BCYE Agar | ISO 11731 Legionella Culture Medium
Buffered Charcoal Yeast Extract Agar for Legionella Isolation
Catalog Number: AS-1133
 
Overview
BCYE Agar (Buffered Charcoal Yeast Extract Agar) is the international gold-standard solid culture medium for the primary isolation and cultivation of Legionella species, particularly Legionella pneumophila, from clinical and environmental samples.
Originally developed by Edelstein (1981) and later standardised in ISO 11731, BCYE Agar contains activated charcoal, ACES buffer, α-ketoglutarate, and essential iron and cysteine supplements that are critical for the recovery and growth of fastidious Legionella organisms.
Ausamics BCYE Agar is formulated to deliver maximum recovery of stressed Legionella from contaminated samples and serves as the reference base medium for both non-selective BCYE and selective BCYE variants (GVPC, MWY, etc.).
Key Features & Benefits
Charcoal + iron + cysteine ensure excellent recovery of Legionella
ACES buffer maintains a highly stable pH (critical for Legionella)
α-Ketoglutarate enhances growth and colony development
Gold-standard reference medium in ISO and national guidelines
Base medium for selective BCYE formulations (GVPC, MWY, BMPA)
Typical Applications
Primary isolation of Legionella pneumophila and other Legionella spp.
Official reference medium in:
ISO 11731:2017
CDC guidelines
National and international water-testing standards
Cultivation of fastidious Legionella from:
Respiratory specimens
Lung tissue
Water systems, cooling towers, and environmental samples
Principle of the Medium
BCYE Agar provides a highly protective and nutrient-rich environment for Legionella species. Activated charcoal neutralises toxic peroxides, while yeast extract supplies essential nutrients. ACES buffer ensures precise pH control, and iron plus L-cysteine supply growth factors that are absolutely required for Legionella metabolism.
Composition (per litre)
Base Medium
Yeast Extract – 10.0 g
Activated Charcoal (powder) – 2.0 g
ACES Buffer – 10.0 g
α-Ketoglutarate (potassium salt) – 1.0 g
Agar – 13.0–15.0 g
Supplements (added after autoclaving, at 50 °C)
L-Cysteine HCl·H₂O – 0.4 g (filter-sterilised)
Iron(III) pyrophosphate (soluble) – 0.25 g (filter-sterilised)
Final pH: 6.9 ± 0.1 at 25 °C (critical parameter)
Preparation
Suspend 36.0–38.0 g of BCYE base in 950 mL purified water
Add 10.0 g ACES buffer and 1.0 g α-ketoglutarate, mix thoroughly
Adjust pH to 6.9 at 50 °C using 1 N KOH (approx. 12–15 mL)
Autoclave at 121 °C for 15 minutes
Cool to 50 °C
Aseptically add:
40 mL filter-sterilised L-cysteine solution (1 %)
10 mL filter-sterilised iron pyrophosphate solution (2.5 %)
Mix thoroughly and pour plates (medium appears black and opaque)
Incubation
Temperature: 35–36 °C
Atmosphere: 5–10 % CO₂, high humidity
Duration: Up to 14 days
Typical Legionella Colonies
Grey-white to iridescent blue-green
“Ground-glass” appearance
Characteristic cut-glass texture under stereomicroscope
Storage & Stability
Dehydrated base: Store below 30 °C in a cool, dry place
Prepared plates: Store at 2–8 °C, sealed and protected from light
Shelf life (plates): Use within 4 weeks
Intended Use
For laboratory use only.
Legionella species are Risk Group 2 organisms.
Not for clinical diagnostic reporting without appropriate biosafety controls.
Quality & Compliance
Conforms to ISO 11731 requirements
Suitable for regulated environmental and microbiology laboratories
Performance comparable to leading international reference media
Customs & Trade Information
HS / AHECC Code: 3821.00.00
Prepared culture media for development or maintenance of microorganisms
Why Buy BCYE Agar from Ausamics?
Ausamics is an Australian life-science supplier specialising in reference-grade microbiological media, offering:
ISO-compliant formulations
Consistent batch quality and documentation
Competitive alternatives to global brands
Reliable supply for routine and regulatory testing