Practical Microbiology Flashcards
1
Q
SDA stands for ____?
A
Sabaroud Dextrose Agar
2
Q
What is SDA used for
A
Isolation of dermatophytes, fungi and yeast
3
Q
SBA stands for ____?
A
Sheep Blood Agar
4
Q
What is SBA used for?
A
To identify haemolytic qualities of bacteria
- Certain bacteria produce haemolysins (which break down RBC’s)
5
Q
MCA stand for ____?
A
MacConkey Agar
6
Q
What is MCA used for?
A
- To differentiate between lactose fermenting bacteria (turns pink) and non lactose fermenting (remains yellow)
- most gram positive bacteria will NOT grow on MCA
7
Q
Why do gram positive bacteria stain purple?
A
Have thick peptidoglycan which retains violet dye even after decolourization step
8
Q
Why do gram negative bacteria stain pink/red
A
Thin peptidoglycan that loses the primary violet stain in decolourization and enables them to stain pink/red with the counterstain.
