colonies are, therefore surrounded by clear areas indicating DNA hydrolysis.
DNAse agar plate Up to six organisms may be tested on the same plate. Hydrochloric acid, 1 mol/l
Divide a DNAse plate into the required number of strips by marking the underside of the plate. Using a sterile loop or swab, spot – inoculate the test and control organisms. Make sure each test area is clearly labeled. Incubate the plate at 36-37OC overnight. Cover the surface of the plate with 1mol/l hydrochloric acid solution. Tip off the excess acid. 58. Look for clearing around the colonies within 5minutes of
adding the acid.
Results Clearing around the colonies -----------------DBAse positive strain. No clearing around to colonies -------------DNAse negative strain.
Controls Positive DNAse control: staphylococcus arureus . Negative DNAse control: staphylococcus epidermidis.