Dehydrated culture media
Rothe Agar (Glucose Agar w/ Azide)
Recommended for the quantitative determination of Enterococcus faecalis.
- Cat. No.
- LC-2035
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
Rothe Agar (Glucose Agar w/ Azide) is a selective medium recommended by Mallmann and Seligmann for the quantification of enterococci in water, food and other materials suspected of being contaminated by waste waters. Enterococci are the best indicators of fecal contamination in water as Escherichia coli is very resistant to chloride.
Key features
Applications
Selective enumeration of enterococci.
Industry
Water.
Preparation
47.9 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
The presence of enterococci is an indicator for fecal contamination, especially when it occurred a long time ago and the less resistant coliform bacteria, including Escherichia coli, may already be dead when the analysis is carried out.
Peptone mixture and casein peptone provide nitrogen, vitamins, minerals and amino acids essential for growth. Glucose is the fermentable carbohydrate providing carbon and energy. Sodium chloride supplies essential electrolytes for transport and osmotic balance. The use of sodium azide to selectively inhibit Gram-negative bacteria first appeared in the studies of Edwards (1938) on the isolation of Streptococcus agalactiae; it was later shown that sodium azide can also be used for the isolation of enterococci from water.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Light amber |
| Final pH (25 °C) | 7.2 ± 0.2 |
| Amount per litre | 47.9 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Glucose | 7.5 |
| Bacteriological agar | 15 |
| Beef extract | 4.5 |
| Peptone mixture | 15 |
| Sodium azide | 0.2 |
| Sodium chloride | 7.5 |
Preparation and use
Preparation
Suspend 47.9 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. Sterilize in autoclave at 121 °C for 15 minutes. Cool to 45-50 °C and dispense into Petri dishes.
Instructions for use
Inoculate and incubate at a temperature of 35 ± 2 °C for 18-24 hours.
Quality control
Microbiological test
Incubation conditions: 35 ± 2 °C / 18-24 h.
| Microorganism | Specification |
|---|---|
| Enterococcus faecalisATCC 19433 | Good growth |
| Escherichia coliATCC 25922 | Total inhibition |
| Staphylococcus aureusATCC 25923 | Total inhibition |
| Enterococcus faecalisATCC 29212 | Good growth |
Bibliography
- Mallmann W.L. Seligmann E.B. AJPH, 1950. 40 286-289
- Standard Methods for the Examination of Water and Wastewater. Eleventh Edition APHA Inc. New-York 1960
- Edwards S.J. (1933) J. Comp. Path Therap., 46.211.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
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