Automated ribotyping and antibiotic resistance determining of Bacillus spp from conjunctiva of diabetic patients

Objective(s): We aimed to characterize the phenotype and genotype of Bacillus spp isolated from diabetic patients’ eyes, by studying the drug sensitivity patterns with a disc-diffusion method. Materials and Methods: Fifty eyes of 25 patients with type II diabetes mellitus, with at least 10 years of diabetes history, were included in the study. We analyzed the eyes for the presence of Bacillus spp.; presumptive isolates were identified by morphological, and biochemical tests, and confirmed by the VITEK system. Automated EcoRI ribotyping was performed with a RiboPrinter® Microbial Characterization System. We determined the antibiotic resistance of the isolates by the Kirby–Bauer disc diffusion test. Results: Seven out of 25 patients were on insulin treatment; 7 on oral anti-diabetic medication; and 11 on combination therapy of insulin and oral medications. Among the 28 Bacillus spp isolates, 14 were B. cereus, 11 were B. pumilus, 2 were B. mojavensis and 1 was B. subtilis. Almost all the strains were either resistant or multiresistant, particularly towards cefuroxime, methicillin, and ceftazidime. Conclusion: Diabetic patients seem to be more prone to B. cereus infections than healthy individuals. It would be greatly beneficial to understand and recognize the prevalence of microorganisms and their resistance patterns for better outcome in ocular surgeries.