Levin environment

Levin environment (M. Levine; synonym eosin-machinenbau agar) - color selective culture medium used for the differentiation of microorganisms, intestinal group microbiological diagnosis of intestinal infections typhoid fever, salmonellosis, dysentery, coloenterites. Stable when stored in a few days. The presence in the environment of lactose allows you to select pathogenic microflora not able to break down the carbohydrates. Included in the environment Levin organic dyes delay the growth of saprophytes, which allows to use environment for direct seeding of the studied material.
To obtain stable results is recommended at manufacturing environment Levin apply ingredients of the same brand. The most convenient separately prepare a basic environment, the solutions of lactose and dyes. These ingredients make for future use and must be mixed.
The primary environment: 1) peptone bacteriological - 10 g; 2) agar-agar - 15 g; 3) potassium phosphate disubstituted (2NRA4) - 2; 4) distilled water - Pour 1 liter of 100 ml and sterilized at 120 degrees within 15-30 minutes
Differential environment: for each 100 ml of molten core environment add at stirring the following solutions prepared on distilled water and sterilized fractional fluid the ferry for three consecutive days. Ingredients: 1) 20% solution of lactose 5 ml; 2) 2% solution eosin bacteriological to 2 ml; 3) 0,5% solution metilenovogo blue - 1,5 ml Environment spill in Petri dishes, dries. Ready environment has a blue-violet color. In the absence of peptone environment can be prepared on the basis of prevara of Hottinger (pH 7.2-7,3). Widely used dry Levin, let out by the industry.
Pathogenic bacteria germs of typhoid fever, salmonellosis, dysentery,is not decomposing lactose, grow on environment Levin in the form of small, round, transparent, often colorless colonies, sometimes pink or bluish tint. E. coli forms on HP small smooth colony dark blue color. Young colonies painting can only be observed in the centre. Proteus is growing in the form of a small orange-yellow colonies, color environment around colonies changed.
Colony other bacteria such pictures do not give.
Cm. also Differential diagnostic environment, the Nutrient medium.