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Principle
- Tinsdale agar base is formulated by Moore and Parsons (1958), and used for isolation and cultivation of Corynebacterium species. The Tinsdale agar base is composed of a peptic digest of animal tissue, sodium chloride, L-cystine, sodium thiosulphate, and agar.
- The peptic digest of animal tissue is the source of nitrogen, carbon, and other essential growth supplements. Sodium chloride maintains the osmotic balance of the medium. L-cystine and sodium thiosulphate form the hydrogen sulfide indicator. Horse serum stimulates the good growth of Corynebacterium.
- The selectivity is enhanced by the presence of inhibitor and differential by means of the ability of an organism to reduce potassium tellurite.
- Potassium tellurite also acts as a selective agent and inhibits most gram-positive and gram-negative bacteria except Corynebacterium species. C. diphtheriae reduces potassium tellurite to tellurium and thereby produces gray-black colored colonies.
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