title: Survival of Escherichia coli O26:H11 exceeds that of Escherichia coli O157:H7 as assessed by simulated human digestion of contaminated raw milk cheeses.
abstract: Shiga toxin producing Escherichia coli (STEC) are an important cause of human foodborne outbreaks. The consumption of raw milk dairy products may be an important route of STEC infection. For successful foodborne transmission, STEC strains must survive stress conditions met during gastrointestinal transit in humans. The aim of this study was to evaluate the survival of two STEC strains of serotypes O157:H7 and O26:H11 during simulated human digestion in the TNO gastro-Intestinal tract Model (TIM) of contaminated uncooked pressed cheeses. The survival of cheese microflora during in vitro gastrointestinal transit was also determined for the first time. The level of STEC increased from 2 log₁₀ CFU/ml to 4 log₁₀ CFU/g during the first 24h of cheese making and remained stable at around 4 log₁₀ CFU/g during cheese ripening and conservation. During transit through the artificial stomach and duodenum, levels of STEC decreased: 0.2% of E. coli O157:H7 and 1.8% of E. coli O26:H11 were recovered at 150 min in the gastric compartment, compared with 14.3% for the transit marker. Bacterial resumption was observed in the jejunum and ileum: 35.8% of E. coli O157:H7 and 663.2% of E. coli O26:H11 were recovered at 360 min in the ileal compartment, compared with 12.6% for the transit marker. The fate of STEC was strain-dependent, the survival of E. coli O26:H11 being 13 times greater than that of E. coli O157:H7 at the end of digestion in the cumulative ileal deliveries. These data provide a better understanding of STEC behavior during gastrointestinal transit in humans after ingestion of contaminated cheese.
authors.affiliation: Université de Lyon, VetAgro Sup Campus Vétérinaire de Lyon, Unité de Recherche CALITYSS, F-63280 Marcy l'Etoile, France; CNIEL, F-75314 Paris, France.
authors.forename: Stéphane D
authors.initials: SD
authors.lastname: Miszczycha
authors.affiliation: Clermont Université, Université d'Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, BP 10448, F-63000 Clermont-Ferrand, France; Clermont Université, Université d'Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, UMR INSERM/Université d'Auvergne U1071 USC-INRA 2018, BP 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Thévenot
authors.affiliation: Clermont Université, Université d'Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, BP 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Denis
authors.affiliation: INRA, UR 545, Recherches Fromagères, F-15000 Aurillac, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Callon
authors.affiliation: Clermont Université, Université d'Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, M2iSH, UMR INSERM/Université d'Auvergne U1071 USC-INRA 2018, BP 10448, F-63000 Clermont-Ferrand, France; CHU Clermont-Ferrand, Service de Bactériologie, F-63003 Clermont-Ferrand, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Livrelli
authors.affiliation: Clermont Université, Université d'Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, BP 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Monique
authors.initials: M
authors.lastname: Alric
authors.affiliation: INRA, UR 545, Recherches Fromagères, F-15000 Aurillac, France.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Montel
authors.affiliation: Clermont Université, Université d'Auvergne, Centre de Recherche en Nutrition Humaine Auvergne, EA 4678 CIDAM, BP 10448, F-63000 Clermont-Ferrand, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blanquet-Diot
authors.affiliation: Université de Lyon, VetAgro Sup Campus Vétérinaire de Lyon, Unité de Recherche CALITYSS, F-63280 Marcy l'Etoile, France; LMAP-NRL STEC, VetAgro Sup Campus Vétérinaire de Lyon, F-63280 Marcy l'Etoile, France. Electronic address: delphine.sergentet@vetagro-sup.fr.
authors.forename: Delphine
authors.initials: D
authors.lastname: Thevenot-Sergentet
mesh_terms: D000818:Animals; D002611:Cheese / Q000382:microbiology*; D004063:Digestion; D004926:Escherichia coli / Q000502:physiology*; D019453:Escherichia coli O157 / Q000502:physiology*; D029968:Escherichia coli Proteins; D005516:Food Microbiology; D006801:Humans; D050296:Microbial Viability; D008892:Milk / Q000382:microbiology; D054323:Shiga-Toxigenic Escherichia coli
chemical_list: D029968:Escherichia coli Proteins
keywords: Digestion; E. coli O157:H7; E. coli O26:H11; Raw milk cheese; STEC