Plasmid profile analysis for enterotoxigenic Escherichia coli and detection of heat stable enterotoxin I (STI) gene by polymerase chain reaction

Abstract

Enterotoxigenic Escherichia coli (ETEC) is one of the food pathogens which may cause diarrhea in humans. The enterotoxins produced by ETEC are heat labile toxins (LT) and heat stable toxins (ST). These pathogenic factors are usually encoded on the plasmid DNA of E. coli cells. In this study, E. coli plasmid DNA was isolated and subjected to 0.7% agarose gel electrophoretic analysis and the STI gene was detected by polymerase chain reaction (PCR) using new primers. It was found that most of the plasmids from ETEC cells showed molecular weights in the range of 2-22 kb and the PCR primers used specifically amplified a 203 bp fragment.