NUTRIENT GELATINE MEDIUM

Technical Data #2525a / 2013.11.01

Nutrient Gelatin Medium is an identification medium for the detection of gelatin liquefaction especially of Enterobacteriaceae.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

5,0

Beef Extract

3,0

Gelatin

120,0

pH 6,8 +/- 0,2 à 25º 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 128 g of dehydrated medium in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Mix thouroughly and dispense into culture tubes. Sterilize at 121° C for 15 minutes.


PROCEDURE
Bring prepared medium at room temperature before inoculation.

  1. Inoculate with 2-3 similar colonies from an overnight growth with inoculating needle; stab to a depth of 1 cm from the bottom of the tube.
  2. Incubate at 35° C for 24-48 hours along with an uninoculated tube as a negative control tube.
  3. Transfer the tubes to a ice bath and examine for medium liquefaction. The control tube should be solid.


QUALITY CONTROL

Expected results after 24 hrs at 35ºC

Organisms

ATCC

GROWTH

LIQUEFACTION

Escherichia coli

25922

+

-

Pseudomonas aeruginosa

27853

+

+


LIMITATIONS OF METHOD
After incubation, examine tubes without mixing. Some microorganisms are growning on the surface of the butt and may give false negative. 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.
  3. Standard Methods for the examination of water and sewage 1960 9th ed. APHA, Washington, D.C.


CATALOGUE NUMBERS

Dehydrated media 500 grams QB-39-3420
     
Prepared media    
tubes 16x125 mm,5 ml 10/pkg 2525

 


 

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