title: Characterisation of the Escherichia coli strain associated with an outbreak of haemolytic uraemic syndrome in Germany, 2011: a microbiological study.
abstract: BACKGROUND
  In an ongoing outbreak of haemolytic uraemic syndrome and bloody diarrhoea caused by a virulent Escherichia coli strain O104:H4 in Germany (with some cases elsewhere in Europe and North America), 810 cases of the syndrome and 39 deaths have occurred since the beginning of May, 2011. We analysed virulence profiles and relevant phenotypes of outbreak isolates recovered in our laboratory.
  
  
  METHODS
  We analysed stool samples from 80 patients that had been submitted to the National Consulting Laboratory for Haemolytic Uraemic Syndrome in Münster, Germany, between May 23 and June 2, 2011. Isolates were screened with standard PCR for virulence genes of Shiga-toxin-producing E coli and a newly developed multiplex PCR for characteristic features of the outbreak strain (rfb(O104), fliC(H4), stx(2), and terD). Virulence profiles of the isolates were determined with PCR targeting typical virulence genes of Shiga-toxin-producing E coli and of other intestinal pathogenic E coli. We sequenced stx with Sanger sequencing and measured Shiga-toxin production, adherence to epithelial cells, and determined phylogeny and antimicrobial susceptibility.
  
  
  RESULTS
  All isolates were of the HUSEC041 clone (sequence type 678). All shared virulence profiles combining typical Shiga-toxin-producing E coli (stx(2), iha, lpf(O26), lpf(O113)) and enteroaggregative E coli (aggA, aggR, set1, pic, aap) loci and expressed phenotypes that define Shiga-toxin-producing E coli and enteroaggregative E coli, including production of Shiga toxing 2 and aggregative adherence to epithelial cells. Isolates additionally displayed an extended-spectrum β-lactamase phenotype absent in HUSEC041.
  
  
  CONCLUSIONS
  Augmented adherence of the strain to intestinal epithelium might facilitate systemic absorption of Shiga toxin and could explain the high progression to haemolytic uraemic syndrome. This outbreak demonstrates that blended virulence profiles in enteric pathogens, introduced into susceptible populations, can have extreme consequences for infected people.
  
  
  BACKGROUND
  German Federal Ministry of Education and Research, Network Zoonoses.
authors.affiliation: Institute for Hygiene and the National Consulting Laboratory for Haemolytic Uraemic Syndrome, University of Münster, Münster, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Bielaszewska
authors.forename: Alexander
authors.initials: A
authors.lastname: Mellmann
authors.forename: Wenlan
authors.initials: W
authors.lastname: Zhang
authors.forename: Robin
authors.initials: R
authors.lastname: Köck
authors.forename: Angelika
authors.initials: A
authors.lastname: Fruth
authors.forename: Andreas
authors.initials: A
authors.lastname: Bauwens
authors.forename: Georg
authors.initials: G
authors.lastname: Peters
authors.forename: Helge
authors.initials: H
authors.lastname: Karch
mesh_terms: D003967:Diarrhea / Q000382:microbiology*; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D016680:Genome, Bacterial; D005858:Germany; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010641:Phenotype; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D022641:Shiga Toxin 2 / Q000235:genetics; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D022641:Shiga Toxin 2