Vogel & Johnson (VJ) Agar (Difco)

VJ Agar, also known as Vogel and Johnson Agar, is used for the early detection of coagulase-positive, mannitol-fermenting staphylococci.

Principles Peptone is a source of carbon, nitrogen, vitamins and minerals. Yeast extract supplies B-complex vitamins which stimulate bacterial growth. Mannitol is the carbohydrate. Inhibition of nonstaphylococcal organisms is achieved by the potassium tellurite additive, which is inhibitory for some species of both gram-positive and gram-negative bacteria, by lithium chloride and by the high glycine content. Staphylococci may be slightly inhibited by the presence of the three inhibitors; however, this is compensated for by the addition of mannitol and glycine. Phenol red is the pH indicator and agar is the solidifying agent.

Coagulase-positive staphylococci reduce the potassium tellurite to metallic free tellurium, producing colonies that are gray-black. The fermentation of mannitol by coagulase-positive staphylococci is detected by a change in the color of the phenol red indicator from red (alkaline) to yellow (acid).

Item No. Product Description Brand Name Size Mfr. Item No. Unit of Measure Your Cost Purchase
Vogel & Johnson Agar Detection of coagulase-positive and mannitol-positive Staphylococcus aureus.
Detection of coagulase-positive and mannitol-positive Staphylococcus aureus. Difco 500 gram 256220 Each
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