Common occurrence of enterotoxin genes and enterotoxicity in Bacillus thuringiensis

Seventy-four strains of Bacillus thuringiensis representing 24 serovars wer e examined for the presence of three enterotoxin genes/operons; the non-hae molytic enterotoxin Nhe. the haemolytic enterotoxin hbl and the Bacillus ce reus toxin beer using polymerase chain reaction. The nheBC genes were found in all strains examined, the hblCD genes in 65 of the 74 strains and bceT in 63 strains. There was little consistency of the distribution of enteroto xin loci among strains of the same serovar in serovars that were well repre sented in our collection. Culture supernatants from all but one strain inhi bited protein synthesis in Vero cells, generally with a toxicity equivalent to that seen in strains of B. cereus isolated from incidents of food poiso ning. (C) 2000 Published by Elsevier Science B.V. on behalf of the Federati on of European Microbiological Societies.