T.S.I. (TRIPLE SUGAR IRON) AGAR

Technical Data #2354a / 2013.06.25

TSI Agar is a differential medium by ability to determine carbohydrate (dextrose, lactose, sucrose) fermentations and hydrogen sulfide production especially of enteric pathogens. Phenol Red is the pH indicator and changes from red to yellow whith a positive result. The butt medium blacknening indicates presence of H2S. Presence of sucrose may suppress the enzyme mechanism resulting in hydrogen sulfide production.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

5,0

Casein Peptone

5,0

Yeast Extract

3,0

Beef Extract

3,0

Meat Peptone

10,0

Sodium Chloride

5,0

Lactose

10,0

Sucrose

10,0

Dextrose

1,0

Ferric Ammonium Citrate

0,2

Sodium Thiosulfate

0,2

Phenol Red

0,025

Agar

12,0

pH 7.3 +/- 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 65 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 sterile culture tubes.


PROCEDURE
Bring prepared medium at room temperature before inoculation.

  1. Inoculate with 2-3 similar colonies and stab the butt to about 0,5 cm from the bottom of the tube.
  2. Incubate at 35 C for 24 heures with loosened caps.
  3. Examine for reactions.


QUALITY CONTROL

Expected results after 24 hrs at 35C

Organisms

ATCC

Slant

Butt

H2S

GAZ

Escherichia coli

25922

Acid

Acid

-

+

Salmonella typhimurium

14028

Alkaline

Acid

+

+

Pseudomonas aeruginosa

27853

Alkaline

Alkaline

-

-


LIMITATIONS OF METHOD
Examine reactions after 24 hours: false positive may occur if read earlier and false negative if read later. Hydrogen sulfide presence means an acidification of butt. This is only a part of the identification. Others tests may be required.


REFERENCES

  1. Ewing, W.H. 1985 Edwards and Ewing's identification of Enterobacteriaceae. 4th ed Elsevier Science Publishing Co. Inc. New York
  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. Washington, J.A., 1981 Laboratory Procedures in Clinical Microbiology. Springer-Verlag, New York


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-4906
     
Prepared media    
Tubes 16x125 mm 10/pkg 2400
  100/box 2400-H
Tubes 13x100 mm 100/pkg 2354-H

 


 

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