Antimicrobial Susceptibility Profile of Bacteria Isolated in the Eyes of Dogs with Keratoconjunctivitis Sicca
The keratoconjunctivitis sicca (KCS) is a chronic eye disease characterized by quantitative and/or qualitative tear deficiency that can also occur secondary to bacterial infection. The objective was to evaluate the antimicrobial susceptibility profile of bacteria isolated in the eyes of 65 dogs with KCS. Conjunctival swabs were collected, and microbiological tests were performed (culture aerobically, antibiotic susceptibility and minimum inhibitory concentration [MIC] for chloramphenicol antibiotics, tobramycin, ofloxacin and moxifloxacin). Of the 65 dogs with KCS, 59 (90.8%) had positive culture for at least one eye. With respect to the sensitivity of the tested antibiotics, polymyxin B (98.6%), tobramycin (82.6%) and chloramphenicol (81.8%) were obtained at higher percentage, whereas tetracycline (40.2%) the lowest percentage. Regarding the results of the MIC, the fifteen most resistant strains of Staphylococcus pseudintermedius and fifteen more resistant strains of gram-negative were selected. S. pseudintermedius tobramycin (93.3%) expressed the highest percentage of sensitivity and gram-negative, ofloxacin and moxifloxacin presented 100% sensitivity, while tobramycin presented 93.3% and chloramphenicol 80%. In three animals, resistance was detected - a sensitive animal on cefazolin, one on vancomycin, and another on polymyxin B and amikacin - and these antimicrobials without commercial presentation in the form of eye drops. In 100% of treated animals, a clinical cure was obtained after 15 days of continuous medication. The tested antibiotics have sensitivity on the bacteria isolated in eyes with KCS; but in cases of resistance, identification of the bacteria and their antimicrobial susceptibility profile is important since bacterial infection (even though secondary) can be an aggravating factor and perpetuating this disease.