Abstract

Staphylococcus intermedius is a commensal bacterium isolated from the mucous of clinically healthy dogs but commonly associated with pyoderma and otitis in dogs, causing opportunistic side infections. Otic exudates samples from 34 dogs affected by recurrent otitis externa and from 15 humans who had daily contact with them as pets were collected. Samples from five individuals who had no contact with any pet were also taken (as control group). Prevalence of antimicrobial resistance of strains of S. intermedius isolated from cases of otitis externa in dogs and their human owners was assessed. Gram stain, haemolysis, catalase and, respectively coagulase production for identification of staphylococci tests were used. Antimicrobial resistance was evaluated using difusometric standardized technique. All strains of S. intermedius isolated from dogs were resistant to polymyxin B (100%), a significant number of strains to erythromycin (66.66%), kanamycin (50%), tetracycline, lincomycin (45.8%), gentamicin and amoxicillin/clavulanic acid (37.5%), but highly susceptible to cefaclor (100%). Resistance high levels were also found among the eleven S. intermediusstrains isolated from humans (100% polymyxin B, 72.7% kanamycin amoxicillin/clavulanic acid, tetracycline 45.5%), and also against lincomycin and gentamicin (27.3%). 13 strains of methicillin-resistant S. intermedius (MRSI) were identified: five strains from dogs and eight strains from humans. Otic, oral, nasal and anal mucosa can serve as excellent S. intermedius reservoir for colonization in dogs. From these places, bacteria can be transferred easily to humans, especially if they are in contact with their pets and vice versa.

Key words: Staphylococcus intermedius, Otic, dogs.