Ready-to-use media
Bile Esculin Azide Agar
Solid medium for the confirmation and enumeration of enterococci in water by the membrane filtration method according to ISO 7899-2.
- Cat. No.
- LC-952
- Category
- Ready-to-use media
- Format
- 20 plates, 90 mm
- ISO 17025 quality control
- Yes
- Storage
- 2 to 14 °C
- Minimum guaranteed shelf life
- 1 month
- Standards
- ISO 7899-2
- Also available
- Dehydrated medium, 1 format (LC-1005)
- Also available
- Dehydrated medium, 1 format (LC-1372)
- Also available
- Ready-to-use medium, 1 format (LC-4701)
Bile Esculin Azide Medium is a modification of the classical Bile Esculin proposed by Isenberg, Goldberg and Sampson in 1970, but with a reduction in the amount of bile and the addition of sodium azide. Brodsky and Schiemann showed that this medium, also known as Enterococci Selective Medium, gave the best results using the membrane filtration technique.
Key features
Applications
Selective isolation of enterococci.
Industry
Water.
Standards
ISO 7899-2.
Presentation
20 prepared plates, 90 mm, with 21 ± 2 mL.
Description and technique
Description
The current formulation according to ISO Standard 7899-2:2000 is used for the second step in the confirmation and enumeration of enterococci in water by the membrane filtration method. The colonies previously selected on Slanetz Bartley Agar must be confirmed by a short incubation on Bile Esculin Azide Medium for verification of esculin hydrolysis in a selective environment.
Technique
After an incubation of 24-48 hours on Slanetz Bartley Agar, the membrane filter showing typical colonies is transferred, with sterile forceps in an upright position, to a pre-warmed plate of Bile Esculin Azide Agar. After two hours of incubation at 44 ± 0.5 °C the membrane filter is inspected. All the typical colonies that show brown to black colour in the surrounding medium are considered positive and therefore intestinal enterococci.
A heterogeneous distribution of the colonies or the presence of abundant and different microorganisms can interfere with the differentiation of positive colonies.
After incubation, enumerate all the colonies that have appeared onto the surface of the agar. Typical colonies of Enterococcus sp. show a brown to black coloured halo.
Each laboratory must evaluate the results according to their specifications. Presumptive isolation of Enterococcus must be confirmed with further microbiological and biochemical tests.
Presentation
| Presentation | 20 prepared plates, 90 mm |
|---|---|
| Filling | 21 ± 2 mL |
| Packaging | 1 box with 2 packs of 10 plates/pack. Single cellophane. |
Composition
| Ingredient | g/L |
|---|---|
| Tryptone | 17.00 |
| Peptone | 3.00 |
| Yeast extract | 5.00 |
| Bile | 10.00 |
| Sodium chloride | 5.00 |
| Esculin | 1.00 |
| Ammonium ferric citrate | 0.50 |
| Sodium azide | 0.15 |
| Agar | 15.00 |
Quality control
Physical/chemical control
| Color | Yellow |
|---|---|
| pH | 7.1 ± 0.1 at 25 °C |
Microbiological control
Incubate the membrane filters (MF) with microorganisms in SB at 37 °C for 24-48 h and transfer to BEA medium.
Aerobic. Incubation at 44 °C, for 2 h. Esculin test.
| Microorganism | Growth |
|---|---|
| Enterococcus faecalisATCC 19433, WDCM 00009 | Good - esculin positive reaction |
| Escherichia coliATCC 25922, WDCM 00013 | Inhibited |
| Enterococcus faecalisATCC 29212, WDCM 00087 | Good - esculin positive reaction |
| Enterococcus faeciumATCC 6057, WDCM 00177 | Good - esculin positive reaction |
Sterility control
Incubation 48 hours at 30-35 °C and 48 hours at 20-25 °C: NO GROWTH.
Check at 7 days after incubation in same conditions.
Bibliography
- ATLAS, R.M. & L.C. PARKS (1993) Handbook of Microbiological Media. CRC Press. Boca Raton. Fla.
- BRODSKY M.H. & D.A. SCHIEMANN (1976) Evaluation of Pfizer Selective Enterococcus and KF media for recovery of fecal streptococci from water by membrane filtration. Appl. Environ. Microbiol. 31:695-699.
- ISENBERG, H.D., D. GOLDBERG & J. SAMPSON (1970) Laboratory studies with a Selective Enterococcus Medium. Appl. Microbiol. 20:433.
- ISO Standard 7899-2 (2000) Water Quality. Detection and enumeration of intestinal enterococci. Part 2: Membrane filtration method.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
Every lot comes with its certificate.
Tracked shipment
Follow your shipment live, from our warehouse to your lab.
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Frequently asked questions
Can I ask for formats other than those listed?
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