Does eyebank tissue processing increase the likelihood of fungal growth in donor rim cultures?
This study found that compared with uncut or unstripped tissue, eyebank preparation of donor corneal tissue for endothelial keratoplasty was a risk factor for fungal growth from donor rims cultures. Experimental findings in the absence of corneal tissue confirmed increased room temperature incubation time promotes growth of Candida species in optisol–gentamicin and streptomycin corneal storage media, and the addition of antifungals reduced growth of Candida in a species dependent manner.
These findings suggest reduced room temperature incubation and addition of antifungals to optisol–gentamicin and streptomycin should be considered when processing corneal tissues.
Fungal contamination and infection from donor tissues processed for endothelial keratoplasty is a growing concern, prompting analysis of donor tissues after processing.
To determine whether eyebank-processed endothelial keratoplasty tissue is at higher risk of contamination than unprocessed tissue and to model eyebank processing with regard to room temperature exposure on Candida growth in optisol–gentamicin and streptomycin (GS) with and without antifungal supplementation.
Design, Setting, and Participants
An examination of the 2013 Eversight Eyebank Study follow-up database for risk factors associated with post-keratoplasty infection identified an increased risk of positive fungal rim culture results in tissue processed for endothelial keratoplasty vs unprocessed tissue. Processing steps at room temperature were hypothesized as a potential risk factor for promotion of fungal growth between these 2 processes. Candida albicans, Candida glabrata, and Candida parapsilosis endophthalmitis isolates were each inoculated into optisol-GS and subjected to 2 different room temperature incubation regimens reflective of current corneal tissue handling protocols.
Main Outcomes and Measures
Eversight Eyebank Study outcomes and measures were follow-up inquiries from 6592 corneal transplants. Efficacy study outcomes and measures were fungal colony–forming units from inoculated vials of optisol-GS taken at 2 different processing temperatures.
Donor rim culture results were 3 times more likely to be positive for fungi in endothelial keratoplasty–processed eyes (1.14%) than for other uses (0.37%) (difference, 0.77%; 95% CI, 0.17-.1.37) (P = .009). In vitro, increased room temperature incubation of optisol-GS increased growth of Candida species over time. The addition of caspofungin and voriconazole decreased growth of Candida in a species-dependent manner.
Conclusions and Relevance
Detectable Candida growth in donor rim cultures, associated with a higher rate of post keratoplasty infection, is seen in endothelial keratoplasty tissue vs other uses at the time of transplantation, likely owing in part to eyebank preparation processes extending the time of tissue warming. Reduced room temperature incubation and the addition of antifungal agents decreased growth of Candida species in optisol-GS and should be further explored to reduce the risk of infection.
Brothers KM, Shanks RMQ, Hurlbert S, Kowalski RP, Tu EY. Association Between Fungal Contamination and Eye Bank–Prepared Endothelial Keratoplasty TissueTemperature-Dependent Risk Factors and Antifungal Supplementation of Optisol–Gentamicin and Streptomycin. JAMA Ophthalmol. Published online September 28, 2017. doi:10.1001/jamaophthalmol.2017.3797
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