“Superbugs” originating in hospitals are now increasingly being found in cats and dogs, and in victims of bites.
Ironically, most animals probably acquired their infections originally from their owners. The bugs then easily spread between pets and household members.
The rise parallels the increasing abundance of community associated methacillin-resistant Staphylococcus aureus (CA-MRSA) over the past decade or so.
“Pet owners need to be aware of the potential for transmission of infections from their pets,” says Richard Oehler of the University of South Florida College of Medicine in Tampa, who has reviewed reported cases of pet infection with MRSA.
“An increase of pet-associated infections has been documented in the literature and has paralleled the increase in human MRSA infections,” he says.
The first case was reported in the UK in 1988, in a pet cat kept on a geriatric ward. 2006 saw the first report in pets of USA300, an emergent “community” strain of MRSA in the US. And, in the same year, researchers in Pennsylvania found that MRSA accounted for 35 per cent of 111 S. aureus samples originally taken from cats and dogs.
Oehler says that the strains pose a special risk because they’re resistant to antibiotics, and so may be more difficult than usual to treat if they result from cat or dog bites. Severe infections occur in about 20 per cent of bites. Sepsis can be a severe complication of bite wounds.
Children are at special risk, especially boys aged five to nine who provoke animals without realising the dangers. Often, because they’re shorter than adults, they receive severe bites to the face, neck or head, whereas adults are most often bitten on the hand.
“Bite infections can result in serious consequences, but MRSA can produce serious infections independent of the method of exposure,” warns Oehler.
One study found, for example, that MRSA often occurs in simple skin infections in pets, and can easily spread to owners.
In the wake of his findings, Oehler recommends measures to avoid infection. “Wash hands before and after pet contact, and be wary of dogs licking your face, any medical devices or open wounds,” he says.
“Also, be aware of your pet’s health status, and keep open wounds on yourself and your pet covered when you’re in contact with each other,” he says.
Oehler says that further research is needed to establish how superbugs circulate to pets, but the most likely route is via the owners.
The US Centers for Disease Control in Atlanta, Georgia, agrees.
“Most MRSA in humans is acquired by direct contact with other humans,” it said in a statement to New Scientist. “In most cases, MRSA in companion animals is a result of humans exposing the animals to MRSA, so pets can become colonised or infected with MRSA by contact with colonised or infected humans.”
Journal reference: The Lancet (vol 9, p 439)