All of the following organisms cause toxin mediated diarrhea, except:
Vibrio parahemolyticus is a gram negative, non spore forming bacterium present mostly in marine environment. It is a halophilic bacterium that causes acute gastroenteritis following ingestion of contaminated seafood such as raw fish or shellfish. After an incubation period of 12-24 hours, nausea and vomiting, abdominal cramps, fever, and watery to bloody diarrhea occurs. Fecal leukocytes are often observed. The enteritis tends to subside spontaneously in 1-4 days with no treatment other than restoration of water and electrolyte balance. No enterotoxin has yet been isolated from this bacterium. Vibrio parahemolyticus when grown on TCBS agar produce blue green colonies. Negative string test and absent sucrose fermentation help to differentiate V parahemolyticus from V.cholera. Ref: The Food Safety Hazrd Guidebook By Richard Lawley, Laurie Cuis, Page 88 ; Handbook of Food Toxicology By Deshpande, Page 507 ; Superantigens and Superallergens By Gianni Marone, Page 24 ; Med Lab Tech Vol 2, 2nd Edition By Kanai and L Mukherjee, Page 533
Vibrio cholerae
Vibrio parahaemolyticus
Staphylococcus aureus
Shigella sp