Microbiology | Bacillus cereus

*Bacillus cereus* is an aerobic, gram-positive, spore-forming rod that causes foodborne illness through the production of enterotoxins. The emetic type, triggered by the heat-resistant toxin cereulide, typically follows the ingestion of reheated rice or pasta and manifests within one to five hours as nausea and vomiting. Conversely, the diarrheal type is associated with contaminated meats and sauces, presenting eight to 18 hours after exposure with watery, non-bloody diarrhea. While diagnosis is primarily clinical, the condition is generally self-limited and managed with conservative rehydration, though severe cases may require antibiotics like clindamycin or aminoglycosides. Distinguishing *B. cereus* from other pathogens is critical; for instance, *Staphylococcus aureus* is often linked to uncooked prepared foods like potato salad, while *Clostridium perfringens* causes delayed-onset diarrhea without vomiting. Proper food handling and storage remain the primary methods for preventing the germination of these heat-resistant spores.