The efficacy of topical ciprofloxacin and norfloxacin in the treatment of experimental Pseudomonas keratitis.
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.
Reidy
J J
JJ
Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans.
Hobden
J A
JA
Hill
J M
JM
Forman
K
K
O'Callaghan
R J
RJ
D000287:Administration, Topical; D000818:Animals; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000627:therapeutic use*; D015169:Colony Count, Microbial; D007634:Keratitis / Q000188:drug therapy* / Q000382:microbiology; D009643:Norfloxacin / Q000008:administration & dosage / Q000627:therapeutic use*; D011552:Pseudomonas Infections / Q000188:drug therapy*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development; D011817:Rabbits; D014031:Tobramycin / Q000008:administration & dosage / Q000627:therapeutic use
D002939:Ciprofloxacin; D009643:Norfloxacin; D014031:Tobramycin