Media
Unless otherwise indicated, the media should be sterilized by heating in an autoclave (see
Steam Sterilization under
Sterilization 1211), the exposure time depending on the volume to be sterilized.
I. Fluid Casein DigestSoy LecithinPolysorbate 20 Medium
Pancreatic Digest of Casein |
20 g |
Soy Lecithin |
5 g |
Polysorbate 20 |
40 mL |
Water |
960 mL |
Dissolve the pancreatic digest of casein and soy lecithin in 960 mL of water, heating in a water bath at 48
to 50
for about 30 minutes to effect solution. Add 40 mL of polysorbate 20. Mix, and dispense as desired.
II. SoybeanCasein Digest Agar Medium
Pancreatic Digest of Casein |
15.0 g |
Papaic Digest of Soybean Meal |
5.0 g |
Sodium Chloride |
5.0 g |
Agar |
15.0 g |
Water |
1000 mL |
pH after sterilization: 7.3 ± 0.2.
III. Fluid SoybeanCasein Digest Medium
IV. MannitolSalt Agar Medium
Pancreatic Digest of Casein |
5.0 g |
Peptic Digest of Animal Tissue |
5.0 g |
Beef Extract |
1.0 g |
D-Mannitol |
10.0 g |
Sodium Chloride |
75.0 g |
Agar |
15.0 g |
Phenol Red |
0.025 g |
Water |
1000 mL |
Mix, then heat with frequent agitation, and boil for 1 minute to effect solution.
pH after sterilization: 7.4 ± 0.2.
V. BairdParker Agar Medium
Pancreatic Digest of Casein |
10.0 g |
Beef Extract |
5.0 g |
Yeast Extract |
1.0 g |
Lithium Chloride |
5.0 g |
Agar |
20.0 g |
Glycine |
12.0 g |
Sodium Pyruvate |
10.0 g |
Water |
950 mL |
Heat with frequent agitation, and boil for 1 minute. Sterilize, cool to between 45
and 50
, and add 10 mL of sterile potassium tellurite solution (1 in 100) and 50 mL of egg-yolk emulsion. Mix intimately but gently, and pour into plates. (Prepare the egg-yolk emulsion by disinfecting the surface of whole shell eggs, aseptically cracking the eggs, and separating out intact yolks into a sterile graduated cylinder. Add sterile saline TS to obtain a 3 to 7 ratio of egg yolk to saline. Add to a sterile blender cup, and mix at high speed for 5 seconds.)
pH after sterilization: 6.8 ± 0.2.
VI. VogelJohnson Agar Medium
Pancreatic Digest of Casein |
10.0 g |
Yeast Extract |
5.0 g |
Mannitol |
10.0 g |
Dibasic Potassium Phosphate |
5.0 g |
Lithium Chloride |
5.0 g |
Glycine |
10.0 g |
Agar |
16.0 g |
Phenol Red |
25.0 mg |
Water |
1000 mL |
Boil the solution of solids for 1 minute. Sterilize, cool to between 45
and 50
, and add 20 mL of sterile potassium tellurite solution (1 in 100).
pH after sterilization: 7.2 ± 0.2.
VII. Cetrimide Agar Medium
Pancreatic Digest of Gelatin |
20.0 g |
Magnesium Chloride |
1.4 g |
Potassium Sulfate |
10.0 g |
Agar |
13.6 g |
Cetyl Trimethylammonium Bromide (Cetrimide) |
0.3 g |
Glycerin |
10.0 mL |
Water |
1000 mL |
Dissolve all solid components in the water, and add the glycerin. Heat, with frequent agitation, and boil for 1 minute to effect solution.
pH after sterilization: 7.2 ± 0.2.
VIII. Pseudomonas Agar Medium for Detection of Fluorescin
Pancreatic Digest of Casein |
10.0 g |
Peptic Digest of Animal Tissue |
10.0 g |
Anhydrous Dibasic Potassium Phosphate |
1.5 g |
Magnesium Sulfate (MgSO4·7H2O) |
1.5 g |
Glycerin |
10.0 mL |
Agar |
15.0 g |
Water |
1000 mL |
Dissolve the solid components in the water before adding the glycerin. Heat, with frequent agitation, and boil for 1 minute to effect solution.
pH after sterilization: 7.2 ± 0.2.
IX. Pseudomonas Agar Medium for Detection of Pyocyanin
Pancreatic Digest of Gelatin |
20.0 g |
Anhydrous Magnesium Chloride |
1.4 g |
Anhydrous Potassium Sulfate |
10.0 g |
Agar |
15.0 g |
Glycerin |
10.0 mL |
Water |
1000 mL |
Dissolve the solid components in the water before adding the glycerin. Heat, with frequent agitation, and boil for 1 minute to effect solution.
pH after sterilization: 7.2 ± 0.2.
X. Fluid Lactose Medium
Beef Extract |
3.0 g |
Pancreatic Digest of Gelatin |
5.0 g |
Lactose |
5.0 g |
Water |
1000 mL |
Cool as quickly as possible after sterilization.
pH after sterilization: 6.9 ± 0.2.
XI. Fluid SeleniteCystine Medium
Pancreatic Digest of Casein |
5.0 g |
Lactose |
4.0 g |
Sodium Phosphate |
10.0 g |
Sodium Acid Selenite |
4.0 g |
L-Cystine |
10.0 mg |
Water |
1000 mL |
Mix, and heat to effect solution. Heat in flowing steam for 15 minutes. Do not sterilize.
