Shigella can be differenciated from E.Coli by all of the following features except -

Ans. is 'c' i.e., Shigella does not ferment mannitol . Fermentation of mannitol is of impoance in classification and shigellae have traditionally been devided into mannitol fermenting and nonfermenting species. E coli Shigella Morphology --> . Capsulated . Gram negative . Motile (by peritrichate flagella) . Fimbriae are found . Non capsulated . Gram negative . Non motile (lack flagella) . Fimbriae may be present Biochemical reactions --> . Lactose is fermented . Glucose is fermented with the production of acid and gas. . Mannitol fermented . IMViC --> + + - - (Indole, methyl red, Voges - Proskauer and citrate) . Lactose is not fermented except shigella sonnei, which ferment it late * Glucose is fermented with the production of acid, without gas except for the New castle and Manchester biotypes of Sh. flexneri, and some strains of Sh. boydii type 13 and 14, which from gas . Mannitol fermented except Sh. dysenteriae . MR --> (+) ve Citrate --> (-) ye VP --> (-) ve Indole ----> Sh. Sonnei (-) ye other show variable reaction Culture --> . Produce pink colonies on MacConkey's medium due to lactose fermentation . Deoxycholate medium (DCA) inhibits the growth . Produce colourless colonies on MacConkey's medium due to lack of lactose fermentation except S. sonnei which ferment it late and produces pink colonies. . DCA is selective medium