The present invention discloses a fusion protein SAmB, a coding gene and an application thereof. The fusion protein provided in the present invention is named SAmB, comprising on the N-terminal a Shiga toxin type-II A subunit mutant protein and on the C-terminal a Shiga toxin type-I B subunit protein. The Shiga toxin type-II A subunit mutant protein is prepared by mutating the active site amino acid residues of Shiga toxin type-II A subunit protein. The fusion protein SAmB provided in the present invention can be used to prepare a medicament for use in the prevetion and/or treatment of a Shiga toxin pathogenic bacteria infection or complication of the infection.
