The principal virulence factors of Bacillus cereus infections include which toxins?

• A. Endotoxin and exotoxin
• B. Enterotoxin and pyogenic toxin
• C. Capsular polysaccharide and fimbriae
• D. Exotoxin A and B

Answer: (B)

Bacillus cereus causes disease mainly through toxin production that damages the gut and tissues. The toxins that drive illness are enterotoxins, which disrupt the intestinal lining and lead to diarrheal symptoms, and toxins that damage cells and tissues (often described as pyogenic or cytotoxins), which contribute to tissue injury and more severe manifestations. The emetic toxin cereulide is also a well-known virulence factor, but the combination of enterotoxins and tissue-damaging toxins best captures the principal toxin-mediated virulence of B. cereus. Endotoxins are associated with Gram-negative bacteria, so they’re not a correct feature here; capsular polysaccharide and fimbriae are adherence factors, not toxins; and exotoxin A and B belong to Clostridium difficile, not Bacillus cereus.