Antibiotic-Resistant Skin Infections (MRSP)
Your dog's skin swab came back MRSP. What a resistant staph infection means, why it's usually treatable, and what the guidelines say about your household.
Written by thecanineledger
This page carries no advertising, and nothing on it is for sale.
“Resistant” is a frightening word on a lab report. Yet the World Association for Veterinary Dermatology’s consensus guidelines say there is “little evidence for a difference in outcome” between resistant and ordinary staph infections in pets, and that “the prognosis for MRS skin infections in pets is good, depending on the underlying cause and co-morbidities” (Morris et al., Veterinary Dermatology 2017).
While that is reassuring, a resistant infection still changes how your vet treats your dog, and what you do at home. This page explains what MRSP is, how it’s treated, and what the guidelines say about the people and pets your dog lives with.
1. What MRSP is
Staphylococcus pseudintermedius is a bacterium that healthy dogs commonly carry, especially in the mouth. It can cause skin and ear infections when the chance arises. The guidelines name it as one of “the primary pathogens encountered in small animal dermatology practice.”
“MR” means meticillin-resistant. Meticillin-resistant strains don’t respond to a whole family of common antibiotics. Many also resist other families. The guidelines say clinical isolates “commonly express MR and MDR”, where MDR is multidrug resistance.
Resistance is not the same as a nastier infection. The guidelines note that “genetic expression of antimicrobial resistance is not a true virulence factor”. A resistant strain is harder to treat with tablets, but it isn’t necessarily more aggressive.
Our note: “A whole family of common antibiotics” is our plain wording. We don’t name the drug classes.
2. Why your vet needs a culture
Guessing is out. The guidelines say that choosing tablets without a test “is always contraindicated when a MRS infection is suspected”. Your vet should send a swab for culture and sensitivity testing, which shows which drugs still work.
This matters for repeat infections. If your dog has had several courses of antibiotics, or an infection that didn’t clear, ask whether a culture has been done.
→ The Itchy Dog: Allergies, Atopic Dermatitis, and What Actually Helps · → Ear Infections: Why They Keep Coming Back
3. How it’s treated
On the skin first. For surface and superficial infections, the guidelines say topical therapy “is the recommended treatment modality”. That means shampoos, sprays, wipes or creams that kill staph on the skin.
Sometimes topical treatment is enough on its own. The guidelines go further: it “should be used as the sole on-animal antibacterial treatment for surface and superficial infections whenever a pet and owner can be expected to be compliant.” Compliant means doing the treatment as often and as long as prescribed.
Tablets for deeper infections. For deep or widespread infections, or dogs that can’t be treated topically, the guidelines say “systemic treatment is indicated”, chosen from the culture results.
Treat the cause. The guidelines tie the prognosis to “the underlying cause and co-morbidities”, and say outcome “appears to depend on restoring the skin barrier function” alongside antibacterial treatment.
What the studies found. In one study the guidelines cite, 93 dogs with MRSP and 123 with ordinary staph skin infections had “no difference in outcome between groups, although individual MRSP infections took longer to resolve.”
Our note: The guidelines date from 2017. We haven’t checked for newer evidence.
4. After the infection clears
Your dog may still carry it. “For MRSP, it was shown that carriage can persist on dogs for more than 1 year after clinically apparent infection had resolved.” Carriage means the bacteria live on the dog without causing infection.
No routine “clearing” treatment. “There is currently not enough evidence to recommend routine decolonization of MRS carrier animals.” The guidelines support good hygiene instead.
Tell your vet next time. A dog known to have had MRSP should have this on its record. It affects how your vet chooses treatment for any future infection.
5. Your household
Can people catch it? The guidelines say transmission of MRSP “has been reported less frequently” than for MRSA, the resistant staph better known in human hospitals. Two studies they cite found “MRSP could be easily transmitted to dogs but not to people.”
It can happen. A 2023 Brazilian study sampled 100 dogs with skin or ear infections, and their owners. In two cases, a dog and its owner carried the same MRSP strain (Guimarães et al., Journal of Infection and Public Health 2023). The authors note that “all animals sharing the same clone slept together in their owner’s beds”, and that the MRSP owners worked in a hospital.
What the guidelines suggest at home.
- “Hand hygiene (proper washing/drying and use of alcohol-based hand sanitizers) is the mainstay of personal responsibility for infection control.”
- Until treatment has started and is working, it is “reasonable to restrict animals from contact situations”.
- At home, that could mean keeping the dog away from “‘at risk’ individuals” and cleaning more.
Who is “at risk”? The guidelines don’t define it for households. If someone in your home is immunocompromised, having cancer treatment, or has open wounds, tell your doctor that your dog has MRSP.
Our note: The “who is at risk” list is ours. The guidelines don’t give one for the home.
Our note: The guidelines don’t say whether to keep a dog with active MRSP off the bed, and the Brazilian study is small.
6. What we could not verify
| Commonly said | What we found |
|---|---|
| “MRSP is a superbug that can’t be treated” | No. The guidelines say the prognosis for resistant skin infections in pets is good. |
| “Resistant means more dangerous” | Not necessarily. Resistance isn’t a virulence factor. It makes treatment choice harder. |
| “It always needs strong antibiotics” | No. Topical treatment alone is recommended for surface infections where possible. |
| “Once it clears, it’s gone” | Not always. Dogs can carry MRSP for more than a year. |
| “My family will catch it” | It’s uncommon, but possible. Hand hygiene is the main protection. |
Sources
- Morris DO, Loeffler A, Davis MF, Guardabassi L, Weese JS. Recommendations for approaches to meticillin-resistant staphylococcal infections of small animals. Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 2017: expert consensus. Self-funded; authors declare industry honoraria and consulting
- Guimarães L, Teixeira IM, da Silva IT, et al. Epidemiologic case investigation on the zoonotic transmission of methicillin-resistant Staphylococcus pseudintermedius among dogs and their owners. J Infect Public Health 2023: cross-sectional study, 100 dogs and owners, Brazil
Always confirm with your vet before acting on anything on this page.