Mitosporic fungus. Hyphomycetes. Teleomorph (sexual state): Ophiostoma (disputed).
Sporothrix species comprise a small proportion of the fungal biota and are most closely related to other colorless hyphomycetes such as Beauveria, Nodulisporium and Calcarisporium. One species, Sporothrix schenckii, is a cause of a subcutaneous infection called sporotrichosis which develops characteristic lesions at regional lymph nodes. The fungus occurs in soil, wet or damp wood and the disease develops in humans most commonly after puncture by thorns or splinters. This genus is rarely found on environmental surfaces but it may be identified by tape lifts, tease mounts from bulk samples, and in air by culturable (Andersen) samples. Many times colorless sporulating fungi such as Sporothrix are difficult to identify, with critical structures only very faintly visible under oil immersion magnification. Thus, these isolates may be placed in the category "Colorless, sporulating, ID unknown" on the Andersen report format. Spores do not have distinctive morphology and would be categorized as "other colorless" on spore trap samples. Natural habitat includes various substrates in contact with soil, such as plant litter, bark, straw and living plants. Sporothrix schenckii is particularly common on the wood of conifers and Eucalyptus, with other recorded isolations from sphagnum moss and timber. No information is available regarding toxicity. Allergenicity has not been studied.