Bacteriologic cure of experimental Pseudomonas keratitis

Area of Science:

• Ophthalmology
• Microbiology
• Pharmacology

Background:

• Pseudomonas keratitis is a serious eye infection.
• Determining optimal antibiotic therapy duration is crucial for effective treatment.

Purpose of the Study:

• To determine the required duration of antibiotic therapy for bacteriologic cure of experimental Pseudomonas keratitis.
• To evaluate the effectiveness of different antibiotic concentrations and durations.

Main Methods:

• Two long-term therapy trials were conducted in guinea pigs with experimental Pseudomonas keratitis.
• Corneas were treated topically with high concentrations of tobramycin, amikacin, ticarcillin, or carbenicillin.
• Bacteriologic cure was assessed by culturing Pseudomonas from corneal samples.

Main Results:

• High-concentration antibiotic therapy for 4 days did not achieve complete bacteriologic cure.
• Topical tobramycin at 20 mg/ml for 6 or more days resulted in sterile corneas in 34 of 36 cases.
• Bacteriologic response occurred in two phases: rapid initial bacterial kill followed by gradual decline.

Conclusions:

• Prolonged topical antibiotic therapy is necessary for bacteriologic cure of Pseudomonas keratitis.
• An optimal therapeutic strategy may involve initial intensive therapy followed by prolonged, less intensive treatment to prevent relapse.