Effectiveness of ciprofloxacin and ofloxacin in a prophylaxis model of Staphylococcus keratitis.

Abstract

To determine the effectiveness of prophylactic fluoroquinolone treatment against staphylococci in a rabbit keratitis model. Prophylactic ciprofloxacin or ofloxacin was applied as one topical drop 15 minutes before infection or as one drop at three time points (19, 17, and 15 minutes) before infection. In a second experiment, rabbits were treated with two, three, or four drops of ciprofloxacin 1 hour before infection. Approximately 250 colony-forming units (CFUs) of Staphylococcus aureus were injected intrastromally, and CFUs were determined 5 hours after infection. The CFUs per cornea in all treatment groups were significantly less than the 5.6 +/- 0.11 log CFUs per cornea in the untreated group ( p < or = 0.0001). Rabbit eyes treated 15 minutes before infection with Ciloxan or Ocuflox had 0.96 +/- 0.48 log CFUs per cornea (three of six sterile corneas) or 1.26 +/- 0.31 log CFUs per cornea (one of six sterile corneas), respectively ( p = 0.5226). Eyes treated with Ciloxan 19, 17, and 15 minutes before infection had 0.0 +/- 0.0 log CFUs per cornea, and all eyes were sterile, whereas eyes treated with Ocuflox had 0.98 +/- 0.48 log CFUs per cornea and two of six eyes sterile ( p = 0.0435). Eyes treated 1 hour before infection with two, three, or four drops of Ciloxan had 2.61 +/- 0.69 log CFUs, 1.23 +/- 0.32 log CFUs, or 0.85 +/- 0.28 log CFUs per cornea, respectively, which was significantly less than untreated eyes ( p < or = 0.0001). Multiple topical drops of a fluoroquinolone administered prophylactically were effective for subsequent staphylococcal ocular infection.