Endo environment

Endo environment (S. Endo) - differential diagnostic environment for isolation and identification of intestinal bacteria bacteriological research of food products, waste water, etc.
The composition of the medium Endo: peptone - 1%, lactose - 1 %, phosphate disubstituted potassium (K2NRA4) - 0,35%, agar-agar - 1,5%. All the ingredients, except lactose, dissolved in water boiling or in the autoclave. In order to avoid the caramelization of sugar lactose add after the dissolution of all other components of the environment. In addition to lactose, the environment should not contain any other carbohydrates, therefore, its production is not recommended the use of meat of water; you can use any peptone or hydrolyzed proteins. The indicator are ex tempore and add to melted nutritional basis. The framework can be used immediately after cooking sterilized; with the need to sterilize for 30 minutes at temperature of 110 C; pH ready environment 7,4-7,6.
The indicator is the connection of the basic fuchsin with sanitarily sodium. Preparation of indicator: 0.25 g anhydrous sanitaranlage sodium or 0.5 grams of crystalline per 100 ml of medium) dissolved in 5 ml of distilled water and add alcohol (1-2%) a solution of the basic fuchsin until then, until the solution of red turns a pale pink.
The ready indicator is added to the molten nutritional basis and after thorough mixing environment poured into a sterile Petri dishes, which are dried in thermostat at 37 deg 30 min in the open state. Ready-to-use environment Endo has a pale pink color or colourless; it should be used during the day as long storage is redness of the environment and it becomes unusable.
Colonies of bacteria, spaziali lactose, environment Endo become intensely red from green with metallic Shine. Bacteria, not sbyivayutsya lactose, colorless form or color of environment of the colony.
In the environment Endo basic fuchsin, chemically derived hydrochloric rosaniline, when connecting to sanitarily sodium due to reduction becomes colourless. With the growth of bacteria decomposing lactose, intermediate product (acetaldehyde), resulting from the oxidation of sugar reacts with sanitarily sodium and Magenta again gets red.
Widespread dry Endo agar, made according to a special recipe and manufactured in powder form. At manufacturing environment Endo take 5 g of powder per 100 ml of distilled water, heated to its dissolution, and, boiling thoroughly 5 minutes, pour in a sterile Petri dishes.
Tivo-partypany and dysentery bacteria on environment Endo form a colorless colony, E. coli and other decomposing lactose microorganisms - red. Remember that Rubin has a bacteriostatic effect, which is more expressed at a temperature of 37 degrees. Therefore, the analysis should be carried out twice: after 24 hours of incubation in the thermostat and 24-48 hours of storage of crops at room temperature. Cm. also Differential diagnostic environment.