Topical prophylaxis with moxifloxacin prevents endophthalmitis in a rabbit model

The prophylaxis potential of the topical antibiotic, 0.5% moxifloxacin (Vigamox), was evaluated to prevent endophthalmitis after bacterial anterior chamber challenge in a rabbit model. An in vivo laboratory investigation. Three regimens of topical 0.5% moxifloxacin were tested for prophylaxis to prevent endophthalmitis: (1) (full prophylaxis) moxifloxacin drops every 15 minutes for 1 hour (five drops), anterior chamber challenge with 5 × 10 4 colony-forming units of Staphylococcus aureus, one drop of moxifloxacin, and four more drops applied over the next 24 hours; (2) (preprophylaxis) prechallenge prophylaxis, S. aureus challenge, and no postchallenge prophylaxis; and (3) (postprophylaxis) no prechallenge prophylaxis, S. aureus challenge, and postchallenge prophylaxis. A saline control was tested concurrently in all three experiments. At 24 hours after injection, the eyes were evaluated by slit lamp in a masked fashion for clinical signs of endophthalmitis, and the anterior and posterior chambers were cultured for bacteria. The median clinical scores for the moxifloxacin group were significantly lower than the saline group for all three treatment regimens. The median clinical score for the full prophylaxis regimen was significantly lower than the preprophylaxis and postprophylaxis regimens alone. The anterior and posterior chambers were negative for S. aureus in all three moxifloxacin treatment regimens. In a rabbit model, a “proof of principle” was demonstrated that topical antibiotic therapy pre- and postintraocular bacterial challenge could prevent bacterial endophthalmitis. Surgical prophylaxis with topical 0.5% moxifloxacin (Vigamox) may prove to be a valuable adjunct for the prevention of endophthalmitis.