Ready-to-use media
Pseudomonas Agar CN ISO
Selective solid medium used for the detection of Pseudomonas aeruginosa according to the ISO 16266 Standard.
- Cat. No.
- LC-4740
- Category
- Ready-to-use media
- Format
- 30 water plates, 55 mm
- ISO 17025 quality control
- Yes
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 2 months
- Standards
- ISO 16266
The CN selective medium for Pseudomonas was progressively developed from the basic media of King, Ward and Raney for the production of pigments. Browne and Lowbury added cetrimide as selective agent and Goto and Enomoto improved efficiency by adding nalidixic acid. The presence of both inhibitors eliminates the contaminant microbiota from heavily polluted specimens, and the medium was adopted by the ISO Standard for the detection of Ps. aeruginosa by membrane filtration in water.
Key features
Applications
Detection and selective enumeration of Pseudomonas aeruginosa.
Industry
Water.
Standards
ISO 16266.
Presentation
30 prepared plates, 55 mm, for filtration purposes, with 9 ± 1 mL.
Description and technique
Technique
Collect, dilute and prepare samples and volumes to be filtered as required according to specifications, directives, official standard regulations and/or expected results.
Filter the sample through a 0.45 µm Ø pore membrane and apply it onto the surface of the agar.
Incubate the plates in room air atmosphere at 36 ± 2 °C for 44 ± 4 h.
(Incubation times longer than those mentioned above or different incubation temperatures may be required depending on the sample and on the specifications.)
After incubation, count the colonies with a blue-greenish appearance due to pigment production by Pseudomonas sp.
Calculate total microbial count per mL of sample by multiplying the average number of colonies per plate by the inverse dilution factor.
Report results as colony forming units (CFU) per mL along with incubation time and temperature.
Presumptive isolation of Pseudomonas sp. must be confirmed by further tests.
Presentation
| Presentation | 30 prepared plates, 55 mm, for filtration purposes |
|---|---|
| Filling | 9 ± 1 mL |
| Packaging | 1 box containing 5 plastic bags with 6 plates of 55 mm/bag. |
Composition
| Ingredient | g/L |
|---|---|
| Gelatin peptone | 16.000 |
| Casein peptone | 10.000 |
| Magnesium chloride | 1.400 |
| Potassium sulfate | 10.000 |
| Cetrimide | 0.200 |
| Sodium nalidixate | 0.015 |
| Glycerol | 10.000 mL |
| Agar | 13.600 |
Quality control
Physical/chemical control
| Color | Off-white / opalescent |
|---|---|
| pH | 7.1 ± 0.2 at 25 °C |
Microbiological control
Membrane filtration / practical range 100 ± 20 CFU; min. 50 CFU (productivity) / 10⁴-10⁶ CFU for selectivity.
Microbiological control according to ISO 11133:2014/Amd 1:2018.
Aerobiosis. Incubation at 36 ± 2 °C, reading at 44 ± 4 h.
| Microorganism | Growth |
|---|---|
| Ps. aeruginosaATCC 9027, WDCM 00026 | Good (≥ 50%) |
| Ps. aeruginosaATCC 27853, WDCM 00025 | Good (≥ 50%) |
| Ps. aeruginosaATCC 10145, WDCM 00024 | Good (≥ 50%) |
| Escherichia coliATCC 8739, WDCM 00012 | Inhibited |
| Enterococcus faecalisATCC 19433, WDCM 00009 | Inhibited |
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
- BROWN, V.L. & E.J.L. LOWBURY (1965) Use of an improved Cetrimide Agar Medium and of culture methods for P. aeruginosa. J. Clin. Pathol. 18:752.
- GOTO S. & S. ENOMOTO (1970) Nalidixic acid cetrimide agar. A new selective plating medium for the selective isolation of P. aeruginosa. Jpn. J. Microbiol. 14:65.
- ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
- ISO 16266 Standard (2006) Water Quality - Detection and enumeration of Pseudomonas aeruginosa - Method by membrane filtration.
- KING, E.O., M.K. WARD & E.E. RANEY (1954) Two simple media for the demonstration of pyocyanin and fluorescein. J. Lab. Clin. Med. 44:301.
- ROBIN, T. & J.M. JANDA (1984) Enhanced recovery of P. aeruginosa from diverse clinical specimens on a new selective agar. Diag. Microbiol. Infect Dis. 2:207.
- SCHWEIZERISCHES LEBENSMITTELBUCH (2005) Kap. 56 Mikrobiologie. Bundesamt für Gesundheit. Direktionsbereich Verbraucherschutz. Bern.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
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Tracked shipment
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