Bacillus A genus of bacteria in which the cells are rod-shaped, often motile, and typically Gram-positive. Endospores can be formed in the presence of air. Bacillus species are chemo-organotrophic. Some can grow only in the presence of air; others can grow in either the presence or absence of air. There are many species, found in a wide range of habitats. Some species can cause disease in vertebrate animals (e.g. anthrax), or in insects; insecticidal species, particularly B. thuringiensis, are used in the biological control of insect pests.

ba·cil·lus / bəˈsiləs/ • n. (pl. -cil·li / -ˈsilī/ ) a disease-causing bacterium. ∎  a rod-shaped bacterium. DERIVATIVES: bac·il·lar·y / ˈbasəˌlerē/ adj. ORIGIN: late 19th cent.: from late Latin, diminutive of Latin baculus ‘stick.’

bacillus (bəsĬl´əs), any rod-shaped bacterium or, more particularly, a rod-shaped bacterium of the genus Bacillus. Some bacterium in the genus cause disease, for example B. anthracis is the cause of anthrax; others are useful in the production of antibiotics (e.g., gramicidin and bacitracin). Many organisms earlier classified as Bacillus species are now placed in different genera but continue to be referred to as baccili.

bacillus Any rod-shaped bacterium. Generally, bacilli are large, Gram-positive, spore-bearing, and have a tendency to form chains and produce a capsule. Some are motile, bearing flagella. They are ubiquitous in soil and air and many are responsible for food spoilage. The group also includes Bacillus anthracis, which causes anthrax.

bacillus (bă-sil-ŭs) n. (pl. bacilli) any rod-shaped bacterium. See also Bacillus, Lactobacillus, Streptobacillus.

bacillus Genus of rod-like bacteria present everywhere in the air and soil. One example of a species that is pathogenic in man is Bacillus anthracis, which causes anthrax.

bacillus XIX. mod. use of late L. dim. of baculum rod, stick. Cf. BACTERIUM.

bacillus A bacterial cell that is rod-shaped (i.e. longer than it is wide).