3-8

Question 1

what is the name of the acid-fast staining technique used in lab?

Answer 1

Ziehl-Neelsen acidfast staining method

Question 2

what is mycolic acid?

Answer 2

waxy-substance in cell walls of acid fast MOs that has a higher affinity for the primary stain and resists decolorization with acid alcohol.

enables cell wall of acid fast MOs to repel typical aqueous solution

Question 3

what is carbolfuchsin?

Answer 3

primary stain

phenolic compound that penetrates mycolic acid in the cell wall of acidfast bacteria because it is lipid soluable

Question 4

why do we steam carbolfuchsin?

Answer 4

enhances staining by driving stain into cell wall

Question 5

Result of Ziehl-Neelsen’s acid fast staining?

Answer 5

bacteria that retain primary stain after decolorization are acid fast while those that donot are non acid fast

Question 6

what are the steps in Ziehl-Neelsens acid fast staining?

Answer 6

primary stain carbolfuchsin
decolorization acid alcohol
secondary stain methylene blue

Question 7

why is the secondary stain not safranin?

Answer 7

Safranin and carbolfuchsin are too close in color, would not be able to differentiate

Question 8

why do put bibulous paper while streaming?

Answer 8

Because if we do not, cells dry (desiccate) and get distort shape

Question 9

what are the color in Ziehl-Neelsens acid fast staining?

Answer 9

hot pink (+) Mycobacterium smegmatis

blue (-) Staphylococcus epidermis/aureus

Question 10

what are two diseases cause by acid fast MOs?

Answer 10

Mycobacterium leprae

Mycobacterium tuberculosis.