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The U.S. Government's Occupational Safety and Health Administration [OSHA]  lists the following as the health effects of Sporothrix mold: Allergen, Irritant, Hypersensitivity pneumonitis, Dermatitis.

Taxonomic Classifications

Kingdom: Fungi
Phylum: Ascomycota
Class: Euascomycetes
Order: Ophiostomatales
Family: Ophiostomataceae
Genus: Sporothrix

Laboratory Culture @ 25C

Laboratory Culture @ 37C

Tissue/Exudate Form

Laboratory culture drawing courtesy of College of Veterinary Medicine, Pathobiology.

Description and Habitats

According to de Hoog (1993), species of Sporothrix have been reported as anamorphs of both ascomycetes and basidiomycetes. However, he believes the name should be restricted to those with ascomycetous relationships and refers the basidiomycetous ones to the genus Cerinosterus. Unfortunately, distinguishing Sporothrix from Cerinosterus with certainty requires an electron microscope or advanced biochemical techniques.

Isolated from soil, decaying plant materials, other fungi, insects, and air. Sometimes causing human disease. Holomorphs: Ophiostoma, Pseudeurotium, Thecotheus, Stephanoascus, Valsonectria, and others. Ref: de Hoog 1974, 1993


The genus Sporothrix contains three active species. The most common one is Sporothrix schenckii, followed by Sporothrix cyanescens.

Health  Effects


Sporotrichosis is usually a chronic infection of the cutaneous or subcutaneous tissue which tends to suppurate, ulcerate and drain. In recent years, a pulmonary disease has been seen more frequently. Occasionally, infection with S. schenckii may result in a mycetoma. Sporotrichosis is caused by another dimorphic fungus. The infection is also known as "rose growers disease." 

The ecologic niche for this organism is rose thorns, sphagnum moss, timbers and soil. A study on the occupational distribution of sporotrichosis showed that forest employees accounted for 17% of the cases, gardeners and florists, 10%; and other soil-related occupations another 16%. Sporotrichosis occurs worldwide. Every aspect of this disease (clinical, pathology, mycology, ecology) was investigated during an epidemic of 3,000 patients in a gold mine in South Africa during the 1940's. Patient history is very important in this disease also. It is often seen in gardeners and begins with a thorn prick on the thumb. A pustule develops and ulcerates. It infects the lymphatic system and then the disease progresses up the arm with ulceration, abscess formation, break down of the abscess with large amounts of pus followed by healing. Progression usually stops at the axilla. 

Clinical material to be sent to the lab may be pus, biopsy material, or sputum from pulmonary patients. The yeast form of this fungus in tissue or in culture, can be round (6-8 um) or fusiform. The fusiform shape is not the usual form but if a cigar-shaped yeast is observed in tissue, it is usually diagnostic of sporotrichosis.  S. schenckii does not stain with the usual histopathological stains. If sporotrichosis is suspected, the pathologist must be informed so he can use special stains. Histologically asteroid bodies, a tissue reaction (also known as Splendori reaction) may be seen around the yeast cell. At 25 degrees C, this colony is white-cream and very membranous, but as it ages for 2-3 weeks it becomes black and leathery. Microscopically, the mycelium is branching, septate and very delicate, 2-3 um in diameter. The pyriform conidia, 2-4 um form a typical arrangement in groups at the end of a conidiophore called "daisies." Serologic tests are not commercially available.

The drug of choice for the cutaneous form is saturated iodides (e.g., potassium iodide) administered orally. The patient begins with 2-3 drops, 3-4/days until tolerance to the drug is built up, then the dose is increased. Potassium iodide may interact with the host immune system. For the systemic form the drug of choice is itraconazole or amphotericin B.

