Cetrimide agar: composition, preparation and uses




Centrimide agar

  • Cetrimide agar is a selective plate medium used occasionally to isolate Pseudomonas species from a mixed bacterial flora. It inhibits the growth of bacteria such as Staphylococcus aureus and coliforms.
  • Cetrimide agar in dehydrated from his available from Gibco Ltd and other manufacturers of culture media.

Composition of centrimide agar

Commercially availavble as Gibco dehydrated medium formula

  • Peptone 190………………………….20.0 g
  • Potassium sulphate……………………10 g
  • Magnesium chloride………………….1.4 g
  • Cetyltrimethyl-ammonium bromide….15.0 g
  • Agar………………………………….15.0 g

Preparation of Centrimide agar:

  • The medium is used at a concentration of 4.67 grams in every 100 ml of distilled water.
  • Prepare as instructed by the manufacturer.
  • Mix well and dispense aseptically in sterile petri dishes.
  • Date the medium and give it a batch number.

Quality control

  • pH of medium: this should be within the range pH 7.0-7.4 at room temperature.

Use of centrimide agar:

  • Itis used as selective medium for Pseudomonasaeruginosa from the mixed culture containing Staphylococcus aureus and Esherichia coli. * E. coli and S. aureus got be inhibited.

Cetrimide agar: composition, preparation and uses