The efficacy of topical ciprofloxacin and norfloxacin in the treatment of experimental Pseudomonas keratitis

• Published in: Cornea Vol. 10; no. 1; p. 25
• Main Authors: Reidy, J J, Hobden, J A, Hill, J M, Forman, K, O'Callaghan, R J
• Format: Journal Article
• Language: English
• Published: United States 01-01-1991
• Subjects: Administration, Topical; Animals; Ciprofloxacin - administration & dosage; Ciprofloxacin - therapeutic use; Colony Count, Microbial; Keratitis - drug therapy; Keratitis - microbiology; Norfloxacin - administration & dosage; Norfloxacin - therapeutic use; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - growth & development; Pseudomonas Infections - drug therapy; Rabbits; Tobramycin - administration & dosage; Tobramycin - therapeutic use
• ISSN: 0277-3740
• DOI: 10.1097/00003226-199110010-00006

An aminoglycoside-resistant strain of Pseudomonas aeruginosa was injected intrastromally into the corneas of rabbits, and keratitis was allowed to develop over a 22-h period. Rabbits were treated with either 0.75% ciprofloxacin, 1% norfloxacin, or 1.36% tobramycin administered topically every 15 min for 1 h and then every 30 min for the following 3 h. All therapy ceased 26 h postinoculation. Rabbits were killed 1 h after the treatment, and the number of bacteria per cornea were quantified in terms of bacterial colony-forming units. Aqueous humor specimens were obtained from rabbits receiving norfloxacin and ciprofloxacin, and bioassays were performed to determine drug concentration. Ciprofloxacin caused a 5 log reduction in the number of bacterial colony-forming units, as compared with untreated controls (p less than 0.0001); it also produced a significantly greater reduction in bacterial colony-forming units than either norfloxacin or fortified tobramycin drops (p less than 0.0001). Norfloxacin produced a 2 log reduction in bacterial colony-forming units, as compared with untreated controls (p less than 0.0001). The mean aqueous concentration of norfloxacin (7.5 micrograms/ml) was substantially less than that achieved by ciprofloxacin (30.5 micrograms/ml). We conclude that ciprofloxacin may be a useful broad spectrum, topical chemotherapeutic agent in the therapy of aminoglycoside-resistant P. aeruginosa keratitis.