Fluoroquinolone therapy in Mycobacterium chelonae keratitis after lamellar keratectomy.

PURPOSE: To characterize a rabbit model of Mycobacterium chelonae keratitis after lamellar keratectomy and assess the effectiveness of fluoroquinolone therapy. SETTING: University Laboratory, University of California, Irvine, California, USA. METHODS: Twenty-eight New Zealand white rabbits had unilateral lamellar keratectomy with placement of 2.5 x 10(5) colony-forming units of log-phase M chelonae under each flap. Eyes (7 per group) were randomized and treated with sterile balanced salt solution, gatifloxacin 0.3%, ciprofloxacin 0.3%, or levofloxacin 0.5% 4 times daily. Two masked observers examined all eyes on days 2, 5, and 7 and weekly for 4 weeks. Severity of disease and bacterial culture results were the main outcomes measured. The means and standard deviations were calculated, and differences between the groups were statistically analyzed. RESULTS: All eyes developed clinical disease. At the time the rabbits were killed, eyes treated with balanced salt solution, ciprofloxacin, levofloxacin, and gatifloxacin were culture positive in 6 (85.7%), 7 (100%), 6 (85.7%), and 3 (42.9%) of 7 eyes per group, respectively. Frequency of positive culture and the severity of clinical disease in gatifloxacin-treated eyes were significantly less (P < .05) than in the other groups combined. CONCLUSIONS: The rabbit model of M chelonae keratitis was successfully developed in our study. A fourth-generation quinolone (gatifloxacin) showed the best performance among the fluoroquinolones tested in our experimental approach. The fourth-generation fluoroquinolone, gatifloxacin, could be effectively used for the treatment of mycobacterial keratitis.

Fluoroquinolone therapy in multiple-drug resistant staphylococcal keratitis after lamellar keratectomy in a rabbit model.

PURPOSE: To assess the effectiveness of a fourth-generation fluoroquinolone for prophylaxis against multiple drug-resistant staphylococcal keratitis after lamellar keratectomy in a rabbit model. DESIGN: Experimental study. METHODS: Twenty-eight New Zealand white rabbits underwent unilateral lamellar keratectomy using a manual microkeratome followed by the placement of 1000 colony-forming units (CFUs) of log-phase Staphylococcus aureus bacteria under each flap. Eyes (seven in each group) were randomized and treated with one of the following agents: sterile balanced salt solution, gatifloxacin (0.3%), ciprofloxacin (0.3%) or levofloxacin (0.5%) immediately and 6, 12, and 18 hours after surgery. Inflammation was graded by two masked observers at 24 and 48 hours, and the presence or absence of infectious infiltrates was determined. The means and standard deviations were calculated, and differences among the groups were statistically analyzed. RESULTS: There were no flap complications encountered during surgery. Eyes treated with ciprofloxacin, levofloxacin, and balanced salt solution developed infectious infiltrates in five of seven eyes per group. Gatifloxacin-treated eyes did not develop clinical infection and exhibited lower mean inflammation scores (P <.01 compared with the other groups). CONCLUSION: The fourth-generation fluoroquinolone, gatifloxacin, is an effective prophylaxis against the development of keratitis after lamellar keratectomy in rabbits with an organism resistant to methicillin, levofloxacin, and ciprofloxacin.