28.feb.08
from a press release

Claims that food animals, such as pigs, are increasingly the source of methicillin-resistant Staphylococcus aureus (MRSA) bacteria in humans are greatly exaggerated, according to information from the Centers for Disease Control and Prevention (CDC).

In a recent letter to House Agriculture Committee Chairman Collin Peterson, D-Minn., and panel members Leonard Boswell, D-Iowa, Bob Goodlatte, R-Va., and Robin Hayes, R-N.C., the CDC said if transmission of MRSA from food animals to people occurs, "it likely accounts for a very small proportion of human infections in the United States."

Studies conducted in Canada and the Netherlands found MRSA in pigs and pork producers on some farms. Citing those studies, several newspaper articles and editorials and critics of the pork industry, including the Pew Commission on Industrial Farm Animal Production, have attempted to link pigs, pork products and the use of antibiotics in livestock and poultry with the recent rise in MRSA-related illnesses.

"Statements connecting pork products and MRSA and linking the bacterial infection to the use of antibiotics in pigs are seriously misleading," said Jill Appell, a pork producer from Altona, Ill., and president of the National Pork Producers Council. "Pigs are not responsible for the increase in MRSA cases contrary to the claims of our critics and some editorial writers."

The Dutch food safety authority, the National Institute for Public Health and the Environment, conducted a risk assessment in the Netherlands and concluded that the MRSA present in food animals such as pigs is not a food-safety threat. And a recent Institute of Food Technologists report stated that correlating the risk of antibiotic use in animals and antibiotic resistance in humans is not possible.
The CDC pointed out that 80 percent of life-threatening MRSA infections appear to be the result of patient-to-patient transmission in inpatient health-care facilities. Additionally, the "vast majority" of community-associated infections result from person-to-person transmission, it said. The agency also pointed out that it has conducted numerous investigations of community-associated MRSA outbreaks, and "in none of these investigations has animal exposure been identified as a risk factor for infection."

The U.S. pork industry has funded research to determine if MRSA is present in the domestic swine herd and supports additional epidemiological research and surveillance systems in health-care facilities to monitor the disease. The industry also has established a panel of U.S., Dutch and Canadian researchers to discuss and coordinate U.S. and international research efforts on MRSA in pigs.
The CDC has several infection surveillance programs for monitoring MRSA, including the Emerging Infections Program and the National Health and Nutrition Examination Surveys.

MRSA is a type of Staphylococcus aureus, a common bacterium found throughout the environment and carried in the nasal passages and on the skin of more than 30 percent of the population. MRSA, however, is resistant to certain antibiotics. There are at least three types of MRSA. Virulent forms are most commonly found in health-care settings such as hospitals and long-term care facilities and can cause serious illness and even death. Less virulent forms of MRSA are commonly found throughout the general population and on animals. A third form, which is less invasive than the health-care-associated forms, recently was discovered on some swine farms in the Netherlands and in Canada.

Groups such as Keep Antibiotics Working, which includes the Human Society of the United States and the Sierra Club, are urging Congress to pass legislation prohibiting the use in livestock and in animal feed of sub-therapeutic antibiotics, which they claim are being overused and, as a result, causing a proliferation of drug-resistant "super bugs" such as MRSA. Sen. Edward Kennedy, D-Mass., and Rep. Louise Slaughter, D-N.Y., are sponsoring bills to ban certain animal antibiotics.

NPPC has been working to defeat the measures and is cautioning lawmakers not to adopt policies that could adversely affect the pork industry without more information about MRSA and any link it may have to pigs. In the Canadian study, for example, while one-fifth of the pork producers were found to be carrying the same form of MRSA as their hogs, they did not have a higher rate of MRSA-associated illness than the general population.