Makindo Medical Notes

Bacillus cereus is a common cause of rapid-onset food poisoning, often seen in exam scenarios. Symptoms include vomiting within hours of consuming contaminated food, particularly fried rice. The illness is usually self-limiting, with resolution within 24 hours.

About

• Bacillus cereus is a key pathogen in foodborne illnesses, especially associated with improperly stored food.
• It is commonly referenced in exams due to its rapid onset and typical clinical presentation.

Source

• Frequently contaminates food production environments, kitchens, and biotechnology processes.
• Commonly found in foods such as fried rice left at room temperature, where spores can germinate.
• Can also contaminate vegetables, cakes, pasta, and sauces if improperly stored.

Characteristics

• Aerobic, Gram-positive, spore-forming bacilli. The spores are resistant to boiling temperatures.
• Produces two toxins: one that causes rapid vomiting (emetic syndrome) and another that causes diarrhoea (diarrhoeal syndrome).
• The spores of Bacillus cereus survive cooking and can germinate when food is stored improperly, such as rice left at room temperature after cooking.

Clinical Features

• Vomiting typically occurs within 1-5 hours after consumption of contaminated food.
• Diarrhoea often follows the vomiting and may last a few hours.
• Symptoms resolve within 24 hours, and the illness is usually self-limiting.
• Rarely, systemic infections such as pneumonia and endocarditis can occur, though these are uncommon in foodborne cases.

Management

• Management is conservative, with oral rehydration being the primary treatment.
• Because the illness is self-limiting, no specific antibiotic treatment is required for typical food poisoning cases.
• Public health notification is important, especially if the source of contamination is a food vendor.

References

• Bacillus cereus at CDC