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School of Molecular & Biomedical Science
The University of Adelaide

Dr David Ellis

Cryptococcus albidus

On Sabouraud's dextrose agar colonies are cream colored, smooth, mucoid and yeast-like in appearance. Microscopic morphology shows globose to ovoid budding yeast-like cells or blastoconidia, 3.5-8.8 x 5.5-10.2 um in size.

India Ink Preparation: Positive - distinct capsules surrounding the yeast cells are present.

Dalmau Plate Culture on Cornmeal and Tween 80 Agar: Budding yeast cells only. No pseudohyphae present.

Physiological Tests:

Germ Tube test is Negative
Hydrolysis of Urea is Positive
Growth on Cycloheximide medium is Negative
Growth at 37C is Negative (Positive)

Fermentation Reactions: Where fermentation means the production of gas and is independent of pH changes.

Negative: Glucose; Sucrose; Lactose; Galactose; Maltose; Trehalose.

Assimilation Tests:

Positive: Potassium nitrate; Glucose; Maltose (weak); Sucrose; Trehalose (weak); D-Xylose (weak); Melezitose; Raffinose (weak); Cellobiose; Inositol; L-Arabinose (weak); D-Mannitol (weak); Citric acid (weak); Succinic acid (weak); Salicin; D-Glucitol.
Variable: Soluble Starch; Lactose; Galactose; Melibiose; L-Rhamnose; D-Arabinose; Ribitol; L-Sorbose; D-Ribose; Galactitol; DL-Lactic acid.
Negative: Erythritol; Glycerol (some positive).

Clinical significance:

Cryptococcus albidus is a common transient on human skin and it has also been reported as a rare cause of pulmonary, CNS and vaginal infection. However, these reports must be viewed with considerable caution, as the culture identifications have not been verified.

Mycosis: Cryptococcosis

Further reading:

Kreger-Van Rij, N.J.W. (ed) 1984. The Yeasts: a taxonomic study. 3rd Edition. Elsevier Science Publishers B.V., Amsterdam, The Netherlands.

Rippon, J.W. 1988. Medical Mycology. 3rd Edition. W.B. Saunders Co., Philadelphia, USA.