Characteristics of Bacillus anthracis
Pp. 24-46 (23)
Robert E. Levin
Bacillus anthracis, the causative organism of anthrax is a member of the B.
cereus group of bacilli. The stained organism exhibits a unique and characteristic “Boxcar”
appearance microscopically. The three forms of anthrax: (1) cutaneous, (2) inhalation, and
(3) gastrointestinal are presented with clinical details. The bacteriology of B. anthracis is
presented in terms of its minimal diagnostic characteristics, cultivation, colony appearance,
along with the use of diagnostic bacteriophage. All of the major outer structural
components of B. anthracis (capsule, cell wall, S layer) are pictorially illustrated and
discussed. The extracellular enzymes such as hemolysins and phospholipases, in addition to
the intracellular superoxide dismutases that presumably influence virulence are presented in
detail. Studies on the long-term persistence of B. anthracis spores in soil are described
along with stability of the 2 major virulence determining plasmids.
Cutaneous anthrax, inhalation anthrax, gastrointestinal anthrax,
bacteriology, morphology, cell wall, Capsule, S-layer, boxcar shape, clinical aspects,
subclinical infections, cultivation, selective media, hemolysins, phospholipases,
superoxide dismutases, γ bacteriophage, Immunoassays, Rhizosphere, Soil.
University of Massachusetts Amherst USA