Sporothrix schenckii

Sporothrix schenckii
Conidiophores and conidia
Scientific classification
Kingdom:	Fungi
Division:	Ascomycota
Class:	Sordariomycetes
Order:	Ophiostomatales
Family:	Ophiostomataceae
Genus:	Sporothrix
Species:	S. schenckii
Binomial name
Sporothrix schenckii Hektoen & C.F.Perkins (1900)

Sporothrix schenckii is a fungus that can be found world-wide in the environment. The species is present in soil as well as in and on living and decomposing plant material such as peat moss. It can infect humans as well as animals and is the causative agent of sporotrichosis, commonly known as "rose handler's disease". The most common route of infection is the introduction of spores to the body through a cut or puncture wound in the skin. Infection commonly occurs in otherwise healthy individuals but is rarely life-threatening and can be treated with antifungals. In the environment it is found growing as filamentous hyphae. In host tissue it is found as a yeast. The transition between the hyphal and yeast forms is temperature dependent making S. schenckii a thermally dimorphic fungus.

Sporothrix schenckii can be found in one of two morphologies, hyphal or yeast. The hyphal form is found in the environment on plants and decaying matter. When the fungus makes the transition into a host, the yeast morphology predominates.

When in the environment or grown in the laboratory at 25 °C (77 °F) S. schenckii assumes its hyphal form. Macroscopically, filaments are apparent and colonies are moist, leathery to velvety, and have a finely wrinkled surface. The colour is white initially and may change color over time to become cream to dark brown (“dirty candle-wax” color). Microscopically, hyphae are septate approximately 1 to 2μm in diameter. Conidia are oval shaped and glass like (hyaline) in appearance. They may be colorless or darkly colored. Conidia are sometimes referred to as resembling a flower.

At 37 °C (99 °F) either in the laboratory or in host tissue, S. schenckii assumes its yeast form. Macroscopically, the yeast form grows as smooth white or off-white colonies. Microscopically, yeast cells are 2 to 6μm long and show an elongated cigar-shaped morphology.

S. schenckii has a worldwide distribution but certain areas of the world including Peru, have a higher incidence of disease. Based on sequence analysis it has been found that S. schenckii isolates can be placed in phylogenetic groups that reflect the region from which they were isolated. S. schenckii is often isolated from plants and associated packing material.Gardeners,landscapers, and foresters are at high risk of infection. Sporothrix infection can also be transmitted by cat bites or scratches. This mode of transmission has been responsible for epidemics of sporotrichosis.Immunocompromised individuals are at increased risk of infection and such patients often exhibit more severe forms of disease.

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Wikipedia