Free‐living amoebae promote Candida auris survival and proliferation in water

Candida auris is an emerging species responsible for life‐threatening infections. Its ability to be resistant to most systemic antifungal classes and its capacity to persist in a hospital environment have led to health concerns. Currently, data about environmental reservoirs are limited but remain essential in control of C. auris spread. The aim of our study was to explore the interactions between C. auris and two free‐living amoeba (FLA) species, Vermamoeba vermiformis and Acanthamoeba castellanii, potentially found in the same water environment. Candida auris was incubated with FLA trophozoites or their culture supernatants. The number of FLA and yeasts was determined at different times and transmission electron microscopy (TEM) was performed. Supernatants of FLAs promoted yeast survival and proliferation. Internalization of viable C. auris within both FLA species was also evidenced by TEM. A water environmental reservoir of C. auris can therefore be considered through FLAs and contamination of the hospital water networks would consequently be possible. Significance and impact of study:Free‐living amoebae promote survival and proliferation of multidrug‐resistant Candida auris. These data indicate that C. auris could be found in the same environmental reservoir than free‐living amoeba. A water environmental or hospital reservoir of C. auris can therefore be considered through free‐living amoebae. C. auris must be sought in these environments and hospital water network management must be adapted to prevent life‐threatening infection.