DESCRIPTIONS OF MEDICAL FUNGI

Descriptions of Medical Fungi 219
Trichosporon Behrend
Key to medically important species (de Hoog et al. 2000).
1. Growth with melibiose 2
No growth with melibiose 3
2. Tolerant to cycloheximide T. mucoides
Not tolerant to cycloheximide
T. cutaneum
3. Growth with myo-inositol, no growth with L-arabinose T. inkin
No growth with myo-inositol, growth with L-arabinose 4
4. Colony with very slow growth; thallus consisting of clumps
of meristematic cells
T. asteroides
Colonies and microscopy otherwise 5
5. Appressoria present in slide cultures T. ovoides
Appressoria absent in slide cultures 6
6. Arthroconidia barrel-shaped; thallus not meristematic T. asahii
Arthroconidia elongate, or thallus meristematic
T. asteroides
Trichosporon asahii Akagi ex Sugita et al.
RG-2 organism.
Morphological Description: Colonies are white to cream-coloured, powdery, suedelike
to farinose with radial furrows and irregular folds. Budding cells and lateral conidia
are absent. Arthroconidia are barrel-shaped. Appressoria absent. This species
assimilates L-arabinose but not melibiose. Growth at 37 O C. Most common species,
especially from invasive infections.
Assimilation Tests: + Positive, - Negative, v Variable, w Weak, s Slow
Glucose + Melibiose - L-Rhamnose + D-Glucitol v
Galactose + Raffinose - D-Glucosamine + α-M-D-glucoside +
L-Sorbose v Melezitose v N-A-D-glucosamine + D-Gluconate +
Sucrose v Soluble Starch v Glycerol v DL-Lactate v
Maltose + D-Xylose v Erythritol + myo-Inositol v
Cellobiose + L-Arabinose + Ribitol v Nitrate -
Trehalose + D-Arabinose + Galactitol - 2-K-D-gluconate +
Lactose + D-Ribose + D-Mannitol v D-Glucuronate +