Antimicrobial Resistance in Bacterial Pathogens of Canine Otitis

Otitis is one of the most frequent infections in dogs. This is attributed to the misuse of drugs enabling generation of multi-resistant micro-organisms. The emergence of multiresistant bacterial strains in veterinary medicine is a reality that must be studied and evaluated by the professionals. The objective of this study was to isolate and evaluate the antimicrobial susceptibility of bacterial pathogens of otitis in dogs. Otologic swabs were collected from 36 dogs with clinical otitis. 41 bacterial strains were isolated and antimicrobial susceptibility tests were performed by disk diffusion method with 34 antimicrobial agents. Presence of the resistance gene mecA of Staphylococcus was examined for 22 strains of staphylococci by PCR. A total of 1108 ratings antimicrobial agents were performed. The percentage of drug resistance was 34.66% (n = 384) of the assessments with partial or total resistance. Major bacterial pathogens were Staphylococcus spp. (65.85%), Pseudomonas spp. (12.19%) and Enterobacteria species (19.51%). 53.66% of the isolates were considered multiresistant. Antimicrobial agents considered most resistant in the strains studied were penicillin (75.00%), tetracyclin (50.00%), amoxicillin (48.78%), trimethoprim-sulfamethoxazole (46.15%), clindamycin and rifampicin (43.24%). 11 strains were phenotypically characterized as MRS, 4 genotypically as MRS, 2 as MLSB-MRS and 2 as gram negative ESBL-producing.