MAC CONKEY AGAR
W/O CRYSTAL VIOLET AND SALT

Technical Data #1118a / 2013.04.22

Mac Conkey Agar w/o crystal violet and salt is a solid differential medium used for the isolation and detection of Enterobacteriaceae, enterococci and some staphylococci. Recommended as a urine culture medium to prevent overgrowth of Proteus. Due to absence of sodium chloride Proteus swarming is usually inhibited. Gram-negative enteric bacteria, lactose fermenters, produce red to pink colonies.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

17,0

Casein Peptone

1,5

Meat Pepton

1,5

Bile Salts

5,0

Lactose

10,0

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 47 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

+

red

Proteus mirabilis

12453

+

colorless
no swarming

Salmonella typhimurium

14028

+

colorless

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.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-2714
     
Prepared media    
Plates, 100x15 mm 10/pkg 1118
Mono-Plates, 100x15 mm 10/pkg 1118M

 


 





 

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