Bacillus cereus

Bacillus cereus is a Gram-positive bacteria sporulate. It is an opportunistic pathogen which is a close relative to Bacillus anthracis, the bacteria that causes anthrax, a severe disease. B. cereus is present in soil, water, plants, and food, especially dry food like rice, dry milk, vegetables and spices. It is a problem to the food industry because spores form a biofilm over the production line. This microorganism causes intestinal and non-intestinal clinical infections: local infections of the eye and traumatic or postsurgical wounds; bacteremia and septicemia; meningitis; endocarditis and pericarditis; and food poisoning: emetic and diarrheagenic syndromes. Both foodborne diseases, emetic and diarrhoeal, are mild and self-limiting, although more serious cases have occurred. The symptoms of the emetic syndrome are nausea and emesis. The incubation time is from 0.5 h to 6 h and the duration is 6 to 24 h. Besides, the diarrheal syndrome presents abdominal pain, watery diarrhea and occasionally nausea and emesis. The incubation time is in the range of 8 h -16 h and the duration is not more than 24 h. Moreover B. cereus produces several toxins: cereulide, the emetic toxin; haemolysin BL, a tripartite enterotoxin; nonhaemolytic enterotoxin, another three-component toxin; cytotoxin K and hemolysin II, a β-barrel pore-forming toxins; phospholipase C (phosphatidylinositol, phosphatidylserine and phosphatidilcholine), proteases and hemolysin IV (Hly-IV), which has a strong effect on plasma membranes with a wide range of compositions. Traditionally the pathogenesis of B. cereus has been associated with the production of exocellular factors. Interestingly, the ability of this microorganism to attach to and invade enterocytes and disrupt the cytoskeleton could increase its pathogenic potential. Thus, B. cereus gastroenteritis may be multifactorial.