Staph A Drug Resistance Passes from Pigs to Man

New study adds evidence that swine feed antibiotics may be problematic.

Published on: Nov 8, 2007

In recent weeks, U.S. newspapers have been reporting a growing concern over antibiotic-resistant Staphylococcus aureus in hospitals and even schools. Now comes a new study published in Veterinary Microbiology which found methicillin-resistant Staph. a. to be prevalent in 20 swine herds in Ontario, Canada.

MRSA was found at 45% of farms and in nearly one in four pigs. One in five pork producers tested also were found to carry MRSA. The research points to hog farms as a possible source of resistant infections, as have earlier European studies, claims Dr. David Wallinga, director of the Institute for Agriculture and Trade Policy's Food and Health Program.

A study published last month in the Journal of the American Medical Association (JAMA) (Klevens et al. 2007) estimated almost 100,000 MRSA infections in 2005, and nearly 19,000 deaths in the United States. In comparison, HIV/AIDS killed 17,000 people that year.

Pressure builds for FDA study

The Keep Antibiotics Working coalition (KAW), including medical, agriculture, and environmental experts, are calling for Congress to compel the U.S. Food and Drug Administration to study whether the use of human antibiotics in animal agriculture is contributing to the reported U.S. surge in MRSA infections and deaths.

"Identifying and controlling community sources of MRSA is a public health priority of the first order," contends Richard Wood, a KAW committee chair. "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."

U.S. veterinarians are documented as carriers of MRSA. In 2005, attendees at an international veterinary convention in Baltimore, Md., were tested for MRSA. Of the 27 who tested positive, 23 were from the United States.

Legislation in Congress

Proposed federal legislation, The Preservation of Antibiotics for Medical Treatment Act, sponsored by Senate Health Committee Chairman Edward Kennedy, D-Mass., and Senators Olympia Snowe, R-Maine, Susan Collins, R-Maine, Sherrod Brown, D-Ohio, and Jack Reed, D-R.I., in the Senate (S. 549) and Rep. Louise Slaughter, D-N.Y., the only microbiologist in Congress, and 34 other House members in the U.S. House of Representatives (H.R. 962), would phase out use of antibiotics important in 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 are among more than 350 health, agriculture and other groups endorsing the bill.