Detection of Three Foodborne Pathogenic Microorganisms by DNA Microarray

Abstract:

A rapid, sensitive and specific method of DNA microarray combined with multiplex PCR that allow the simultaneous detection and identification of Shigella dysenteriae, Salmonella spp. and E. coli O157. The invasion-associated plasmid antigen H of S. dysenteriae(ipaH), Salmonella spp. enterotoxin gene(stn) and Escherichia coli O157 Shiga-Toxin gene(slt) were used as target genes, and then three pairs of primers and captured oligonucleotide probes were designed and synthesized. The multiplex PCR products were hybridized with DNA microarray, which contained specific probes of three foodborne pathogenic microorganisms. Genomic DNAs from 26 bacterial strains were detected, and only 3 index bacteria were positive. The detection limit of this assay was around 8 pg genomic DNA. In addition, this method was applied to detect artificially contaminated food samples, and the detection limit was 50 CFU/mL for non-cultured samples. These results suggested that detection of pathogenic microorganisms by DNA microarray is an effective procedure with high specificity and sensitivity. The DNA microarray assay developed in this study could provide an informative supplement to conventional microbiological methods for routine monitoring of food.

Key words:DNA microarray, Multiplex PCR, Microorganism, Detection