A sputum sample from a patient with chronic cavitary lung disease is cultured on Sabouraud dextrose agar at 25°C. The colony is cottony white initially, then develops a greenish-yellow center with a white border. Lactophenol cotton blue mount shows septate hyphae with conidiophores bearing flask-shaped vesicles with phialides arranged in a single row (uniseriate) covering the upper half only. Which Aspergillus species is identified?
- A Aspergillus niger
- B Aspergillus flavus
- C Aspergillus fumigatus ✓
- D Aspergillus terreus
Correct answer: C. Aspergillus fumigatus
Explanation
Aspergillus fumigatus shows blue-green colonies and produces uniseriate, columnar conidiophores with phialides covering only the upper portion of a flask-shaped vesicle. A. niger has biseriate, radiate conidiophores with dark conidia. A. flavus can be uniseriate or biseriate with globose vesicles. A. terreus has aleurioconidia on submerged hyphae and is often amphotericin B resistant.
Reference: Koneman's Color Atlas and Textbook of Diagnostic Microbiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.