MAC CONKEY WITHOUT CRYSTAL VIOLET AGAR

Technical Data #1037a / 2013.04.22

Mac Conkey Agar without crystal violet is a selective solid medium for isolation and differentiation of lactose fermenting coliforms from lactose non-fermenting enteric pathogens. Crystal violet suppression permits staphylococci and enterococci growth from urine, feces, foods and water. Lactose fermentation by coliform acidifies medium, precipitate bile salts and produce deep red colonies. Colourless colonies are lactose non-fermenting organisms.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

17,0

Casein Peptone

1,5

Meat Peptone

1,5

Bile Salts

5,0

Lactose

10,0

Sodium Chloride

5,0

Neutral Red

0,04

Agar

12,0

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 52 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. If stool 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

Escherichia coli

25922

+

red

Proteus mirabilis

12453

+

colourless

Salmonella typhimurium

14028

+

colourless

Streptococcus faecalis

29212

+

red

Staphylococcus aureus

25923

+

pink


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-39-2712
     
Prepared media    
Plates, 100x15 mm 10/pkg 1037
Mono-Plates, 100x15 mm 10/pkg 1037M
     
Enteric Pathogen Transport, Vial 100/cs EPT-100
 


 





 

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