title: Whole Genome Sequencing demonstrates that Geographic Variation of Escherichia coli O157 Genotypes Dominates Host Association.
abstract: Genetic variation in an infectious disease pathogen can be driven by ecological niche dissimilarities arising from different host species and different geographical locations. Whole genome sequencing was used to compare E. coli O157 isolates from host reservoirs (cattle and sheep) from Scotland and to compare genetic variation of isolates (human, animal, environmental/food) obtained from Scotland, New Zealand, Netherlands, Canada and the USA. Nei's genetic distance calculated from core genome single nucleotide polymorphisms (SNPs) demonstrated that the animal isolates were from the same population. Investigation of the Shiga toxin bacteriophage and their insertion sites (SBI typing) revealed that cattle and sheep isolates had statistically indistinguishable rarefaction profiles, diversity and genotypes. In contrast, isolates from different countries exhibited significant differences in Nei's genetic distance and SBI typing. Hence, after successful international transmission, which has occurred on multiple occasions, local genetic variation occurs, resulting in a global patchwork of continental and trans-continental phylogeographic clades. These findings are important for three reasons: first, understanding transmission and evolution of infectious diseases associated with multiple host reservoirs and multi-geographic locations; second, highlighting the relevance of the sheep reservoir when considering farm based interventions; and third, improving our understanding of why human disease incidence varies across the world.
authors.affiliation: School of Biological Sciences, The University of Aberdeen, Cruickshank Building. St Machar Drive, Aberdeen, Scotland, United Kingdom, AB24 3UU.
authors.forename: Norval J C
authors.initials: NJ
authors.lastname: Strachan
authors.affiliation: School of Biological Sciences, The University of Aberdeen, Cruickshank Building. St Machar Drive, Aberdeen, Scotland, United Kingdom, AB24 3UU.
authors.forename: Ovidiu
authors.initials: O
authors.lastname: Rotariu
authors.affiliation: School of Medicine and Dentistry, The University of Aberdeen, Foresterhill, Aberdeen, Scotland, United Kingdom, AB25 2ZD.
authors.forename: Bruno
authors.initials: B
authors.lastname: Lopes
authors.affiliation: School of Medicine and Dentistry, The University of Aberdeen, Foresterhill, Aberdeen, Scotland, United Kingdom, AB25 2ZD.
authors.forename: Marion
authors.initials: M
authors.lastname: MacRae
authors.affiliation: Centre for Genome Enabled Biology, 23 St Machar Drive, Aberdeen, Scotland, United Kingdom, AB24 3UU.
authors.forename: Susan
authors.initials: S
authors.lastname: Fairley
authors.affiliation: Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, 225089 Township Road 9-1 (Box 640), Lethbridge, Alberta, Canada, T1J 3Z4.
authors.forename: Chad
authors.initials: C
authors.lastname: Laing
authors.affiliation: Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, 225089 Township Road 9-1 (Box 640), Lethbridge, Alberta, Canada, T1J 3Z4.
authors.forename: Victor
authors.initials: V
authors.lastname: Gannon
authors.affiliation: Scottish E. coli O157/VTEC Reference Laboratory, NHS Lothian, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh, Scotland, United Kingdom, EH16 4SA.
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Allison
authors.affiliation: Scottish E. coli O157/VTEC Reference Laboratory, NHS Lothian, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh, Scotland, United Kingdom, EH16 4SA.
authors.forename: Mary F
authors.initials: MF
authors.lastname: Hanson
authors.affiliation: Public Health England, 61 Colindale Avenue, London, United Kingdom, NW9 5EQ.
authors.forename: Tim
authors.initials: T
authors.lastname: Dallman
authors.affiliation: Public Health England, 61 Colindale Avenue, London, United Kingdom, NW9 5EQ.
authors.forename: Philip
authors.initials: P
authors.lastname: Ashton
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Infectious Disease Control (CIb), P.O. Box 1, 3720 BA Bilthoven, the Netherlands.
authors.forename: Eelco
authors.initials: E
authors.lastname: Franz
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Centre for Infectious Disease Control (CIb), P.O. Box 1, 3720 BA Bilthoven, the Netherlands.
authors.forename: Angela H A M
authors.initials: AH
authors.lastname: van Hoek
authors.affiliation: mEpiLab, Infectious Disease Research Centre, Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: Nigel P
authors.initials: NP
authors.lastname: French
authors.affiliation: mEpiLab, Infectious Disease Research Centre, Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: Tessy
authors.initials: T
authors.lastname: George
authors.affiliation: mEpiLab, Infectious Disease Research Centre, Institute of Veterinary Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Biggs
authors.affiliation: School of Medicine and Dentistry, The University of Aberdeen, Foresterhill, Aberdeen, Scotland, United Kingdom, AB25 2ZD.
authors.forename: Ken J
authors.initials: KJ
authors.lastname: Forbes
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000235:genetics*; D002417:Cattle; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000235:genetics* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification*; D014644:Genetic Variation; D016678:Genome; D059014:High-Throughput Nucleotide Sequencing; D054884:Host-Pathogen Interactions / Q000235:genetics*; D006801:Humans; D009520:New Zealand / Q000453:epidemiology; D058974:Phylogeography; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012756:Sheep