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 color in alkaline condition. Color change from purple to yellow and then back to purple is positive reaction. Salmonella Typhi shows positive arginine decarboxylation reaction.
- Appearance: Light yellow to grey homogeneous free flowing powder
- Gelling: Semisolid, comparable with 0.3% Agar gel
- Color and Clarity of prepared medium: Purple colored clear to slightly opalescent gel forms in tubes as butts
- Reaction of 1.93% w/v aqueous solution at 25°C. pH : 6.0±0.2
- Cultural characteristics observed after an incubation at 35-37°C for 18-24 hours