Columbia Agar | DM115

Columbia Agar | DM115

A versatile and nutritious medium for growth of fastidious organisms.

In the clinical laboratory the most important culture medium is blood agar, which has traditionally been a meat infusion or casein hydrolysate. The former type tends to give sharply defined haemolytic reactions, typical colonial morphology and improved pigmentation, while the latter type gives more rapid and luxuriant growth. As early as 1947 it had been shown by Casman1 that starch improved the growth of neisseria and enhanced haemolytic reactions of some streptococci. Ellner et al.2
used these properties in developing Columbia Agar Base, a starch containing medium which combined the advantages of the two types of blood agar. Columbia Agar has proved to be a very versatile medium and has been used, with the addition of
serum, in virulence tests for diphtheria3 and as a presumptive identification medium for Group B streptococci.

2. Technical Formula*

3. Directions
1. Suspend by swirling 39.0g of powder in 1 litre or the contents of the sachet in the stated volume of distilled water.
2. Autoclave at 121ºC (15p.s.i.) for 15 minutes.
3. Cool to 50ºC and add 5-7% sterile defibrinated horse blood where required.

4. In Use
Columbia Agar can be used alone, or with the addition of 5-7% blood. The medium can be made selective with the addition of
various antibiotics