Microbiology
Summary
Sporothrix schenckii is a dimorphic fungus responsible for a subcutaneous infection called sporotrichosis, often referred to as rose gardenerÕs disease. When observed microscopically in its yeast form, S. schenckii often presents as cigar-shaped cells. While the fungus can indeed be associated with rose thorns, it is also found on tree bark, bushes, and other plants. The organism typically enters the human body through physical trauma, such as a puncture wound from a thorn. Once introduced, the fungus can lead to the formation of a local pustule or ulcer. Over time, additional nodules can appear in an ascending pattern along the lymphatic channels.
For diagnosing sporotrichosis, the gold standard is a culture of the organism. However, a biopsy revealing granulomas containing histiocytes, multinucleated giant cells, and yeast cells is also diagnostic. The preferred treatment for lymphocutaneous sporotrichosis is itraconazole. Another therapeutic option, although less commonly used in modern times, is the saturated solution of potassium iodide.
Lesson Outline
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FAQs
Sporothrix schenckii is a species of dimorphic fungus that is known to cause a subcutaneous infection known as sporotrichosis, which is often referred to as rose gardener's disease due to its common occurrence among gardeners. The fungus exhibits a branching hyphae form at environmental temperatures and turns into a cigar-shaped yeast form at body temperature.
Sporotrichosis, caused by Sporothrix schenckii, is usually contracted through direct inoculation of the fungus into the skin, often via scratches or puncture wounds from plant materials or soil. It may present as a localized, chronic, painless nodular lesion at the site of inoculation, often the hand or arm. In cases of lymphocutaneous sporotrichosis, secondary nodules can appear along the lymphatic vessels. Systemic infection, though rare, could lead to symptoms like weight loss, fatigue and joint pain.
The most common treatment options for sporotrichosis include antifungal medications or traditional skin remedies. Itraconazole is often the drug of choice for all forms of the disease. Another common treatment includes the use of potassium iodide, especially for cutaneous and lymphocutaneous forms, which is thought to inhibit the fungal enzyme system. In refractory cases, or patients who can't tolerate these treatments, other antifungals like amphotericin B may be used.
Sporotrichosis, caused by the fungus Sporothrix schenckii, is often referred to as "rose gardener's disease." This is because the fungus is commonly found in soil, rose thorns, hay, sphagnum moss, and other plant materials. Gardeners, farmers and agricultural workers are often at a higher risk of getting pricked by contaminated objects, making it a more likely occupational hazard for them, hence the name.
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