MITOMYCIN-INDUCED SYNTHESIS OF A SHIGA-LIKE TOXIN FROM ENTEROPATHOGENIC ESCHERICHIA-COLI-HI8

Escherichia coli H.1.8, an 0128 infant diarrhea isolate, produces low titers of a unique Shiga-like toxin (SLT), called SLT-IIva, which is a variant of SLT-II. We investigated induction of toxin synthesis and t he putative association of a bacteriophage with toxin synthesis. Induc tion of broth cultures of strain H.I.8 with mitomycin yielded a 3,000- fold increase in SLT-IIva, production of a colicin, and appearance of a bacteriophage. Southern hybridization demonstrated that the genes fo r SLT-IIva were not carried by the bacteriophage.