Molecular Detection of Enterohemorrhagic Escherichia coli O157:H7 and Its Toxins in Beef

Most Escherichia coli strains are harmless commensals in the human gut, but some strains are known to cause disease. The enterohemorrhagic E. coli (EHEC ) strains of serotype O157:H7 causes hemorrhagic colitis, which may develop into life-threatening hemolytic uremic syndrome. Polymerase chain reaction (PCR) is a powerful tool to multiply a target molecule to detectable quantities. In the multiplex PCR method, two or more primer sets are used to simultaneously amplify multiple target sequences. Many researchers developed multiplex PCR for the detection of the LT (heat-labile toxin), SLT-I (Shiga-like toxin) and SLT-II producing E. coli . Antibody- or DNA-based assays for identifying SLTs or bacteria-carrying SLT genes will not discriminate O157:H7 isolates from the numerous other serotypes that also produce SLTs enterotoxins.