The pattern of toxin genes and expression of diarrheal enterotoxins in Bacillus thuringiensis strains isolated from commercial bioinsecticides

摘要

Bacillus thuringiensis (Bt) is a gram positive sporeforming bacillus included in the Bacillus cereus group. Bt produces a parasporal insecticidal protein crystal, a protoxin of the δ-endotoxin that has insecticidal properties (Schnepf et al. 1998). Bt has been used in bioinsecticidal formulations for decades and it is either sprayed directly on plants or else used to coat the seeds. However, some outbreaks of foodborne disease due to Bt have been reported and a large number of its strains can produce enterotoxins (EFSA 2007). Bacillus cereus (Bc) is the most representative species of the Bacillus cereus group and is identified as the species of this group that typically causes foodborne disease in humans. Bc does not produce the parasporal crystal. It can develop and produce toxins in food, causing emetic syndrome, or in the human intestine, causing gastroenteritis (Schoeni and Wong 2005).