Introduction

INTRODUCTION
  • Genus Bacillus consists of a large number of Gram positive, aerobic, spore forming bacilli.
  • They are fairly large sized organisms. When grown on blood agar, Bacillus produces large, spreading, gray-white colonies with irregular margins.
  • A unique characteristic of this bacterium is its ability to produce endospores when environmental conditions are stressful.
  • The only other known spore-producing bacterium is Clostridium (anaerobic).
  • Although most species of Bacillus are harmless saprophytes, two species are considered medically significant: B.anthracis and B. cereus.
  • Bacillus anthracis is the only important pathogen of animals and human in this genus.
  • In man Bacillus anthracis causes malignant pustules and wool sorter’s disease (Pneumoniae).
  • In animals, it causes Anthrax. It is transmitted to humans via direct contact with animal products or inhalation of endospores
  • Under the microscope, B. anthracis cells appear to have square ends and seem to be attached by a joint to other cells.
  • The spores are best observed when the bacterium is cultured on artificial media.
  • The infection is classified as one of three types:
    • CUTANEOUS INFECTION (95% of human cases)
    • INHALATION ANTHRAX (rare)
    • GASTROINTESTINAL ANTHRAX (very rare)
  • Anthrax can be treated with penicillin or tetracycline.
  • A vaccine is available but is only used on individuals at high risk.
Last modified: Monday, 4 June 2012, 6:18 AM