Detection of five Shiga toxin-producing Escherichia coli genes with multiplex PCR

Authors

Insook Son, U.S. Food & Drug AdministrationFollow
Rachel Binet, U.S. Food and Drug AdministrationFollow
Anna Maounounen-Laasri, Oak Ridge Research Institute for Science and EducationFollow
Andrew Lin, U.S. Food and Drug Administration San Francisco District LaboratoryFollow
Thomas S. Hammack, U.S. Food & Drug AdministrationFollow
Julie A. Kase, U.S. Food & Drug AdministrationFollow

Date of this Version

2014

Citation

Food Microbiology 40 (2014) 31-40; http://dx.doi.org/10.1016/j.fm.2013.11.016

Abstract

Escherichia coli serogroup O157 is the pathogen most commonly associated with foodborne disease outbreaks, but epidemiological studies suggest that non-O157 Shiga toxin-producing E. coli (STEC) is a major player as well. The ten most clinically relevant STECs belong to serogroups O26, O103, O111, O145, O157, O91, O113, O128, O45, and O121; but emerging strains, such as O104:H4 that was identified with the 2011 German outbreak, could become more prevalent in the future. A 75-min conventional multiplex PCR assay, IS-5P, targeting the four virulence factors stx1, stx2, eae, and ehxA plus the O157:H7- specific +93 uidA single nucleotide polymorphism was developed to better assess the potential pathogenicity of STEC isolates. All 212 STEC DNAs showed one to five amplification products, while the non- E. coli DNA did not react to this multiplex PCR assay. Enrichment broths obtained from baby spinach, alfalfa sprouts, and cilantro artificially inoculated with O26, O103, and O121 STECs reacted positively to the multiplex assay. Unlike the current FDA BAM 5P PCR, designed for the specific detection of O157:H7, IS-5P will identify potentially harmful O157:H7 and non-O157 STECs so they can be removed from the nation’s food supply.