MIO Medium (Motility Indole Ornithine Medium) is supplied by Micromaster. It is available in the form of a light yellow to pale green homogeneous free flowing powder which has a pH in the range of 6.3 to 6.7. It is advisable to store this product below 8C.

Quantity provided: 500 g/pack

Motility Indole Ornithine Medium (MIO Medium) is used for the identification of Enterobacteriaceae on the basis of motility, indole production and ornithine decarboxylase activity. Motility can be demonstrated microscopically (hanging drop) or macroscopically (tube method), where motility is observed as a diffused zone of growth flaring out from the line of inoculation. Casein enzymic hydrolysate and peptic digest of animal tissue provide amino acids and other nitrogenous substances. Yeast extract is the source of vitamin B complex. Dextrose is the fermentable carbohydrate. Test cultures are stab-inoculated into the medium butts. Motility and ornithine decarboxylation reactions are read before testing indole production. On addition of the Kovacs reagent, colour of the medium changes to yellow. Positive ornithine decarboxylase test (purple) could be misinterpreted as negative (yellow). Organisms ferment dextrose to form acid, which causes the pH indicator bromocresol purple to change from purple to yellow. Organisms possessing ornithine decarboxylase enzyme, decarboxylate ornithine to putrescine which increases the pH making it alkaline, indicated by a colour change from yellow to purple throughout the medium. Decarboxylase negative reaction is indicated by yellow colour or yellow with a purple band near the top of the medium. Indole is produced from tryptophan present in casein enzymic hydrolysate. The indole produced combines with the aldehyde present in the Kovacs reagent to form a red complex.