Species distribution and antimicrobial susceptibility of staphylococci isolated from canine otitis externa

The diversity of species of the genus Staphylococcus sp. and the antimicrobial resistance of isolates from 151 unmedicated dogs of both sexes with a clinical diagnosis of otitis were recorded. Ninety-one isolates of Staphylococcus spp. were identified by biochemical reactions and tested for susceptibility to 15 antimicrobials. Coagulase-positive species were most common; S. pseudintermedius (38.4%), S. schleiferi schleiferi (15.4%), S. aureus (14.3%), S. epidermidis (11%), S. simulans (11%), S. schleiferi coagulans (8.8%) and S. saprophyticus (1.1%). All the isolates showed resistance to at least one drug and 89% were multiresistant. Amoxicillin combined with clavulanic acid and oxacillin were the most effective, while resistance was widely observed for neomycin and erythromycin. The results highlight the recognition and the potential need for bacterial culture with species identification and antimicrobial susceptibility tests for appropriate antimicrobial therapy.