title: Lessons learned from a textbook outbreak: EHEC-O157:H7 infections associated with the consumption of raw meat products, June 2012, Limburg, Belgium.
abstract: BACKGROUND
  On 5 June 2012 several enterohemorrhagic Escherichia coli, EHEC, O157:H7 infections were reported to the public health authorities of Limburg.
  
  
  METHODS
  We performed a case-control study, a trace back/forward investigation and compared strains isolated from human cases and food samples. A case was defined as anyone with a laboratory-confirmed E. coli O157:H7-infection in North-East Limburg from May 30 2012 till July 15 2012. Family members with bloody diarrhea were also included as cases. E. coli O157 was isolated by culture and the presence of the virulence genes was verified using (q)PCR. Isolates were genotyped and compared by Pulsed Field Gel Electrophoresis (PFGE) and insertion sequence 629-printing (IS629-printing).
  
  
  RESULTS
  The outbreak involved 24 cases, of which 17 were laboratory-confirmed. Five cases developed Hemolytic Uremic Syndrome (HUS) and fifteen were hospitalized. Cases reported a significantly higher consumption of "steak tartare", a raw meat product (OR 48.12; 95% CI; 5.62- 416.01). Cases were also more likely to buy meat-products at certain butcheries (OR 11.67; 95% CI; 1.41 - 96.49). PFGE and IS629-printing demonstrated that the vtx1a vtx2a eae ehxA positive EHEC O157:H7 strains isolated from three meat products and all seventeen human stool samples were identical. In a slaughterhouse, identified by the trace-back investigation, a carcass infected with a different EHEC strain was found and confiscated.
  
  
  CONCLUSIONS
  We present a well described and effectively investigated foodborne outbreak associated with meat products. Our main recommendations are the facilitation and acceleration of the outbreak detection and the development of a communication plan to reaches all persons at risk.
  Foodborne diseases, Shiga-toxigenic Escherichia coli, Enterohemorrhagic Escherichia coli, Meat products, Case control studies, Electrophoresis, Gel, Pulsed-Field.
authors: Scientific Institute of Public Health, Department Epidemiology, Epidemiology of infectious diseases, Juliette Wytsmansstraat 14, 1050 Brussels, Belgium.
authors: Toon
authors: T
authors: Braeye
authors: Scientific Institute of Public Health, Scientific service of foodborne Pathogens, NRL VTEC in Food-NRL Foodborne Outbreaks, Juliette Wytsmansstraat 14, 1050 Brussels, Belgium.
authors: Sarah
authors: S
authors: Denayer
authors: Department of Microbiology, NRC STEC/VTEC, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium.
authors: Klara
authors: K
authors: De Rauw
authors: Department of Infectious Disease Control, Agency for Care and Health, Koningin Astridlaan 50, 3500 Limburg, Belgium.
authors: Anmarie
authors: A
authors: Forier
authors: Federal Agency for Safety of the Food Chain, FASFC, Kruidtuinlaan 55, 1000 Brussel, Belgium.
authors: Jurgen
authors: J
authors: Verluyten
authors: Federal Agency for Safety of the Food Chain, FASFC, Kruidtuinlaan 55, 1000 Brussel, Belgium.
authors: Ludo
authors: L
authors: Fourie
authors: Scientific Institute of Public Health, Scientific service of foodborne Pathogens, NRL VTEC in Food-NRL Foodborne Outbreaks, Juliette Wytsmansstraat 14, 1050 Brussels, Belgium.
authors: Katelijne
authors: K
authors: Dierick
authors: Scientific Institute of Public Health, Scientific service of foodborne Pathogens, NRL VTEC in Food-NRL Foodborne Outbreaks, Juliette Wytsmansstraat 14, 1050 Brussels, Belgium.
authors: Nadine
authors: N
authors: Botteldoorn
authors: Scientific Institute of Public Health, Department Epidemiology, Epidemiology of infectious diseases, Juliette Wytsmansstraat 14, 1050 Brussels, Belgium.
authors: Sophie
authors: S
authors: Quoilin
authors: Federal Agency for Safety of the Food Chain, FASFC, Kruidtuinlaan 55, 1000 Brussel, Belgium.
authors: Pascale
authors: P
authors: Cosse
authors: Federal Agency for Safety of the Food Chain, FASFC, Kruidtuinlaan 55, 1000 Brussel, Belgium.
authors: Jeannine
authors: J
authors: Noyen
authors: Department of Microbiology, NRC STEC/VTEC, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels, Belgium.
authors: Denis
authors: D
authors: Pierard
keywords: Case control studies; Enterohaemorrhagic E. coli – EHEC; Escherichia coli O157; Food-borne infections; IS629-printing; Outbreaks; PFGE; Vero cytotoxin-producing E. coli – VTEC