Wickerhamomyces anomalus

Synonymy: 
Candida pelliculosa

Wickerhamomyces anomalus has been reported from cases of candidaemia and catheter related infections in humans and has been isolated from soil, grains, fruit and warm-blooded animals.

RG-1 organism.

Culture: 
Colonies (SDA) white to cream-coloured smooth, glabrous, yeast-like.

Microscopy: 
Spherical to ellipsoidal budding blastoconidia, 2-4 x 2-6 µm. Pseudohyphae may be present. Asci when present, containing one to four hat-shaped ascospores.

India ink preparation: 
Negative - no capsules present.

Dalmau plate culture: 
Spherical to ellipsoidal budding yeast cells and abundant pseudohyphae in most strains.

Molecular identification: 
ITS sequencing recommended.

MALDI-TOF MS: 
Able to accurately identify this species.

Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow, nd No Data
Germ Tube - L-Sorbose - L-Arabinose v D-Glucitol +
Fermentation   Sucrose + D-Arabinose - 𝝰-M-D-Glucoside +
Glucose + Maltose + D-Ribose v D-Gluconate v
Galactose v Cellobiose + L-Rhamnose - DL-Lactate +
Sucrose + Trehalose + D-Glucosamime - myo-Inositol -
Maltose v Lactose - N-A-D-glucosamine - 2-K-D-Gluconate -
Lactose - Melibiose - Glycerol + D-Glucuronate nd
Trehalose - Raffinose + Erythritol + Nitrate +
Assimilation   Melezitose + Ribitol v Urease -
Glucose + Soluble Starch + Galactitol - 0.1% Cycloheximide -
Galactose v D-Xylose v D-Mannitol + Growth at 37C v

Key features: 
Germ tube negative yeast and sugar assimilation pattern.

Antifungal susceptibility: Wickerhamomyces anomalous (Diekema et al. 2009 and Australian national data); MIC µg/mL.
Antifungal No ≤0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 32 ≥64
AMB 48     3 14 21 9 1          
FLU 48           3 12 27 7      
ISAV 5 1 4                    
VORI 48 3 2 27 13 3              
POSA 48 1 1 3 9 6 14 12 2        
ITRA 8 1 1 3 3                
ANID 22 21 1                    
MICA 22 20 2                    
5FC 8   7                 1  

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