Assessment of quinolone resistance in bacteria isolated from corneal ulcers in dogs

corneal ulcers or ulcerative keratitis is the loss of continuity of corneal epithelium leading to exposure of corneal stroma. It is a highly painful condition in dogs. The common aetiological agents responsible for this condition are bacteria and for treatment, antibiotics are widely used. Indiscriminate and prolonged use of antibiotics can cause antimicrobial resistance (AMR) in bacteria. The present communication deals with the isolation of bacteria from corneal ulcers in dogs and the assessment of quinolone resistance. A total of 15 corneal swab samples were collected from dogs suffering from corneal ulcers, presented to the Department of Veterinary Surgery and Radiology, Teaching Veterinary Clinical Complex, College of Veterinary and Animal Sciences, Mannuthy. They were inoculated on to brain heart infusion agar as well as blood agar and incubated at 37 °C for 24 h for the isolation of aerobic bacteria. Eighteen isolates obtained were then subjected to antibiotic susceptibility test by disc diffusion method using the quinolone group of antibiotics, viz. ciprofloxacin, enrofloxacin, ofloxacin and moxifloxacin. Majority of the isolates exhibited varying resistance to these antibiotics. Polymerase chain reaction was performed to amplify gyrA gene, which is reported to be one of the reasons responsible for quinolone resistance with respect to its mutation. Seven out of the 18 isolates amplified gyrA gene. The amplicon obtained corresponding to a representative sample, which was found resistant by disc diffusion method was sequenced and a single point mutation was detected.