Trichosporon asahii

Colonies on Sabouraud dextrose agar at 25°C are white, dry to creamy, and slightly farinose at the center with a wide margin containing deep transverse fissures. Colony size is 16-24 mm after 7 days incubation.

On cornmeal following 72 hours incubation at 25°C, it produces true hyphae that disarticulate into rectangular arthroconidia with rounded ends measuring approximately 3-4 x 4-7 µm. Appressoria are absent [1270].

This isolate is urease positive and fails to grow on media cycloheximide or at 42°C. Type strains were isolated from the fingernail of a patient with psoriasis and from shrimp. This species is the most frequent cause of disseminated trichosporonosis in the immunocompromised patient and has been recovered from blood, sputum, urine, and tissue. Trichosporon asahii may be distinguished from T. asteroides by lack of growth on cycloheximide and by farinose rather than smooth colonies. The source of infections is also important in separating the species, with T. asahii being primarily isolated from systemic disease, and T. asteroides being primarily implicated in superficial infections of white piedra [928].

AMB	CAS	ITRA	VORI	5FC	POSA
0.25 µg/ml=6	4.0 µg/ml=5	0.06 µg/ml=1	0.03 µg/ml=3	16 µg/ml=3	0.06 µg/ml=2
0.5 µg/ml=2	8.0 µg/ml=8	0.125 µg/ml=3	0.06 µg/ml=4	32 µg/ml=2	0.125 µg/ml=1
1.0 µg/ml=4	16 µg/ml=2	0.25 µg/ml=4	0.125 µg/ml=8
2.0 µg/ml=5		0.5 µg/ml=1	0.25 µg/ml=3
8.0 µg/ml=1		1.0 µg/ml=2

Drug/N	AMB/18	CAS/15	ITRA/11	POSA/3	VORI/18
MIC Range	0.25-8.0	4.0-8.0	0.06-1.0	0.06-0.125	0.03-0.25
MIC₅₀	1.0	8.0	0.25	**	0.125
MIC₉₀	2.0	8.0	1.0	**	0.25

* Fungus Testing Laboratory unpublished data (CLSI M27-A2)

PubMed

GenBank

References

928. Gueho, E., M. T. Smith, G. S. de Hoog, G. Billon-Grand, R. Christen, and W. H. Batenburg-van der Vegte. 1992. Contributions to a revision of the genus Trichosporon. Antonie Van Leeuwenhoek. 61:289-316.

1270. Kurtzman, C. P., and J. W. Fell (ed.). 2000. The Yeasts. A Taxonomic Study. Elsevier Scientific B.V., Amsterdam, The Netherlands.