The medium used for isolation and differentiation of Shigella. The complex indicator eosin-methylene blue stains the colonies which ferment the lactose in dark blue or purple (sometimes almost black). Microorganisms that are not able to ferment lactose grow as colorless colonies. Cultivate the seeded Petri dishes, 37 ° C for 24 hours.

Appointment of Lewin's Environment: Differentiation of microorganisms.

Principle of action Levine medium: Bacteria that ferment lactose, grow in the form of colorless colonies. In the environment there is eosin and methylene blue, which paints lactose-positive bacteria in a dark-violet color with a metallic shine. Staphylococcus grows with a dark center, in a small amount. Most gram-positive bacteria are inhibited.

Composition of the Levine Environment:

Lactose - 10 g / l

The peptone is enzymatic - 10 g / l

Agar microbiological - 10 g / l

Potassium hydrophosphate - 1 g / l

Sodium chloride - 3.5 g / l

Eosin - 0.4 g / l

Methylene blue - 0.06 g / l

Instructions for using the Lewin environment:

1. Dissolve 35 g of medium when heated in 1 liter of purified water

2. Boil for 2-3 minutes until complete dissolution of the components.

3. Autoclaving for 20 minutes at 110 C.

4. Cool to 50-45 С and pour into sterile Petri dishes, dry by adhering to aseptic rules.

PH level: 7.2-0.2 ° at 25 ° C