Characteristics of Bacillus anthracis

Abstract

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.

Keywords: 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.