Tryptose Cycloserine Azide Agar Base

Tryptose Cycloserine Azide Agar Base is recommended for enumeration of sulphite reducing anaerobes essentially Clostridia. This medium was later modified by decreasing the concentration of D-cycloserine, sulphite and iron and by the addition of sodium azide. This medium utilizes the selective inhibitory properties of D-cycloserine and an indicator system involving sulphite and iron. Growth of non-mesophilic organisms are suppressed while C. perfringens and related species will reduces the sulphite and form black colonies due to the production of ferrous sulphide.