[26S rDNA D1/D2 domain sequence analysis of the pathogenic strain from the first case of disseminated trichosporonosis in China].

OBJECTIVE: To determine the large-subunit (26S) rDNA D1/D2 domain sequence of AS 2.217 4, the pathogenic strain from the first case of disseminated trichosporosis in China, and study the feasibility of applying DNA sequencing in rapid identification of pathogenic yeast.
METHOD: The strain of Trichosporon (AS 2.2174) was collected from the skin lesion of a case of disseminated trichosporosis. Nuclear DNA was extracted from the cells of AS 2.2174 by a simplified protocol and the 26S rDNA D1/D2 domain was amplified by PCR. The PCR product was then directly sequenced with the ABI PRISM BigDye cycle sequencing kit.
RESULTS: The 26S rDNA D1/D2 domain of strain AS 2.2174 was determined (GenBank accession number: AF337949). Comparison analysis indicated that the D1/D2 sequence of AS 2.2174 is identical with that of the type strain of Trichosporon asahii, and differs from those T. asteroides, T. faecale and T. coremiiforme in 3, 5 and 8 nucleotides, respectively. The latter three species are phenotypically indistinguishable from T. asashii.
CONCLUSION: The strain AS 2.2174 was confirmed to belong to Trichosporon asahii. This species is the first record in China clinically and taxonomically. DNA sequencing shows an advantage in fast and accurate identification of clinically relevant yeast species.