Efficacy of Penicillin G, Cefazolin, and Gentamicin in M-K Medium at 4 C

Abstract

• Corneal-scleral shells are routinely stored in McCarey-Kaufman (M-K) medium at 4° C. Antibiotics are added to the medium to suppress bacterial growth. We examined the antibacterial activity of penicillin G potassium, 100 μg/ml, cefazolin sodium, 100 μg/ml, and gentamicin sulfate, 20 μg/ml against test organisms in M-K medium at 4°, 23°, and 37° C for periods up to 18 hours. Within the limits of the experimental conditions, none of the antibiotics used could be relied on to sterilize an inoculum of sensitive bacteria in M-K medium at 4° C, the recommended storage temperature.