Pets Pass Superbug to Humans

The superbug, a strain of bacteria known as MRSA, has evolved a resistance to antibiotics. It has long plagued hospitals but in recent years has become more common in homes. MRSA has even invaded beaches.

Only about two years ago, scientists began to seriously suspect pets were transmitting the bacteria.

In the July edition of The Lancet Infectious Diseases, Richard Oehler of the University of South Florida College of Medicine and colleagues lay out the latest thinking on MRSA (methicillin-resistant Staphylococcus aureus) and pets.

The infections can be transmitted by animal bites and most threaten young children, the researchers note.

"As community-acquired strains of MRSA increase in prevalence, a growing body of clinical evidence has documented MRSA colonization in domestic animals, often implying direct acquisition of S aureus infection from their human owners," they write. "MRSA colonization has been documented in companion animals such as horses, dogs, and cats, and these animals have been viewed as potential reservoirs of infection."

Dog and cat bites make up about 1 percent of emergency room visits in the United States.

Some facts presented in the journal:

• Women and the elderly are most at risk of being bitten by a cat.
• Men in general and those aged under 20 of both sexes are most likely to be injured.
• Most bite exposures occur in young children, involve unrestrained dogs on the owner's property, and about 20 percent involve a non-neutered dog.
• Risk is highest in young boys aged 5 to 9 years, due to their small size and lack of understanding of provocative behavior.

Severe infections can occur in about 20 percent of all cases, the researchers state, and are caused by Pasteurella, Streptococcus, Fusobacterium, and Capnocytophaga bacteria from the animal's mouth, plus possibly other pathogens from the human's skin.

"Proper treatment of dog and cat bites should involve treatment of the immediate injury (whether superficial or deep) and then management of the risk of acute infection, including washing with high pressure saline if possible, and antibiotics in selected cases," the researchers suggest.

"Bites to the hands, forearms, neck, and head have the potential for the highest morbidity," the scientists warn. They conclude: "Much more remains to be learned about MRSA and pet-associated human infections."

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