"It's good to see more people doing retail testing because it shows us
that our meat is far less sanitary than most consumers would think,"
he said.

But 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 Assn., 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 for 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 in both
animals and people with no ill effects for animals or ranchers, 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."

http://www.latimes.com/health/la-he-meat-contamination-20110416,0,261049.story
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