Meyerozyma guilliermondii

Synonymy: 
Candida guilliermondii.

Meyerozyma guilliermondii has been isolated from numerous human infections, mostly of cutaneous origin.

It is also found on normal skin and in sea water, faeces of animals, fig wasps, buttermilk, leather, fish and beer.

RG-1 organism.

Culture: 
White to cream-coloured smooth, glabrous, yeast-like colonies.

Microscopy: 
Spherical to subspherical budding yeast-like cells or blastoconidia, 2.0-4.0 x 3.0-6.5 µm.

India ink preparation: 
Negative - no capsules present.

Dalmau plate culture: 
Branched pseudohyphae with dense verticils of blastoconidia.

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 v L-Arabinose v D-Glucitol v
Fermentation   Sucrose + D-Arabinose v 𝝰-M-D-Glucoside v
Glucose + Maltose + D-Ribose + D-Gluconate v
Galactose v Cellobiose v L-Rhamnose v DL-Lactate v
Sucrose + Trehalose + D-Glucosamime + myo-Inositol -
Maltose - Lactose - N-A-D-glucosamine + 2-K-D-Gluconate +
Lactose - Melibiose v Glycerol + D-Glucuronate nd
Trehalose + Raffinose + Erythritol - Nitrate -
Assimilation   Melezitose v Ribitol + Urease -
Glucose + Soluble Starch - Galactitol v 0.1% Cycloheximide v
Galactose + D-Xylose + D-Mannitol v Growth at 37C v

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

Antifungal susceptibility: Meyerozyma guilliermondii (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 198 4 9 70 70 27 9 2 1 1     5
FLU 199       1 4 5 75 75 7 11 4 7
ISAV 10 1     4 3 1   1        
VORI 197 36 88 52 9 3 1 2     6    
POSA 194 10 14 47 79 30 4 4     6    
ITRA 24     6 3 12 2 1          
ANID 120 1 2 6 5 9 41 48 8        
MICA 109 4 4 10 14 39 29 8     1    
CAS 175 2 9 24 35 63 25 8 2 3 4    
5FC 24 8 12 1 1 1 1            

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