Enriched media · Selective supplement
Columbia CNA Supplement – selective supplement for Gram-positive cocci
Columbia CNA Supplement makes Columbia blood agar selective for Gram-positive cocci. It suppresses most Gram-negative bacteria, including Proteus, so staphylococci and streptococci can be isolated from mixed samples.
- Selective for Gram-positive cocci
- Suppresses Gram-negative bacteria and Proteus
- One vial per 100 mL
How Columbia CNA Supplement works
A polymyxin antibiotic and nalidixic acid inhibit Gram-negative rods. The vial is dissolved in sterile water and added to the cooled Columbia blood agar base together with the blood.
Technical data
| Use | One vial per 100 mL Columbia Agar Base with sheep blood, added aseptically at 45–50 °C |
| Storage | 2–8 °C |
| Shelf life | 1 year |
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 CNA Supplement: Reconstitute the vial just before use and add it at 45–50 °C; do not reheat the medium.
Good practice with media and supplements: 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 CNA Supplement 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 CNA Supplement, please send us a request. With every delivery of Columbia CNA Supplement you receive the lot number and expiry date, and on request we send the available documentation for Columbia CNA Supplement.
Where Columbia CNA Supplement 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 CNA Supplement | PRO7703 | 10 vials |
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
Polje ob Sotli 4, SI-3255, Slovenia
Quotations and technical support for culture media and microbiology products across our international sales territory. B2B prices are net, excluding VAT.
COLO.SCIENCE | MICROBIOLOGY SUPPORT
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.
