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