Different efficacies of common disinfection methods against Candida auris and other Candida species

Background

Candida auris is a multidrug-resistant yeast that has caused serious outbreaks in hospitals worldwide since it was first identified. Unlike many other Candida species, it can persist on skin and hard surfaces for long periods and survives many disinfection routines that were originally designed for other pathogens. This has left infection control teams uncertain about which cleaning and disinfection methods actually work against it. A research team based in China set out to test a range of commonly used hospital disinfection approaches against C. auris and other Candida species side by side, to find out which methods hold up and which fall short.

Study design

The researchers tested 12 yeast isolates spanning five Candida species, including three strains of C. auris. Four disinfection approaches were compared: chemical disinfectants, including quaternary ammonium compounds, assessed by measuring the minimum concentration needed to stop growth; an ultraviolet-C (UV-C, 253.7 nanometre wavelength) light source, tested at different distances and exposure times; an ozone disinfection unit, also tested across a range of exposure times; and a hand hygiene protocol using an ex vivo pig skin model, comparing plain soap washing, drying, and application of an ethanol-based hand sanitiser gel.

Findings

The C. auris isolates were consistently harder to kill than the other Candida species tested. They showed greater resistance to quaternary ammonium disinfectants, to UV-C light, and to ozone. UV-C effectiveness dropped off sharply once the light source was more than one metre from the surface being treated. Ozone was able to eliminate the yeast, but only with longer exposure times than would typically be used in a standard hospital disinfection cycle. By contrast, the hand hygiene protocol performed strongly: 30 seconds of washing with soap, followed by drying and 15 seconds of an ethanol-based hand sanitiser gel, completely eradicated C. auris from the pig skin model.

What the authors concluded

The authors concluded that current disinfection protocols using UV-C and ozone may need longer exposure times to reliably eliminate C. auris compared with other Candida species. They recommended that hospitals extend UV-C and ozone treatment durations where C. auris contamination is a concern, and highlighted that a simple soap-wash, dry, and ethanol-based sanitiser sequence was highly effective for decontaminating skin and could be a practical addition to infection control practice.

Limitations of this study

This was a laboratory and ex vivo (pig skin) study rather than a real-world hospital trial, so results may not translate directly to clinical surfaces, equipment, or human skin in practice. Only 12 isolates were tested in total, including just three C. auris strains, which limits how far the findings can be generalised across the wider diversity of this species. The ozone and UV-C devices used were specific hospital-grade disinfection units rather than home or therapeutic ozone equipment, and ozone was only one of four methods evaluated rather than the study's main focus. Real hospital environments also involve organic material, varied surface types, and repeated contamination that were not fully replicated here.