To Xin Ni

For the S. aureus:

Some organisms require growth factor X while others may require growth factor V. Some organisms may even need both growth factors. But the blood agar only contains factor X. So S. aureus is needed to provide the factor V. ^[2] S. aureus is also used to detect Haemophilius influenza virus. This is known as satellitism.


For the different medium/ media:

Cooked meat

Enriched media

Amino acids (from meat particles), other nutrients (e.g glucose, hemin and Vitamin K), reducing agents (e.g glutathione)

Favours the growth of anaerobes [4]

Growth in medium = turbid medium or gas bubbles in medium. Blackened and disintegration of meat particles = proteolysis occurred.

GC plates	Selective medium	1.Peptone mixture 2. Corn starch 3. Buffering system	To isolate Neisseria gonorrhoeae 2. Absorbs toxic metabolites 3. Maintain neutral pH[6]	If N. gonorrhoeae is present, colonies can be observed on the plates.
LIM broth	Selective enrichment media	Todd Hewitt broth*, yeast extract, colistin, nalidixic acid.	Detect presence of Group B streptococci (e.g Streptococcus agalactiae), especially on specimens from the genital area. [7] Yeast extract is used to enhance growth of group B streptococci.	The broth will be subcultured on blood agar plate and incubated at 5% CO2. If the bacteria are present, colonies can be observed on the plates.

* Todd Hewitt broth consists of: Heart infusion from solids, peptonen, dextrose, sodium chloride, disodium phosphate and sodium carbonate.

Hope it helps =).

-Li Ping-