Unique Cell Surface Mannan of Yeast Pathogen Candida auris with Selective Binding to IgG

The emerging, multidrug-resistant yeast pathogen Candida auris is responsible for healthcare-associated outbreaks across the globe with high mortality. The rapid spread of C. auris is linked to its successful colonization of human skin, followed by bloodstream infections. We compared glycomics and proteomics of C. auris to closely and distantly related human pathogenic yeasts, C. haemulonii and C. albicans, with the aim to understand the role of cell surface molecules in skin colonization and immune system interactions. Candida auris mannan is distinct from other pathogenic Candida species, as it is highly enriched in β-1,2-linkages. The experimental data showed that C. auris surface mannan β-1,2-linkages were important for the interactions with the immune protein IgG, found in blood and in sweat glands, and with the mannose binding lectin, found in the blood. Candida auris mannan binding to IgG was from 12- to 20-fold stronger than mannan from the more common pathogen C. albicans. The findings suggest unique C. auris mannan could be crucial for the biology and pathogenesis of this emerging pathogen.