Incidence of bacterial and fungal contamination of donor corneas preserved by organ culture

Abstract

We reviewed the results of sterility testing from culture media of 1,134 donor corneas preserved by organ culture at 37 degrees C in our eye bank. All corneas were stored in minimal essential medium containing 2% fetal calf serum, 0.1 mg/ml penicillin G, 0.1 mg/ml streptomycin, and 2.5 micrograms/ml amphotericin B. After removal of ocular adnexal tissue, donor globes were rinsed with sterile saline solution, incubated in 3% polyvinylpyrrolidone-iodine solution for 3-5 min, and subsequently rinsed again with sterile saline solution. Samples for microbiological evaluation were obtained from the initial evaluation medium, at every medium change (every 10 days), and from the medium used for deswelling of the individual cornea 1 day before transplantation. Incidence of contamination was 0.53% (6 of 1,134 corneas). Three corneas were contaminated by Micrococcus species, three by fungi. We conclude from our study that a combination of rinsing donor globes with sterile saline solution, the initial use of a disinfectant, and the employment of penicillin/streptomycin and amphotericin B in the organ culture medium, which have been commonly used in cell culture for decades, result in a low incidence of bacterial and fungal contamination of corneas preserved by organ culture.