Arginine Dihydrolase Broth

Arginine Dihydrolase Broth is recommended for detection of arginine dihydrolase producing microorganisms. It is used to differentiate bacteria on the basis of their decarboxylating activity of the amino acid. Arginine decarboxylase enzyme is also known as Arginine dihydrolase. Bacteria producing arginine dihydrolase enzyme decarboxylate arginine present in this medium to putrescine. The production of amine, putrescine, elevates the pH. Bromo cresol purple , the pH indicator which forms purple colour in alkaline condition. Colour change from purple to yellow and then back to purple is positive reaction. Salmonella Typhi shows positive arginine decarboxylation reaction.