Enriched media · Blood agar base
Columbia Agar Base – versatile base for blood agar
Columbia Agar Base is a highly nutritious base for blood agar. With 5 % sheep blood it supports good growth of streptococci, staphylococci, Listeria and other demanding bacteria and gives clear haemolysis zones. It is also used in the confirmation of Listeria monocytogenes and Bacillus cereus.
- Base for sheep blood agar
- Clear haemolysis zones
- With CNA supplement selective for Gram-positive cocci
How Columbia Agar Base works
A mixture of peptones, yeast extract and starch provides nutrients, and the starch absorbs toxic metabolites. After the blood is added at 45–50 °C, haemolysis appears as a clear zone (β) or a green zone (α) around the colonies.
Typical reactions
| Organism | On blood agar |
| Staphylococcus aureus | β-haemolysis |
| Streptococcus pneumoniae | α-haemolysis (green zone) |
| Listeria monocytogenes | Narrow β-haemolysis |
Technical data
| Preparation | 44 g/L; boil to dissolve, autoclave 121 °C 15 min; for blood agar add 5–10 mL sterile defibrinated sheep blood per 100 mL at 45–50 °C |
| Final pH | 7.3 ± 0.2 |
| Incubation | 35–37 °C, 24 h |
| Storage | Dry, dark place; keep the container tightly closed |
| Shelf life | 3 years unopened |
Applications and practical notes
Enriched bases with blood, haemoglobin or supplements are needed for fastidious bacteria such as streptococci, Neisseria and Haemophilus, and for reading haemolysis. Their performance is checked with reference strains according to ISO 11133. Typical applications include:
- Blood agar for haemolysis reading
- Culture of streptococci and other fastidious bacteria
- Chocolate and GC media for Neisseria and Haemophilus
- Research and reference laboratories
Working with Columbia Agar Base: Add the blood only after cooling the base to 45–50 °C and mix gently to avoid bubbles and lysis of red cells.
Good practice with dehydrated media: keep the bottle tightly closed in a cool, dry place, weigh the powder quickly to avoid moisture uptake, and use fresh distilled or deionised water. Check the pH of each new batch after preparation and before use, and label prepared media with the date. Performance of each lot can be verified with reference strains according to ISO 11133, the standard for the preparation, production, storage and performance testing of culture media.
About general-purpose media: general-purpose media are not tied to one reference method. They are used in every laboratory for cultivation, revival of reference strains, purity checks and as bases for enriched and test media. Their performance is verified with reference strains according to ISO 11133, and media for susceptibility testing follow the requirements of EUCAST and CLSI. COLO.Science offers general media, enriched bases, supplements and QC strains from one source.
Complete sets from one supplier: COLO.Science supplies culture media, supplements, rapid tests, identification kits and QC strains as complete sets for the method you follow. Send us your sample types and standards, and we will prepare an offer with the matching products and documentation.
Columbia Agar Base is supplied by COLO.Science in the pack sizes listed under Ordering information. For larger quantities, regular deliveries or method-specific sets that include Columbia Agar Base, please send us a request. With every delivery of Columbia Agar Base you receive the lot number and expiry date, and on request we send the available documentation for Columbia Agar Base.
Where Columbia Agar Base fits in general microbiology
- Sample preparation – Peptone Water, Phosphate Buffer and other diluents
- Cultivation and revival – Nutrient, BHI and Columbia media
- Fastidious organisms – blood, chocolate and GC media with supplements
- Testing and identification – Mueller Hinton for susceptibility, CLED and chromogenic agar for urine, biochemical tests
See all general-purpose media in the Microbiology Catalogue →
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| Columbia Agar Base | PRO7479 | 500 g |
Product notice: preparation, storage conditions and shelf life are given on the label. Technical data on this page are for orientation; the label and the lot documentation apply. B2B prices are quoted net, excluding VAT.
Sales and technical support
COLO LabExperts
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Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
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Need the complete set for your method?
Send the sample type, target organism and the standard you follow. COLO.Science will put together the media, supplements, QC strains and confirmation tests for the whole procedure.
