title: Detection of non-O157 Shiga toxin-producing Escherichia coli in 375 grams of beef trim enrichments across multiple commercial PCR detection platforms.
abstract: Although serotype O157:H7 remains the pathogenic Shiga toxin-producing Escherichia coli (STEC) of primary concern worldwide, some focus in the United States has shifted to six particular non-O157 STEC serogroups (O26, O45, O103, O111, O121, and O145). Some of these serogroups have also emerged as concerns elsewhere around the world, including Europe. The objective of this work was to compare commercial detection methods with the U.S. Department of Agriculture (USDA) reference method for detection of non-O157 STEC in 375 g of beef trim using a limit of detection study design. Overall, the commercial platforms performed well, showing similar levels of sensitivity for detection of presumptive positives for O45, O26, O103, and O121 (PCR screen results only). For O111, one method that utilizes an integrated immunomagnetic separation and PCR approach was more sensitive than a PCR-only screen approach. Additionally, one commercial method showed more presumptive and confirmed positives overall. Use of an immunomagnetic separation tool, such as antibody-coated beads, aided considerably with the confirmation procedures and is an important step when confirming suspect samples. A secondary goal of this study was to evaluate isolation and International Organization for Standardization confirmation protocols used in Europe compared with strategies provided by the USDA Microbiology Laboratory Guidebook (MLG). Generally, results from the USDA confirmation plates (modified Rainbow agar) were better than the European Union confirmation plates (MacConkey agar with or without rhamnose). In summary, detection of non-O157 STEC in 375 g of beef trim can be performed by any of the three methods on the market evaluated in the study.
authors.affiliation: Silliker Food Science Center, 3600 Eagle Nest Drive, Crete, Illinois 60417, USA.
authors.forename: Sarita Raengpradub
authors.initials: SR
authors.lastname: Wheeler
authors.affiliation: Silliker Food Science Center, 3600 Eagle Nest Drive, Crete, Illinois 60417, USA.
authors.forename: Preciaus
authors.initials: P
authors.lastname: Heard
authors.affiliation: Silliker France, 1 rue de la Croix des Maheux, 95031 Cergy-Pontoise cedex, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Dufour
authors.affiliation: University of Lyon, VetAgro Sup, French National Reference Laboratory for Escherichia coli, 1 avenue Bourgelat, 69280 Marcy l'Etoile, France; University of Lyon, Research Group on Bacterial Opportunistic Pathogens and Environment, UMR 5557 Microbial Ecology, University Lyon 1, National Center for Scientific Research, VetAgro Sup, 69622 Villeurbanne cedex, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Thevenot-Sergentet
authors.affiliation: University of Lyon, VetAgro Sup, French National Reference Laboratory for Escherichia coli, 1 avenue Bourgelat, 69280 Marcy l'Etoile, France; University of Lyon, Research Group on Bacterial Opportunistic Pathogens and Environment, UMR 5557 Microbial Ecology, University Lyon 1, National Center for Scientific Research, VetAgro Sup, 69622 Villeurbanne cedex, France.
authors.forename: Estelle
authors.initials: E
authors.lastname: Loukiadis
authors.affiliation: Mérieux NutriSciences, 111 East Wacker Drive, Suite 2300, Chicago, Illinois 60601, USA.
authors.forename: Russell S
authors.initials: RS
authors.lastname: Flowers
authors.affiliation: Silliker Food Science Center, 3600 Eagle Nest Drive, Crete, Illinois 60417, USA. wendy.mcmahon@silliker.com.
authors.forename: Wendy
authors.initials: W
authors.lastname: McMahon
mesh_terms: D000362:Agar; D000818:Animals; D002417:Cattle; D005060:Europe; D005062:European Union; D018189:Immunomagnetic Separation / Q000379:methods*; D008460:Meat / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D054323:Shiga-Toxigenic Escherichia coli / Q000302:isolation & purification*; D014481:United States
chemical_list: D000362:Agar