Comparison of fluorescence assay and real time PCR in DNA-based quantification methods for determination of Escherichia coli O157:H7

Abstract

Escherichia coli O157:H7 is strains that are harmful to humans with a high toxicity level. Comprehensive methods are required to provide a specific, sensitive, quantitative and accurate analysis of infection by E. coli O157:H7. Due to the lack of a method that have all these criteria, we evaluated new fluorescence assay and compared with established real time PCR method for its efficacy in quantifying the fliC gene of E. coli O157:H7. Result suggests that the new developed methods are competitive with established real time PCR method. Graphene and gold (GQDs-AuNPs) based fluorescence assay could quantify genomic DNA target in dynamic range of 0.05 ng/μL to 500 ng/μL. The limit of detection is 7.57 x 10-1 ± 1.41 ng/μL for n = 3. This method can be used to monitor the outbreak of E. coli O157:H7 and also to be used in future quantification of other food-borne pathogenic bacteria.