EN
For the last 25 years, Shiga toxin-producing E. coli (STEC) has been a serious cause of human diseases, responsible for the progression of hemorrhagic colitis (HC), hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Cattle and other ruminants are the main reservoirs of these bacteria. The infections are mainly associated with strains belonging to serogroups O157, O26, O103, O111 and O113. The main source of the bacteria is contaminated food of animal origin (especially beef) but water and person-to-person transmission may play a significant role in human infections. Large outbreaks connected to STEC can affect many people causing serious morbidity and mortality, making this bacteria one of the most significant food-borne pathogens. In this paper several plasmid and chromosomal genes responsible for the expression of important virulence determinants of STEC have been described. Among them, Shiga toxin (Stx) encoded by the stx genes is the best characterized pathogenic marker. This review should improve the knowledge of STEC and the function of the virulence markers described, but further studies are needed to evaluate the role of STEC genes in e.g. apoptosis or quorum sensing processes.