Shigella Chromogenic Medium

Description: Specially used for the rapid detection of Shigella in food and patient stool samples. The colonies of Shigella are white or colorless, some sonnei Shigella have blue center; Escherichia coli and Coliforms have green or yellow colonies; salmonella are yellow or colorless and have a black center; other are blue-green or yellow. Proteus and Pseudomonas aeruginosa basically do not grow; it is an ideal culture medium for rapid detection.

Ingredients (g / L)

*Adjusted and/or supplemented as required to meet performance criteria

Directions:

Suspend 17.12g/200mL, heat in 1 minute. When cooling to 45-50 ℃, pour into sterile petri dishes.

Warning: Prepared medium must be kept dry, can place inverted culture in incubator at 36 ± 1 ℃ for 1-2 hours.

Procedures:

1. Prepared sample solution according to national standards, SN standard, FDA standards or other methods.

2. Transfer 25g sample solution into 225mL GN Broth or Shigiella Broth, enrichment culture for 18- 24hours at 36 ± 1 ℃;

3. Take one ring enrichment broth with a 3mm inoculation loop, streak to inoculated o Shigella Chromogenic Medium, make two plates

4. Culture at 36 ± 1 ℃ for 20-24 hours, the colonies of Shigella are white or colorless, some sonnei Shigella have blue center; Escherichia coli and Coliforms have green or yellow colonies; salmonella are yellow or colorless and have a black center; other are blue-green or yellow. Proteus and Pseudomonas aeruginosa basically do not grow

5.  For typical colonies, do Shigella serological test and full set of biochemical tests.

Quality Control:

1. Appearance:

The dehydrate powder medium is homogeneous, having good flowability, grey white to pale pink, prepared medium is red solid.

2. Microbial sensitivity test:

Incubated at 36 ± 1 ℃ 18-24h:

Methods limitations:

The typical Shigella on t medium must be do serological test and biochemical tests

Typical features:

The colonies of Shigella are white or colorless, some sonnei Shigella have blue center; Escherichia coli and Coliforms have green or yellow colonies; salmonella are yellow or colorless and have a black center; other are blue-green or yellow. Proteus and Pseudomonas aeruginosa basically do not grow.

Storage:

The prepared plates can be kept for 2-5 days, avoid direct exposure to light. The powder medium should be placed in a dark, dry place, storage temperature 2-8 ℃, avoid direct exposure to light.

Failure:

Dry powder media which are over the shelf life, caking and color variation cannot be used.

Note:

This medium is only for laboratory use.

Reference:

1. Restaino, L., E. W. Frampton, W. C. Lionberg, and A. L. Restaino. 2007. Detection of Shigella sp.using a selective and differential chromogenic plating medium. Abstract P3-43. IAFP.