Sporotrichosis is an an chronic infection of subcutaneous tissues caused by a fungus called Sporothrix schenckii, which is a dimorphic fungus. Human acquire sporotrichosis infection through trauma (thorns, splinters), usually to the hand, arm, or leg.
What is the natural habitat of Sprothrix schenckii?
Sprothrix schenckii has a worldwide distribution. Its natural habitat is living or dead vegetation.
Who is commonly affected by Rose Gardner’s disease?
Sporotrichosis disease is occupational hazards for farmers, nursery workers, gardeners, florists and miners. Pulmonary infection may occur after inhalation of spores but is very rare.
How is Sporotrichosis diagnosed?
Clinical specimen: Exudate aspirated from unopened subcutaneous nodules or from open draining lesions.
Methods for Diagnosis:
Direct microscopy: It is very difficult to observe the yeast form of Sporothrix schenckii in the clinical specimen. So the diagnostic significance of direct microscopy is very less. Sporothrix schenckii appears as small, round to oval to cigar-shaped yeast cells. Periodic acid-schiff (PAS) method can be used to stain histological slides.
Culture: Colonies of Sprothrix schenckii grow rapidly (3-5 days) and may be mistaken with yeast colonies. On further incubation these colonies become membranous, wrinkled, dark brown or black in color. The consistency of the colony may be leathery. If the culture is incubated at 37°C Sprothrix schenckii colony transforms to a soft, cream colored to white yeast like colony (dimorphism). Conversion from mold form to yeast form takes place within 1-5 days.
Microscopy from the culture
The hyphae of Sprothrix schenckii are delicate, septate and branching. Flowerette arrangement of conidia (single celled conidia borne in clusters from the tip of single conidiophore) is seen. If the yeast like colony is taken form plate cultured at 37°C singly or multiply budding oval or elongate, cigar-shaped yeast cells are seen.