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

## TL;DR

This study investigates whether Candida auris can develop resistance to UVC radiation after repeated exposure cycles.

## Contribution

The study demonstrates that Candida auris may develop resistance to UVC radiation over multiple exposure cycles.

## Key findings

- The log reduction of Candida auris decreased with each UVC irradiation cycle.
- Resistance to UVC radiation was observed after 16 consecutive irradiation-recovery cycles.
- A constant UVC dose of 18.2 mJ/cm² was used throughout the experiment.

## Abstract

Candida auris
is a yeast that is increasingly pathogenic due to increased multiresistance to antimycotics. UV (ultraviolet) radiation is still capable of reducing
C. auris
and offers possible applications in radiation disinfection of surfaces and air. However, it is unknown whether
C. auris
could also develop a resistance against UV radiation. For this reason, the extent to which
C. auris
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.