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)
Special
Nutrients
|
70.2
|
Chromogenic
reagent
|
0.4
|
Agar
|
15.0
|
Final pH 7.3±0.1 at 25 ℃
|
*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:
QC
Strains
|
Strains
No.
|
Growth
|
Colonies
color
|
Shigella
flexneri
|
ATCC12022
|
+++
|
Colorless
or white, the diameter of colonies is 1-3mm
|
Shigella
dysentery
|
CMCC51252
|
+++
|
Colorless
or white, the diameter of colonies is 1-3mm
|
Shigella
boydii
|
CMCC51582
|
+++
|
Colorless
or white, the diameter of colonies is 1-3mm
|
sonnei Shigella
|
CMCC51592
|
+++
|
Colorless
or white, the diameter of colonies is 1-3mm, with blue center
|
Staphylococcus
aureus
|
ATCC25923
|
-
|
/
|
E. coli
|
ATCC25922
|
+++
|
green
|
salmonella
|
ATCC14028
|
+++
|
Colorless
with black center
|
Proteus
mirabilis
|
ATCC35029
|
-/+
|
Colorless,
diameter<1mm
|
Klebsiella
pneumoniae
|
ATCC10031
|
++
|
Colorless
with black center
|
Freundii
Citrobacter
|
ATCC43864
|
+++
|
Colorless
with black center
|
Pseudomonas
aeruginosa
|
CICC10211
|
-/+
|
Colorless,
diameter<1mm
|
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.