What is the purpose of doing an acid fast stain?
It is a differential stain used to detect cells capable of retaining a primary stain when treated with acid alcohol.
What bacteria is an acid fast stain used to identify?
Mycobacterium
What are the 3 primary steps involved in doing an acid fast stain?
- Stain with carbolfuchsin
- Decolorize with alcohol
- Counterstain with methylene blue
What three organisms would be positive for a capsule stain?
Bacillus anthracis, Streptococcus pneumoniae, Klebsiella pneumoniae
What is a capsule stain?
A differential stain which selectively stains external capsules surrounding bacterial cells.
What is the purpose of doing an endospore stain?
To detect the presence, shape, and location of endospores in bacterial cells.
What are the two main genera identified by the presence of endospores?
- Bacillus
- Clostridum
What is the procedure for endospore stain?
- Stain with malachite green
- Heat fix
- Decolorize with water
- Counterstain with safranin
Blood Agar is selective for...
Streptococcus
Blood Agar is differential for...
An organism's ability to hemolyze red blood cells
Blood Agar: Alpha hemolysis
Mild or incomplete hemolysis
Blood Agar: Beta hemolysis
Complete hemolysis
Blood Agar: Gamma Hemolysis
No hemolysis
Mannitol Salt Agar is selective for...
Staphylococcus aureus
Mannitol Salt Agar is differential for...
An organism's ability to ferment the carbohydrate mannitol.
Color of a pathogen on Mannitol Salt Agar plate?
Yellow
Color of nonpathogen on Mannitol Salt Agar plate?
Red
Eosin Methylene Blue (EMB) Agar is selective for...
Members of enteric bacteria (Gram negative rods)
Eosin Methylene Blue (EMB) Agar is differential for...
An organism's ability to ferment lactose.
Color of nonpathogen on EMB Agar?
Green
Color of weak pathogen on EMB Agar?
Pink
Color of strong pathogen on EMB Agar?
White
MacConkeys Agar is selective for....
Enteric gut bacteria
MacConkeys Agar is differential for...
An organism's ability to ferment lactose
Color of nonpathogen on MAC Agar?
Pink
Color of pathogen on MAC Agar?
White
Selective Media
Suppresses the growth of some organisms and promotes the growth of others (Gram + or Gram -)
Differential Media
Allows you to differentiate between two types of bacteria (fermentation of lactose.)