Dr. Carrie McColgan of TVV Lilburn-Stone Mountain reports...
We’ve probably all heard about MRSA (methicillin-resistant Staphylococcus aureus) infections in hospitalized human patients, but how common are methicillin-resistant infections in our patients and pets? Are they more dangerous or contagious than other infections? And, most importantly, can they be transferred from our animals to us (or vice-versa), and what are the implications of that?
The prevalence of methicillin- resistant infections in dogs and cats is increasing to the point that it is not uncommon to find them in our patients. These infections most commonly come in the form of a post-surgical wound infection, skin infection (dermatitis or pyoderma), ear infection, or urinary tract infection. Some common factors between pets that are diagnosed with these infections include recent hospitalization, surgery, prior antibiotic use or exposure to a person with MRSA. Therapy dogs and cats tend to have an increased risk of infection. The methicillin-resistant bugs in question include MRSA, an emerging problem in veterinary medicine. Since 2006, however, MRSP, methicillin-resistant Staph pseudointermedius, is identified as the more common infectious agent in dogs (and cats).
While MRSA and MRSP can be found in both healthy and infected animals, their main similarity is this: they are both bacteria that are methicillin-resistant, or resistant to some commonly used antibiotics in the penicillin and cephalosporin families (called beta-lactams). This doesn’t mean that they can’t be treated or are somehow more dangerous or contagious than other infections. In fact, most of the time, they can be treated successfully by using topical and/or oral antibiotics that are stocked routinely at the veterinary clinic. And, although MRSA infections can occur in our pets and therefore are a potential risk to people, MRSA infections are mainly acquired by people in the hospital. The main methicillin-resistant bug in dogs (and cats, but less common) is MRSP, and, fortunately, infections in people are very rare.
S. psudointermedius is frequently found on the skin and nose of healthy dogs and can be found in the nasal passages of a small number of people (colonization versus infection); it is a common cause of infections, particularly of the skin. It is not always methicillin-resistant. It is presumed that when it’s found on people, the source is a pet. MRSP is of low zoonotic risk, meaning while not impossible, it is very unlikely to cause infection in people. Exceptions always exist, and appear to be limited to immunosuppressed individuals (HIV, cancer or transplant patients). According to Dr. J. Scott Weese from the Worms and Germs blog (check it out!): “Yes, there is a reasonable chance that MRSP can be passed between people and pets, but that’s different than getting sick.”
The prevalence of methicillin-resistant S.aureus in healthy pets is similar to people: about 4%. Veterinarians or people working in vet clinics or with livestock are more likely to be colonized by the bacteria. Again, it is possible, but not likely, for a person to contract a MRSA infection from one’s pet. The majority of MRSA infections are treatable, provided prompt, proper treatment is instituted. If a person is infected with MRSA, it is not necessary to screen all pets in the household unless directed by a physician as part of an intervention program. Frequent hand-washing, avoidance of contact with the pet’s nose, and preventing the pet from licking affected or broken skin can prevent transmission from a person to the pet.
If your pet has been diagnosed, via a tissue or skin culture, with MRSP (or less likely, MRSA), there are several things to remember:
- First, medicated shampoos (typically chlorhexidine based) will probably be prescribed to be used as often as every day. Second, oral antibiotics may, but won’t always, be prescribed. It is imperative to follow directions closely and finish all medications prescribed in order to prevent further drug resistance.
- Frequent hand-washing or use of a hand-sanitizer is still the best prevention to acquiring any type of infection.
- Wash your dog’s bedding, bowls, leashes, collars and toys minimally several times weekly in hot water.
- Avoid contact with the infected site, or wear gloves when contacting it. Don’t let your dog lick you in the face; in fact, avoid contacting his or her nose altogether if you can if your pet is infected.
- These bacteria are susceptible to most household cleaning agents. You don’t need to rip out carpets or throw away furniture.
- Don’t allow your pet to sleep in bed with you.
Ask your veterinarian if you have specific questions regarding treatment or prevention of these bacterial infections. We are always happy to help and to advise our clients!
Dowling, Patricia, DVM, MSc, DACVIM, DACVCP. “MRSA and MRSP in Small Animals (SA240).” Western Veterinary Conference 2012. www.vin.com/members/proceedings
Moriello, Karen A. DVM, DACVD. “5 Things Veterinarians Should Know About Methicillin-Resistant Infections.” Clinician’s Brief, www.cliniciansbrief.com, July 20, 2012.
Weese, J. Scott, DVM. “My Dog Has MRSP. Should I Be Concerned?” Reprinted from Worms and Germs Blog. VP Client Information Sheets. www.vin.com/Members/SearchDB/vp/vpa03298.htm, Oct. 7, 2011.
Weese, J. Scott, DVM. “ MRSA: Methicillin-resistant Staphylococcus aureus.” VP Client Information Sheets. www.vin.com/Members/SearchDB/vp/vpa03006.htm, Nov. 4, 2009.