title: Genomic Comparison of Two O111:H- Enterohemorrhagic Escherichia coli Isolates from a Historic Hemolytic-Uremic Syndrome Outbreak in Australia.
abstract: Enterohemorrhagic Escherichia coli (EHEC) is an important cause of diarrhea and hemolytic-uremic syndrome (HUS) worldwide. Australia's worst outbreak of HUS occurred in Adelaide in 1995 and was one of the first major HUS outbreaks attributed to a non-O157 Shiga-toxigenic E. coli (STEC) strain. Molecular analyses conducted at the time suggested that the outbreak was caused by an O111:H(-) clone, with strains from later in the outbreak harboring an extra copy of the genes encoding the potent Shiga toxin 2 (Stx2). Two decades later, we have used next-generation sequencing to compare two isolates from early and late in this important outbreak. We analyzed genetic content, single-nucleotide polymorphisms (SNPs), and prophage insertion sites; for the latter, we demonstrate how paired-end sequence data can be leveraged to identify such insertion sites. The two strains are genetically identical except for six SNP differences and the presence of not one but two additional Stx2-converting prophages in the later isolate. Isolates from later in the outbreak were associated with higher levels of morbidity, suggesting that the presence of the additional Stx2-converting prophages is significant in terms of the virulence of this clone.
authors.affiliation: Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: McAllister
authors.affiliation: School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Bent
authors.affiliation: Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Nicola K
authors.initials: NK
authors.lastname: Petty
authors.affiliation: Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Skippington
authors.affiliation: Australian Infectious Diseases Research Centre and School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Beatson
authors.affiliation: Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
authors.forename: James C
authors.initials: JC
authors.lastname: Paton
authors.affiliation: Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia adrienne.paton@adelaide.edu.au.
authors.forename: Adrienne W
authors.initials: AW
authors.lastname: Paton
mesh_terms: D001315:Australia / Q000453:epidemiology; D004196:Disease Outbreaks; D054324:Enterohemorrhagic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016680:Genome, Bacterial; D023281:Genomics; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology*; D006801:Humans; D010802:Phylogeny
chemical_list: D029968:Escherichia coli Proteins