<prompt> Following species of shigella ferment mannitol EXCEPTShigella sonneiShigella flexneriShigella boydiiShigella dysenteriae  <response>: Ans. d Shigella dysenteriae Ref. Ananthanarayan Microbiology 7thpg. 285 Shigella sonnei, Shigella boydii and Shigella flexneri ferment mannitol, while Shigella dysenteriae does not. Colonies on MacConkey agar are colorless due to the absence of lactose fermentation. An exception is S. sonnie hich ferments lactose late and forms pale pink colonies.SHIGELLA DYSENTERIAE SUBGROUP A Mannitol nonfermenting bacilli consisting of 10 serotypes. Indole negative. Only member of the shigella family that is always catalase negative. It is the only Species of Shigella that produces exotoxin. Q Sh. Dysentariae type 1 forms a toxin shigella toxin, the earliest eg. of an exotoxin produced by a gram negative bacillus. Three types of toxic ativities noted:- Neurotoxicity 