Molecular Epidemiological Characteristics, Antifungal Resistance and Pathogenicity of Candida auris in Guangzhou, South China

Background Candida auris represents a global health threat with increasing incidence in China, yet the molecular epidemiology and virulence traits of this pathogen remain poorly characterized. Methods This study comprehensively analyzed 39 C. auris isolates from 37 patients across three Guangzhou hospitals using whole genome sequencing (WGS), antifungal susceptibility testing, extracellular hydrolases detecting, biofilm-forming capacity analyzing, and a Galleria mellonella infection model. Based on the WGS data, single nucleotide polymorphism (SNP) analysis, phylogenetic analysis and resistance gene analysis were conducted. Results Phylogenetic analysis revealed 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 were found to harbor ERG11 mutation ( K143R or F126L ) associated with fluconazole resistance, while no mutations related to echinocandin and amphotericin B resistance genes were detected within the testing range. Clade I isolates displayed potent secreted aspartyl protease activity, correlating with elevated pathogenicity and mortality in Galleria mellonella infection models. Clade III demonstrated enhanced biofilm-forming capacity, potentially facilitating skin and healthcare environment colonization. Conclusions In this study, we revealed two major clades of C. auris prevalent in the Guangzhou area and compared the differences in epidemiology, drug resistance, and virulence between the two clades, including the mutation status of drug - resistant genes, the activity of hydrolases, the biofilm - forming ability, and the pathogenicity in the Galleria mellonella infection model. This provides valuable references for understanding the biological characteristics of C. auris , and laying a foundation for the drug - resistance mechanisms and virulence. Our findings not only expand the genetic database of C. auris but also provides a scientific basis for guiding infection control and antifungal stewardship in South China.