Bacterium
Bacillus cereus
Reheated-rice food poisoning rod
buh-SIL-us SEER-ee-us
High-yield clue
Reheated rice held warm is the classic clue: the heat-stable emetic toxin cereulide causes vomiting, while a separate heat-labile enterotoxin causes watery diarrhea.
Overview
A spore-forming Gram-positive soil rod used in coursework to connect two distinct foodborne toxin syndromes with the same organism. Its heat-stable emetic toxin makes it a classic teaching example of preformed-toxin food poisoning.
Classification
- Gram-positive
- Rod (bacillus)
- Spore-forming
- Facultative/aerobic
- Beta-hemolytic
Lab & identification clues
- Large box-car Gram-positive rods
- Endospore-forming
- Beta-hemolytic colony vocabulary
- Motile teaching distinction
Associations
- Reheated fried rice food poisoning
- Emetic (cereulide) vs diarrheal enterotoxin syndromes
- Ocular/keratitis study association
Commonly confused with
- Bacillus anthracis
- Staphylococcus aureus preformed-toxin poisoning
Frequently asked questions
What is Bacillus cereus?
A spore-forming Gram-positive soil rod used in coursework to connect two distinct foodborne toxin syndromes with the same organism. Its heat-stable emetic toxin makes it a classic teaching example of preformed-toxin food poisoning.
What is the Gram stain of Bacillus cereus?
Bacillus cereus is Gram positive.
What are the lab clues for Bacillus cereus?
Lab clues for Bacillus cereus include Large box-car Gram-positive rods, Endospore-forming, Beta-hemolytic colony vocabulary, and Motile teaching distinction.
What is Bacillus cereus commonly confused with?
Bacillus cereus is commonly confused with Bacillus anthracis and Staphylococcus aureus preformed-toxin poisoning.
Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.