Detection and identification of E. coli producing heat-labile enterotoxin type I by enzymatic amplification of a specific DNA fragment

摘要: The polymerase chain reaction (PCR) was used to identify strains of Escherichia coli which produce heat-labile toxin type I (LTI). Amplification primers were designed detect E. human as well porcine origin. This assay test the ATCC 37218 strain, carries a recombinant plasmid with genetic information for production LTI (pLTI). In addition, three clinical isolates and one origin tested. All reported enterotoxin (hLTI pLTI, respectively) when tested by Y1 adrenal cell method and/or CHO method. yielded expected 275 bp DNA fragment after enzymatic amplification. further identified allele specific oligonucleotide hybridization. Alternatively, SmaI restriction enzyme site is present in genes both isolated from humans pigs. detection limit determined water strain 20 bacteria. amplified sequence included CfoI polymorphism allowed distinguish between coding pLTI hLTI. showed this expected. Depending on identification chosen, digestion or hybridization, pure can be analysed within 8 h 12 h, respectively. may adapted environmental food samples.