Marquandomyces marquandii

In a review of the molecular phylogeny and classification of the genus Metarhizium, Mongkolsamrit et al.(2020), have transferred Paecilomyces marquandii into a new genus as Marquandomyces marquandii.

M. marquandii is a soil fungus of worldwide distribution from temperate to tropical regions and is seldom associated with human infection.

Culture of Paecilomyces marquandii

Culture of Marquandomyces marquandii.

RG-1 organism.

Morphological description:
Colonies are fast growing, suede-like to floccose, pale vinaceous to violet coloured, with a yellow to orange yellow reverse. Conidiophores are erect, arising from submerged hyphae, 50-300 µm in length, bearing loose whorls of branches and phialides. Conidiophore stipes are 2.5-3.0 µm wide, hyaline and smooth-walled. Phialides are swollen at their bases, tapering into a thin, distinct neck. Conidia are ellipsoidal to fusiform, smooth-walled to slightly roughened, hyaline to purple in mass, 2.5-3.0 x 2-2.2 µm. Spherical to ellipsoidal chlamydospores, 3-5 µm diameter are present. No growth at 37oC.

Paecilomyces marquandii conidiophores, phialides and conidia

Marquandomyces marquandii conidiophores, phialides and conidia.

Key features: Colony pigmentation with yellow reverse pigment, phialides with swollen bases, smooth conidiophore stipes, presence of chlamydospores, and no growth at 37oC. Note: Purpureocillium lilacinum has no yellow reverse pigment, rough-walled conidiophore stipes, absence of chlamydospores and growth at 37oC.

Antifungal susceptibility: M. marquandii very limited data (Australian national data); MIC µg/mL.

  No ≤0.03 0.06 0.125 0.25 0.5 1 2 4 8 ≥16
AmB 8       1     1 1 1 4
VORI 5   1 3     1        
POSA 3 1   1 1            
ITRA 8 1     2 3   1     1

Samson (1974), Domsch et al. (1980, 2007), de Hoog et al. (2000, 2015).

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