Presurgical antimicrobial prophylaxis: effect on ocular flora in health patients

OBJECTIVE: Evaluation of presurgical antimicrobial prophylaxis for reduction of ocular flora.SETTING: Ophthalmology Section, Department of Medicine and Surgery, University of Catania, Italy.METHODS: Three days before photorefractive keratectomy (PRK), conjunctiva of 70 healthy patients (100 eyes) were swabbed. After 3 days of instillation of ofloxacin 0.3% (3 times daily), conjunctival swabs were taken again. Bacteria were isolated and identified from each swab.RESULTS: A total of 191 independent isolates were obtained prior to antimicrobial treatment. Bacteria were isolated from all 100 eyes sampled. Gram-positive species predominated, with Staphylococcus epidermidis and Staphylococcus aureus cultured from 69% and 25% of eyes sampled, respectively. Species of the anaerobic genera Peptococcus and Peptostreptococcus were found in 22% and 14% of eyes, respectively. After prophylaxis with ofloxacin, bacteria could be cultured from only 7% of eyes (10 independent isolates). All isolates were sensitive to ofloxacin except 5 strains of S. epidermidis, which displayed intermediate sensitivity. No infections occurred after PRK.CONCLUSION: Prophylaxis by instillation of ofloxacin 0.3% 3 times daily for 3 days substantially reduced the ocular flora of 100 healthy eyes prior to refractive surgery.