E.M.B. (EOSIN METHYLENE BLUE) AGAR, LEVINE

Technical Data #1859a / 2013.06.15

E.M.B. Agar, Levine is a solid medium for isolation and identification of gram-negative enteric bacteria in water, dairy products, foods and clinical specimens. Eosin Y and Methylene Blue dyes inhibit a large quantity of gram-positive and differentiate lactose fermenters from lactose nonfermenters. Lactose fermenters produce blue black colonies with metallic sheen for Escherichia coli. Lactose nonfermenters appear colorless, transparent or amber. Fecal streptococci will grow on this medium and form pinpoint colonies.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

10,0

Lactose

10,0

Dipotassium Phosphate

2,0

Eosin Y

0,4

Methylene Blue

0,065

Agar

15,0

pH 7.4 +/- 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 37,5 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Sterilize at 121 C for 15 minutes. 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.
  2. Incubate at 35 C for 24-48 hours.


QUALITY CONTROL

Results after 24 hrs at 35C

Organisms

ATCC

Growth

Colour

Escherichia coli

25922

+

black/metallic sheen

Salmonella typhimurium

14028

+

colourless

Pseudomonas aeruginosa

27853

+

colourless

Enterobacter aerogenes

13048

+

brownish

Streptococcus faecalis

29212

+

inhibition (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. Mac Faddin, Jean F., 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol.1. Baltimore, MD.: Williams & Wilkins.
  3. Standard Methods for Examination of Dairy Products 1985 15th ed. APHA Washington D.C.
  4. Standard Methods for Examination of Water and Wastewater 1985 15th ed. APHA Washington D.C.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-2506
     
Prepared media    
Plates, 100x15 mm 10/pkg 1859
Mono-Plates, 100x15 mm 10/pkg 1859M

 


 

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