Identification and antimicrobial susceptibility of bacteria isolated from corneal ulcers and healthy eyes of canines in Ibagué-Tolima, Colombia

Objective To identify the ocular microbiota of healthy dogs and with corneal ulcers, and the sensitivity-resistance of the isolated bacteria to antibiotics. Animal studied 60 dogs were included. 30 of them free of clinical or ophthalmic disease; 30 diagnosed with a corneal ulcer. Procedures Samples for microbiological analysis were obtained by a sterile swab passed over the conjunctival sac and the cornea. The samples were inoculated on agars and identified by microscopy, Gram stain, and biochemical tests. Sensidiscs of sulfa, ciprofloxacin, tobramycin, tetracycline and gentamicin were included for the antibiogram. Results 67% of the patients with corneal ulcers showed bacterial growth; 83% were Gram-positive bacteria. Staphylococcus spp., Streptococcus spp., and Pseudomonas spp. were the most frequently isolated bacteria and were mainly sensitive to ciprofloxacin, followed by tobramycin, sulfa drugs, gentamicin, and tetracycline. 33% of the healthy patients showed bacterial growth with predominance of Gram-positive bacteria. The bacterial genera mainly isolated were Staphylococcus spp., Bacillus spp. and Acinetobacter spp., which in turn were sensitive to ciprofloxacin, sulfa drugs and gentamicin, and resistant to tetracycline and tobramycin. Conclusion Staphylococcus was the most frequently isolated genus in healthy and dogs with corneal ulcers. In corneal ulcers, Streptococcus and Pseudomonas also predominate. The bacteria isolated in dogs with and without corneal ulcers were mainly sensitive to ciprofloxacin, hence its use is recommended in these patients, and the use of tetracycline and gentamicin is advised against due to their significant resistance results.