Dehydrated culture media
Clostridium Perfringens Agar Base (m-CP)
For the enumeration and isolation of Clostridium perfringens in water samples.
- Cat. No.
- LC-1132
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
- Standards
- Council Directive 98/83/ECISO 11133
Clostridium Perfringens Agar Base (m-CP) is a medium used for the rapid isolation and presumptive identification of Clostridium perfringens from water samples. m-CP Agar was first described by Bisson and Cabelli for the rapid quantification of Clostridium perfringens from various water samples (seawater, drinking water and sewage) for human consumption and from environmental water samples. It is recommended in European Council Directive 98/83/EC for testing the quality of water intended for human consumption by the membrane filtration technique.
Supplement to be added: m-CP Supplement LC-6073
Key features
Applications
Selective enumeration and isolation of Clostridium perfringens.
Industry
Water.
Standards
Council Directive 98/83/EC, ISO 11133.
Preparation
35.57 g in 500 mL of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
The medium was shown to give better recovery of Clostridium perfringens from water and sewage samples. It can be used for monitoring all types of waters. C. perfringens is present in large numbers in water and sewage and its spores are resistant to wastewater treatment practices, extremes in temperature, and environmental stress. The medium has been recommended for the examination of chlorinated waters and untreated water containing industrial wastes lethal to non-spore-forming bacteria, sewage sludge, and situations in which the detection of remote as well as recent pollution is desirable.
Tryptose provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group, essential for bacterial growth. Sucrose is a complex carbohydrate energy source. L-Cysteine hydrochloride is the reducing agent and bromocresol purple is the pH indicator. Bacteriological agar is the solidifying agent.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Purple |
| Final pH (25 °C) | 7.6 ± 0.2 |
| Amount | 35.57 g in 500 mL |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Bacteriological agar | 15 |
| Bromocresol purple | 0.04 |
| L-Cysteine hydrochloride | 1 |
| Magnesium sulfate heptahydrate | 0.1 |
| Sucrose | 5 |
| Tryptose | 30 |
| Yeast extract | 20 |
Preparation and use
Preparation
Suspend 35.57 grams of the medium in 500 mL 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 aseptically add 1 vial of m-CP Supplement (LC-6073) per 500 mL of medium. Mix well and distribute into sterile containers.
Instructions for use
Membrane filtration method:
- Filter a measured volume of the sample, or a dilution of it, through a membrane with a pore of 45 micrometers.
- For water intended for human consumption, it is usual to filter a volume of 100 mL.
- Place the membrane grid face upwards on an m-CP agar plate, ensuring that no air bubbles are trapped under the filter.
- Incubate the plates with the filters anaerobically at 44 ± 1 °C for 21 ± 3 hours, inverted to avoid interference with the condensing water.
Quality control
According to ISO 11133
Incubation conditions: productivity, selectivity, specificity (44 ± 1 °C / 21 ± 3 h).
Inoculation conditions: productivity quantitative (100 ± 20 CFU, min. 50 CFU) / selectivity (10³-10⁴ CFU) / specificity (10⁴-10⁶ CFU).
Reference media: TSA or other non-selective media for anaerobes.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Clostridium perfringensATCC 13124 | Good growth, > 50% | Yellow colonies; phosphatase test positive |
| Clostridium bifermentansCECT 550 | Blue colonies; phosphatase test negative | |
| Escherichia coliATCC 8739 | Total inhibition (0) |
Bibliography
- Armon, R., and Payment, P., 1988, A modified m-CP medium for enumerating Clostridium perfringens from water samples: Canadian Journal of Microbiology, v. 34, p. 78-79.
- Bisson, J.W., and Cabelli, V.J., 1979, Membrane filter enumeration method for Clostridium perfringens: Applied and Environmental Microbiology, v. 37, no. 1, p. 55-66.
- E.U. (1998) 98/83/EC of Council of 3rd of November 1998 on the quality of water intended for human consumption. Off. J. Eur. Commun., L330, 32-54.
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