Ecology: A cosmopolitan fungus commonly isolated from soil.
Pathogenicity: Low pathogenicity for humans however reports of keratitis and pulmonary infections have been reported in immunocompromised patients. Commonly considered to be a contaminant. Some Beauveria species are recognized as important insect pathogens particularly as the agent of muscardine disease of the silkworm.
Macroscopic Appearance: Beauveria is a moderately rapid growing fungus. Texture has been described as floccose,velvety, powdery to cottony. The isolate I present below has the appearance of a dollop of shaving cream dispensed from pressurized can. The colour is generally a bone white which can take on a pale yellow tinge with age. The reverse is a non-descript pale colour.
Microscopic Appearance: Hyphae are rather narrow and septate. Conidiogenous cells may grow singly or aggregate in dense clusters along the hyphae. They appear inflated at the base then become thinner at the apex giving a flask-like appearance. At the terminus there is what most sources describe as a thin zigzag filament or extension which bears a conidium at each bend (sympodial geniculate growth). Conidia are single celled, hyaline, smooth walled, round to oval and about 2-4µm in diameter, each singly attached via a fine denticle.
Beauvaria species on SAB after 5 Days at 30oC
(My isolate looked like canned shaving cream)
Beauveria species, slide culture (LPCB X200 Nikon)
Beauveria species, slide culture (LPCB X400 Nikon)
Beauveria species, slide culture (LPCB X400 DMD-108)
(Many clusters of conidiodgenous cells)
Beauveria species, slide culture (LPCB X400 DMD-108)
Beauveria species (LPCB -oops, magnification not noted)
(Resolution at magnification not sufficient to show attachment of conidia)
Beauveria species (oops, magnification not noted)
Beauveria species - both individual conidiogenous cells and clusters seen
I will try to get a higher magnification photo of the conidiogenic cell bearing the conidia from the zigzag like apex. I seem to lose the resolution on the photos or they are so overgrown with conidia that the structure is obscured. Stay tuned...
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