Which morphological feature described is associated with Alternaria growth on Sabouraud agar?

Which morphological feature described is associated with Alternaria growth on Sabouraud agar?

• A. Spherical conidia in clusters
• B. Pseudohyphae with bud forms
• C. Chaining macroconidia with longitudinal and horizontal septations
• D. Yeast-like cells

Answer: (C)

In identifying Alternaria on Sabouraud agar, focus on its distinctive conidial morphology. Alternaria forms long chains of macroconidia that are multicellular and pigmented. These macroconidia exhibit septations in two directions—longitudinal (along the length) and horizontal (across the width)—producing a chain of segmented, beaked spores. This chaining of crosswise and lengthwise septate conidia is a classic, characteristic feature of Alternaria cultures. Other descriptions don’t fit as well: pseudohyphae with budding are typical of yeasts like Candida, and yeast‑like cells or spherical conidia in clusters aren’t the hallmark for Alternaria. So the description of chain-forming macroconidia with both longitudinal and horizontal septations best matches Alternaria growth on Sabouraud agar.

In identifying Alternaria on Sabouraud agar, focus on its distinctive conidial morphology. Alternaria forms long chains of macroconidia that are multicellular and pigmented. These macroconidia exhibit septations in two directions—longitudinal (along the length) and horizontal (across the width)—producing a chain of segmented, beaked spores. This chaining of crosswise and lengthwise septate conidia is a classic, characteristic feature of Alternaria cultures.

Other descriptions don’t fit as well: pseudohyphae with budding are typical of yeasts like Candida, and yeast‑like cells or spherical conidia in clusters aren’t the hallmark for Alternaria. So the description of chain-forming macroconidia with both longitudinal and horizontal septations best matches Alternaria growth on Sabouraud agar.