AZIDE BLOOD AGAR BASE

Azide Blood Agar Base is recommended for the isolation and cultivation of Streptococcus species from clinical and non-clinical specimens. It is a modification of the broth medium originally formulated by Edwards for the detection of Streptococci from bovine mastitis cases. The original broth medium of Edwards was modified to a blood agar by Packer containing sodium azide and crystal violet.
The media can be supplemented with sterile defibrinated blood to prepare blood agar. Blood serves as an additional source of growth factors and it also helps to visualize the haemolytic pattern. The pH of the medium influences the inhibitory action of sodium azide. At pH 7.2, sodium azide does not interfere with the haemolytic reactions of Streptococci; however, haemolytic pattern of Streptococci is different on Azide Blood Agar as compared on nonselective blood agar. For best results, use light inoculum and incubate anaerobically for enhancement in haemolytic reaction. Different types of haemolysis can be visualized on blood agar plates.

for selective isolation and cultivation of Staphylococci & Streptococci from mixed bacterial ?ora