Population structure of the Yersinia pseudotuberculosis complex according to multilocus sequence typing

Abstract

SummaryMultilocus 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

Historical variations in mutation rate in an epidemic pathogen, Yersinia pestis

“…According to this interpretation, the Y. pestis genealogy is rooted by Y. pseudotuberculosis at the base of branch 0, and SNPs have accumulated serially along branch 0 and subsequently along branches 1 and 2. All Y. pestis isolates, including the genomes analyzed here, cluster within one multilocus sequence type that is embedded within the Y. pseudotuberculosis population structure (20). These observations show that Y. pestis is a genetically monomorphic clone of Y. pseudotuberculosis, which has greater diversity.…”

Molecular typing of Yersinia pseudotuberculosis strains isolated from livestock in Brazil

“…The Y. pseudotuberculosis O:1a strains isolated in Brazil were clustered in the largest population group defined by an MLST-based population structure study (Laukkanen-Ninios et al, 2011). In addition, the Y. pseudotuberculosis O:1a strains deposited in the Y. pseudotuberculosis MLST database were typed into seven STs (9, 12, 16, 42, 43, 85, and 86) and have also been isolated worldwide from human and nonhuman sources (Fredriksson-Ahomaa, 2007;Laukkanen-Ninios et al, 2011).…”

“…In a global analysis of all Y. pseudotuberculosis strains listed in the Y. pseudotuberculosis MLST database including the strains of this study, it was observed that the Y. pseudotuberculosis O:3 strains were distributed into 17 different STs (3,4,14,19,25,30,32,43,50,57,58,59,60,61,62,63,and 64). These strains were isolated globally from human and nonhuman sources and are described as having low pathogenic potential (Fukushima et al, 2001;Fredriksson-Ahomaa, 2007;Laukkanen-Ninios et al, 2011). Despite the low pathogenicity characteristic of Y. pseudotuberculosis O:3 strains isolated around the world, some Y. pseudotuberculosis O:3 strains isolated in Brazil were responsible for severe and sometimes fatal diarrhea in cattle (Warth et al, 2012).…”

“…Despite the fact that several reports regarding the genotypic diversity of Yersinia species, including Y. pseudotuberculosis strains isolated around the world have been published, the molecular epidemiology of Y. pseudotuberculosis strains isolated from livestock in Brazil remains unclear (Kim et al, 2003;Voskressenskaya et al, 2005;Martins et al, 2007;Souza et al, 2010;Ch'ng et al, 2011;Laukkanen-Ninios et al, 2011).…”

“…The MLST assay was performed using 7 housekeeping genes (adk, argA, aroA, glnA, thrA, tmk, and trpE) according to the method of Laukkanen-Ninios et al (2011). A detailed protocol for the MLST procedure, including the primers used for the amplification of the seven housekeeping genes and the annealing temperature is available in the Y. pseudotuberculosis MLST database (http://mlst.ucc.ie/mlst/dbs/Ypseudotuberculosis).…”