Will the Fortification of Optisol GS® With Moxifloxacin Reduce the Contamination Rate of Corneal Donor Rim Cultures?

Abstract

Abstract: : Purpose: To assess the efficacy of moxifloxacin as an additive to Optisol GS^® (gentamicin 100 micrograms/ml and streptomycin 200 micrograms/ml) in reducing corneal donor rim contamination. Methods: 100 consecutive donor rims from corneal buttons that had been stored in Optisol GS^® used in penetrating keratoplasty were bisected under sterile conditions by the operating surgeon, placed back in the storage medium and sent to the microbiology laboratory. Two separate preparations of "fresh" Optisol GS^® solution were prepared for each half donor rim. One preparation contained standard storage medium while the other preparation was fortified with 250 micrograms/ml of moxifloxacin. One half of the rim was placed in the standard medium and the other half in fortified medium and refrigerated at 3ºC for 24 hours. The rims were then removed and placed in thioglycolate broth (BBL) and incubated at 37º C for 7 days. Turbidity was assessed daily. If turbidity was noted, gram stain and subculture on chocolate agar (BBL) was performed. Results: The rate of culture positive donor rims in the Optisol GS^® was 14% (14/100). The rate of positive culture in the fortified medium was 3% (3/100). The differences were statistically significant (p< .01; chi square test). The organisms cultured in standard medium were (P.acnes (5), S. epidermidis (3), S. viridans (2), S. aureus (1), Strep. Group B (1), E. coli (1), C. albicans (1). The organisms cultured in the moxifloxacin fortified medium were S. epidermidis, Strep. GroupB, and C. albicans. All the isolates in the moxifloxacin–fortified medium were also cultured in the standard medium. Conclusions: From a microbiologic standpoint the addition of moxifloxacin to cornea storage medium appears to significantly reduce the rate of positive cultures from corneal donor rims. Issues regarding stability, toxicity, and optimum temperature range for moxifloxacin in corneal storage medium will require further study.

Keywords: cornea: storage • antibiotics/antifungals/antiparasitics