NAME: Bacillus cereus
IMAGE SIZE: 70 microns
IMAGE CREDITS: Shirley Owens and Cathy McGowan, Microbe Zoo Project, Comm Tech Lab, Michigan State University.
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Bacillus cereus is a Gram positive, aerobic, spore-forming, rod-shaped bacterium. Like many bacteria, B. cereus is both a friend and a foe of humans. Sometimes it behaves as a friend in that it is used as a form of biocontrol to help us get rid of unwanted pests. For example, B. cereus deters certain fungi from rotting seedling plants.
B. cereus can also be a serious foe when it causes food poisoning. Although B. cereus is only bit player in a large cast of villains, it does account for around 2% of reported incidents of food poisoning. B. cereus does its dirty work by secreting a toxic substance (an enterotoxin) that causes the small intestine to secrete massive quantities of fluid resulting in diarrhea. This exotoxin is similar to that from the infamous E. coli which causes food poisoning. Most cases of B. cereus poisoning occur from people eating contaminated rice.
© 1999 Comm Tech Lab, Michigan State Univeristy. This work was created with support from the National Science Foundation and the Center for Microbial Ecology at Michigan State University. Current maintenance is supported by the International Society for Microbial Ecology and the Comm Tech Lab.