Azide Dextrose Broth | Principle | Preparation | Interpretation

Ⅰ. Overview

Ⅱ. Preparation / composition

Suspendre les composants, poudre déshydratée, dans l'eau (34.7g dans 1000 ml d'eau purifiée/distillée). Porter le milieu à ébullition sous agitation constante. NE PAS SURCHAUFFER.
Distribute in test tubes and sterilize in an autoclave at 121°C for 15 minutes./p>

◈ This product has low toxicity, gloves, mask and eye protection should be worn when handling the powder.

Ⅲ. Principle of Rothe brothe

A mixture of peptone and glucose in the medium makes dextrose azide broth highly nutritious and sodium chloride maintains osmotic balance.

Selectivity against Gram-negative organisms is provided by sodium azide.

The phosphate buffer system controls the pH.

Ⅳ. Utilization

Inoculate 10 ml of medium with 1 ml of the sample to be tested. Inoculate 3 other tubes with 0.1 ml, 0.01 ml and 0.001 ml of sample respectively. Incubate all tubes at 37°C and examine turbidity after 24 and 48 hours.

Note: When large volumes of water samples are to be examined, a dual strength medium is used. Turbidity in the tubes indicates the presence of enterococci, however, it should be confirmed by inoculation in EVA broth (ethyl violet azide, litsky) and biochemical tests.

Ⅴ. Interpretation

◈ Incubate all tubes for 24 and 48 hours at 37°C. A positive culture causes cloudiness in the tubes. These will be subject to confirmation.