Candida auris Forms High-Burden Biofilms in Skin Niche Conditions and on Porcine Skin

Abstract

Emerging pathogen <i>Candida auris</i> causes nosocomial outbreaks of life-threatening invasive candidiasis. It is unclear how this species colonizes skin and spreads in health care facilities. Here, we analyzed <i>C. auris</i> growth in synthetic sweat medium designed to mimic axillary skin conditions. We show that <i>C. auris</i> demonstrates a high capacity for biofilm formation in this milieu, well beyond that observed for the most commonly isolated <i>Candida</i> sp., <i>Candida albicans</i> The <i>C. auris</i> biofilms persist in environmental conditions expected in the hospital setting. To model <i>C. auris</i> skin colonization, we designed an <i>ex vivo</i> porcine skin model. We show that <i>C. auris</i> proliferates on porcine skin in multilayer biofilms. This capacity to thrive in skin niche conditions helps explain the propensity of <i>C. auris</i> to colonize skin, persist on medical devices, and rapidly spread in hospitals. These studies provide clinically relevant tools to further characterize this important growth modality.<b>IMPORTANCE</b> The emerging fungal pathogen <i>Candida auris</i> causes invasive infections and is spreading in hospitals worldwide. Why this species exhibits the capacity to transfer efficiently among patients is unknown. Our findings reveal that <i>C. auris</i> forms high-burden biofilms in conditions mimicking sweat on the skin surface. These adherent biofilm communities persist in environmental conditions expected in the hospital setting. Using a pig skin model, we show that <i>C. auris</i> also forms high-burden biofilm structures on the skin surface. Identification of this mode of growth sheds light on how this recently described pathogen persists in hospital settings and spreads among patients.