Ornithine Decarboxylase Broth

Principle
Ornithine Decarboxylase Broth is modification of Moeller decarboxylase broth (1954-55). The media is
composed of l-ornithine monohydrochloride, yeast extract, glucose and bromocresol purple. yeast extract
provides nitrogen, vitamins, minerals, amino acids and growth factors. Glucose is carbon or energy source
for the growth of microorganisms. L-ornithine monhydrochloride decarboxylated to from putrescine.
Bromo cresol purple and cresol red are the pH indicators. When glucose is fermented by bacteria, the pH is
lowered due to acid production, which changes the colour of the indicator from purple to yellow. Acid
produced stimulates decarboxylase enzyme. Decarboxylation of ornithine yields putrescine in alkaline
conditions, revert to purple colour. If the organisms do not produce decarboxylase enzyme, the colour of the
medium remains yellow. glucose non-utilizers will not show any change in the medium color. Use light
inoculate and do not read the tests after 24 hours incubation, as some organisms require longer incubation
time of up to 4 days.
Use: Recommended for detection of ornithine decarboxylating microorganisms.
Contents*

* Formula adjusted for optimum performance and parameters