Comparative Evaluation of Temperature, Bottle Type, and Amphotericin B on Fungal Detection in Corneal Preservation...

Fungal contamination of donor corneas, although rare, constitutes a serious infection risk to recipients. Therefore, microbiological quality control with methods optimized for fungal detection is crucial in eye banks to detect and discard contaminated corneas. This study aimed to compare the performance of different BACT/ALERT^® bottles (iFA Plus and iLYM) incubated at different temperatures (32 °C and 37 °C) when corneal preservation media, with or without amphotericin B, were cultured. A total of 6 culture conditions were compared by inoculation of fewer than 100 colony-forming units of 18 fungi (10 yeasts and 8 filamentous fungi). iFA Plus bottles incubated at 32 °C reliably detected 94.4% of fungi, regardless of amphotericin B presence, while iLYM bottles detected 77.8% in the absence of amphotericin B and 72.2% in its presence. At 37 °C, iFA Plus fungal detection decreased to 61.1%. iFA Plus bottles incubated at 32 °C provided the highest detection rates, effectively neutralizing the effect of amphotericin B and enabling recovery of both yeasts and filamentous fungi, except for Cladosporium. Our findings support that the optimal strategy for cornea sterility testing is incubating iFA Plus bottles at 32 °C for optimal fungal recovery, while maintaining iFN Plus at 37 °C to allow timely detection of anaerobic bacteria.