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.

Light beige, homogeneous, free flowing powder

Reddish grey, clear, complete

As Reported

Dissolve 10.5grams per liter of distilled/ deionized (DDI) water, add 1% of L- or 2% of DL- lysine, arginine or ornithine as desired, heating with stirring until completely solubilized. Dispense into appropriate containers, loosen caps and autoclave for 10 minutes at 121ºC (15psi). Aseptically overlay inoculated broth tubes and controls with 4-5 mm of sterile mineral oil.

Store powdered media at RT. Stable for 12 months after receipt. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.