XII. Fluid Tetrathionate Medium
Pancreatic Digest of Casein |
2.5 g |
Peptic Digest of Animal Tissue |
2.5 g |
Bile Salts |
1.0 g |
Calcium Carbonate |
10.0 g |
Sodium Thiosulfate |
30.0 g |
Water |
1000 mL |
Heat the solution of solids to boiling. On the day of use, add a solution prepared by dissolving 5 g of potassium iodide and 6 g of iodine in 20 mL of water. Then add 10 mL of a solution of brilliant green (1 in 1000), and mix. Do not heat the medium after adding the brilliant green solution.
XIII. Brilliant Green Agar Medium
Yeast Extract |
3.0 g |
Peptic Digest of Animal Tissue |
5.0 g |
Pancreatic Digest of Casein |
5.0 g |
Lactose |
10.0 g |
Sodium Chloride |
5.0 g |
Sucrose |
10.0 g |
Phenol Red |
80 mg |
Agar |
20.0 g |
Brilliant Green |
12.5 mg |
Water |
1000 mL |
Boil the solution of solids for 1 minute. Sterilize just prior to use, melt the medium, pour into petri dishes, and allow to cool.
pH after sterilization: 6.9 ± 0.2.
XIV. XyloseLysineDesoxycholate Agar Medium
Xylose |
3.5 g |
L-Lysine |
5.0 g |
Lactose |
7.5 g |
Sucrose |
7.5 g |
Sodium Chloride |
5.0 g |
Yeast Extract |
3.0 g |
Phenol Red |
80 mg |
Agar |
13.5 g |
Sodium Desoxycholate |
2.5 g |
Sodium Thiosulfate |
6.8 g |
Ferric Ammonium Citrate |
800 mg |
Water |
1000 mL |
Heat the mixture of solids and water, with swirling, just to the boiling point.
Do not overheat or sterilize. Transfer at once to a water bath maintained at about 50
, and pour into plates as soon as the medium has cooled.
XV. Bismuth Sulfite Agar Medium
Beef Extract |
5.0 g |
Pancreatic Digest of Casein |
5.0 g |
Peptic Digest of Animal Tissue |
5.0 g |
Dextrose |
5.0 g |
Sodium Phosphate |
4.0 g |
Ferrous Sulfate |
300 mg |
Bismuth Sulfite Indicator |
8.0 g |
Agar |
20.0 g |
Brilliant Green |
25 mg |
Water |
1000 mL |
Heat the mixture of solids and water, with swirling, just to the boiling point.
Do not overheat or sterilize. Transfer at once to a water bath maintained at about 50
, and pour into plates as soon as the medium has cooled.
XVI. Triple SugarIronAgar Medium
Pancreatic Digest of Casein |
10.0 g |
Pancreatic Digest of Animal Tissue |
10.0 g |
Lactose |
10.0 g |
Sucrose |
10.0 g |
Dextrose |
1.0 g |
Ferrous Ammonium Sulfate |
200 mg |
Sodium Chloride |
5.0 g |
Sodium Thiosulfate |
200 mg |
Agar |
13.0 g |
Phenol Red |
25 mg |
Water |
1000 mL |
pH after sterilization: 7.3 ± 0.2.
XVII. MacConkey Agar Medium
Pancreatic Digest of Gelatin |
17.0 g |
Pancreatic Digest of Casein |
1.5 g |
Peptic Digest of Animal Tissue |
1.5 g |
Lactose |
10.0 g |
Bile Salts Mixture |
1.5 g |
Sodium Chloride |
5.0 g |
Agar |
13.5 g |
Neutral Red |
30 mg |
Crystal Violet |
1.0 mg |
Water |
1000 mL |
Boil the mixture of solids and water for 1 minute to effect solution.
pH after sterilization: 7.1 ± 0.2.
XVIII. Levine EosinMethylene Blue Agar Medium
Pancreatic Digest of Gelatin |
10.0 g |
Dibasic Potassium Phosphate |
2.0 g |
Agar |
15.0 g |
Lactose |
10.0 g |
Eosin Y |
400 mg |
Methylene Blue |
65 mg |
Water |
1000 mL |
Dissolve the pancreatic digest of gelatin, the dibasic potassium phosphate, and the agar in the water, with warming, and allow to cool. Just prior to use, liquefy the gelled agar solution, add the remaining ingredients, as solutions, in the following amounts, and mix: for each 100 mL of the liquefied agar solution5 mL of lactose solution (1 in 5), 2 mL of the eosin Y solution (1 in 50), and 2 mL of methylene blue solution (1 in 300). The finished medium may not be clear.
pH after sterilization: 7.1 ± 0.2.
XIX. Sabouraud Dextrose Agar Medium
Dextrose |
40 g |
Mixture of equal parts of Peptic Digest of Animal Tissue and Pancreatic Digest of Casein |
10 g |
Agar |
15 g |
Water |
1000 mL |
Mix, and boil to effect solution.
pH after sterilization: 5.6 ± 0.2.
XX. Potato Dextrose Agar Medium
Cook 300 g of peeled and diced potatoes in 500 mL of water prepared by distillation, filter through cheesecloth, add water prepared by distillation to make 1000 mL, and add the following: |
Agar |
15 g |
Glucose |
20 g |
Dissolve by heating, and sterilize.
pH after sterilization: 5.6 ± 0.2.
For use, just prior to pouring the plates, adjust the melted and cooled to 45
medium with sterile tartaric acid solution (1 in 10) to a pH of 3.5 ± 0.1. Do not reheat the pH 3.5 medium.