Modification of methods for detection of Escherichia coli O157:H7 on produce

3' end of eae gene-based fluorescence DNA nanosensor for detection of E. coli O157:H7

Escherichia coli O157:H7 bacterium as a zoonotic pathogen is one of the most important causative agents of foodborne illnesses worldwide. Due to the serious concerns in public health and enormous economic losses in agriculture and food industry, it is very necessary to develop novel technology-based methods for sensitive and rapid detection of this bacterium in contaminated resources. In this study, a sensitive and selective fluorescence DNA nanosensing platform based on graphene oxide (GO) and the 3' end of eae gene as specific sequence was developed for the detection of E. coli O157:H7. In this platform, fluorescence resonance energy transfer (FRET) process between GO- and FAM-labeled eae gene probe was used for the diagnosis of E. coli O157:H7. Following the immobilization of the eae gene probe on GO, fluorescence emission of FAM was quenched. In hybridization reaction, by adding the complementary DNA, fluorescence emission of FAM was significantly increased and recovered to 93%. The performance of sensor for detection of E. coli O157:H7 genomic DNA was determined 10 pg genomic DNA per 1 ml Tris-HCl hybridization buffer which was significantly more sensitive than PCR method. In conclusion, the results indicated that GO eae gene-based nanosensor has potential to be developed as a rapid and sensitive diagnostic device besides PCR methods for the detection of E. coli O157:H7 bacteria.