Microbiology of Bacillus cereus

Abstract The species Bacillus cereus belongs to the so-called B. cereus group, which includes Gram-positive, aerobic or facultative, sporulating, motile rods that are almost ubiquitous in the natural environment. The organism is a cause of food poisoning and severe and potentially lethal nonintestinal infections in humans. When B. cereus is isolated from a clinical sample it is usually hard to label it as a pathogen or an innocent contaminant, so isolates must be carefully evaluated case by case instead of being aprioristically dismissed as colonizers. In fact, outside its notoriety in the etiology of food-related enteric tract diseases, this bacterium may be involved in a multitude of clinical pictures, such as anthrax-like pneumonias, fulminant bacteremias, devastating central nervous system diseases, postsurgery wound infections, and primary pathologic processes involving skin structures and mimicking clostridial gas gangrene, that usually complicate traumatic events.