Bärarskap av meticillinresistent Staphylococcus pseudintermedius (MRSP) hos svenska hundar

During the last years, meticillin resistant Staphylococcus pseudintermedius (MRSP) have caused an increasing number of infections in Swedish dogs. MRSP is resistant against a majority of the antimicrobials available for dogs in Sweden, making it difficult to treat the infection. Our knowledge of the bacterium is limited, making it hard to handle infected dogs in a proper way. The aim of this study was to investigate for how long time dogs, who have an infection caused by MRSP, become carriers of the bacterium. Other factors like treatment with antimicrobials, the correlation between clinical symptoms and carriage, common diagnoses and institutionalization where also looked upon. Increased knowledge in this field will improve the handling of patients and the advises to owners. Bacterial swabs where sampled from 23 Swedish dogs with known carriage of MRSP. Samples where collected on two occasions from four different locations: the nose, around anus, the pharynx and from any infected area on the dog. If the dog was asymptomatic, samples were instead taken from lip commissures. Culturing and identificationing and antimicrobial susceptibility tests were carried out in compliance with chosen method. Oxacillin resistant colonies where indirectly tested for the presence of the mecA gene with latexagglutination and this is used to confirm it as a MRSP. Among the 23 dogs that where sampled, almost 86 % where still positive within one to five months time. After six to thirteen months, almost 77 % of the dogs were sampled negative for MRSP. MRSP was isolated from one dog 12 months after it was first diagnosed. All of the dogs had been treated with antimicrobials within three months prior to MRSP culture. Among the dogs that tested positive for MRSP both dogs with and without clinical symptoms of infections where found. Above all, two diagnoses where prominent in the study; post operative wound infections and pyoderma. All of the dogs had been treated at veterinary clinics and 16 of 23 dogs had been hospitalised more than two nights. Rigourous hygiene routines are imperative in preventing spread of infection. Prudent use of antimicrobials and increased bacterial sampling, including resistance patterns, are further steps essential in reducing the selection for MRSP.