A multiplex polymerase chain reaction (PCR) combined with denaturing highperformance liquid chromatography (DHPLC) method to simultaneously detect foodborne enterotoxigenic Escherichia coli (ETEC), enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC) and enteroinvasive E. coli (EIEC) were described. Following the design of PCR primer pairs specific for ETEC, EPEC, EHEC and EIEC, respectively, the multiplex PCR was developed, and then PCR products were subjected to DHPLC analysis under nondenaturing condition. The specificity and potential diagnostic capability of the multiplex PCR-DHPLC method were evaluated, and results demonstrated that the multiplex PCR-DHPLC is an effective method to rapidly identify the major four categories of diarrheagenic E. coli, simultaneously.
PRACTICAL APPLICATIONSIn practice, we collected 690 import and export food samples including beef, pork, sausage, chicken and milk and 189 samples of patients' fecal materials, which were used to evaluate the potential diagnostic capability of the multiplex PCR-DHPLC method. The results showed that a total of 60 positive samples were detected by the method established in this work, which accorded with the testing results of conventional diagnosis method, indicating that the PCR-DHPLC is an efficient method for rapid identification of the main four diarrheagenic E. coli.