Development of a multiplex PCR [m-PCR] test for rapid identification of genes encoding heat-labile [LTI] and heat-stable [STI and STII] toxins of enterotoxigenic Escherichia coli [ETEC] with internal control of amplification

A multiplex PCR system was developed for specific identification of genes encoding heat-labile (LTI) and heat-stable (STI and STII) toxins of enterotoxigenic Escherichia coli (ETEC) strains. In addition, primers specific for the E. coli gene coding for 16S rRNA were used as an internal control of the DNA amplification. The specificity of the method was validated by single PCR tests performed with reference to E. coli strains as well as pig-isolated bacteria and 100% correlation was observed. The developed multiplex PCR allowed rapid and specific identification of enterotoxin-positive E. coli and may be used as a sensitive and specific method for a direct determination of ETEC and to differentiate them from other E. coli isolates.