Bismuth Nanoantibiotics Display Anticandidal Activity and Disrupt the Biofilm and Cell Morphology of the Emergent Pathogenic Yeast Candida auris

Abstract

<i>Candida auris</i> is an emergent multidrug-resistant pathogenic yeast, which forms biofilms resistant to antifungals, sanitizing procedures, and harsh environmental conditions. Antimicrobial nanomaterials represent an alternative to reduce the spread of pathogens-including yeasts-regardless of their drug-resistant profile. Here we have assessed the antimicrobial activity of easy-to-synthesize bismuth nanoparticles (BiNPs) against the emergent multidrug-resistant yeast <i>Candida auris</i>, under both planktonic and biofilm growing conditions. Additionally, we have examined the effect of these BiNPs on cell morphology and biofilm structure. Under planktonic conditions, BiNPs MIC values ranged from 1 to 4 µg mL^-1 against multiple <i>C. auris</i> strains tested, including representatives of all different clades. Regarding the inhibition of biofilm formation, the calculated BiNPs IC₅₀ values ranged from 5.1 to 113.1 µg mL^-1. Scanning electron microscopy (SEM) observations indicated that BiNPs disrupted the <i>C. auris</i> cell morphology and the structure of the biofilms. In conclusion, BiNPs displayed strong antifungal activity against all strains of <i>C. auris</i> under planktonic conditions, but moderate activity against biofilm growth. BiNPs may potentially contribute to reducing the spread of <i>C. auris</i> strains at healthcare facilities, as sanitizers and future potential treatments. More research on the antimicrobial activity of BiNPs is warranted.