Supplements and additives
Nalidixic Selective Supplement
Selective supplement for isolation of Pseudomonas aeruginosa spp. formulated according to ISO standard.
- Cat. No.
- LC-6046
- Category
- Supplements and additives
- Format
- 10 vials, each for 500 mL of medium
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
- Standards
- ISO 16266
The nalidixic acid sodium salt, added to the appropriate medium base in order to obtain Cetrimide (CN) Agar, gives improved performance with respect to Cetrimide Agar.
Key features
Applications
Selective enumeration and selective isolation of Pseudomonas aeruginosa.
Industry
Water.
Standards
ISO 16266.
Presentation
10 freeze-dried vials with 3 ± 0.1 g.
Description and technique
Description
This supplement, in combination with the reduction of cetrimide, allows a better recovery of Pseudomonas aeruginosa spp. over Klebsiella, Proteus and Providencia spp., which are the common contaminants of conventional cetrimide.
A blue-green or brown pigmentation, or fluorescence, are the characteristics of Pseudomonas spp.
Technique
Collect, dilute and prepare samples and volumes as required according to specifications, directives, official standard regulations and/or expected results.
Reconstitute the vial with the sterile diluent in aseptic conditions and add it to 500 mL of agar base cooled to 50 °C.
Do not overheat once supplemented.
Pour the complete medium into Petri dishes and, once solidified on a flat surface, spread the plates by streaking or spiral method.
Incubate the plates in aerobic atmosphere at 35 ± 2 °C for 24-48 h.
Incubation times longer than those mentioned above or different incubation temperatures may be required depending on the sample or the specifications.
After incubation, count all the colonies that have appeared on the surface of the agar.
Presumptive isolation of Pseudomonas sp. must be confirmed by further tests.
Presentation
| Presentation | 10 freeze-dried vials |
|---|---|
| Filling | 3 ± 0.1 g |
| Packaging | 22 ± 0.25 x 55 ± 0.5 mm glass vials, tag labelled, white plastic cap - 10 vials per box. |
Composition
| Ingredient | g/vial |
|---|---|
| Nalidixic acid sodium salt | 0.0075 |
| Excipient | Sufficient amount |
Reconstitute the original freeze-dried vial by adding 6 mL of sterile distilled water.
Note: each vial is sufficient to supplement 500 mL of Cetrimide Agar Base CN.
Quality control
Physical/chemical control
| Color | White-grey |
|---|
Microbiological control
Reconstitute 1 vial as indicated in Composition; shake and dissolve completely.
Add 1 vial to 500 mL of medium base. DO NOT HEAT once supplemented.
Distribute the complete medium, cooled to 50 °C, into 90 mm plates.
Incubate according to the instructions for the complete medium indicated in Composition.
Aerobiosis. Incubation at 35 ± 2 °C, reading at 24-48 hours.
| Microorganism | Growth |
|---|---|
| Ps. aeruginosaATCC 27853 | Good |
| Ps. aeruginosaATCC 9027, WDCM 00026 | Good |
| Escherichia coliATCC 8739, WDCM 00012 | Inhibited |
Sterility control
Add 5 mL of the sample to 100 mL of TSB and to 100 mL of Thioglycollate.
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.
- EN 12780 Standard (2002) Water Quality. Detection and enumeration of P. aeruginosa by membrane filtration.
- 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 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
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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