Torulaspora delbrueckii

Synonymy: 
Candida colliculosa

Torulaspora delbrueckii is a rare cause of candidaemia.

RG-1 organism.

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

Microscopy: 
Spherical to ellipsoidal budding blastoconidia, 2-6 x 3-7 µm in size. Ascospores may be produced on 5% malt extract or cornmeal agar after 5-30 days at 25C.

India ink preparation: 
Negative - no capsules present.

Dalmau plate culture: 
Budding yeast cells only. No pseudohyphae or true hyphae produced.

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

Key features: 
Asci containing one to four spheroidal ascospores, strong growth at 37C and a variable sugar assimilation profile.

Antifungal susceptibility: Torulaspora delbrueckii very limited data (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 2       2                
FLU 2                 2      
VORI 2   1 1                  
POSA 2   1 1                  
ITRA 2     2                  
CAS 1   1                    
5FC 2 2                      

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