Frequently asked questions about MRSP

Staphylococcus pseudintermedius and MRSP

Staphylococcus pseudintermedius is a bacterium found on the skin and the mucous membranes of dogs. It is very common in healthy animals but can also cause various infections. Infections most frequently caused by S. pseudintermedius include different types of skin and wound infections. Bone and joint infections as well as urinary tract infections are found less frequently.

S. pseudintermedius resistant to methicillin antibiotic is referred to as MRSP, or methicillin-resistant Staphylococcus pseudintermedius. MRSP is usually resistant to several other antibiotics as well - which is why many antibiotics commonly used for dogs are ineffective against infections caused by MRSP. About 15 % of S. pseudintermedius bacteria are MRSP bacteria.

What does MRSP cause?

MRSP causes similar infections as S. pseudintermedius. MRSP differs from regular S. pseudintermedius bacteria only by its susceptibility to antibiotics. MRSP does not cause infections more commonly than regular S. pseudintermedius bacteria. The treatment of infections caused by MRSP is more difficult due to the limited choice of effective antibiotics. Dogs can also be carriers of the MRSP bacterium without any symptoms. MRSP bacteria do not cause any danger to healthy animals.

How common is MRSP in Finland?

MRSP bacteria are most often found in dogs suffering from recurring skin or ear infections, or in dogs which for some other reason are often put on a course of antibiotics. Dogs of this type form the risk group for MRSP bacteria, and studies suggest that approximately 10 % of dogs in this risk group carry the MRSP bacterium. The prevalence of the MRSP bacterium is not as high in other dogs. According to a Finnish study, about 3 % of guide dogs were carriers of MRSP (source: Grönthal et al. 2015). The prevalence is probably of the same order of magnitude in dogs treated in veterinary clinics for a suspected bacterial infection. MRSP is extremely rare in cats in Finland.

How does MRSP spread?

MRSP is in most cases transmitted between animals by touch. It colonizes the skin and the mucous membranes of the dog, particularly when the dog is put on a course of antibiotics. During treatment susceptible bacteria are killed by antibiotics, whereas resistant bacteria multiply. MRSP can also be transmitted from one dog to another via the environment or various utensils (for example brushes, bowls, toys), or via human hands or clothing. Therefore, animals carrying the MRSP bacterium are treated in contact isolation.

Can MRSP be transmitted from animals to people?

People do not normally get infections caused by MRSP. Only some isolated cases of infections in humans have been reported globally. People in continuous contact with dogs can be asymptomatic carriers of MRSP, but it is very rare and probably short-term.

Can spreading of MRSP be prevented?

The propagation of all resistant bacteria can be prevented by reducing the use of antibiotics. The use of antibiotics should always be carefully considered. Sampling and analyses are the cornerstones for controlled use of antibiotics. In recurring skin and ear infections, the cause must be identified and treated. Antibiotics are not always needed: skin infections, for example, can often be treated locally.

If you know your dog to be infected with MRSP, let your veterinarian know already when making an appointment. This makes it possible for the veterinarian to plan your visit to the clinic without transmitting MRSP to other patients. The same applies also to other multi-resistant bacteria.

Can MRSP infection be prevented ?

Dog breeders should pay attention to the health of dogs used for breeding. Allergies and skin folds make dogs susceptible to skin infections and increase the use of antibiotics. Dog owners must look after the health of their dogs to avoid the need for antibiotics. Vaccinations should be kept up-to-date and teeth cared for properly, and animals should be provided with appropriate food and enough exercise. If an animal is ill, it should be taken to a veterinarian without undue delay. Animals should also be accustomed to being handled and treated with medicine to make appropriate treatment easier, if the animal gets ill.


Grönthal T, Ollilainen M, Eklund M, Piiparinen H, Gindonis V, Junnila J, Saijonmaa-Koulumies L, Liimatainen R and Rantala M., Acta Vet Scand. 2015; 57 (1): 37.

Page last updated 7/12/2019