- DNAse agar is a plate biochemical medium used to identify Staphylococcus aureus from other species.
- It is most economically prepared from the dehydrated medium available commercially
Composition of DNAse agar:
- Tryptose……………………….20 gm/ltr
- Deoxyribonucleic acid…………2 gm/ltr
- Sodium chloride………………..5 gm/ltr
- Agar……………………………12 gm/ltr
Preparation of DNAse agar:
- The medium is used at a concentration of 3.9 grams in every 100 ml of distilled water.
- Prepare and sterilize as instructed by the manufacturer.
- When the medium has cooled to 50-55°C, mix well and dispense in sterile petri dishes.
- Date the medium and give it a batch number.
Quality control
- pH of medium: this should be within the range pH7.1-7.5 at room temperature.
- Test the medium each time it is used by inoculating on the same plate as the test organisms, Staphyloccal species known positive and negative DNAse activity.
- Store the plates at 2-8°C in sealed plastic bags to prevent loss.
Use of DNAse agar:
- Used to isolate Staphylococcus aureus from other species.