NON PRODUCTION OF SHIGA-LIKE TOXINS BY ESCHERICHIA-COLI SEROGROUP O-26

We have investigated the production of Shiga-like toxins (SLTs) by 41 strains of Escherichia coli O-26 belonging to serotypes O-26:H-, O-26: H-10, O-26:H-11, O-26:H-32 and O-26:H-NT which were isolated from huma n and calf specimens and also from meat products. The production of SL Ts was tested on HeLa and Vero cell cultures and by DNA hybridization with probes specific for SLT(I) and SLT(II) I. None of the Brazilian s trains were SLTs producers, whereas 8 reference strains of E. coli O-2 6:H-11 were confirmed as SLT(I) producers. These results suggest that SLT may not be an important virulence factor among Brazilian E. coli O -26 isolates.