Investigation on possible resistance of Candida auris to irradiation with UVC (254 nm)

<i>Candida auris</i> is a yeast that is increasingly pathogenic due to increased multiresistance to antimycotics. UV (ultraviolet) radiation is still capable of reducing <i>C. auris</i> and offers possible applications in radiation disinfection of surfaces and air. However, it is unknown whether <i>C. auris</i> could also develop a resistance against UV radiation. For this reason, the extent to which <i>C. auris</i> can develop resistance to UVC radiation (254 nm) over several irradiation cycles is being examined. The yeast is irradiated with a UVC dose of 18.2 mJ/cm ² per cycle, followed by a recovery phase under dark conditions. This irradiation-recovery process was repeated for 16 consecutive cycles, ensuring that the UVC dose of 18.2 mJ/cm ² remained constant throughout all cycles. It was observed that the log reduction (a log 1 reduction corresponds to a 90% reduction) decreased with increasing number of cycles. Resistance development against UVC could be presented.