The evening news and the morning papers often carry stories about the scary “super bug” Staphylococcus aureus, or MRSA. These stories can be so frightening as reporters describe patients who have succumbed to overwhelming infections unresponsive to antibiotics.

To make matters worse, MRSA was recently in the news again. This time, researchers are suggesting our pets may be to blame for infecting human family members. Needless to say, these articles are causing alarm in many households where pets reside.

Hopefully the following information will help pet owners understand more about how this super bug is transmitted and what you should ask your veterinarian if you have concerns.

First of all, MRSA is an uncommon bacteria. However, when transmission does occur, it happens on one of two ways. If the bacteria causes disease in animals or humans it is called infection. Infections usually occur in a surgical incision, a wound and occasionally without a prior injury. People and pets may also be “colonized,” meaning the MRSA is present, but not causing disease. Both forms of MRSA have been reported in dogs and cats.

The potential for colonization of pets has been known for many years and most often occurs via transmission by infected humans or from environmental contamination. Pets are innocent bystanders in cases of colonization. In a recent study of dogs involved in animal assisted programs (Journal of the American Veterinary Medical Association, June 2009), the nostrils and feces of 200 dogs were screened for MRSA at baseline and none were found to be colonized or infected. Of the 116 dogs that were exposed to health care facilities as part of their animal assisted program, 7 dogs tested positive for MRSA during the course of the study, while only 2 of the 78 dogs not exposed to health care facilities tested positive for MRSA. Clearly, dogs exposed to human healthcare facilities are at risk for MRSA colonization.

MRSA infection has been documented in pets, typically following orthopedic surgery or as a result of a pet’s skin allergy. Infectious disease experts have expressed concern that pets infected or colonized with MRSA could transmit the infection to their family members. Pets may serve as a reservoir for MRSA and facilitate recurrent infections in the human members of the household. Another potential route of MRSA infectious may be through bite injury. Two recent publications, one from the human side (The Lancet, Infectious Diseases, July 2009) and one from the veterinary side (Journal of the American Veterinary Medical Association, February 2009) have highlighted the risks of bite injuries from pets. At this time, bite injury transmission of MRSA has not been documented.

Is my pet is at risk for MRSA?

1. If your pet has had an infection at the site of a surgery or developed an infection from a wound, ask your veterinarian to do a culture to identify the type of bacteria so that the appropriate antibiotic therapy can be prescribed.

2. If a human household member has been infected with MRSA, ask your veterinarian to culture the nostrils and feces of the pet or pets residing in the household. Pets and humans with positive cultures should be treated to eliminate colonization and break the transmission cycle.

3. If your pet is a therapy cat or dog who often visit nursing homes, hospitals or children’s centers, have your vet conduct a thorough examination and develop a preventive healthcare program, with an emphasis on preventing diseases which may be transmitted to humans. For example, it is important for therapy pets to receive treatments for parasite prevention, rabies vaccination and screening nasal swabs and fecal cultures for MRSA. Pets eating a raw food diet may be at greater risk for shedding Salmonella and E. coli in the feces, which could present a hazard to humans participating in animal assisted therapy.

___________________________
For nearly a century, The Animal Medical Center has been a national leader in animal health care, known for its expertise, innovation and success in providing routine, specialty and emergency medical care for companion animals. Thanks in part to the enduring generosity of donors, The AMC is also known for its outstanding teaching, research and compassionate community funds. Please help us to continue these efforts. Send your contribution to: The Animal Medical Center 510 East 62nd Street, New York, NY 10065. For more information, visit www.amcny.org. To make an appointment, please call 212.838.7053.