2.4.4: Exercise #9 Lab Wrap-Up

Answer the following questions:

1. Why is the acid-fast stain considered a differential stain?
2. What makes bacteria in the Mycobacterium genera resistant to staining?
3. If you conducted an acid-fast stain on a sputum sample from a person with tuberculosis, what would you expect to see on the slide? (Consider color, shape, etc.)
4. Why is it essential for healthcare workers to correctly identify acid-fast organisms like Mycobacterium tuberculosis in patient samples before initiating treatment? Consider the risks of misdiagnosis or delayed treatment.
5. Place the steps of the acid-fast stain in the proper order, by placing the appropriate number 1-4 under the images.

   

   

   

   Credit: Sherry Smith

6. For each image indicate whether the result is acid-fast or non-acid fast.

   

7. Describe how each type of cell will appear in the following scenarios in which the Gram stain was incorrectly performed.
   1. The decolorizer step was omitted.
      1. Acid-fast cells
      2. Non-acid-fast cells
   2. The counter-stain step was forgotten.
      1. Acid-fast cells
      2. Non-acid-fast cells