Shiga Toxins of Shigella dysenteriae and Escherichia coli

The Shiga toxins constitute a family of functionally and structurally related toxins produced by Shigella dysenteriae type 1 (also called Shiga’s bacillus) and a subset of diarrheagenic Escherichia coli called STEC (for Shiga toxin-producing E. coli). Shiga toxins of STEC were formerly called Shiga-like toxins and are alternatively named Vero toxins (Calderwood et al. 1996; Karmali et al. 1996). We favor the Shiga-toxin nomenclature system based largely on historical precedence. Indeed, the prototype for the Shiga-toxin family, Shiga toxin produced by S. dysenteriae type 1, was first described in 1903 by Conradi (Conradi 1903) and, independently, by Neisser and Shiga (Neisser and Shiga 1903). Conradi made the seminal observation that lysates of Shiga’s bacillus caused hind-leg paralysis when injected into rabbits.