Candida tropicalis
On Sabouraud's dextrose agar colonies are white to cream colored, smooth, glabrous and yeast-like in appearance. Microscopic morphology shows spherical to subspherical budding yeast-like cells or blastoconidia, 3.0-5.5 x 4.0-9.0 um in size.
India Ink Preparation: Negative - no capsules present.
Cornmeal and Tween 80 Agar Plate: Abundant long, wavy, branched pseudohyphae with numerous ovoid blastoconidia budding off. Terminal vesicles (chlamydoconidia) are not produced.
Physiological Tests:
Germ Tube test is Negative
Hydrolysis of Urea is Negative
Growth on Cycloheximide medium is Positive
Growth at 37C is Positive
Fermentation Reactions: Where fermentation means the production of gas and is independent of pH changes.
Positive: Glucose; Maltose; Galactose; Trehalose (delayed).
Variable: Sucrose.
Negative: Lactose.
Assimilation Tests:
Positive: Glucose; Galactose; Maltose; Trehalose; D-Xylose; Soluble Starch; Succinic acid; D-Mannitol; L-Arabinose (weak); D-Glucitol.
Variable: Sucrose; Salicin; Melezitose; Glycerol; Cellobiose; D-Ribose; Ribitol; L-Sorbose; Citric acid; DL-Lactic acid.
Negative: Potassium nitrate; L-Rhamnose; Lactose; Raffinose; Melibiose; Galactitol; Erythritol; Inositol; D-Arabinose.
MIC data is limited. Antifungal susceptibility testing of individual strains is recommended.
| Antifungal | MIC ug/mL | Antifungal | MIC ug/mL |
||
Range |
MIC90 |
Range |
MIC90 |
||
| Fluconazole | 0.125-128 |
2 |
Amphotericin B | 0.03-8 |
0.5 |
| Itraconazole | 0.03->8 |
0.5 |
Flucytosine | 0.03->64 |
0.125 |
| Posaconazole | 0.008->8 |
0.06 |
Caspofungin | 0.03->8 |
0.25 |
| Voriconazole | 0.008->8 |
0.25 |
Anidulafungin | 0.03->8 |
nd |
Clinical significance:
Candida tropicalis is a major cause of septicemia and disseminated candidiasis, especially in patients with lymphoma, leukemia and diabetes. It is the second most frequently encountered medical pathogen, next to C. albicans, and is also found as part of the normal human mucocutaneous flora. Sucrose negative variants of C. tropicalis have also been increasingly found in cases of disseminated candidiasis. Environmental isolations have been made from faeces, shrimp, kefir, and soil.
Mycosis: Candidiasis
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.
