Identification and antimicrobial susceptibility of bacteria isolated from dogs with chronic otitis externa

Otitis externa (OE) is an inflammatory disease of the externa auditory meatus that occurs commonly in dogs. Antimicrobial susceptibility tests should be performed in case of chronic OE for successful treatment. In this study, identification and antimicrobial susceptibility test of bacteria isolated from dogs with chronic OE was performed. From 60 dogs with chronic OE, 60 bacterial species were identified. The most frequently identified species were Staphylococcus spp. (51%), followed by Pseudomonas spp. (15%) and Enterococcus spp. (14%). A single bacterial infection and multiple bacterial infections were observed in 67.5% and 32.5%, respectively. Staphylococcus spp. was susceptible to imipenum. Pseudomonas spp. was found to be susceptible to amikacin, cefepime, imipenum and piperacillin-tazobactam. Enterococcus spp. was susceptible to ampicillin-sulbactam, imipenum and piperacillin-tazobactam. Imipenum was highly susceptible antibiotic against both Gram-positive and negative bacteria whereas aztreonam and vancomycin were highly resistant. These results could suggest the optimal choice of antimicrobial agents for canine OE treatment.