Differential Stain- Acid Fast Staining

Question 1

Purpose of Acid Fast Staining

Answer 1

used to detect groups of microbes that do not readily take up dyes (usually Mycobacterium species) (usually bacterias that stain Gram Positive)

Question 2

What is special about cell walls of mycobacterium that typically undergo acid fast staining?

Answer 2

Their cell walls contains high levels of mycolic acids (wax like fatty acids) that prevent uptake of dyes and require harsher methods

Question 3

Once mycobacterium are stained,

Answer 3

they are resistant to decolorization (acid fast).

Question 4

Acid fast technique is great for

Answer 4

diagnosing pathogenic species like mycobacterium, TB and leprosy

Question 5

Acid Fast/ Ziel-Neelson Stains

Answer 5

Primary Stain is red carbolfuchsin , rinse w distilled water, DECOLORIZING agent w/ acid alcohol applied (REMOVES CARBOLFUCHSIN from all cells except acid fast) , Counterstain Methylene Blue is used. If acid fast, cell is red. If not, stains blue

Question 6

Acid fast technique and time (5-1-1min)

Answer 6

Carbol fuchsin for 5 mins, rinse w/ distilled water, Add decolorizer (acid-alochol) for 1 min, rinse w/ distilled water, Add methylene bkue for 1 mins, Rinse, Blot dry

Question 7

Although Acid Fast bacteria stain Gram Positive, the difference in their cell wall is that

Answer 7

it contains mycolic acid (waxy lipid) as its primary component. this wax like component makes it difficult to stain

Question 8

Primary Stain used to penetrate wax like mycolic acids in Acid Fast Staining

Answer 8

Carbol Fuchsin

Question 9

If cell retains carbol fuchsin, it is considered

Answer 9

Acid Fast

Question 10

If cell is decolorized by acid alcohol, and picks up counterstain of methylene blue

Answer 10

it is Acid fast negative

Question 11

Primary Stain, Mordant, Decolorizer, Counter stain in Acid Fast procedure are

Answer 11

Carbol Fuchsin, “Heat”, Acid-Alcohol, Methylene Blue