Himedia DNase Test Agar Base w/o DNA

DNase Test Agar Base w/o DNA is recommended with the addition of DNA it is used for detection of deoxyribonuclease activity of bacteria and fungi, especially Staphylococci. Tryptone and soya peptone provides essential nutrients. DNase activity is detected by flooding the surface of the medium with 1 N HCl and observing for clear zones around the colonies on the medium (with added DNA and mannitol and no bromothymol blue). In the absence of DNase activity, cloudy precipitate is formed due to reaction of HCl with nucleic acids.When bromothymol blue is used, yellow zones are formed. Further confirmatory tests for the identification should be carried out. Serratia marcescens positive reaction, change in colour from green to yellow around the growth.