The Ziehl-Neelsen stain is particularly used for organisms with which cell-wall feature?

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Multiple Choice

The Ziehl-Neelsen stain is particularly used for organisms with which cell-wall feature?

The test hinges on the waxy, lipid-rich outer layer of certain bacteria. Organisms like Mycobacterium have long-chain mycolic acids in their cell walls, creating a thick, waxy barrier. This makes them resistant to decolorization with acid-alcohol during staining, so they keep the red dye from the primary stain (carbol fuchsin) even after that step. That’s why the Ziehl-Neelsen stain is described as acid-fast: the key feature detected is the presence of mycolic acids in the cell wall. Capsules or the absence of peptidoglycan aren’t the defining factors for this stain, and while the method is an acid-fast stain, the critical cell-wall characteristic it reveals is mycolic acids.

The test hinges on the waxy, lipid-rich outer layer of certain bacteria. Organisms like Mycobacterium have long-chain mycolic acids in their cell walls, creating a thick, waxy barrier. This makes them resistant to decolorization with acid-alcohol during staining, so they keep the red dye from the primary stain (carbol fuchsin) even after that step. That’s why the Ziehl-Neelsen stain is described as acid-fast: the key feature detected is the presence of mycolic acids in the cell wall. Capsules or the absence of peptidoglycan aren’t the defining factors for this stain, and while the method is an acid-fast stain, the critical cell-wall characteristic it reveals is mycolic acids.

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