Staph aureus bacterial contamination found in US meat and poultry stirs controversy

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Meat and poultry across the US has been found to be widely contaminated with Staphylococcus (staph) aureus bacteria. According to findings from the Translational Genomics Research Institute (TGen), half of the "staph" bacteria found in grocery meat produce are drug-resistant. TGen is concerned about the findings, funded by the Pew Commission. The American Meat Association says meat and poultry are safe.

Meat and poultry contamination coming from animals

The meat and poultry contamination is not coming from humans, say the study authors. The animals are likely the harbingers of staph infection, based on DNA testing.

Handling contaminated meat could pose problems to humans, but the researchers say more studies are needed. S. aureus could contaminate kitchen counter tops, utensils and cutting boards, potentially causing human infection.

Researchers analyzed bacteria in beef, chicken, pork and turkey from 26 retail grocery stores in Los Angeles, Chicago, Fort Lauderdale, Flagstaff and Washington, D.C.

They found 52 percent of Staphylococcus aureus - common bacteria found on human skin and in mucous membranes - were resistant to antibiotics.

Normally, the bacteria pose no problems. When bacteria overgrowth occurs Staphylococcus causes boils, pimples, abscesses, cellulitis and impetigo.

Systemic infection with staph can lead to hospitalization from pneumonia and sepsis. Strains of the bacteria have caused food poisoning. The penicillin resistant form found in humans is known as MRSA (methicillin resistant Staphylococcus aureus).

Lance B. Price, Ph.D., senior author of the study and Director of TGen's Center for Food Microbiology and Environmental Health says, "For the first time, we know how much of our meat and poultry is contaminated with antibiotic-resistant Staph, and it is substantial."

He says the problem is "densely stocked industrial farms" where bacteria flourish among animals given low-dose antibiotics that create bacterial resistance to common drugs that treat infection.

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When the bacteria move from animals to humans, physicians have limited choices for treating human infection, says Price. Staph contamination in meat and poultry is so widespread that Price says it “…demands attention to how antibiotics are used in food-animal production today

Paul S. Keim, Ph.D., Director of TGen's Pathogen Genomics Division and Director of the Center for Microbial Genetics and Genomics at Northern Arizona University (NAU) recognizes the problem as significant. He says, "The emergence of antibiotic-resistant bacteria — including Staph — remains a major challenge in clinical medicine.”

Antibiotic resistance has become a major focus of infectious disease specialists who recently warned that new antibiotics are “urgently” needed to combat the problem of antibiotic drug resistance.

Last year, the "Journal of Zoo and Wildlife Medicine" published findings that fish are beginning to harbor antibiotic resistant bacteria. The study was conducted by Mark Mitchell, a professor of veterinary clinical medicine at the University of Illinois.

Mitchell said"...there's probably a threshold at some point where there’s going to be a spillover and (antibiotic resistant bacteria in the environment) will start to affect us as a species.”

The next step, notes Dr. Keim, is to determine what the TGen findings mean in terms of human health. He suggests the need for close screening of meat and poultry for staph contamination.

American Meat Association says bacteria comes from handlers

Janet Riley, a spokesperson for the American Meat Institute says the study is too small of a sampling to raise concerns. In contrast said Riley, the U.S. Department of Agriculture studies "thousands" of meat samples over long periods. The American Meat Institute says the study "misleads" the public.

In response to the Pew study, Ellin Doyle, Ph.D., of the University of Wisconsin’s Food Research Institute has authored a new white paper, citing humans as the source of S. aurea bacteria that are so common and linked to humans from past food-borne illnesses.

Eighty brands of beef, chicken, turkey, beef and pork were included in the study. Forty seven percent of the meats and poultry were contaminated with staph and 52 percent of the meats and poultry contained staphylococcus aureus that is resistant to at least three classes of antibiotics. The American Meat Institute insists cooked meat and poultry is safe and the bacteria found likely comes from humans.

Clinical Infectious Diseases: doi: 10.1093/cid/cir181
"Multidrug-Resistant Staphylococcus aureus in US Meat and Poultry"
Andrew E. Waters, Tania Contente-Cuomo, Jordan Buchhagen, Cindy M. Liu, Lindsey Watson, Kimberly Pearce, Jeffrey T. Foster, Jolene Bowers, Elizabeth M. Driebe, David M. Engelthaler, Paul S. Keim, and Lance B. Price

Image attribution :DougsTech at en.wikipedia

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