Molecular epidemiological characteristics, antifungal resistance and pathogenicity of Candidozyma auris in Guangzhou, South China.

BACKGROUND : Candidozyma (candida) auris poses a global health threat with increasing incidence in China, yet the molecular epidemiology and virulence traits of this pathogen remain insufficiently characterized. METHODS: This study conducted a comprehensive analysis of 39 C. auris isolates from 37 patients in three hospitals in Guangzhou using whole genome sequencing (WGS), antifungal susceptibility testing, extracellular hydrolase detection, biofilm-forming capacity assessment, and a Galleria mellonella infection model. Single nucleotide polymorphism (SNP) analysis, phylogenetic analysis, and resistance gene analysis were performed based on the WGS data. RESULTS: Phylogenetic analysis identified two major clades: Clade I (74.4%) and Clade III (25.6%), with co-infection by both clades observed in one patient. All isolates showed resistance to fluconazole but were sensitive to echinocandins, while most of Clade I showed resistance to amphotericin B. All isolates carried ERG11 mutation (K143R or F126L) associated with fluconazole resistance, while no mutations related to echinocandin and amphotericin B resistance genes were detected. Clade I isolates exhibited potent secreted aspartyl protease activity (SAP), which correlated with elevated pathogenicity and mortality in Galleria mellonella infection models. Clade III exhibited enhanced biofilm-forming capacity, which may facilitate colonization of the skin and healthcare environments. CONCLUSIONS: In this study, we identified two major clades of C. auris prevalent in the Guangzhou area and compared their epidemiological characteristics, drug resistance profiles, and virulence factors. These include mutations in drug-resistant genes, hydrolase activity, biofilm formation ability, and pathogenicity in the Galleria mellonella infection model. Understanding the biological characteristics of C. auris, as well as studying its drug resistance mechanisms and virulence, is crucial for advancing our knowledge in this field. Our study contributes to the expansion of the genetic database of C. auris and provides a scientific foundation for enhancing infection control strategies and antifungal stewardship in South China.