Posted: September 21st, 2009 - 11:05pm
Source: New York Times

For decades, the drug-resistant germ called MRSA was almost exclusively a concern of humans, usually in hospitals and other health care settings.
But in recent years, the germ has become a growing problem for veterinarians, with an increasing number of infections turning up in birds, cats, dogs, horses, pigs, rabbits and rodents. And that, infectious-disease experts say, is becoming a hazard to humans who own or spend time with these animals.
“What’s happened for the first time that we’ve noticed is that you’re getting flip back and forth,” said Scott Shaw, head of the infection control committee at the Cummings School of Veterinary Medicine at Tufts University.
It is unknown how often pets play a role in human infections by methicillin-resistant Staphylococcus aureus and vice versa; physicians and veterinarians do not routinely trace such infections to their source. When such scientific sleuthing is conducted, however — usually in the case of multiple or recurring infections — the results suggest a strong link.
The first cases of MRSA in pets, about five years ago, appeared to be in therapy dogs and other animals exposed to patients or health care workers. Those animals are still thought to be at greatest risk, but the pattern might be changing.
In a study this summer in The American Journal of Infection Control, Elizabeth A. Scott and her colleagues at the Center for Hygiene and Health in Home and Community at Simmons College in Boston swabbed household surfaces like kitchen and bathtub drains, faucet handles, toilets, high chairs, trash cans and kitchen sponges at 35 randomly selected addresses to see what germs they would find. They found MRSA in nearly half of the homes they sampled.
When they tried to figure out what might make it more likely to have the bacteria at home, they ruled out many supposed risk factors, including working out at a gym, having children who attended day care, having a recent infection or recent antibiotic use, and even working in a health care facility.
The one variable that overwhelmingly predicted the presence of the germ was the presence of a cat. Cat owners were eight times more likely than others to have MRSA at home.
J. Scott Weese, a veterinary internist and microbiologist at the University of Guelph in Ontario, believes MRSA infections transmitted between people and animals are relatively rare.
His tests of randomly selected dogs, for example, have shown that at any given time only 2 to 3 percent carry MRSA on their fur or skin or in their saliva. And even if a pet becomes colonized, meaning that the bacteria take up residence and reproduce, veterinarians say most healthy animals should be rid of it in a matter of weeks.
For protection, Dr. Oehler recommends hand washing or using hand gels before and after playing with a pet, not letting a pet lick people around the face, and not washing pet food or water bowls in the same sink that food is prepared.
People should also wear gloves when attending to pets that have open wounds, he said, and should keep any of their own broken skin bandaged.
“If you think about the individuals with whom you have the closest contact in terms of duration, intensity, intimacy, in most people, it’s going to be the spouse, then small children, then pets,” Dr. Weese said. “For some people, pets are No. 1 on the list.”