DESCRIPTIONS OF MEDICAL FUNGI

50
Descriptions of Medical Fungi
Candida tropicalis is a major cause of septicaemia and disseminated candidiasis. It is
also found as part of the normal human mucocutaneous flora and environmental isolations
have been made from faeces, shrimp, kefir and soil.
RG-2 organism.
Candida tropicalis (Castellani) Berkhout
Culture: Colonies (SDA) white to cream-coloured smooth, glabrous, yeast-like.
Microscopy: Spherical to subspherical budding yeast-like cells or blastoconidia, 3.5-7
x 5.5-10 µm.
India Ink Preparation: Negative - no capsules present.
Dalmau Plate Culture: Abundant, long, wavy, branched pseudohyphae with numerous
ovoid blastoconidia, budding off. Terminal vesicles (chlamydospores) are not produced.
Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow
Germ Tube - L-Sorbose v L-Arabinose - D-Glucitol +
Fermentation Sucrose v D-Arabinose - M-D-glucoside v
Glucose + Maltose + D-Ribose v,s D-Gluconate v
Galactose + Cellobiose v L-Rhamnose - DL-Lactate v
Sucrose v Trehalose + D-Glucosamine v myo-Inositol -
Maltose + Lactose - N-A-D-glucosamine + 2-K-D-gluconate +
Lactose - Melibiose - Glycerol v D-Glucuronate -
Trehalose +,s Raffinose - Erythritol - Nitrate -
Assimilation Melezitose v Ribitol v Urease -
Glucose + Soluble Starch + Galactitol - 0.1% Cycloheximide +
Galactose + D-Xylose + D-Mannitol + Growth at 40 O C +
Key Features: Germ tube negative yeast and sugar assimilation pattern. Colonies are
dark blue on Candida CHROMagar.
Antifungal Susceptibility: C. tropicalis (Australian National data); MIC µg/mL.
CLSI clinical breakpoints are marked where available (Pfaller and Diekema 2012).
No 64
AmB 284 1 8 45 94 97 38 1
FLU 284 1 10 46 98 65 32 14 4 4 10
VORI 251 10 17 37 64 58 34 14 6 5 1 4 1
POSA 190 4 7 28 35 53 33 17 6 2 5
ITRA 284 2 13 22 94 98 43 2 1 1 1 7
ANID 126 9 8 29 67 11 1 1
MICA 126 8 28 69 16 2 1 1 1
CAS 207 1 15 68 67 40 9 3 1
5FC 284 49 139 54 21 5 2 1 1 2 1 2 7