Micro| Bacillus Species

3.08 Bacillus Species Microbiology review for the USMLE Step 1 exam Bacillus species are aerobic, sporulating, gram + rod-shaped bacteria found in nature such as soil, water, and air Two main species to discuss: Bacillus cereus and Bacillus anthracis Bacillus cereus is associated with foodborne infections and specifically with reheated rice, as spores can survive cooking and continue to grow in refrigerated rice, leading to enteritis symptoms Bacillus anthracis causes anthrax, most commonly contracted through contact with infected animals, particularly grazing animals such as sheep, goats, and cattle. There are three forms of anthrax: cutaneous anthrax, inhalation anthrax, and gastrointestinal anthrax Cutaneous anthrax is the most common form and results from inoculation of spores through a cut or opening in the skin Inhalation anthrax occurs when spores are inhaled and leads to systemic illness, mediastinal widening, septic shock, and death Gastrointestinal anthrax results from ingesting spores in contaminated food and leads to severe abdominal symptoms.