Mycology · NEET PG Preparation Microbiology
A gardener presents with a nodular, ulcerating skin lesion on his right index finger, along with similar painless subcutaneous nodules tracking up th…
Practice question from Mycology (NEET PG Preparation Microbiology), with the correct answer and a step-by-step solution.
medium · MCQ · Q-27B98D
A gardener presents with a nodular, ulcerating skin lesion on his right index finger, along with similar painless subcutaneous nodules tracking up the lymphatic drainage of the arm. The causative agent is cultured at 25 degrees Celsius and 37 degrees Celsius. What is the characteristic microscopic morphology of this dimorphic fungus at 25 degrees Celsius (room temperature)?
- A.Broad, aseptate hyphae with sporangiospores
- B.Spherules containing endospores
- C.Tuberculate macroconidia and smooth microconidia
- D.Thin, septate hyphae with delicate conidia arranged in rosettes (daflower-like)Correct answer
Solution
The patient has sporotrichosis caused by Sporothrix schenckii (rose gardener's disease). It is a thermally dimorphic fungus. At 25 degrees C (mold phase), it produces thin, septate hyphae bearing oval conidia arranged in rosettes or daisy-like clusters. At 37 degrees C, it transitions to a yeast phase.
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