Columbia agar | Principle | Composition | Reading

Ⅰ. Overview

Ⅱ. Composition of Columbia agar

Suspend the components, dehydrated powder, in water (42.5 grams in 1000 ml of purified/distilled water). The medium is boiled for a few seconds until the ingredients are completely dissolved. Distribute in tubes or bottles and sterilize by autoclaving at 121°C for 15 minutes.

Ⅲ. Preparation from Columbia Agar Base

🏼 With the Columbia base, it is possible to prepare the following media::

• Preparation of the blood agar : at 45°C, mix homogeneously 5 to 10% sterile defibrinated blood, after shaking, avoiding including air bubbles, distribute in Petri dishes. It allows to determine haemolytic reactions.
• Preparation of cooked blood agar (chocolate) : Add 5% sterile blood. Heat the mixture in a bain-marie for about 10 minutes at 80°C, stirring all the time, until the medium turns chocolate brown, divide into Petri dishes.
• Blaser–Wang Campylobacter medium preparation : Columbia agar (890mL) + Sheep blood (100mL) + Antibiotic supplement 10ml (Cephalothin, Vancomycin, Trimethoprim, Amphotericin B, Polymyxin B).
  Note : In the same way: Karmali's Campylobacter medium and Butzler's Campylobacter medium.
• Columbia Agar Base can be used to prepare Milk Lactose and Egg Yolk Emulsion Agar for the isolation of fastidious clostridia
• Selective medium for Gardnerella vaginalis and Medium for Haemophilus ducreyi.

🏼 Autres applications :

• CAMP Test
• Nagler Test
• Elek Test

Alpha hemolysis

Beta hemolysis

CAMP TEST