AZIDE DEXTROSE BROTH 500 grams/bottle

Azide Dextrose Broth is used for the detection and enumeration of enterococci/streptococci in water, sewage, foods and other materials. The medium contains Sodium azide, which inhibits the growth of the accompanying flora in Gram-negative bacteria and permits the growth of enterococci. The presence of enterococci is an indicator for faecal contamination, especially when occurred a long time ago and the less resistant coliform bacteria, including Escherichia coli, may already be dead when the analysis is carried out. Beef Extract and Casein peptone provide nitrogen, vitamins, minerals and amino acids essential for growth. Dextrose is the fermentable carbohydrate providing carbon and energy. Sodium chloride supplies essential electrolytes for transport and osmotic balance. The use of Sodium azide to selectively inhibit Gram-negative bacteria first appeared in the studies of Edwards (1938) on the isolation of Streptococcus agalactiae, later was showed that Sodium azide can also be used for the isolation of enterococci from water.