Abstract
Purpose :
Recently, post-keratoplasty fungal infections, most commonly Candida species, have been more commonly after endothelial keratoplasty when compared to penetrating keratoplasty. It is hypothesized that the additional warming of the cornea, for endothelial keratoplasty processing, may allow for fungal growth. Previous studies determined an amphotericin b concentration of 0.255 ug/ml effectively eliminated Candida albicans in cornea organ culture, without toxicity. However, there remains a knowledge gap regarding the optimal timing of amphotericin B supplementation in cold storage, as is used in the USA. In this study we investigated whether the addition of amphotericin b to cold cornea storage media, at the time of tissue processing, eliminates Candida albicans from the corneal storage media and donor cornea.
Methods :
40 human donor corneas were placed in individual 20ml vials of Optisol GS (Bausch and Lomb, US). Candida albicans was added at a concentration of 2.5 X 103 CFU/ml. The corneas remained in the storage media for 2 days, which was followed by a 2 hour warming period (to simulate the tissue processing for DSAEK or DMEK). This was followed by an additional 1 day of storage. At this point the fungal assay was performed by plating the cornea and media on Sabouraud agar. Next, viable colony forming units of the culture plates were counted. The groups: Group 1) 20 of the vials had amphotericin b (0.255 ug/ml) added to the storage media after the 2 hour warming period. Group 2) 20 vials did not have amphotericin b added (control group).
Results :
All 20 samples from the control group produced more than 100 CFU of Candida. The 20 samples with amphotericin b demonstrated a mean of 35.25 CFU (std deviation = 16.3), with a range of 15 to 70 CFU. The reduction in CFU by the addition of amphotericin was statistically significant (P=0.0102).
Conclusions :
Although the addition of amphotericin b, after the simulated processing of the cornea for endothelial keratoplasty, did significantly reduce the number of Candida organisms, it did not totally eliminate candida from the media. Further studies are necessary to determine if the significant reduction in fungal organisms is acceptable or whether additional amphotericin b should be added during the initial placement of the cornea in the storage media or whether other measures are necessary.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.