A study published in Veterinary Microbiology found methicillin-resistant Staphylococcus aureus -- or MRSA -- prevalent in Canadian swine farms and their workers.
The Veterinary Microbiology study (Khanna et al. 2007) is the first to show that North American pig farms and farmers commonly carry MRSA. It looked for MRSA in 285 pigs in 20 Ontario farms, and found MRSA at 45 percent of farms (9/20) and in nearly one in four pigs (71/285). One in five producers studied (5/25) also were found to carry MRSA. This is a higher rate than in the general North American population. The strains of MRSA bacteria found in Ontario pigs and producers included a strain common to human MRSA infections in Canada.
A study published last month in the Journal of the American Medical Association (JAMA) (Klevens et al. 2007) estimated nearly 100,000 MRSA infections in 2005, and 19,000 deaths in the United States. Until recently, the thought was that MRSA was an opportunistic infection occurring mainly in hospitals. The JAMA study found that even healthy people are developing MRSA infections.
Members of the Keep Antibiotics Working coalition, including medical, agriculture and environmental experts, are calling for Congress to ask the U.S. Food and Drug Administration to study whether using human antibiotics in animal agriculture is contributing to MRSA infections in the United States.
“Identifying and controlling community sources of MRSA is a public health priority of the first order,” says Richard Wood, Executive director of Food Animal Concerns Trust and steering committee chairman of Keep Antibiotics Working. “Are livestock farmers and farms in the United States also sources? We don’t know for sure, because the U.S. government is not systematically testing U.S. livestock for MRSA.”
“Last summer, when we raised the MRSA issue, FDA told us that it had no plans to sample U.S. livestock to see if they carry MRSA,” says David Wallinga, MD, Director of the Institute for Agriculture and Trade Policy’s Food and Health Program. “Given the latest science that hog farms may generate MRSA, we need Congress to give FDA and other relevant agencies the necessary funding and a sense of urgency. Sampling needs to be done as soon as possible.”
A 2005 survey of attendees at an international veterinary convention in Baltimore, MD, who were tested for MRSA found that of the 27 who tested positive, 23 were from the United States.
In Europe, MRSA has been shown to be transmitted from pigs to farmers, their families, veterinarians, and hospital staff treating farm-infected patients. The same pig strain that was detected in Canada has been associated in Europe with human illness including skin, wound, breast, and heart infections, as well as pneumonia. Another European study showed that swine farms routinely using antibiotics were more likely to have MRSA than farms with limited antibiotics use.
Proposed federal legislation, The Preservation of Antibiotics for Medical Treatment Act, sponsored by Senate Health Committee Chairman Edward Kennedy (D-MA) and Sens. Olympia Snowe (R-ME), Susan Collins (R-ME), Sherrod Brown (D-OH) and Jack Reed (D-RI) is currently in the Senate (S. 549). Rep. Louise Slaughter (D-NY), a microbiologist, and 34 other U.S. House members have proposed a bill (H.R. 962) to phase out the use of antibiotics related to human medicine as animal-feed additives within two years. The American Medical Association, the Infectious Diseases Society of America, and the American Academy of Pediatrics and a vast array of other groups that have endorsed this bill.
Source: Keep Antibiotics Working coalition