Deoxycholate Citrate Agar w/1.5% Agar

Deoxycholate Citrate Agar w/1.5% Agar is a selective medium recommended for the isolation of enteric pathogens. Sodium deoxycholate, sodium citrate and ferric citrate are inhibitory agents in the medium. Lactose is the fermentable carbohydrate. Lactose fermenters utilize lactose and produce acidic conditions around the lactose fermenting colony. This acidity causes the pH indicator, neutral red, to change its colour to red. The reduction of sodium thiosulphate to sulfide is indicated by the formation of black iron sulfide. Salmonella and Shigella species do not ferment lactose but Salmonella may produce H2S forming colorless colonies with orwithout black centers. Escherichia coli produces pink coloured colony w/bile precipitate, Enterobacter aerogenes produce pink colony.