Agar Bayer-Parker is used to isolate and quantitatively calculate staphylococci. The environment consists of a solution of potassium tellurite and lithium chloride, which are inhibitors of the growth of the concomitant microflora. Staphylococcus also restores tellurium from potassium tellurite, which paints its colony in black. Glycine and sodium pyruvate simulate staphylococcal growth. The egg yolk suspension is added to the prepared medium, which allows to check the lecithin activity in staphylococci.
Purpose: agar Bide-Parker is recommended for the selection and calculation of coagulase-positive staphylococci from food and other materials according to EP. Brief description and explanation: This medium is cited as the agar medium O in the European Pharmacopoeia, 2008 and is recommended for the selection and calculation of coagulase-positive Staphylococcus aureus. It was developed by Baird-Parker based on the tellurite-glycine formula Zebovitz et al. To isolate coagulase-positive Staphylococcus aureus from food. Types of Staphylococcus are commonly used food, milk, pharmaceutical and cosmetics related condoms. This medium is recommended for checking the sterility of materials to detect Staphylococcus aureus. The Bird-Parker environment is referred to as the best medium for selective detection of coagulase-positive and intestinal-toxicogenic Staphylococcus. Coagulase-positive staphylococci can grow and multiply in cosmetic products. These products are tested for coagulase-positive staphylococci using standard microbiological methods. This medium, as it has been established, inhibits S. aureus less than other environments, while remaining more selective. Later it was officially adapted by AOHA and the European Pharmacopoeia.
Principle of action: Agar Baird-Parker contains a meat extract, a yeast extract and a pancreatic gaseous casein that provides important minerals, vitamins, nitrogenous substances and other growth factors. Sodium pyruvate protects damaged cells and helps to restore them, as well as stimulates the growth of staphylococcus aureus, while retaining selectivity. Lithium chloride and potassium telluride suppress most of the contaminating microflora other than S.aureus. The recovery of tellurite is a characteristic of coagulase-positive staphylococci, and it gives colonies a black color. Glycine, pyruvate stimulate Staphylococcus growth. When the egg yolk is added, the medium becomes yellow and opaque. Glycine neutralizes aldehyde, while egg yolk neutralizes phenolic compounds, if any, in the test samples. Adding egg yolk, in addition to enrichment, also helps in the identification process, demonstrating lecithin activity (egg yolk reaction). Staphylococci containing lecithinase, spread egg yolk and form transparent areas around colonies. Transparent zones and gray-black colonies in this environment are diagnostic for coagulase-positive staphylococci. When further incubation around the colonies formed an opaque zone, which may be associated with lipolytic activity. The identity of the staphylococcus aureus isolated on the Beida Parker agar should be confirmed by a reaction with coagulase and a deoxyribonucleic acid test. The sterility of the product is confirmed by the lack of growth of staphylococcus aureus in this environment.
Pancreatic gaze of casein - 10.00 Gram / liter
Meat extract - 5,00 grams / liter
Yeast extract - 1.00 grams / liter
Glycine - 12,00 grams / liter
Pyruvate Sodium - 10.00 grams / liter
Lithium chloride - 5,00 grams / liter
Agar - 20,00 grams / liter
1. Dissolve 63 g of medium in 950 ml of distilled water.
2. To warm up, if necessary, to the complete dissolution of the medium.
3. Sterilize autoclave for 15 minutes at 121 oC and 1.1 at. 4. Cool to 50 ° C and add in aseptic conditions 50 ml of concentrated egg yolk emulsion and 1 bottle of sterile additive 1% potassium tellurite.
5. Mix thoroughly and pour into sterile Petri dishes.
Test procedure: 1. Samples of food are ground in a suitable broth environment, make dilution if desired and inoculate on a dry agar surface. 2. The cups are incubated in aerobic conditions for 24 hours at 35 - 37 ° C. 3. For detailed information on specific procedures, see the relevant links. Results: 1. Coagulase-positive Staphylococcus aureus forms a gray-black, shiny, convex colony with integral edges and transparent zones (reaction to egg yolk) with or without opaque zones. 2. Coagulase-negative staphylococci usually grow scanty or do not grow at all. In the case of growth, form black colonies; typical transparent and opaque zones form rarely. 3. Most other organisms are inhibited or grow scanty. In case of colony growth, dark brown mat with no transparent and opaque zones.
Limit procedure: 1. Agar Beida-Parker is selective for coagulase-positive staphylococci, but other bacteria can also grow. 2. To differentiate coagulase-positive staphylococci from other organisms, microscopic examination and biochemical tests must be performed. 3. For more detailed information and recommended procedures, refer to the relevant texts.
Delivery time: 5 d.
Information updated: 02.03.2018
baird parker agar base, 250 gr
- Brands ООО "Фармактив" Украина
- Product Code: 250 гр
- Availability: 2-3 Days