Microbial contamination of donor corneoscleral rims and storage medium in keratoplasty.

PURPOSE: To investigate the prevalence and spectrum of microbial contamination of donor corneoscleral rims and storage medium in keratoplasty and to report a case of donor-derived fungal keratitis.

STUDY

DESIGN

Single-center, retrospective study.

METHODS

We reviewed 285 eyes that underwent keratoplasty at Hiroshima University Hospital between October 2022 and January 2025. Donor corneas were preserved using Optisol®-GS. The donor rim and storage medium were separately cultured intraoperatively, and the minimum inhibitory concentrations (MICs) were determined.

RESULTS

Culture positivity was identified in 10 of the 285 eyes (3.5%): six from donor rims and four from storage media, with no eye yielding positive results in both. All tested bacterial isolates were Gram-positive; three of six tested were not susceptible to levofloxacin and gatifloxacin (MIC ≥4 μg/mL), including methicillin-resistant Staphylococcus aureus, but retained susceptibility to vancomycin and meropenem. All fungal isolates were Candida with low MICs for voriconazole and micafungin. C. albicans and C. glabrata were recovered from the mate corneas of a single donor; the recipient of the cornea contaminated with C. albicans developed keratitis requiring repeat penetrating keratoplasty, whereas the recipient of the C. glabrata-contaminated cornea did not.

CONCLUSION

Adding storage medium to the rim culture improved the detection of donor-associated microorganisms. When donor-derived C. albicans keratitis developed, susceptibility data from contemporaneous cultures enabled prompt targeted antifungal therapy and globe preservation, although repeated penetrating keratoplasty was ultimately required.