Macconkey Agar with Sorbitol for the research of E. coli 0157:H7

  • Macconkey Agar with Sorbitol  is Selective and differential medium for the research of E. coli 0157:H7 which cause Hemorrhagic Collitis and HUS (haemolytic uraemic syndrome).
Colonoscopic view of colon - haemorragic colitis by E. coli 0157:H7

Colonoscopic view of colon – haemorragic colitis by E. coli 0157:H7


 Macconkey Agar with Sorbitol Composition

Macconkey Agar with Sorbitol Composition

Macconkey Agar with Sorbitol Composition


Preparation:

  • Suspend 51,5 grams of the medium in one liter of distilled water. Heat to boiling with frequent agitation until totally dissolved. Dispense and sterilize at 121° C (15 lbs psi) for 15 minutes. Distribute into sterile Petri dishes. If needed, allow the plate surface to dry.

Uses:

  • Sorbitol MacConkey Agar is based on the formula developed by Rappaport & Henig. This medium is recommended for the research of E. coli 0157:H7. The composition is similar to MacConkey Agar but the lactose has been substituted by sorbitol. E. coli 0157:H17 does not ferment the sorbitol and therefore produces colourless colonies. Most of the other E. coli do ferment it and therefore their colonies are pink.
  • E. coli 0157:H7 has been recognized as being responsible for haemorragic colitis, characterized by a blooding diarrhea with intense abdominal ache. Optimal temperature for E. coli 0157:H7 is 35°C -37°C.
 E coli O157:H7 on a sorbitol-MacConkey agar plate Arrow indicates distinctive colourless E coli O157:H7 colony.


E coli O157:H7 on a sorbitol-MacConkey agar plate
Arrow indicates distinctive colourless E coli O157:H7 colony.

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