<prompt> True about cornebacterium diphtheriae is all except?Deep invasion is not seenEleks test is done for toxigenicityMetachromatic granules are seenToxigenicity is mediated by chromosomal change  <response>: Ans. is d i.e., Toxigenicity is mediated by chromosomal change . This has been asked so many times in most of the examinations :? . Toxigenicity of diphtheria is not due to chromosomal change, it is phase mediated. About other options . Diphtheria is a toxemia, the bacilli remain confined to the site of entry, where they multiply and form toxin. . Eleks gel precipitation test is an in vitro test for toxigenicity. . Metachromatic granules volutin or babes Ernest granules are seen. 