Skip to content

Mould Identification: A Virtual Self Assessment

Excellent you have really done well.

Please find additional information below

Unknown 36 = Trichosporon asahii

Case History
A 43-year-old man with newly diagnosed acute myeloblastic leukemia and non-insulin-dependent diabetes mellitus developed fungemia. The diagnosis was based on repeated isolation of the fungus shown below.
Culture

Colonies (SDA) are white to cream-coloured, powdery, suede-like to farinose with radial furrows and irregular folds.
Microscopy

Hyphae and arthroconidia of Trichosporon asahii.  Budding cells and lateral conidia are absent. Arthroconidia are barrel-shaped. Appressoria absent.
Sugar Assimilation Results
Assimilation Tests: + Positive, - Negative, V Variable,
Glucose
+
L-Rhamnose
+
Galactose
+
D-Glucosamine
+
L-Sorbose
v
N-A-D-glucosamine
+
Sucrose
v
Glycerol
v
Maltose
+
Erythritol
+
Cellobiose
+
Ribitol
v
Trehalose
+
Galactitol
-
Lactose
+
D-Mannitol
v
Melibiose
-
D-Glucitol
v
Raffinose
-
∝-M-D-glucoside
+
Melezitose
v
D-Gluconate
+
Soluble Starch
v
DL-Lactate
v
D-Xylose
v
myo-Inositol
v
L-Arabinose
+
Nitrate
-
D-Arabinose
+
2-K-D-gluconate
+
D-Ribose
+
D-Glucuronate
+

This species assimilates L-arabinose but not melibiose. Growth at 37C.

Comment: The genus Trichosporon is characterised by the development of hyaline, septate hyphae that fragment into oval or rectangular arthroconidia. Some blastoconidia are also seen. The colonies are usually raised and have a waxy appearance, which develop radial furrows and irregular folds.

Trichosporon species are a minor component of normal skin flora, and are widely distributed in nature. They are regularly associated with the soft nodules of white piedra, and have been involved in a variety of opportunistic infections in the immunosuppressed patient. Disseminated infections are most frequently caused by T. asahii and have been associated with leukaemia, organ transplantation, multiple myeloma, aplastic anaemia, lymphoma, solid tumours and AIDS. Disseminated infections are often fulminate and widespread, with lesions occurring in the liver, spleen, lungs and gastrointestinal tract. Infections in non-immunosuppressed patients include endophthalmitis after surgical extraction of cataracts, endocarditis usually following insertion of prosthetic cardiac valves, peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD), and intravenous drug abuse.

About Trichosporon Back to Virtual Assessment

What is your identification?

Geotrichum candidum
Onychocola canadensis
Trichosporon asahii

Sorry, that answer is incorrect. Please try again.
School of Biological Sciences
Address

THE UNIVERSITY OF ADELAIDE
SA 5005 AUSTRALIA

Contact

Dr David Ellis
Email