Macroscopic Features

I. Sporothrix schenckii. It is a thermally dimorphic fungus and the colony morphology varies depending on the temperature of growth. At 25C, colonies grow moderately rapidly. They are moist, leathery to velvety, and have a finely wrinkled surface. From the front and the reverse, the color is white initially and becomes cream to dark brown in time ("dirty candle-wax" color). At 37C, colonies grow moderately rapidly. They are yeast-like and creamy. The color is cream to beige. The conversion of the mold form to the yeast form is required for definitive identification of Sporothrix schenckii.

II. Sporothrix cyanescens. At 25C, colonies are velvety to powdery and slightly raised in texture. From the front, the color is initially white and turns to pale purple in time. From the reverse, an intense lavender-colored diffusing pigment formation is typical. This pigment is produced on potato dextrose agar after an incubation of about 3 weeks while it is usually not expressed on Sabouraud dextrose agar. The production of this lavender-colored pigment helps in differentiation of Sporothrix cyanescens from Sporothrix schenckii

Microscopic Features

I. Sporothrix schenckii. Similar to its colony morphology, microscopic features of Sporothrix schenckii also vary depending on the temperature of growth. At 25C, septate hyaline hyphae, conidiophores, and conidia are observed. Conidiophores are sympodial and appear weakly differentiated from the vegetative hyphae. They often have an inflated base and arise at right angles from the hyphae. Conidia have two types. The first type are unicellular, hyaline to brown, oval, thin-walled, and are typically arranged in rosette-like clusters at the tips of the conidiophores. The second type of conidia are brown (dematiaceous),oval or triangular, thick-walled, cessile, and are attached directly to the sides of the hyphae. The latter type of conidia are typically present only in freshly isolated strains. At 37C, Sporothrix schenckii produces oval to cigar-shaped (also called "cigar bodies") yeast cells. Single or multiple buds may be produced by a single yeast cell.

Sporothrix schenckii var. luriei differs from Sporothrix schenckii by producing large, often septate, budding cells and by not assimilating creatine and creatinine.

II. Sporothrix cyanescens. Septate hyaline hyphae, conidiogenous cells, denticles (tooth-like conidium-bearing projections), and primary and secondary conidia are visualized. The terminal conidiogenous cells have an inflated appearence. They bear denticles on their surface. The primary conidia (4-9 x 1.5-3 m) are hyaline and smooth in appearence. They are ellipsoidal in shape and bear 1-3 secondary conidia on small denticles. The secondary conidia (2.5-5 x 0.8-2 m) are smaller than primary conidia and pyriform in shape. The conidia rapidly dislodge and the dislodged conidia look like budding yeast cells. The production of secondary conidia and the absence of dematiaceous sessile conidia on the hyphae help in differentiation of Sporothrix cyanescens from Sporothrix schenckii.

III. Ophiostoma stenoceras. Being the telemorph of Sporothrix sp., this fungus produces a long-necked perithecia (the round or pear-shaped structure with an ostiole and containing asci and ascospores inside) after an incubation of 2-3 weeks.

Laboratory Precautions

No special precautions other than general laboratory precautions are required.


Available data suggest that in vitro activity of amphotericin B and itraconazole against Sporothrix schenckii is variable and strain-dependent. (Primary) amphotericin B-resistant isolates have been identified. Terbinafine, naftifine, and amorolfine are active in vitro against Sporothrix schenckii. On the other hand, fluconazole, voriconazole and ravuconazoleyield high MICs for isolates of Sporothrix schenckii.

Potassium iodide is one of the oldest therapeutic modalities used for treatment of sporotrichosis. Amphotericin B, ketoconazole, and itraconazole are now more commonly used in treatment of Sporothrix schenckii infections. Amphotericin B-resistantand itraconazole-refractory cases have been reported. Initial treatment with amphotericin B followed by long term maintenance therapy with itraconazole may be beneficial in cases with sporotrichosis and AIDS.

The mycological information gathered and organized in this extensive research on the
different Pathogenic Molds was  sourced out from the list of websites below: | | | | | | | | | | | |


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