Exp 15, Differential & selective media

Question 1

Objective exp 15

Answer 1

To explore various differential & selective medias in order to learn what information these media can offer about the mo tested

Question 2

Differential media exp 15

Answer 2

Places mod into specific categories

Question 3

Selective media exp 15

Answer 3

Inhibits the growth of particular mos while encouraging the growth of others

Question 4

Phenylethyl alcohol agar
Selective
exp 15

Answer 4

Gram positives grow in it, gram negatives don’t.

Question 5

If an mo grew in Phenylethyl alcohol agar, what is the gram status>

Answer 5

Gram positive

Question 6

Mannitol Salt agar
Selective
exp 15

Answer 6

Only Staph grows in it

Question 7

Would E.coli grow in MSA?

Answer 7

NO, only staph

Question 8

Mannitol Salt agar

Differential

Answer 8

Mannitol fermentors: break down, media turns yellow

Mannitol nonfermentors; no break down, media stays red

Question 9

McConkey Agar

Selective

Answer 9

Gram negative will grow in it

Gram positive will not

Question 10

McConkey Agar

Differential

Answer 10

Lactose fermenters: mo turns red (darker)

Lactose nonfermenters: mo stays clear red

Question 11

Eosin Methylene Blue

Selective

Answer 11

Gram negative will grow in it

Gram positive will not

Question 12

Eosin Methylene Blue

Differential

Answer 12

Eosin fermenter: metallic green

Eosin nonfermenter: no metallic green

Question 13

Blood Agar

DIfferential

Answer 13

Gamma hemolytics: no breakdown, media remains red
Alpha hemolytic: Some breakdown, pale green color
Beta hemolytic: complete breakdown, transparency surrounding mo