King B Agar is used to differentiate species of Pseudomonas aeruginosa in bottled water and other kinds of water which contain weak interfering flora, such as swimming pool water and water intended for human consumption (membrane filtration method) according to ISO Standard. This media is ready to use media.
Principle
P. aeruginosa are classified as Gram-negative microorganisms that grow on selective media containing cetrimide and produces pyocyanin, or as microorganisms that grow on selective media containing cetrimide, are oxidase positive, fluoresce under UV light (360 ± 20 nm), and can produce ammonia from acetamide. Colonies producing pyocyanin on CN Agar medium confirmed for their ability to synthesize pyoverdine using KING B medium. The medium contains high concentrations of magnesium sulphate that provide the cations necessary for activation of pyoverdine giving the culture medium a fluorescent greenish yellow color. Most strains (98%) produce a water-soluble fluorescent pigment.
Theoretical Composition
| Bacteriological peptone "B" | 20 g |
| Di-potassium hydrogen phosphate K2SO2 (anhydrous) | 1.5 g |
| Magnesium sulphate heptahydrate MgSO4, 7H2O | 1.5 g |
| Glycerol | 10 ml |
| Agar | 12 g |
| Distilled water | 1,000 ml |
| Final pH at 25 ⁰C = 7.2 ± 0.2 |
Reconstitution Ratio
Ready to use media, 7 ml x 25 tubes
Storage
Store ready-to-use medium at 2-8 ⁰C
References
- ISO 16266:2006