Published online by Cambridge University Press: 21 June 2016
Candidiasis is a well-recognized complication of immunosuppression, parenteral nutrition, surgery and broad spectrum antimicrobial chemotherapy. The majority of cases of candidiasis are caused by Candida albicans. Since the mid-1970's, however, Candida tropicalis has assumed an increasingly important pathogenic role, especially in granulocytopenic patients.
C tropicalis is a unicellar yeast organism that belongs to the genus Candida, the family Cryptococcaceae and the group Deuteromycetes (Fungi Imperfecti). C tropicalis grows well at 25°C and 37°C on blood and Sabouraud agars in an aerobic atmosphere, producing white, smooth colonies (Figure 1). It forms pellicle in broth. Microscopic examination shows round, oval or oblong noncapsulated budding cells (blasto-conidia), 2.5 μm X 3-14 μm in size. Singe cells, clusters or chains may be seen. C tropicalis forms hyphae and pseudohyphae, but not the germ tubes, unlike C albicans. (C tropicalis strains forming morphologically atypical germ tubes have been repotted, but are rare.) N 0 chlamydospores are produced on cornmeal agar. C tropicalis assimilates glucose, maltose, sucrose, galactose, cellobiose, xylose and trehalose, and ferments glucose, maltose, sucrose, galactose and trehalose. (Sucrose-negative variants have been described.”) Several commercially available biochemical panels are widely used for identifying C tropicalis.