title: Variable tellurite resistance profiles of clinically-relevant Shiga toxin-producing Escherichia coli (STEC) influence their recovery from foodstuffs.
abstract: Tellurite (Tel)-amended selective media and resistance (Tel-R) are widely used for detecting Shiga toxin-producing Escherichia coli (STEC) from foodstuffs. Tel-R of 81 O157 and non-O157 STEC strains isolated from animal, food and human was thus investigated. Variations of STEC tellurite minimal inhibitory concentration (MIC) values have been observed and suggest a multifactorial and variable tellurite resistome between strains. Some clinically-relevant STEC were found highly susceptible and could not be recovered using a tellurite-based detection scheme. The ter operon was highly prevalent among highly Tel-R STEC but was not always detected among intermediately-resistant strains. Many STEC serogroup strains were found to harbor sublines showing a gradient of MIC values. These Tel-R sublines showed statistically significant log negative correlations with increasing tellurite concentration. Whatever the tellurite concentration, the highest number of resistant sublines was observed for STEC belonging to the O26 serogroup. Variations in the number of these Tel-R sublines could explain the poor recovery of some STEC serogroups on tellurite-amended media especially from food products with low levels of contamination. Comparison of tellurite MIC values and distribution of virulence-related genes showed Tel-R and virulence to be related.
authors.affiliation: University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Kerangart
authors.affiliation: University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France; Institut National de Recherche Agronomique, Unité de Recherches Fromagères, 15000 Aurillac, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Douëllou
authors.affiliation: Université Paris-Est, ANSES, Laboratoire de Sécurité des Aliments, Plateforme IdentyPath, 14 Rue Pierre et Marie Curie, 94701 Maisons-Alfort, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Delannoy
authors.affiliation: Université Paris-Est, ANSES, Laboratoire de Sécurité des Aliments, Plateforme IdentyPath, 14 Rue Pierre et Marie Curie, 94701 Maisons-Alfort, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Fach
authors.affiliation: National Reference Laboratory for Escherichia coli (Including VTEC), Department of Biological Safety, Federal Institute for Risk Assessment (BfR), D-12277 Berlin, Germany.
authors.forename: Lothar
authors.initials: L
authors.lastname: Beutin
authors.affiliation: University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France; University of Lyon, VetAgro Sup, LMAP Laboratory, National Reference Laboratory for Escherichia coli (Including VTEC), Marcy L'Etoile, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Sergentet-Thévenot
authors.affiliation: University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Cournoyer
authors.affiliation: University of Lyon, Research Group on «Bacterial Opportunistic Pathogens and Environment», UMR5557 Microbial Ecology, University Lyon 1, CNRS, VetAgro Sup, 69622 Villeurbanne Cedex, France; University of Lyon, VetAgro Sup, LMAP Laboratory, National Reference Laboratory for Escherichia coli (Including VTEC), Marcy L'Etoile, France. Electronic address: estelle.loukiadis@vetagro-sup.fr.
authors.forename: Estelle
authors.initials: E
authors.lastname: Loukiadis
mesh_terms: D018829:Adhesins, Bacterial; D000818:Animals; D003470:Culture Media; D024881:Drug Resistance, Bacterial; D004927:Escherichia coli Infections / Q000382:microbiology; D019453:Escherichia coli O157 / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000235:genetics; D005516:Food Microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D009876:Operon; D016133:Polymerase Chain Reaction; D065288:Serogroup; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification*; D013691:Tellurium / Q000494:pharmacology*; D014774:Virulence / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D003470:Culture Media; D029968:Escherichia coli Proteins; C026899:potassium tellurate(IV); D013691:Tellurium
keywords: Foodstuff; STEC; Selective media; Tellurite resistance; ter genes