HEKTOEN ENTERIC AGAR

Technical Data #1882a / 2013.06.15

Hektoen Enteric Agar is a selective and differential solid medium for the cultivation and isolation of gram-negative enteric microorganisms from clinical and nonclinical specimens. Addition of sucrose, salicin and lactose differentiate enteric pathogens from slow-lactose-fermenting organisms. Bile salts inhibit gram-positive. Complex sodium thiosulfate-ferric ammonium citrate produces black-centered colonies when ferric ammonium citrate precipitates (H2S production).

 


 

FORMULA
in grams per liter purified filtered water

Meat Peptone

12,0

Yeast Extract

3,0

Lactose

12,0

Sucrose

12,0

Salicin

2,0

Bile Salts

9,0

Sodium Chloride

5,0

Ferric Ammonium Citrate

1,5

Sodium Thiosulfate

5,0

Acid Fuchsin

0,1

Bromthymol Blue

0,065

Agar

14,0

pH 7.6 +/- 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 75.7 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. DO NOT STERILIZE. Cool to 45-50 C. Mix gently and dispense into sterile Petri dishes.


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

  1. Directly, inoculate plate as soon as possible with specimen and streak for isolation.If inoculation will be delayed, an Enteric Pathogen Transport Medium as EPT-100 should be used.
  2. Incubate at 35 C for 24-48 hours.


QUALITY CONTROL

Results after 24 hrs at 35C

Organisms

ATCC

Growth

Colour

Salmonella typhimurium

14028

+

blue w/ H2S

Shigella flexneri

12022

+

blue

Escherichia coli

25922

- or partial

 

Streptococcus faecalis

29212

- or partial

 


LIMITATIONS OF METHOD
This medium is only a part of the identification. Other 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. N.C.C.L.S. 1990 Quality Assurance for Commercially Prepared Microbiological Culture Media. Approved Standard. Vol.10. No.14. NCCLS Document M22-A.
  3. Mac Faddin, Jean F., 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol.1. Baltimore, MD.: Williams & Wilkins.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-2006
     
Prepared media    
Plates, 100x15 mm 10/pkg 1882
Mono-Plates, 100x15 mm 10/pkg 1882M
     
Enteric Pathogen    
Transport, Vial 100/cs EPT-100

 


 

 

2325, Dandurand, Suite 300 Phone Fax Internet
Montreal (Quebec) (514) 277-2558 (514) 277-4714 http://www.quelab.com
Canada H2G 1Z9 1 (800) 579-0998 1 (800) 579-8177 info@quelab.com