Legionella · Cultivation and confirmation
BCYE Agar Base – BCYE agar and cysteine-free BCYE for Legionella
BCYE Agar Base (buffered charcoal yeast extract) is used in two ways in ISO 11731: with the BCYE Growth Supplement it gives BCYE agar for the cultivation of Legionella, and without the supplement it gives BCYE-Cys agar (without cysteine) for the confirmation of presumptive colonies.
- BCYE agar with growth supplement
- BCYE-Cys agar without cysteine
- Cysteine-requirement confirmation
How BCYE Agar Base works
Activated charcoal and the ACES buffer protect Legionella from toxic oxygen products and keep the pH stable. Legionella needs L-cysteine: it grows on BCYE agar but not on BCYE-Cys agar, while most other bacteria grow on both.
Typical colony appearance
| Organism | Colonies |
| Legionella pneumophila on BCYE | Grey-white, convex, moist colonies |
| L. pneumophila on BCYE-Cys | No growth |
| E. coli, S. epidermidis on BCYE-Cys | Growth |
Technical data
| Preparation | 39.05 g/L; boil to dissolve, autoclave 121 °C 15 min; cool to about 50 °C; pour directly for BCYE-Cys agar, or add 1 vial of BCYE Growth Supplement per 100 mL for BCYE agar |
| Final pH | 6.8 ± 0.2 |
| Incubation | 36 ± 1 °C, 2–5 days |
| Storage | Powder dry and dark |
| Shelf life | 3 years |
Applications and practical notes
Legionella grows in warm water systems and causes Legionnaires’ disease; water is tested according to ISO 11731. Typical applications include:
- Hot and cold water systems in buildings
- Cooling towers and evaporative condensers
- Hospitals, hotels and spa pools
- Industrial process water
Working with BCYE Agar Base: Subculture each presumptive colony on BCYE agar and on BCYE-Cys agar and incubate both for 2–5 days at 36 °C.
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 the Legionella method: ISO 11731 describes the enumeration of Legionella in water by direct plating or membrane filtration on BCYE and the selective GVPC agar, with incubation at 36 °C for up to 10 days. Presumptive colonies are confirmed by their need for L-cysteine: they grow on BCYE agar but not on BCYE agar without cysteine. L. pneumophila and its serogroups are then identified by latex agglutination. COLO.Science offers media, supplements, latex kits and rapid tests for these steps.
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.
BCYE 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 BCYE Agar Base, please send us a request. With every delivery of BCYE Agar Base you receive the lot number and expiry date, and on request we send the available documentation for BCYE Agar Base.
Where BCYE Agar Base fits in Legionella testing
- Sample preparation – membrane filtration, with heat or acid treatment for samples with high background flora
- Culture – GVPC agar and BCYE agar, 36 °C, up to 10 days
- Confirmation – subculture on BCYE and on BCYE without cysteine
- Identification – latex agglutination; qPCR or LAMP for fast screening
Ordering information
| Product | COLO code | Pack |
|---|---|---|
| BCYE Agar Base (BCYE-Cys Agar) | PRO7540 | 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.
