Candida auris (Candidozyma auris, C. auris) is a fungal pathogen presenting therapeutic challenges, with multidrug and disinfectant resistance. These traits enable it to persist and be continuously transmitted in the environment, posing significant challenges for preventing and controlling clinical infections. Our study aimed to elucidate the phylogenetic relationships of C. auris isolates collected in China, and to explore the tolerance of C. auris to antifungal drugs and disinfectant agents commonly used in hospital. This study also intended to comprehensively characterize the drug resistance genes and amino acid substitutions in C. auris. Whole-genome sequencing was used to identify and construct a phylogenetic tree for 8 strains of C. auris. The minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) of antifungal agents against C. auris isolates were determined using broth dilution. Quantitative suspension tests were conducted to evaluate the killing effects of different disinfectant agents on C. auris isolates. Resistance genes and mutation sites were identified using bioinformatic analysis. Five isolates of C. auris were closely related to the C. auris B13916 (clade I) and three isolates were closest to B17721 (clade III). All isolates showed resistance to fluconazole; five of them showed reduced susceptibility to amphotericin B. Compared with Candida albicans, benzalkonium chloride, didodecyl dimethylammonium chloride, chlorhexidine gluconate, and hydrogen peroxide showed increased MIC and MBC values against C. auris isolates. Under specific conditions, the anti-fungal effects of benzalkonium chloride, chlorhexidine gluconate, sodium hypochlorite, ethanol, and povidone-iodine were effective. however, didodecyl dimethylammonium chloride and hydrogen peroxide were less effective. C. auris isolates exhibited amino acid substitutions in ERG11, ERG2, ERG4, CIS2, TAC1, and CDR1. They also possessed resistance genes associated with antimicrobial target alterations and efflux pump. The decreased susceptibility of C. auris to fluconazole, amphotericin B, didodecyl dimethylammonium chloride, and hydrogen peroxide, which could be attributed to resistance genes and single-nucleotide mutations, reminds medical institutions to rationally select the type, concentration, and exposure time of antifungal agents targeting C. auris. The emergence of C. auris resistance to antifungal drugs and disinfectant agents may involve common molecular mechanisms involving nucleotide mutations, requiring further studies.
Xie et al. (Thu,) studied this question.