Azide Dextrose Broth is recommended by the APHA for the isolation of fecal streptococci. Sodium Azide is used to inhibit Gram negative microorganisms, by inhibiting cytochrome oxidase, while allowing the growth of Gram positive microorganisms, particularly Streptococcus sp. Selective broth medium used for cultivating streptococci in water, sewage and milk. (Alpha Biosciences # A01-114-500gm)
Use: Selective broth medium used for cultivating streptococci in water, sewage and milk.
Description: Azide Dextrose Broth is recommended by the APHA for the isolation of fecal streptococci. Sodium Azide is used to inhibit Gram negative microorganisms, by inhibiting cytochrome oxidase, while allowing the growth of Gram positive microorganisms, particularly Streptococcus sp.
Formula* per Liter:
- Casein Digest Peptone ................... 7.5g
- Dextrose ......................................... 7.5g
- Peptic Digest of Animal Tissue ...... 7.5g
- Sodium Chloride ............................ 7.5g
- Beef Extract ...................................... 4.5g
- Sodium Azide ................................ 0.2g
 Final pH: 7.2 ± 0.2 at 25.0°C
* Grams per liter may be adj. or formula supplemented to obtain desired performance
Preparation: Mix 34.7 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 121.0°C for 15 minutes.
Quality Control Specifications:
- The powder is homogeneous, free flowing and light beige.
- Visually the prepared medium is clear and light to medium amber.
- Expected cultural response after 18-48 hours at 35.0°C.
Organism                                                             Result
Enterococcus faecalis ATCC 19433Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Growth
Escherichia coli ATCC 259Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Inhibited
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.
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