title: Population structure of the Yersinia pseudotuberculosis complex according to multilocus sequence typing.
abstract: Multilocus sequence analysis of 417 strains of Yersinia pseudotuberculosis revealed that it is a complex of four populations, three of which have been previously assigned species status [Y. pseudotuberculosis sensu stricto (s.s.), Yersinia pestis and Yersinia similis] and a fourth population, which we refer to as the Korean group, which may be in the process of speciation. We detected clear signs of recombination within Y. pseudotuberculosis s.s. as well as imports from Y. similis and the Korean group. The sources of genetic diversification within Y. pseudotuberculosis s.s. were approximately equally divided between recombination and mutation, whereas recombination has not yet been demonstrated in Y. pestis, which is also much more genetically monomorphic than is Y. pseudotuberculosis s.s. Most Y. pseudotuberculosis s.s. belong to a diffuse group of sequence types lacking clear population structure, although this species contains a melibiose-negative clade that is present globally in domesticated animals. Yersinia  similis corresponds to the previously identified Y. pseudotuberculosis genetic type G4, which is probably not pathogenic because it lacks the virulence factors that are typical for Y. pseudotuberculosis s.s. In contrast, Y. pseudotuberculosis s.s., the Korean group and Y. pestis can all cause disease in humans.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, P.O. Box 66, FI-00014, University of Helsinki, Finland.
authors.forename: Riikka
authors.initials: R
authors.lastname: Laukkanen-Ninios
authors.forename: Xavier
authors.initials: X
authors.lastname: Didelot
authors.forename: Keith A
authors.initials: KA
authors.lastname: Jolley
authors.forename: Giovanna
authors.initials: G
authors.lastname: Morelli
authors.forename: Vartul
authors.initials: V
authors.lastname: Sangal
authors.forename: Paula
authors.initials: P
authors.lastname: Kristo
authors.forename: Carina
authors.initials: C
authors.lastname: Brehony
authors.forename: Priscilla F M
authors.initials: PF
authors.lastname: Imori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fukushima
authors.forename: Anja
authors.initials: A
authors.lastname: Siitonen
authors.forename: Galina
authors.initials: G
authors.lastname: Tseneva
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Voskressenskaya
authors.forename: Juliana P
authors.initials: JP
authors.lastname: Falcao
authors.forename: Hannu
authors.initials: H
authors.lastname: Korkeala
authors.forename: Martin C J
authors.initials: MC
authors.lastname: Maiden
authors.forename: Camila
authors.initials: C
authors.lastname: Mazzoni
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Carniel
authors.forename: Mikael
authors.initials: M
authors.lastname: Skurnik
authors.forename: Mark
authors.initials: M
authors.lastname: Achtman
mesh_terms: D000818:Animals; D004269:DNA, Bacterial / Q000235:genetics; D014644:Genetic Variation; D005828:Genetics, Population; D006801:Humans; D058885:Multilocus Sequence Typing; D009154:Mutation; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D037521:Virulence Factors / Q000235:genetics; D015010:Yersinia pestis / Q000145:classification* / Q000235:genetics; D015011:Yersinia pseudotuberculosis / Q000145:classification* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D037521:Virulence Factors