The enterotoxin T (BcET) from Bacillus cereus can probably not contribute to food poisoning

Abstract

A polymerase chain reaction (PCR) fragment from strain NVH 38 (containing bceT) was cloned, sequenced and expressed in Escherichia coli. This sequence showed 50^60% identity to the original. When this bceT clone was expressed in E. coli no biological activity was found in either supernatants or cell extracts. Cell extracts from the Bacillus cereus strains (NVH 38 and B-4ac) were also negative on Vero cells. Neutralisation of supernatant from B. cereus B-4ac using a monoclonal antibody (reacting with NheB and HblD) abolished the activity. A test for cytotoxic enterotoxins was negative for both cell extracts and supernatants. Our data suggest that BcET either has an unknown type enterotoxic action or non at all.

Distribution of Genes Encoding Putative Virulence Factors and Fragment Length Polymorphisms in the vrrA Gene among Brazilian Isolates of Bacillus cereus and Bacillus thuringiensis

“…More recently, it has been suggested that the bceT sequence actually represents a cloning artifact, formed by the ligation of four individual restriction fragments derived from B. cereus genomic DNA (22). An additional study indicated that the BceT toxin was most likely an experimental artifact that probably could not contribute to food poisoning (10). Nevertheless, other workers have demonstrated that it is possible to detect at least part of the original published sequence in both B. cereus and B. thuringiensis, and for that reason, we decided to include that region of the sequence as a target in our study using previously described primers (17).…”

Bacillus cereus, the causative agent of an emetic type of food‐borne illness

“…In addition, two other proteins, referred to as enterotoxin T and FM [45,46], have been described. However, these proteins presumably do not contribute to food-borne illness [47]. The enterotoxin T has been shown to be the result of cloning artifact [48] while the role of EntFM is cryptic since no biological studies have been performed on this protein.…”

Detection of coding genes for enterotoxins in Bacillus cereus by PCR and their products by BCET-RPLA and ELISA Assay

“…The nucleotide sequence denoted bceT has been reported to encode a single component toxin T (BceT, 41-kDa protein) which exhibits Vero cell cytotoxicity and has also been attributed to having a role in the diarrheal syndrome (Agata et al, 1995a). An additional study has indicated that the BceT enterotoxin was most likely an experimental artifact that probably could not contribute to food poisoning (Choma and Granum, 2002). CytK toxin is a pore-forming cytotoxin linked to human necrotic enteritis cases (Hardy et al, 2001).…”