Direct detection of Trichosporon asahii in blood using a qPCR assay: development and validation in spiked samples

Trichosporon asahii is an emerging opportunistic yeast and the leading cause of invasive trichosporonosis, a life-threatening infection in immunocompromised and critically ill patients. Clinical management is complicated by the severity of underlying conditions and intrinsic resistance to echinocandins, underscoring the urgent need for rapid and accurate species-level diagnosis. Objectives: here, we developed and validated the first probe-based quantitative PCR (qPCR) assay targeting the intergenic spacer 1 (IGS1) region of T. asahii ribosomal DNA. Methods: the assay was evaluated using spiked human blood bottles inoculated with reference and clinical isolates at established concentrations. Results: analytical specificity was assessed against a panel of clinically relevant fungal and bacterial pathogens causing bloodstream infections. The qPCR assay achieved 100% analytical sensitivity and specificity, with no cross-reactivity against non-target pathogens or human DNA, and generated results within three hours of blood culture positivity. Conclusions: this novel qPCR assay provides a rapid, sensitive, and specific tool for the detection of T. asahii directly from positive blood cultures. Although validation in clinical samples remains necessary, these findings highlight its potential to significantly improve early diagnosis and therapeutic decision-making in invasive trichosporonosis.