In this study, a total of 277 unmedicated dogs with otitis externa were used. Overall, 413 agents were isolated from 277 ear swab samples; 52.7% of the cases were mono-infections (146 cases), and 37.1% of the cases were poly-infections (103 cases). In 10.1% (28) of the cases, neither bacteria nor yeasts were isolated. Coagulase-positive Staphylococcus spp. were the most frequently isolated bacteria and were found in 90 (21.8%) of the samples. Fifty-eight samples, (14%) were positive for Staphylococcus aureus, 51 (12.3%) for Pseudomonas aeruginosa, 27 (6.5%) for Proteus mirabilis, 27 (6.5%) for Malassezia pachydermatis, 21 (5%) for Corynebacterium spp., 21 (5%) for β-haemolytic Streptococcus spp., 15 (3.6%) for Staphylococcus pseudointermedius, 12 (2.9%) for Proteus spp., 12 (2.9%) for Escherichia coli, 9 (2.1%) for Acinetobacter calcoaceticus, 7 (1.6%) for Trichophyton mentagrophytes, 5 (1.2%) for Staphylococcus auricularis, and 46 (11.1%) for different bacteria and yeasts. A total of 14 different bacteria and yeasts were isolated and identified. Kirby-Bauer antibiotic susceptibility testing was carried out for 10 different antibiotics. The bacterial isolates were found to be resistant to amoxicillin-clavulanic acid (45%), gentamycin (28%), ampicillin/cloxacillin (69%), tobramycin (28%), amikacin (23%), enrofloxacin (47%), chloramphenicol (58%), doxycycline (65%), lincomycin/spectinomycin (58%) and polymyxin B (62%). In conclusion, it is important to test the antimicrobial sensitivity of aetiological agents of otitis externa before treatment so as to prevent the development of antibiotic resistance in bacteria and yeasts.
August J. R.: Otitis externa. A disease of multifactorial etiology. Vet. Clin. North Am. Small Anim. Pract. 1988, 18, 731-742.
Borum A. E., Çeçen G., Demir G., Çetin C., Şentürk S.: Determination and antimicrobial susceptibility of microorganisms isolated from otitis externa with dogs. Kocatepe Vet. Derg. 2014, 7, 27-31.
CLSI (Clinical Laboratory Standard Institute): National committee for clinical and laboratory standards and methods for antimicrobial susceptibility testing of anaerobic bacteria, Approved standard. 6th edition, NCCLS, Wayne, PA, Document M11-A6, 2004.
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