Can’t answer a Question in Microbiology!

Hey, I’ve got a question (I’ll write below) and don’t know how to answer it or word it.

My question is What are the selective and diagnostic properties of the four types of media (Blood, MacConkey, CLED and Pseudomonas cetrimide) agar plates?

Thanks!

It's easiest to start with a sentence and then work from there.

[W] agar is selective for [X] and differentiates between [Y] and [Z].

You may then wish to go into defining how each plate does what it does. Look at the key ingredients in each type of agar and their purpose. e.g. for MacConkey agar, I would suggest focusing on bile salts, crystal violet, neutral red, and lactose.


To use an example not on your list:

Mannitol Salt Agar (MSA) is selective for gram-positive cocci and is also used to differentiate between coagulase-positive and coagulase-negative Staphylococci. In a clinical context it is often used to isolate and identify Staphylococcus aureus. So I would first mention how it's high NaCl content inhibits the growth of most other bacteria while promoting the growth of Staphylococci. Then I would discuss how mannitol and phenol red allow coagulase-positive and coagulase-negative Staphylococci to be differentiated.