ACID FAST STAIN Flashcards
What is the acid fast stain?
a differential stain used primarily in the identification of the tuberculosis bacillus (Mycobacterium tuberculosis & Mycobacterium leprae)
Are the genus, Mycobacterium, stain readily by simple staining?
No they do not
Do the genus mycobacterium have waxy cell walls? Why?
They do have waxy cell walls, because it contains a lot of lipoidal material (mycolic acids)
What happens in the Ziehl-Neelsen procedure?
the smear is flooded with carbolfuchsin (dark red dye), then heated to penetrate the stain into the bacteria
What is the Kinyoun modification?
It is a cold stain, the concentrations of phenol and carbolfuchsin are increased and a detergent is added
Are all acid-fast organisms gram positive?
Yes, but not all gram-positive organisms are acid-fast
Give each an example of a acid-fast positive & negative
Negative : Staphylococcus epidermidis
Positive : Mycobacterium phlei
What is responsible for the properties of acid-fast bacteria?
the ability of the bacteria to resist decolourization w/ acid alcohol
What important genus of bacteria is used to identify in the acid fast stain?
Mycobacterium
What was the purpose of heating the stain in acid-fast technique?
Why didn’t we use Ziehl-Neelsen procedure?
Heat prevents the cell from being washed off the slide w/ rinsing and staining. It penetrates the cell wall
Do some species in the genus Mycobacterium, readily stain by simple stain or gram stain procedures?
No they do not
