Microbiological characteristics and drug resistance rates of Candida auris isolates in Japan.

Candida auris (C. auris) was initially isolated from a Japanese patient, and this species is an emerging fungus nowadays owing to its long-term colonization capabilities and high resistance to antifungal drugs. However, accurate domestic epidemiology of C. auris remains unknown. We here collected C. auris isolates reported from hospitals, public health centers, and public health institutes based on the administrative liaison. Moreover, we collected stocked C. auris isolates from three nongovernmental laboratory companies. Seventy C. auris isolates were collected during the study period. C. auris isolates predominantly originated from ear discharge clinical samples. Clade determination based on ITS-D1/D2 regions and CauMT1 locus revealed that almost all isolates belonged to clade II; however, one ear discharge-derived isolate belonged to clade I. Whole genome sequencing also confirmed this clade I C. auris isolate. Regarding drug susceptibilities, 20% of isolates were resistant to fluconazole; however, no isolates exhibited polyene or echinocandin resistance. Therefore, C. auris isolates in Japan were generally derived from ear discharges and belonged to clade II. However, ear discharge-derived isolates may not exclusively belong to clade II. Although no invasive cases were reported during the study period, continuing surveillance program for describing clear domestic epidemiology would be necessary.