Macroscopic: colonies grow rapidly with wooly texture (sometimes mucoid), and white, yellow, pink, purple, or pale brown surface and pale, red, violet, brown, or blue reverse.
Microscopic: septate hyaline hyphae. Microconidia are unicellular (sometimes bicellular) and hyaline, ovoid to ellipsoid, in chains or singly from denticles. Macroconidia are curved and multicellular, with a foot cell at the base. Chlamydospores may be present.
The macroconidia are the typical finding used to identify Fusarium spp.
Species of medical importance include:
F. solani: most common overall, and a common cause of keratitis
F. oxysporum: second-most common
F. verticillioides: third-most common
F. moniliforme
F. proliferatum
F. chlamydosporum
F. anthophilum
F. dimerum
F. sacchari
Epidemiology
Ubiquitous, common in soil and organic debris, and a common cause of disease in plants.
In humans, infection is rare and generally occurs after penetrating trauma.
Disseminated and CNS disease is more common in immunocompromised hosts, including prolonged neutropenia.
Clinical Manifestations
Superficial
Keratitis and endophthalmitis: big outbreak associated with contact lens solution back in the day
Onychomycosis
Skin and musculoskeletal infections (including mycetoma)
Some species are inherently resistant to amphotericin, so may need to treat with combination amphotericin and voriconazole until susceptibilities are available
