When supplemented with appropriate substrates, used to differentiate gram negative enteric bacteria.
Moeller first described the use of an amino acid decarboxylase test to distinguish between various microorganisms. He further noted that the production of lysine, arginine, ornithine and glutamic acid decarboxylase helped to differentiate between gram-negative enteric bacteria. Ewing et al. concluded, after investigating the decarboxylase activity of 2937 cultures of the Enterobacteriaceae, that the Moeller formulation should be considered the standard medium for studying decarboxylate reactions. Bacteria which produce decarboxylase will produce an alkaline reaction (purple or violet). Decarboxylase negative bacteria will give an acidic reaction (yellow) due to the fermentation of dextrose. To insure proper reactions overlay medium with sterile mineral oil.
