News briefing： Bacillus subtilis cytotoxin (sub) is a kind of cytotoxin that may cause the virulence of virulent Escherichia coli (VTEC) strains in humans.

Bacillus subtilis cytotoxin (sub) is a kind of cytotoxin that may cause the virulence of virulent Escherichia coli (VTEC) strains in humans. It is known that there are 3 mutants of SubAB encoding gene (subAB1, subAB2-1, and subAB2-2), and the positive strains of 2 mutants of subAB may be more likely to cause human diseases. In this study, 188 subAB2 positive VTEC strains isolated from goats and sheep were PCR tested to confirm the existence of subAB2-1 and subAB2-2 mutants.

81 (61.4%) of 132 goat strains and 36 (64.3%) of 56 sheep strains had subAB2-1 mutants. Except one of them, all other sheep and goat strains were positive for subAB2-2 mutation. The results of this study were the first time that subAB2-1 and subAB2-2 variants were found in goat subAB2 positive VTEC strains, and two subAB2 variants were confirmed by detecting sheep subAB2 positive VTEC strains. Since there is no significant difference between the two subAB2 variants found in the serotype strains related to serious human diseases and they do not belong to these serotypes, the occurrence of the two subAB2 variants does not seem to be related to the higher risk of serious human diseases.