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2018 Agenda and Abstracts | < Previous Next >

2018 OMIG Abstract

Is 2.5% (25mg/ml) Vancomycin the Same as 5% (50 mg/ml) in the Treatment of MRSA Keratitis?

RP Kowalski, EG Romanowski, JE Romanowski, KA Yates, A Mammen, DK Dhaliwal, V Jhanji
The Charles T. Campbell Laboratory. University of Pittsburgh, Pittsburgh, PA


Purpose: Topical 5% (50 mg/ml) vancomycin is used for the treatment of MRSA keratitis, but patient comfort has many clinicians using 2.5% (25 mg/ml). This rabbit study compares different concentrations of vancomycin in the treatment of experimental MRSA keratitis.

Methods: The corneas of both eyes of 45 rabbits were infected with 2000 CFU (colony forming units) of MRSA. The corneal epithelium was abraded in the left eyes to mimic corneal ulceration. After 4 hours, 9 rabbits were euthanized to determine the CFU of MRSA at the onset of treatment. The remaining rabbits were divided into 4 treatment groups (n=9): 1) 5% vancomycin, 2) 2.5% vancomycin, 3) 1.25% (12.5 mg/ml) vancomycin, and 4) saline. The rabbits were treated topically in both eyes every 15 minutes for 5 hours. One hour after treatment, the rabbits were euthanized, the corneas were removed, and standard colony counts were determined to statistically analyze vancomycin penetration, treatment efficacy, and bactericidal effect (3-log10 decrease in CFU).

Results: For abraded corneas, the CFU of the 5% vancomycin group were statistically lower than 2.5% and 1.25%, and all vancomycin groups were lower than saline. The CFU of 2.5% were lower but statistically similar to 1.25%. The 5% vancomycin group demonstrated a bactericidal effect and the best penetration. The CFU of the abraded corneas treated with saline were statistically lower than the intact corneas indicating a possible antibacterial effect from the ocular surface.

Conclusion: Our rabbit study indicates that 5% vancomycin is the most potent concentration for the treatment of MRSA keratitis. The clinician may need to reassess treatment with regards to antibacterial efficacy and patient comfort.

Disclosure: N


2018 Agenda and Abstracts | < Previous Next >