Emergence and Characterization of Mixed Candida auris Strain Infections in China

Abstract Purpose The multidrug-resistant fungal pathogen Candida auris poses an increasing global health threat due to its high transmissibility and persistence in healthcare environments. We identified five cases of mixed C. auris-strain infections in China and investigated the genetic and biological diversity of the isolates to explore the potential causes of C. auris infection. Methods C. auris isolates from 5 infection cases were distinguished by colony morphology and verified by D1/D2-ITS alignment. Phylogenetic and genomic diversity analysis of all isolates were conducted using whole genome sequences. Comparative biological analysis of all isolates, including cellular and colony morphology, antifungal susceptibility, biofilm formation, SAP activity, and both in vitro and in vivo survival capabilities were performed. Results Five cases of mixed C. auris-strain infections in China were identified. Comparative genomic analysis revealed these infections involved strains from two distinct genetic clades (I and III) or strains from the same clade but with genetic alterations. Comparative biological analysis demonstrated the strains from mixed infections exhibit differences in several key aspects, including colony morphology, biofilm formation, SAP activity, and both in vitro and in vivo survival capabilities. Conclusion Comparative analyses revealed notable differences in biofilm formation, environmental survival, and secretion of virulence factors between the co-infecting strains of C. auris. These biological and genetic disparities may present significant challenges for the diagnosis and treatment of C. auris infections, as strains with different genetic backgrounds may exhibit varying abilities to colonize host or environmental niches.