Dehydrated culture media
Bile Esculin Azide Broth
Selective medium recommended for the isolation and presumptive identification of intestinal Enterococcus.
- Cat. No.
- LC-1359
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
Bile Esculin Azide Broth is a selective medium for the differentiation, isolation and presumptive identification of enterococci.
Key features
Applications
Detection and selective isolation of enterococci.
Preparation
41.6 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
The ability to hydrolyze esculin is a characteristic of enterococci. Organisms positive for esculin hydrolysis hydrolyze the glucoside esculin to esculetin and dextrose. The esculetin reacts with the ferric citrate to form a dark brown or black colony. Ox bile does not inhibit enterococci while other Gram-positive bacteria are inhibited. Sodium azide inhibits Gram-negative bacteria. Tryptone, peptone and yeast extract supply the nutrients essential for growth. Sodium chloride provides the osmotic balance. Bacteriological agar is the solidifying agent.
The presence of intestinal enterococci is an indicator for faecal contamination, especially when the contamination occurred a long time before and the less resistant coliform bacteria, including Escherichia coli, may already be dead when the analysis is carried out.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Toasted |
| Color of the prepared medium | Litmus |
| Final pH (25 °C) | 7.0 ± 0.2 |
| Amount per litre | 41.6 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Esculin | 1 |
| Ferric ammonium citrate | 0.5 |
| Ox bile | 10 |
| Peptone | 3 |
| Sodium azide | 0.15 |
| Sodium chloride | 5 |
| Tryptone | 17 |
| Yeast extract | 5 |
Preparation and use
Preparation
Suspend 41.6 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Dispense into appropriate containers and sterilize in autoclave at 121 °C for 15 minutes.
Instructions for use
Inoculate and incubate at 35 ± 2 °C and observe after 18-24 hours.
Quality control
Microbiological test
Incubation conditions: 35 ± 2 °C / 18-24 h.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Enterococcus faecalisATCC 11700 | Good growth | Esculin (+) |
| Streptococcus pyogenesATCC 19615 | Null growth | Esculin (-) |
| Escherichia coliATCC 25922 | Null growth | Esculin (-) |
| Enterococcus faeciumATCC 8043 | Good growth | Esculin (+) |
Bibliography
- FACKLAM, R.R.: Recognition of group D streptococcal species of human origin by biochemical and physiological test. - Appl. Microbiol., 23; 1131-1139 (1972).
- FACKLAM, R.R.: Comparison of several laboratory media for presumptive identification of enterococci and group D streptococci. - Appl. Microbiol., 26; 138-145 (1973).
- SWAN, A.: The use of bile-esculin medium and of Maxted's technique of LANCEFIELD grouping in the identification of enterococci. (Group D streptococci). J. Clin. Pathol., 7: 160-163 (1954).
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.
Other products in the same category
Frequently asked questions
Can I ask for formats other than those listed?
Yes: custom formats and OEM packs are available on request. Tell us the quantities you need.
How do I see the prices?
Prices are shown after you sign in to the customer area, with your account discount already applied.
How long does delivery take?
We give you the availability with the quote, within 24 hours of your request.