DNASE TEST AGAR BASE (W/O INDICATOR) *

Description

DNase Test Agar is used for detecting deoxyribonuclease activity of bacteria and fungi and particularly for identification of pathogenic Staphylococci. With added toluidine blue, it is used in differentiation and identification of non-pigmented Serratia species isolated from clinical sources that might be improperly identified as Enterobacter and Klebsiella species. The correlation between DNase activity and coagulase activity was first studied by Weckman and Catlin. Jeffries et al demonstrated DNase activity by the agar plate method employing a semi-synthetic medium. Positive DNase activity was visualized as clear zones (around colonies) when the plates were flooded with 1 N hydrochloric acid. DiSalvo confirmed the correlation between coagulase activity and DNase activity by incorporating DNA into the medium along with calcium chloride to activate the enzyme. Di Salvo incorporated DNA and calcium chloride to activate DNase enzyme. Schreier modified DNase medium by adding toluidine blue by. This modified medium achieved faster identification of Serratia marcescens and could differentiate Serratia from other members of the Enterobacteriaceae.