CYSTINE TELLURITE AGAR BASE

Cystine Tellurite Agar Base was originally formulated by Tinsdale which was later on modified by Moore and Parsons and then by Imre et al. Present formulation of Cystine Tellurite Agar Base with the addition of sterile sheep blood is used for selective isolation and differentiation of Corynebacterium diphtheriae types.
Potassium tellurite inhibits most upper respiratory tract normal flora other than Corynebacterium species and also inhibits the growth of majority of gram-negative bacteria. This medium is differential on the basis of the ability of Corynebacterium species to reduce tellurite whereas diphtheroids found in upper respiratory tract are not able to reduce tellurite. L-Cystine is the source of amino acid, which enhances H2S production. Further biochemical tests are necessary to distinguish between C.diphtheriae and C.ulcerans due to similar reactions on this medium.

for selective isolation and di?erentiation of Corynebacterium diphteriae types