Microbial flora and antimicrobial susceptibility patterns from dogs with otitis media

This study evaluated the middle ear microbial flora and antimicrobial susceptibility patterns from dogs with otitis media. Antimicrobial susceptibility patterns were obtained on 164 micro-organisms from 107 ears of 82 dogs with otitis media that presented to Louisiana State University over a 12-year period. The most common micro-organisms isolated were Staphylococcus intermedius (26.8%), Pseudomonas aeruginosa (23.2%), beta -haemolytic streptococcus (12.8%), Proteus spp. (11.0%) and Staphylococcus epidermidis (8.5%). Antimicrobial susceptibility testing was performed on all isolates employing the disk diffusion method (Kirby-Bauer). Minimum inhibitory concentration (MIC) testing for enrofloxacin and ciprofloxacin was performed on 10 of the is P. aeruginosa isolates found to be resistant to enrofloxacin on Kirby-Bauer. Of these isolates, 6 (60%) were susceptible, 1 (10%) was intermediate and 3 (30%) were resistant to enrofloxacin. Eight of these isolates (80%) were susceptible to ciprofloxacin, 1 (10%) showed intermediate susceptibility and 1 (10%) was resistant.