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Bacillus

    Bacillus anthracisBacillus cereusBacillus coagulans
    Paenibacillus larvae
    Bacillus natto
    Bacillus subtilisBacillus thuringiensisBacillus is a genus of rod-shaped bacteria The word bacillus is also used to describe any rod-shaped bacterium and in this sense bacilli are found in many different groups of bacteria When the particular genus Bacillus is referred to, it is capitalized and italicized Likewise Bacilli refers to the particular class Bacillus belongs to, while bacilli are any rod-shaped bacteria
    The genus Bacillus belongs to the Firmicutes and like most other members has a Gram-positive stain They are either obligate or facultative aerobes and test positive for catalase When conditions are stressful the cells produce oval endospores that can stay dormant for extended periods These characters originally defined the genus but not all such species are closely related and many have been moved to other genera
    Bacillus are ubiquitous in nature including both free-living and pathogenic species Two species are considered medically significant: B anthracis which causes anthrax and B cereus which causes a foodborne illness similar to that of Staphylococcus The type species is B subtilis and is an important model organism It is also a notable food spoiler as is B coagulans
    An easy way to isolate Bacillus is by placing non-sterile soil in a test tube with water shaking placing in melted mannitol salts agar and incubating at room temperature for at least a day Colonies are usually large spreading and irregularly-shaped Under the microscope the Bacillus appear as rods and a substantial portion usually contain an oval endospore at one end making it bulge