Rapid Detection of ERG11-Associated Azole Resistance and FKS-Associated Echinocandin Resistance in Candida auris

Abstract

Candida auris is an emerging multidrug-resistant yeast that can cause serious invasive infections. The accurate and rapid assessment of antifungal resistance is important for effective patient management. A novel and highly accurate diagnostic platform was established for the rapid identification of ERG11 mutations conferring azole resistance and FKS1 mutations associated with echinocandin resistance in C. auris Using allele-specific molecular beacons and DNA melting curve analysis following asymmetric PCR, a duplex ERG11 assay and a simplex FKS1 HS1 assay were developed to identify the most prominent resistance-associated mutations (Y132F and K143R in ERG11; S639F in FKS1 HS1) within 2 h. Assays were validated by testing a panel of 94 C. auris clinical isolates in a blind manner. The molecular diagnostic results from the assays were 100% concordant with DNA sequencing results. This platform has the potential to overcome the deficiencies of existing in vitro susceptibility-based assays to identify azole- and/or echinocandin-resistant C. auris, and thus, it holds promise as a surrogate diagnostic method to direct antifungal therapy more effectively.

Keywords: Candida auris; ERG11; FKS; azole; echinocandin; molecular beacons; resistance.

FIG 1

Representative melting profiles for C. auris ERG11 genotypes, including Y132WT and Y132F (A) and K143WT and K143R (B) and FKS1 HS1 genotypes, including WT and S639F (C).

FIG 2

ERG11 Y132 (A), ERG11 K143 (B), and FKS1 HS1 (C) T_m distributions of 94 C. auris clinical isolates tested in a blind manner.