Magnusiomyces capitatus

Synonymy:
Saprochaete capitata (Diddens & Lodder) de Hoog & M.Th. Smith Geotrichum capitatum (Diddens & Lodder) v. Arx; Trichosporon capitatum Diddens & Lodder; Blastoschizomyces capitis (Diddens & Lodder) Salkin et al.

Based on a phylogenetic analysis of rDNA gene sequences, de Hoog and Smith (2004) transferred Geotrichum capitatum to the genus Magnusiomyces.

Magnusiomyces capitatus occurs quite commonly in humans, usually as a transient component of normal skin flora and sputum. Systemic infections including pulmonary, fungaemia and endocarditis have been reported in immunosuppressed patients.

RG-1 organism.

Morphological description:
Colonies are moderately fast growing, flat, whitish, and finely suede-like with no reverse pigment. Hyphae are profusely branched at acute angles, with terminal and intercalary conidiogenous cells which form long, cicatrised rachids on which conidia are borne. Conidia are hyaline, smooth, one-celled, cylindrical to clavate, with a rounded apex and flat base, 7-10 x 2.5-3.5 μm. Rectangular arthroconidia are also often present.

Molecular identification:
ITS sequencing recommended (de Hoog and Smith 2004).

Note: Magnusiomyces capitatus and Saprochaete clavata are human pathogens that are closely related and are frequently mistaken for each other. Based on ITS sequences, Desnos-Ollivier et al. (2014) proposed species-specific carbon assimilation patterns and MALDI-TOF MS fingerprints to enable the identification of S. clavata, M. capitatus and Geotrichum candidum (Galactomyces candidus) to the species level.

Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow, nd No Data
Germ Tube - L-Sorbose v L-Arabinose - D-Glucitol +
Fermentation   Sucrose - D-Arabinose - 𝝰-M-D-glucoside -
Glucose - Maltose - D-Ribose - D-Gluconate -
Galactose - Cellobiose - L-Rhamnose - DL-Lactate +
Sucrose - Trehalose - D-Glucosamine - myo-Inositol -
Maltose - Lactose - NAD-glucosamine nd 2-K-D-Gluconate -
Lactose - Melibiose - Glycerol + D-Glucuronate nd
Trehalose - Raffinose - Erythritol - Nitrate -
Assimilation   Melezitose - Ribitol - Urease -
Glucose + Soluble Starch - Galactitol - 0.1% Cycloheximide +
Galactose + D-Xylose - D-Mannitol + Growth at 40C +

References: de Hoog and Smith (2004, 2011c), de Hoog et al. (2015), Garcia-Ruiz et al. (2013), Desnos-Ollivier et al. (2014), Arendrup et al. (2015).

Antifungal susceptibility: Magnusiomyces capitatus limited data (Garcia-Ruiz et al. 2013, Australian national data); MIC μg/mL. Note: Isolates of M. capitatis are intrinsically resistant to echinocandins (Arendrup et al. 2015).

  No ≤0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 32 ≥64
AmB 9     1 1 4 3            
FLU 9             1 1 2 3 2  
VORI 8 2 2 2 1   1            
POSA 8   2 1 2 2 1            
ITRA 9     1 4 4              
5FC 4   2 1   1              


Back to Hyphomycetes