SIMMONS CITRATE AGAR

Technical Data #1155a / 2013.06.22

Simmons Citrate Agar is a differential medium used to identify microorganisms on the basis of citrate utilization, especially for the Enterobacteriaceae. A positive change in color from green to blue color produces increasing of pH.

 


 

FORMULA
in grams per liter of purified filtered water

Magnesium Sulfate

0,2

Ammonium Phosphate, dihydrogen

1,0

Potassium Phosphate, dibasic

1,0

Sodium Citrate

2,0

Sodium Chloride

5,0

Bromthymol Blue

0,08

Agar

15,0

pH 6,9 +/- 0,2 25 C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for IN VITRO diagnostic use only.


STORAGE
Store prepared media at 2-8 C protected from direct light and dehydrated powder, in a dry place in tightly-sealed containers at 2-25 C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. prepared media should not be used if there are signs of contamination (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 24,2 g in 1000 ml of purified water. Heat with frequent agitation and boil for one minute. Sterilize at 121 C for 15 minutes. Cool to 45-50 C. Mix thouroughly and dispense into Petri dishes or into sterile culture tubes.


PROCEDURE
Bring prepared medium at room temperature before inoculation.

  1. Inoculate with a solution of 2-3 similar colonies from an overnight growth.
  2. Incubate at 35 C for 24-48 hours or longer. Tubes should be incubated with loosened caps.


QUALITY CONTROL

Expected results after 24 hrs at 35C

Organisms

ATCC

Color

Klebsiella pneumoniae

13883

+ blue

Escherichia coli

25922

- green


LIMITATIONS OF METHOD
A too heavy inoculum may result in a light yellow color without affecting the color of the medium and should be considered as a negative result.This is only a part of the identification. Others tests may be required.


REFERENCES

  1. Lennette, E.H., Ballows, A., Hausler, W.J.Jr., and Shadomy, H.J. Manual of Clinical Microbiology. 4th ed. 1985 Washington D.C.: American society for Microbiology.
  2. Mac Faddin, Jean F. 1985 Media for Isolation-Cultivation Identification-Maintenance of Medical Bacteria. Vol. I, Baltimore, MD.: Williams & Wilkins.


CATALOGUE NUMBERS

Dehydrated media 500 grams QB-39-4106
Prepared media    
Petri,100x15 mm 10/pkg 1155
Mono-Plates, 100x15 mm 10/pkg 1155M
Tubes, 16x125 mm 10/pkg 2746
Tubes, 16x125 mm 100/box 2746-H
Tubes, 13x100 mm 100/box 2443-H

 


 

 

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