(AB) MR-VP Broth, 500 grams

Clark and Lubs noted the ability of coliforms to produce and maintain acid products when cultivated in certain test media. The aerogenes group was found to produce lesser amounts of acid and eventually become alkaline on extended incubation. Methyl red was found to be a satisfactory indicator of acidity. A test described by Voges and Proskauer determines the differential ability of bacteria to produce acetyl methyl carbinol. Some organisms such a E. aerogenes produce acetyl methyl carbinol after sufficient incubation. One method for demonstration of the presence of acetyl methyl carbinof involves addition of a potassium hydroxide-creatine reagent to a test culture with production of a delicate eosin-pink color (positive reaction). MR-VP (Methyl Red-Voges Proskauer) Broth is used in the differentiation of bacteria based on their methyl red and Voges Proskauer reactions. (Alpha Biosciences # M13-105-500gm)

Use: MR-VP (Methyl Red-Voges Proskauer) Broth is used in the differentiation of bacteria based on their methyl red and Voges Proskauer reactions.

Description: : Clark and Lubs noted the ability of coliforms to produce and maintain acid products when cultivated in certain test media. The aerogenes group was found to produce lesser amounts of acid and eventually become alkaline on extended incubation. Methyl red was found to be a satisfactory indicator of acidity. A test described by Voges and Proskauer determines the differential ability of bacteria to produce acetyl methyl carbinol. Some organisms such a E. aerogenes produce acetyl methyl carbinol after sufficient incubation. One method for demonstration of the presence of acetyl methyl carbinof involves addition of a potassium hydroxide-creatine reagent to a test culture with production of a delicate eosin-pink color (positive reaction).

Formula* per Liter:

• Casein Digest Peptone ................... 3.5g
• Dextrose ...................................... 5.0g
• Peptic Digest of Animal Tissue....... 3.5g
• Potassium Phosphate ............... 5.0g

Final pH: 6.9 ± 0.2 at 25.0°C

* Grams per liter may be adj. or formula supplemented to obtain desired performance

Preparation: Mix 17 grams of the medium in one Liter of purified water until evenly dispersed. Heat with repeated stirring and boil for one minute to dissolve completely. Distribute and autoclave at 121°C for 15 minutes.

Quality Control Specifications:

1. The powder is homogeneous, free flowing and light beige.
2. Visually the prepared medium is clear and light gold to amber.
3. Expected cultural response after 2 days at 35.0°C.

Organism                                                                                Result

Enterobacter aerogenes ATCC 13048                           Growth, MR -, VP +

Escherichia coli ATCC 25922                                         Growth, MR +, VP -

Storage: Store the sealed bottle containing the dehydrated medium at 2 to 30.0°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original light beige color.