Anthrax and Related Organisms, Pulmonary

Synonyms

Bacillus anthracis: inhalational anthrax; Bacillus cereus, Bacillus thuringiensis: anthrax-like infection; Woolsorter’s disease

Definition

Anthrax

Bacillus anthracis

Bacillus anthracis, the causative organism of anthrax infections, is a gram-positive, catalase-positive, aerobic, and facultative anaerobic large rod-shaped bacterium. This biphasic organism produces endospores under aerobic conditions. Spores may remain dormant within the environment and soil for decades and are resistant to harsh conditions. Herbivores are the predominant organism host after ingestion of spores while grazing. Spores then germinate into vegetative organisms that replicate, eventually killing the host. Infected animals and animal products, including meat and hides, are the reservoir for human disease.

Four forms of human anthrax infections have been described including cutaneous (most common), inhalational, gastrointestinal, and injectional anthrax. Fortunately, all forms of anthrax are rare....