Lab | General Concepts of Media

Question 1

Component:
› Trypticase soy agar
› Brucella Agar/Beef Heart
› 5% sheep blood

Answer 1

Sheep Blood (BA)

Question 2

Purpose:
› Cultivation of non-fastidious microorganism
› Determination of hemolytic reactions

Answer 2

Sheep Blood (BA)

Question 3

Component:
› Dextrose
› Pork brain
› Heart dehydrated infusions

Answer 3

Brain-heart infusion Agar or Broth

Question 4

Purpose: Cultivation of fastidious organism

Answer 4

Brain-heart infusion Agar or Broth

Question 5

Component:
› Peptone Base
› Enriched solution of 2%
Hemoglobin

Answer 5

Chocolate Agar

Question 6

Purpose:
› Cultivation of fastidious organism
› Haemophilus spp.
› Brucella spp.
› Pathogenic Neisseria spp.

Answer 6

Chocolate Agar

Question 7

Colistin (C) - disrupts GN cell membrane
Nalidixic acid (NA) – blocks DNA replication

Answer 7

Columbia colistin-nalidixic acid (CAN) Agar

Question 8

Purpose: Selective isolation of gram+ cocci
Component:
› Peptone sources
› 5% defibrinated sheep
blood

Answer 8

Columbia colistin-nalidixic acid (CAN) Agar

Question 9

Component:
› Mannitol – primary carbon source
› Sodium citrate & Sodium deoxycholate – bile salts that inhibit GP organisms
› Peptone base broth with glucose

Answer 9

Gram Negative (GN) Broth

Question 10

Purpose: Selective (enrichment)
liquid medium for enteric pathogens

Answer 10

Gram Negative (GN) Broth

Question 11

Component:
› Peptone-base sugar with bile salts, lactose, sucrose, agar salicin, and ferric ammonium citrate
› Indicator: bromthymol blue and acid fuchsin

Answer 11

Hektoen Enteric (HE) Agar

Question 12

Purpose:
Differential, selective medium for the isolation and differentiation of Salmonella and Shigella spp. From other gram-negative enteric bacilli

Answer 12

Hektoen Enteric (HE) Agar

Question 13

Component:
› Peptone base with lactose
› Gram-positive organisms inhibited by crystal violaet and bile salts
› Indicator: neutral red

Answer 13

MacConkey Agar

Question 14

Purpose: Isolation and differentiation of lactose fermenting and non-lactose-fermenting enteric bacilli

Answer 14

MacConkey Agar

Question 15

Component:
› Nutrient agar base
› Phenylethyl alcohol inhibits
growth of gram-negative
organisms
› 5% sheep blood

Answer 15

Phenylethyl Alcohol (PEA) Agar

Question 16

Purpose: Selective isolation of aerobic gram-positive cocci and bacilli

Answer 16

Phenylethyl Alcohol (PEA) Agar

Question 17

Component:
› Blood agar based enriched with hemoglobin and supplement B

Colistin = inhibit GN
Vancomycin = inhibit GP
Nystatin = inhibit yeast
Trimethoprim = inhibit Proteus spp.

Answer 17

Modified Thayer-Martin Agar

Question 18

Purpose:
› Selective isolation of aerobic gram-positive cocci and bacilli ( N. gonorrhoeae & N. meningitidis)
› Supports growth of Francisella and Brucella spp.

Answer 18

Modified Thayer-Martin Agar

Question 19

Component:
› Pancreatic digest of casein
› Soy broth
› Glucose

Answer 19

Thioglycollate Broth

Question 20

Purpose:
› broth/semi- solid
› Supports of anaerobes, aerobes, microaerophilic, and fastidious microorganisms

Answer 20

Thioglycollate Broth

Question 21

Component:
› Yeast extract agar w/ lysine, xylose, lactose & sacrose

Sodium deoxycholate = inhibits GN
Phenol Red = pH indicator
Ferric ammonium citrate = H2s indicator

Answer 21

Xylose-Lysine-Deoxycholate (XLD) Agar

Question 22

Purpose:
Isolation and differentiation of Salmonella and Shigella spp. From other gram- negative enteric bacilli

Answer 22

Xylose-Lysine-Deoxycholate (XLD) Agar and