Investigating the genetic relationship of Trichosporon asahii isolates using a newly developed microsatellite typing assay

The basidiomycetous yeast-like fungus Trichosporon asahii is increasingly encountered in the clinic and has been known to cause nosocomial infections. Here, we aim to develop a microsatellite typing tool to investigate the genetic relatedness of Trichosporon asahii isolates. Six microsatellite markers were selected from a nanopore long-read sequencing de novo assembled genome of the T. asahii type-strain CBS 2479. PCR reactions amplified three di-, tri-, or tetranucleotide repeats, respectively. All six microsatellite markers were used to analyze 111 T. asahii isolates, including single and related-patient isolates from clinical and environmental sources. Each marker exhibited between 11 and 37 alleles in this population, resulting in 71 different microsatellite genotypes. The Simpsons diversity index ranged from 0.6452 to 0.8280 for the individual markers, and for the combined set of microsatellites 0.9793, indicating the high discriminatory power of the reported panel. In summary, this panel combines high reproducibility and specificity, making it suitable for use in epidemiological studies of T. asahii and in investigations of potential outbreaks caused by this pathogen.