The Collaborative International Dictionary of English v.0.48:

Salmonella \Sal`mo*nel"la\, prop. n. [After Daniel E. Salmon, a
   U. S. pathologist (1850-1914).]
   A genus of gram-negative bacteria that may be motile or
   non-motile; they are typically rod-shaped and may be aerobic
   or facultatively aerobic. They may be pathogenic for humans
   and other animals. Their metabolism is fermentative, and they
   produce acid and usually gas from glucose, but they do not
   metabolize lactose. The type species is Salmonella
   cholerae-suis, which is found in pigs. Other species,
   pathogenic in man, are Salmonella typhi (Salmonella
   typhosa), Salmonella typhimurium, and Salmonella
   schotmulleri, whih cause typhoid fever, food poisoning, and
   enteric fever, respectively. --Stedman.
   [PJC]

WordNet (r) 3.0 (2006):

Salmonella typhimurium
    n 1: a form of salmonella that causes food poisoning in humans