Microbial Metabolism

Question 1

Enriched Media

Answer 1

Contain diverse growth factors to aid growth

blood agar
chocolate agar

Question 2

Selective Media

Answer 2

Designed to inhibit some microbes and allow others

MAC
EMB
CNA

Question 3

Differential Media

Answer 3

Allow growth of more than one microorganism but create distinguishable qualities

Question 4

Blood Agar

Answer 4

Enriched and Differential

Beta, Alpha, and non-hemolytic

Gram-positive cocci

Question 5

CNA Agar

Answer 5

Selective and Differential

Selects for G-positive

antibiotics that inhibit g-negatives: Colistin (polymixen B), and Naladixic Acid

5% sheeps blood: hemolytic differentiation

Question 6

MAC Agar

Answer 6

Selective and Differential

Crystal violet and bile salts

Inhibit gram-positives, selects for g-negatives

lactose substrate

pH indication Neutral Red

Differentiates g-negatives based on their ability to ferment lactose

Lactose fermentation causes red acidic products

Question 7

EMB Agar

Answer 7

Selective and Differential

Eosin dye
Methylene blue dye

inhibit g-positives, select for g-negatives

lactose substrate

High lactose fermentation= green/metalic

Low lactose fermentation= pink

No lactose fermentation= purple (matches medium)

Question 8

MSA Agar

Answer 8

Selective and Differential

7.5% NaCl- selects for halotolerants (staphylococcus)

mannitol substrate

pH indicator: Phenol Red

Mannitol fermentation: yellow growth

Question 9

MH Agar

Answer 9

Best for antibiotic sensitivity testing