um MICROBIOLOGICAL PROFILE OF BACTERIAL ISOLATES FROM CORNEAL ULCERS IN DOGS AND CATS TREATED AT A VETERINARY TEACHING HOSPITAL

PERFIL MICROBIOLÓGICO DE BACTÉRIAS ISOLADAS DE ÚLCERAS CORNEANAS EM CÃES E GATOS ATENDIDOS EM HOSPITAL VETERINÁRIO UNIVERSITÁRIO

Abstract

This study aimed to characterize and evaluate the antimicrobial susceptibility profile of bacterial agents isolated from corneal ulcers in dogs and cats diagnosed with ulcerative keratitis treated at the Veterinary Teaching Hospital of the Federal University of Pelotas (HCV/UFPel). The study was conducted between November 20, 2022, and January 20, 2024, and included 19 dogs and one cat presenting ulcerative keratitis with varying degrees of severity. Following topical application of an ophthalmic anesthetic solution, 20 samples were collected from both healthy and ulcerated corneal surfaces using sterile swabs, which were subsequently placed in Stuart transport medium until laboratory processing. Bacterial isolation and characterization were performed, as well as antimicrobial susceptibility testing against drugs commonly used in veterinary ophthalmology. Bacterial growth was observed in 52.6% of canine samples, while no growth was detected in the feline sample. Among the isolates, 90% were Gram-positive and 10% Gram-negative bacteria, with Staphylococcus spp. (50%) being the most prevalent genus. Norfloxacin and chloramphenicol showed the highest efficacy against Gram-positive isolates. In the Gram-negative group, Escherichia coli was the only species identified and did not exhibit full susceptibility to any of the tested antimicrobials. Notably, bacterial resistance of up to 40% to amikacin was observed in both Gram-positive and Gram-negative isolates. These findings emphasize the importance of microbiological identification and antimicrobial susceptibility testing for the rational selection of topical antimicrobial therapies in cases of ulcerative keratitis, aiming to improve therapeutic efficacy and reduce the risk of bacterial resistance.