- Bacillus cereus is a gram-positive, rod-shaped, spore-forming bacterium commonly found in soil and vegetation. Its ability to form heat-resistant spores and produce various toxins makes it a significant foodborne pathogen.
- The organism possesses several virulence factors. It produces two types of food poisoning toxins: the emetic toxin (cereulide) and three different diarrheal enterotoxins (hemolysin BL, non-hemolytic enterotoxin, and cytotoxin K). The emetic toxin is heat-stable and preformed in food, while diarrheal toxins are produced in the intestine after ingestion of contaminated food.
- B. cereus can grow at temperatures between 10°C and 48°C, with optimal growth at 28-35°C. The spores can survive cooking temperatures and germinate when food is cooled slowly or stored at room temperature. The bacteria can grow in both aerobic and anaerobic conditions, making it versatile in various food environments.
- Common food sources include rice, pasta, meat products, vegetables, dairy products, and dried foods. The organism’s ability to form biofilms on food processing equipment makes it particularly problematic in food industry settings. Additionally, some strains can grow at refrigeration temperatures, though growth is slower.
- Beyond food poisoning, B. cereus can cause other infections, particularly in immunocompromised individuals. These include eye infections, wound infections, and rarely, systemic infections. Some strains have developed antimicrobial resistance, complicating treatment of serious infections.
