PARMA, ITALY — An opinion on the public health significance of meticillin-resistant Staphylococcus aureus (M.R.S.A.) in animals and foods published by the European Food Safety Authority’s Panel on Biological Hazards (B.I.O.H.A.Z.) found that there is currently no evidence that eating or handling food that may be contaminated with M.R.S.A. may lead to an increased risk of humans becoming healthy carriers or infected with this bacterium.

Where M.R.S.A. prevalence in food-producing animals is high, people in contact with live animals, especially farmers, veterinarians and their families, are at greater risk than the general population, the panel also concluded.

In the case of food-producing animals, a specific type of M.R.S.A., known as CC398, has emerged and is often carried without symptoms by intensively-reared animals. The panel noted this strain represents a small proportion of the overall cases of M.R.S.A. in the European Union. Various types of M.R.S.A., including CC398, can be found in slaughterhouses and on raw meat, but the panel stated that, based on current data, the risk of infection for slaughterhouse workers and persons handling meat appears to be low.

"There’s no evidence to date that humans can become infected with the CC398 strain of M.R.S.A. from eating contaminated food," said Professor Dan Collins, chair of the B.I.O.H.A.Z. panel. "Neither is there evidence that this strain has caused food poisoning."

The occurrence of CC398 varies widely throughout Europe, the panel further noted. A risk for people in contact with live food-producing animals has been identified and veterinarians and farmers, as well as their families are at greater risk of becoming carriers or infected than the general population. In affected countries, the CC398 strain is mostly detected in pigs, veal calves, and broiler chickens.

Animal movement and contact between animals are each likely to be an important factor for the transmission of CC398, the panel said. It added since the most important routes of transmission to humans are through direct contact with live animals and their environments, the most effective control measures are likely to be at farm level.

Systematic monitoring of M.R.S.A. should be carried out to evaluate trends in the development of M.R.S.A. in food-producing animals in all member States, the B.I.O.H.A.Z. panel said. Further work should be performed on harmonizing methods for sampling, detecting and quantifying M.R.S.A. in humans and animals, and for detecting M.R.S.A. as a contaminant in food and in the environment. The panel also recommended guidelines for screening of patients admitted to hospitals should be expanded to include professional categories exposed to intensively reared livestock.

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