CETRIMIDE AGAR

Technical Data #1229a / 2013.04.30

Cetrimide Agar is a solid selective medium used for the isolation and identification of Pseudomonas aeruginosa. Cetrimide inhibits bacterial growth except Pseudomonas aeruginosa and enhances fluorescein and pyocyanin pigment production.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

20,0

Potassium Sulfate

10,0

Magnesium Chloride

1,4

Cetrimide

0,3

Agar

13,6

Glycerol

10 ml

pH 7,2 +/- 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 or deterioration (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 45,3 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Add 10 ml of Glycerol (#8467). Sterilize at 121 C for 15 minutes. Cool to 45-50 C. Mix gently and dispense into sterile Petri dishes or sterile culture tubes.


PROCEDURE
Prior to inoculate, the prepared media should be brought to room temperature.

  1. Directly, inoculate plates with specimens and streak for isolation. Tubes used for identification, should be inoculated with a 24 hours growth.
  2. Incubate at 35 C for 24-48 hours.


QUALITY CONTROL

Results after 24 hrs at 35C

Organisms

ATCC

Growth

Pigmentation

Pseudomonas aeruginosa

27853

+

positive

Pseudomonas putida

12633

+

negative

Xanthomonas maltophilia

13637

-

negative

Escherichia coli

25922

- or partial

negative


LIMITATIONS OF METHOD
This medium is only a part of the identification. Other tests may be required.


REFERENCES

  1. Brown, V.I., Lowbury, E.J.L. 1965 Use of an improved cetrimide agar medium and of culture methods for Pseudomonas aeruginosa J. Clin. Pathol. 18: 752
  2. King, E.O., M.K. Ward, D.E. Raney. 1954 Two simple media for the demonstration of pyocyanin and fluorescein. J. Lab. Clin. Med. 44:301-307
  3. 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.
  4. Mac Faddin, Jean F., Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria Vol.1 1985 Baltimore, MD. Williams & Wilkins.
  5. Washington, J.A. Laboratory Procedures in Clinical Microbiology 1981. Springer-Verlag, New York.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-0806
     
Glycerol 100 ml 8467
     
Prepared media    
Plates, 100x15 mm 10/pkg 1229
Mono-Plates, 100x15 mm 10/pkg 1229M
Tubes, 16x125 mm 10/pkg 2791

 


 





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