Comparative efficacy of besifloxacin and other fluoroquinolones in a prophylaxis model of penicillin-resistant Streptococcus pneumoniae rabbit endophthalmitis.

PURPOSE

To study the efficacy of topical administration of gatifloxacin (0.3%), moxifloxacin (0.5%) ophthalmic solutions, and besifloxacin (0.6%) ophthalmic suspension as prophylaxis and treatment of pneumococcal endophthalmitis.

METHODS

Four groups of New Zealand white rabbits were topically treated with gatifloxacin, moxifloxacin, besifloxacin, and phosphate-buffered saline (PBS) at the following time points: 60, 45, 30, and 15 min before infection, immediately after infection, and then 6, 12, 18, and 24 h postinfection. Penicillin-resistant Streptococcus pneumoniae (PRSP; 10(6) colony-forming unit [CFU] in 50 microL) was injected into the aqueous humor of each eye. The clinical severity of the eyes was assessed by 2 masked observers 24 h postinfection. Aqueous and vitreous samples were collected, diluted, and plated to determine recovered CFU.

RESULTS

Fluoroquinolone-treated eyes had significantly lower clinical scores and bacteria recovered from the aqueous humor than the PBS-treated eyes. There was no difference, however, among the fluoroquinolone-treated groups. In contrast, none of the fluoroquinolones reduced the number of bacteria recovered (CFU) from the vitreous humor.

CONCLUSIONS

Besifloxacin is as effective as moxifloxacin and gatifloxacin in a rabbit model for topical prophylaxis and treatment of PRSP-induced endophthalmitis.