Prophylactic effect of topical fluoroquinolones in a rabbit model of Staphylococcus aureus endophthalmitis

To evaluate the prophylactic effects of topical gemifloxacin, pazufloxacin, moxifloxacin, and levofloxacin for experimental Staphylococcus aureus endophthalmitis in a rabbit model.

Rabbits were randomly divided into 5 groups with 14 rabbits each. The control group received balanced salt solution (BSS); the other 4 groups received 1 drop of gemifloxacin, pazufloxacin, moxifloxacin, or levofloxacin ophthalmic solution, respectively, in the left eye at each of the following time points: 60, 45, 30, and 15 min before infection, immediately after infection, and then 6, 12, 18, and 24 h postinfection. S. aureus ATCC25923 [5×10(5) colony-forming units (CFUs) in 50 μL] was injected into the aqueous humor of each eye, and the clinical severity of the eyes was assessed 24 h postinfection. Two random eyeballs from each group were collected for histopathologic observation. Aqueous and vitreous samples of 12 other eyes were collected, diluted, and plated to determine the number of recovered CFUs.

Fluoroquinolone-treated eyes had significantly lower clinical scores and lower numbers of bacteria recovered from the aqueous humor than the BSS control group eyes. There was no difference, however, among the 4 fluoroquinolone-treated groups. In contrast, none of the fluoroquinolones reduced the number of bacteria recovered (CFUs) from the vitreous humor. In terms of the histopathologic results, less severe inflammation and relatively well-preserved ocular architecture were observed in fluoroquinolone-treated eyes, when compared with the control group.

Gemifloxacin and pazufloxacin may be as effective as moxifloxacin and levofloxacin for topical prophylaxis and for the treatment of S. aureus-induced endophthalmitis in the rabbit model.