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Quantitative comparison of fluoroquinolone therapies of experimental gram-negative bacterial keratitis
Brett A Thibodeaux1, Joseph J Dajcs, Armando R Caballero
1Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
Purpose:
To determine the effectiveness of topically applied fluoroquinolones for experimental Pseudomonas or Serratia keratitis.
Methods:
Bacteria were injected intrastromally (10(3) colony forming units [CFU]). From 16 to 22 hours post-infection (PI), a single topical drop of moxifloxacin (Vigamox, 0.545%), levofloxacin (Quixin, 0.5%), ofloxacin (Ocuflox, 0.3%) or ciprofloxacin (Ciloxan, 0.3%) was applied every 30 minutes. At 23 hours PI, corneas were cultured quantitatively.
Results:
For Pseudomonas keratitis, untreated eyes contained 7 log CFU/cornea and antibiotic-treated eyes demonstrated a > or = 5-log reduction in CFU/cornea (p < or = 0.0001). Moxifloxacin, levofloxacin, or ciprofloxacin therapies were not significantly different from each other (p > or = 0.67). For Serratia keratitis, untreated eyes contained 7 logCFU/cornea whereas treated eyes had a > or = 2-log reduction (p < or = 0.0001). Moxifloxacin therapy proved most effective (p < or = 0.001).
Conclusions:
Overall, moxifloxacin was the most effective of the four fluoroquinolones in reducing CFU/cornea in the rabbit model of gram-negative keratitis.
