Abstract
Purpose :
Antifungals are not used in the preservation of donor corneas despite the serious complications of a postkeratoplasty fungal infection. This study investigates the efficacy of amphotericin B supplementation following long term frozen storage in reducing growth of Candida albicans for future incorporation into corneal tissue preservation by eye banks.
Methods :
Triplicate Optisol-GS samples were inoculated with 106 colony-forming units (CFUs) of C. albicans. Each set of triplicate cultures were supplemented with 2.5 µg/ml of amphotericin B that was either freshly resuspended and never frozen, frozen overnight at -20 °C and thawed, or frozen at -20 °C for four weeks and thawed. These cultures were stored at 4 °C with aliquots taken at 0, 6, 24, and 72 hours for quantification of CFUs. The efficacy of each preparation of amphotericin B in reducing C. albicans growth was assessed at different time points for potential future use at eye banks.
Results :
A 1.33 log10 CFU reduction resulted after 6 hours of supplementation with 2.5 µg/ml of amphotericin B that was freshly resuspended. Comparatively, a 1.31 and 1.18 log10 CFU reduction resulted with amphotericin B frozen overnight and thawed or frozen for four weeks and thawed, respectively. At 72 hours, fresh amphotericin B and overnight freeze-thawed amphotericin B showed a 2.72 and 2.64 log10 CFU reduction, respectively. Amphotericin B that had been frozen for four weeks demonstrated a 2.18 log10 CFU reduction at this same time point.
Conclusions :
Our results show that a 2.5 µg/ml supplement of amphotericin B frozen for four weeks at -20 °C storage leads to > 90% reduction in growth of C. albicans by 6 hours and > 99% reduction in growth by 72 hours. Supplementation of amphotericin B frozen for long periods of time maintain high efficacy in reducing fungal growth in Optisol-GS media.
This is a 2020 ARVO Annual Meeting abstract.