Christensen Citrate Sulphite Agar 500G

Christensen Citrate Sulphite Agar for differentiation of enteric bacilli on the basis of citrate utilization and hydrogen sulphide production. L-Cysteine hydrochloride is a reducing agent. Some members of Salmonella like Salmonella Typhi are weakly positive and require 2-5 days for hydrogen sulphite production. Phenol red acts as indicator. The reduction of ferric ammonium citrate to iron sulphide by H2S producing organisms is indicated by blackening of the medium. Sodium thiosulphate enhances H2S production. Organisms that metabolize citrate changes colour from orange red to cerise.