DNase Test Agar Base is recommended for detection of deoxyribounclease activity of bacteria and fungi, and especially for identification of pathogenic Staphylococci. Addition of toluidine blue in the media is used for differentiation and identification of non-pigmented Serratia species isolated from clinical sources that might be improperly identified as Enterobacter and Klebsiella species. Positive DNase activity is visualized as clear zones (around colonies) when the plates were flooded with 1 N hydrochloric acid.