DNase Test Agar with Methyl Green is a differential medium used for the detection of deoxyribonuclease activity to aid in the identification of bacteria isolated from clinical specimens. Methyl green forms a complex with intact (polymerized) DNA to form the green color of the medium. DNase activity depolymerizes the DNA, breaking down the methyl green-DNA complex, which results in the formation of colorless zones around colonies of the test organism. A negative test is indicated by the absence of a colorless zone around the colonies.
