INDOLE NITRATE MEDIUM

Technical Data #2086a / 2013.06.23

Indole Nitrate Medium is a semi-liquid medium used to determine indole production and nitrate reduction by a wide variety of organisms. Even this medium is capable of supporting growth of aerobes and anaerobes organisms, is not recommended for the Enterobacteriaceae indole production due to the reduction of nitrate to nitrite which prevents detection of indole.

 


 

FORMULA
in grams per liter purified filtered water

Casein Peptone

20,0

Sodium Phosphate, dibasic

2,0

Dextrose

1,0

Potassium Nitrate

1,0

Agar

1,0

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 (evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 25 g in 1000 ml of purified 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 each of two tubes, with 1-2 similar colonies from an overnight growth.
  2. Incubate at 35 C for 24-48 hours.

Nitrate Reaction
Add 0,5 ml of Sulfanilic Acid (8560) and 0,5 ml of Dimethylnaphtylamine (8559) Reagents.
Note the results. Positive result: red color. Negative result: no change in color.

Indole Production
Add 2-3 drops of Kovac's Reagent. Positive result: red ring. Negative result: yellow ring

 

QUALITY CONTROL
Expected results after 48 hrs at 35C

Organisms

ATCC

Growth

Indole

Nitrate

Clostridium perfringens

13124

+

-

+

Clostridium sporogenes

11437

+

-

-

Fusobacterium nucleatum

2586

+

+

-

Staphylococcus aureus

25923

+

-

+


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


REFERENCES

  1. Finegold, S.M., E.J. Baron 1986 Bailey and Scott's Diagnostic Microbiology 7th ed. C.V. Mosby St. Louis
  2. 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.
  3. Mac Faddin, Jean F. 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol. I, Baltimore, MD.: Williams & Wilkins.
  4. Smith, R.F., R.R. Rogers, C.L. Bettge 1972 Inhibition of indole test reaction by sodium nitrite. Appl. Microbiol. 23:423


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-2205
     
Prepared media    
Tubes 16x125 mm, 5 ml 10/pkg 2086
     
Sulfanilic Acid 30 ml 8560
     
N,N,-Dimethyl-Naphtylamine 30 ml 8559
     
Kovac's Reagent 30 ml 8552

 


 





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