Antimicrobial Efficacy of Prophylactic Gatifloxacin 0.3% and Moxifloxacin 0.5% in Patients Undergoing Phacoemulsification Surgery

Purpose. To evaluate the ocular surface and aqueous antimicrobial effects of gatifloxacin and moxifloxacin administered in two dosing regimens to patients undergoing phacoemulsification. Methods. Patients were divided between two treatment groups and randomized to receive gatifloxacin 0.3% or moxifloxacin 0.5% within each group. Group 1 patients received antibiotics four times per day for 2 days before surgery with one additional drop the morning of surgery (n = 50, each drug). Group 2 patients were treated as in group 1, plus four drops (one drop every 10 minutes) during the hour before surgery (n = 60, each drug). Conjunctival and eyelid swabs were taken before surgery, and aqueous humor cultures were obtained immediately after surgery. Pathogens were identified and colony-forming units (CFUs) were counted. Results. No differences were observed between the antibiotics in mean CFUs in conjunctival cultures from group 1 (gatifloxacin, 59.9 ± 165.6 CFUs; moxifloxacin, 57.0 ± 214.7 CFUs; P=0.939) or group 2 (gatifloxacin, 76.7 ± 327.7 CFUs; moxifloxacin, 92.0 ± 486.1 CFUs; P=0.830). No differences were observed between antibiotics in mean CFUs in eyelid cultures from group 1 (gatifloxacin, 198.1 ± 330.1 CFUs; moxifloxacin, 168.3 ± 379.0; P=0.840) or group 2 (gatifloxacin, 556.8 ± 1,029.3 CFUs; moxifloxacin, 596.5 ± 1,013.5 CFUs; P=0.832). The overall rate of positive aqueous cultures in the 220 patients from groups 1 and 2 combined was less than 1% (i.e., no difference between antibiotics in either group). Conclusions. Preoperative topical ophthalmic gatifloxacin and moxifloxacin produced similar preoperative eyelid and conjunctival bacterial counts and identically low postsurgical aqueous contamination rates.