Methicillin-resistant subspecies associated with otitis externa and pyoderma in dogs.

Background: Dermatological infections are the most common cases in the daily pet clinic. Since its discovery in 1990, subspecies have been reported more frequently in canine otitis externa and pyoderma and even in cases of zoonoses.

Aim: Detect the presence of subsp. of canine otitis externa and pyoderma, its antimicrobial resistance, and the presence of Agen.

Methods: Three-hundred-thirty-one swabs from dogs with otitis externa and pyoderma were cultured on bacteriological agar for bacterial isolation and subsequent biochemical and molecular identification. The identified subsp. were evaluated for their antimicrobial susceptibility using the Kirby-Bauer technique, including an oxacillin disk, and subsequently, a PCR was run to identify which ones had the A gene.

Results: Thirty-four (22.97%) and twelve (6.56%) isolates were identified as subspecies from otitis externa and pyoderma, respectively. Fluoroquinolones, the most widely used group of antibiotics in Peru, showed a susceptibility of 58.82% (20/34) in cases of otitis externa and 50% (6/12) in cases of canine pyoderma. Meanwhile, nitrofurantoin was the antibiotic with the best efficacy in both cases, with 97% (33/34) in otitis externa and 83% (10/12) in pyoderma. Furthermore, 40% (13/34) of subsp. isolated from otitis externa were resistant to methicillin, and 85.29% (29/34) had the A gene. On the other hand, the only methicillin-resistant isolate from pyoderma was also the only one with a A gene.

Conclusion: This study is the first report of subsp. in Peru, finding a higher percentage than reported in other South American countries.