Which organism is a Gram-positive, branching rod that forms breadcrumb-like colonies and is partially acid-fast?

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Multiple Choice

Which organism is a Gram-positive, branching rod that forms breadcrumb-like colonies and is partially acid-fast?

Nocardia is identified by its Gram-positive, branching filamentous rods that stain only partially acid-fast due to the presence of mycolic acids in the cell wall. On culture they typically form dry, chalky, crumbly colonies described as breadcrumb-like. This combination of morphology, partial acid-fastness, and the distinctive colony appearance is characteristic of Nocardia. Propionibacterium or Corynebacterium are Gram-positive rods but not notably branching and they aren’t characteristically acid-fast. Listeria monocytogenes is a non-branching Gram-positive rod, and Haemophilus influenzae is Gram-negative, so neither fits the pictured features.

Nocardia is identified by its Gram-positive, branching filamentous rods that stain only partially acid-fast due to the presence of mycolic acids in the cell wall. On culture they typically form dry, chalky, crumbly colonies described as breadcrumb-like. This combination of morphology, partial acid-fastness, and the distinctive colony appearance is characteristic of Nocardia.

Propionibacterium or Corynebacterium are Gram-positive rods but not notably branching and they aren’t characteristically acid-fast. Listeria monocytogenes is a non-branching Gram-positive rod, and Haemophilus influenzae is Gram-negative, so neither fits the pictured features.

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