Dehydrated culture media
King A Medium (Pseudomonas P) Agar USP/ISO
For the identification and confirmation of Pseudomonas spp. based on pyocyanin production.
- Cat. No.
- LC-1531
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
King A Medium (Pseudomonas P Agar) is prepared according to the formula described by King et al. for the detection and differentiation of Pseudomonas aeruginosa from other Pseudomonas based on pyocyanin production.
Key features
Applications
Confirmation of Pseudomonas aeruginosa and detection of Pseudomonas.
Industry
Water.
Preparation
46.4 g in one liter of distilled water with 10 mL of glycerol; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
Pseudomonas aeruginosa is a free-living bacterium, present in soil and water. It has become more and more known as an emerging opportunistic pathogen of clinical importance. Various different epidemiological studies track its occurrence as a nosocomial pathogen and claim that antibiotic resistance is increasing in clinical isolates.
This medium promotes the production of pyocyanin, a blue-green pigment which oxidizes to brown, is water-soluble and, unlike fluorescein, is soluble in chloroform. The pigment diffuses throughout the medium and the blue color is observed. Confirmation of pyocyanin production is by chloroform extraction. Add 2 mL of chloroform to a tube of medium and shake gently to remove pigment.
This medium contains pancreatic digest of gelatin as a rich nitrogen source, and other nutrients for growth such as vitamins, minerals and amino acids. Gelatin peptone is low in phosphorus to reduce the inhibitory action on pyocyanin production. Potassium sulfate and magnesium chloride provide cations to activate pyocyanin production and enhance pigment production. Glycerol is a carbon source. Bacteriological agar is the solidifying agent.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Light beige |
| Color of the prepared medium | Amber, slightly opalescent |
| Final pH (25 °C) | 7.2 ± 0.2 |
| Amount per litre | 46.4 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Bacteriological agar | 15 |
| Gelatin pancreatic digest | 20 |
| Potassium sulfate | 10 |
| Magnesium chloride | 1.4 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 46.4 grams of the medium in one liter of distilled water. Add 10 mL of glycerol. 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.
According to ISO 22717
For the confirmation of Pseudomonas aeruginosa according to ISO 22717:
- Subculture the presumptive colonies of Pseudomonas aeruginosa (yellow-green pigment and fluorescence under UV radiation) obtained in Cetrimide Agar (LC-1102).
- Incubate the plates at 32.5 ± 2.5 °C for 24, 48 and 72 h.
- Pseudomonas aeruginosa forms colonies surrounded by a blue to green zone due to pyocyanin formation or with a red to dark brown zone due to pyorubin production.
Quality control
Microbiological test
Incubation conditions: 32.5 ± 2 °C / 24-48-72 h.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Pseudomonas aeruginosaATCC 10145 | Good growth | Pyocyanin production (blue-green colonies) |
| Burkholderia cepaciaATCC 25608 | Good growth | No pyocyanin production |
| Pseudomonas aeruginosaATCC 27853 | Good growth | Pyocyanin production (blue-green colonies) |
| Pseudomonas fluorescensATCC 49838 | Good growth | No pyocyanin production |
| Pseudomonas aeruginosaATCC 9027 | Good growth | Pyocyanin production (blue-green colonies) |
Bibliography
- King E.O., Ward M.K., Raney D.E. J. Lab. and Clin. Med., 1954. 44. 301-307.
- Bacteriological Analytical Manual, 8th edition. 1995. AOAC International, Gaithersburg, MD.
- The United States Pharmacopoeia. 1995. The United States Pharmacopoeia, 23rd ed. United States Pharmacopoeial Convention, Rockville, MD.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
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