Hospital outbreaks predominated by Clade I Candida auris in Beijing, China, and evaluation of screening strategies

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• Picked for Microbiology (medical) (top studies of the week, 8 November 2026): Candida auris outbreak genomics and evaluation of screening methods

Abstract

BACKGROUND: Candida auris has emerged as a global public health threat, with an increasing number of outbreak events reported in Beijing, the capital city of China. This study aimed to characterize the epidemic clones currently circulating in the city through population genomic analysis, and to evaluate and optimize targeted screening strategies. METHODS: A total of 227 C. auris isolates were analyzed, including 106 C. auris isolates collected from 23 patients admitted to Peking Union Medical College Hospital (PUMCH) during 2021-2025, and an additional 121 Clade I C. auris genomes from 10 cities in China. Phylogenetic analysis and pairwise single nucleotide polymorphisms (SNPs) were used to determine genomic relatedness of isolates. Nosocomial screening of patients and the healthcare environment was conducted using on-site direct and enrichment culture, and a real-time PCR-based assay. RESULTS: In PUMCH, 20 out of 23 (93.40%) patients were colonized by Clade I C. auris isolates. Whole genome sequencing analysis of 173 Clade I C. auris isolates collected in Beijing revealed three major sublineages. Notably, Beijing Sublineages I and II formed phylogenetically independent clusters, whereas Beijing Sublineage III clustered with a major sublineage circulating in East China, indicating inter-regional dissemination. High-resolution pairwise SNP analysis further suggested multiple introductions into the predominant department, the medical intensive care unit at PUMCH, and provided evidence for inter-institutional transmission. Comparative analysis of screening methods demonstrated that enrichment culture increased the C. auris screen-positive rate by 18.52% (10/54) compared with using direct culture alone. Real-time PCR cycle threshold (Ct) values showed a good correlation with semi-quantitative culture results, and samples with Ct values ≤ 30 exhibited high culture positive rates compared with those with Ct values > 30, Additionally, decolonization attempts with chlorhexidine resulted in only a brief increase in Ct values, with the patient's fungal loads returning to baseline within 7 days. CONCLUSION: Clade I C. auris isolates constituted the predominant lineage spreading in Beijing. Given that evidence of both inter-regional and inter-institutional dissemination has been collected, effective coordination and information sharing between healthcare institutions are critical. Ct value-based stratification of transmission risk may complement the limited sensitivity of culture-based methods, and support practical implementation of infection prevention and control measures.

Abstract as published, via PubMed.