The acid-fast stain
A) is useful for distinguishing a small group of organisms, including Mycobacterium AND reflects differences in cytoplasmic membrane structure.
B) is useful for distinguishing a small group of organisms, including Mycobacterium AND uses carbolfuchsin and methylene blue.
C) is useful for distinguishing a small group of organisms, including Mycobacterium AND uses carbolfuchsin and safranin.
D) is useful for distinguishing a small group of organisms, including Mycobacterium AND uses crystal violet and safranin.
E) is useful for distinguishing a small group of organisms, including Bacillus AND uses crystal violet and safranin.

Question

The acid-fast stain
A) is useful for distinguishing a small group of organisms, including Mycobacterium AND reflects differences in cytoplasmic membrane structure.
B) is useful for distinguishing a small group of organisms, including Mycobacterium AND uses carbolfuchsin and methylene blue.
C) is useful for distinguishing a small group of organisms, including Mycobacterium AND uses carbolfuchsin and safranin.
D) is useful for distinguishing a small group of organisms, including Mycobacterium AND uses crystal violet and safranin.
E) is useful for distinguishing a small group of organisms, including Bacillus AND uses crystal violet and safranin.

Quizplus · Accepted Answer

The acid-fast stain is indeed used to distinguish a small group of organisms, including Mycobacterium, due to their unique cell wall structure that retains the primary stain carbolfuchsin, even when exposed to acid-alcohol. The counterstain used in some acid-fast staining protocols is methylene blue, not safranin or crystal violet, which are used in Gram staining.

The Acid-Fast Stain