Bacillus anthracis

• Causes anthrax

Background

Microbiology

• Gram-positive bacillus that is distinguished from other Bacillus species by being non-motile and non-hemolytic
• Colonies are gray, flat, and may have a "Medusa head" or "comet" appearance

Clinical Manifestations

Cutaneous anthrax

• Caused by inoculation of spores into soft tissue
• Incubation period of 2 to 5 days
• Lesion develops at site of inoculation, starting as erythemaous papule, then ulceration, then eschar
• May progress to sepsis

Pulmonary anthrax

• Caused by inhalation of spores
• Also known as woolsorter's disease
• Start with malaise, fever, and nonproductive cough, followed by respiratory distress, severe pulmonary edema, and death

Gastrointestinal anthrax

• Caused by ingestion of spores
• Infects oropharynx or abdomen
• Causes sepsis