Killing of Candida auris by UV-C: Importance of exposure time and distance.

BACKGROUND: Candida auris is a globally emerging yeast, causing severe infections in patients with underlying diseases. This yeast is responsible for several outbreaks within healthcare facilities, where it can be found on hospital surfaces and patient care devices. Spread from these fomites may be prevented by improving the decontamination of hospital surfaces. UV-C decontamination may constitute an effective adjunct to routine room cleaning.

OBJECTIVES: Our aim was to investigate the effect of different UV-C exposure times and distance in killing C auris, using strains from different countries.

METHODS: Candida auris was seeded on glass slides and exposed to UV-C for 5, 10, 20 and 30 minutes at 2 and 4 m.

RESULTS: A maximal effect of C auris killing was found after 30 minutes of UV-C exposure at 2 m. With half the time or twice the distance, the efficacy strongly diminished to ~10 and ~50 fold, respectively. At suboptimal exposure times and distances, the C auris strains from Japan/Korea were more sensitive to UV-C killing than C auris strains originating from Venezuela, Spain and India.

CONCLUSIONS: Altogether, UV-C exposure times and distance are the most critical parameters to kill C auris, while strain variations of C auris also determine UV-C efficacy. Future studies should aim to determine the effect and place of UV-C on surface decontamination in hospital setting.