Cultural isolation and antibiotic sensitivity in cases of otitis externa in dogs

Otitis externa is a common problem encountered in canine practice worldwide and is frequently associated with bacterial and fungal pathogens. The present study was conducted on 50 dogs with clinical signs of otitis externa to determine the causative microorganisms and evaluate their antimicrobial susceptibility. A total of 42 (84%) samples yielded microbial growth. Staphylococcus spp. (40.4%) were the predominant isolates followed by Pseudomonas spp. (26.1%), Proteus spp. (9.5%), Escherichia coli (7.1%), and Klebsiella spp. (4.7%). Fungal isolates (Malassezia pachydermatis) accounted for 11.9%. Staphylococcus spp. were highly sensitive to enrofloxacin (85.7%), gentamicin (81.0%), and amoxicillin-clavulanic acid (76.2%) but resistant to penicillin G (23.8%) and ampicillin (28.6%). Pseudomonas spp. were sensitive to imipenem (88.0%) and amikacin (72.0%) but resistant to tetracycline (16.0%) and chloramphenicol (20.0%). Culture-guided therapy resulted in faster recovery (10-14 days) compared to empirical treatment (> 21 days). The findings highlight the importance of routine culture and antibiotic sensitivity testing for rational management of canine otitis externa and prevention of antimicrobial resistance.