- A large family of bacteria that have a rod-like shape. They include the bacteria that cause food to spoil, and also those responsible for some types of diseases. Helpful members of the bacillus family are used to make antibiotics, or colonize the human intestinal tract and aid with digestion.
* * *A genus of aerobic or facultatively anaerobic, sporeforming, ordinarily motile bacteria (family Bacillaceae) containing Gram-positive rods. Motile cells are peritrichous; spores are thick-walled and stain poorly with Gram stain; these organisms are chemoheterotrophic and are found primarily in soil. A few species are animal pathogens; some species evoke antibody production. The type species is B. subtilis. [L. dim. of baculus, rod, staff]- B. anthracis a bacterial species that causes anthrax in humans, cattle, swine, sheep, rabbits, guinea pig s, and mice; contains virulence plasmids associated with capsule and toxin production.- B. brevis a bacterial species found in soil, air, dust, milk, and cheese; some strains produce the antibiotic gramicidin or tyrocidin.- B. cereus a bacterial species that causes an emetic type and a diarrheal type of food poisoning in humans, and can cause infections in humans and other mammals. It can cause a highly destructive infection of the traumatized eye.- B. circulans a bacterial species found in soil that has been incriminated in human infections including septicemia, mixed abscess infections, and wound infections.- B. hemolyticus former name for Clostridium haemolyticum.- B. histolyticus former name for Clostridium histolyticum.- B. megaterium a saprophytic bacterial species of experimental interest; strains produce bacteriocins (megacins).- B. polymyxa a bacterial species found in soil, water, milk, feces, and decaying vegetables; some strains produce the antibiotic polymyxin.- B. pumilis a usually saprophytic species of bacteria that has been associated with food poisoning and rarely with abscess or bowel fistula formation.- B. sphaericus a bacterial species that is an insect pathogen and that has been associated with occasional human and other mammalian infections, especially in immunocompromised hosts; human infections have included meningitis, endocarditis, and food poisoning.- B. subtilis a bacterial species found in soil and decomposing organic matter; some strains produce the antibiotic subtilin, subtenolin, or bacillomycin; it has been associated with human infections primarily of immunocompromised patients, and with food poisoning. It is the type species of the genus B.. SYN: grass b., hay b..- B. thuringiensis a bacterial species that is an insect pathogen used for vector control that has been implicated in human and mammalian infections. In the laboratory it may be misdiagnosed as a strain of B. cereus.
* * *1 a) cap a genus of rod-shaped gram-positive endospore-producing usu. aerobic bacteria of the family Bacillaceae that include many saprophytes and some parasites (as B. anthracis of anthrax)b) any bacterium of the genus Bacillus broadly a straight rod-shaped bacterium2) BACTERIUM esp a disease-producing bacterium
* * *n.a large genus of Gram-positive spore-bearing rodlike bacteria. They are widely distributed in soil and air (usually as spores). Most feed on dead organic material and are responsible for food spoilage. The species B. anthracis, which is nonmotile, causes anthrax, a disease of farm animals transmissible to humans. B. polymyxa, commonly found in soil, is the source of the polymyxin group of antibiotics. B. subtilis may cause conjunctivitis in humans; it also produces the antibiotic bacitracin.
* * *Ba·cil·lus (bə-silґəs) [L. â€œlittle rodâ€] a genus of bacteria of the family Bacillaceae, including large aerobic or facultatively anaerobic, spore-forming, rod-shaped cells, the great majority of which are gram-positive and motile. Most species are saprophytic soil forms; three are pathogenic or potentially pathogenic. Many organisms historically called Bacillus are now classified in other genera.
Medical dictionary. 2011.