Sorbitol MacConkey agar is used for which strain of EGEC -

Ans. is 'a' i.e., O 157: H7 Culture of O157: H7 E.coli* E.coli O157:H7 is not identified on routine stool cultures.* E.coli O157:H7 can be specifically detected by the use of modified Mac Conkey media which containssorbitol in place of lactose (SMAC).* Sorbitol Mac Conkey media is specifically useful for the detection of E.coli O157:H7 as unlike most strains of E. coli, the O157: H7 strain does not ferment sorbitol.* Non fermenting colonies on a Sorbitol Mac Conkey plate (SMAC) therefore suggest the diagnosis of E.coli O157:H7.* Sorbitol Mac Conkey media is the screening method of choice for E.coli O157:H7.