Biased distribution of IS629 among strains in different lineages of enterohemorrhagic Escherichia coli serovar O157

Yokoyama, Eiji; Hashimoto, Ruiko; Etoh, Yoshiki; Ichihara, Sachiko; Horikawa, Kazumi; Uchimura, Masako

doi:10.1016/j.meegid.2010.10.007

Cited by 29 publications

(44 citation statements)

References 25 publications

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“…When IRI values were compared among stx genotypes or LSPA6 lineages, significant differences were observed in the heat and starvation stresses. Interestingly, the stx 1 stx 2 genotype and LI and LI/II strains, which showed greater resistance to these stresses, have been shown to be more frequently associated with human infection (19,43,45). This suggests that responses of STEC O157 to these two stresses play more important roles in their ecology than other stresses do.…”

Section: Discussionmentioning

confidence: 99%

“…LSPA6 lineages are associated with stx genotypes and the genetic clades defined by single nucleotide polymorphisms (SNP clades). In previous studies, LSPA6 lineage I (LI) strains were more likely to carry stx 2 than LSPA lineage II (LII) strains (19,43,45). Only limited information is available about the association between LSPA6 lineage and SNP clade; however, the hypervirulent SNP clade, clade 8, belongs to LSPA6 lineage I/II (LI/II) (12,18).…”

Section: Methodsmentioning

confidence: 99%

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Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Lee

French

Jones

et al. 2012

Appl Environ Microbiol

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ABSTRACTTo evaluate the relationship between bacterial genotypes and stress resistance patterns, we exposed 57 strains of Shiga toxin-producingEscherichia coli(STEC) O157 to acid, freeze-thaw, heat, osmotic, oxidative, and starvation stresses. Inactivation rates were calculated in each assay and subjected to univariate and multivariate analyses, including principal component analysis (PCA) and cluster analysis. Thestxgenotype was determined for each strain as was the lineage-specific polymorphism assay (LSPA6) genotype. In univariate analyses, strains of thestx1stx2genotype showed greater resistance to heat than strains of thestx1stx2cgenotype; moreover, strains of thestx1stx2genotype showed greater resistance to starvation than strains of thestx2orstx2cgenotypes. LSPA6 lineage I (LI) strains showed greater resistance to heat and starvation than LSPA6 lineage II (LII) strains. PCA revealed a general trend that a strain with greater resistance to one type of stress tended to have greater resistance to other types of stresses. In cluster analysis, STEC O157 strains were grouped into stress-resistant, stress-sensitive, and intermediate clusters. Instxgenotypes, all strains of thestx1stx2genotype were grouped with the stress-resistant cluster, whereas 72.7% (8/11) of strains of thestx1stx2cgenotype grouped with the stress-sensitive cluster. In LI strains, 77.8% (14/18) of the strains were grouped with the stress-resistant cluster, whereas 64.7% (11/17) of LII strains were grouped with the stress-sensitive cluster. These results indicate that the genotypes of STEC O157 that are frequently associated with human illness, i.e., LI or thestx1stx2genotype, have greater multiple stress resistance than do strains of other genotypes.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Lee

French

Jones

et al. 2012

Appl Environ Microbiol

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“…However, the elevated IS629 transposition frequency observed among O157:H7 strains might explain the highly diverse distribution of IS629 in the O157:H7 genomes (14) and suggests that, in addition to impacting genomic evolution, IS629 might increase pathogenicity in those strains. Additionally, it might contribute to the appearance of atypical pathogenic strains, like O rough:H7 (gne::IS629 mutant) strains (11,12).…”

Section: ϫ8mentioning

confidence: 99%

Different IS 629 Transposition Frequencies Exhibited by Escherichia coli O157:H7 Strains in the Stepwise Evolutionary Model

Rump

Fischer

González-Escalona

2011

Appl Environ Microbiol

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The insertion sequence IS629, which is highly prevalent in Escherichia coli O157:H7 genomes, was found to be absent in O157:H؊ strains, which are on a divergent pathway in the emergence of O157:H7. Although O157:H؊ is deficient in IS629, it permits IS629 transposition, with an excision frequency higher than that of ancestral O55:H7 strains but significantly lower than that of pathogenic O157:H7 strains.

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“…Molecular typing and microbial genomics have facilitated the characterization and comparison of E. coli O157 : H7 strains recovered from different isolation sources demonstrating non-random distribution of genotypes among clinical and non-clinical strains (Besser et al, 2008;Franz et al, 2012;Hartzell et al, 2011;Lee et al, 2011;Whitworth et al, 2010;Yang et al, 2004;Yokoyama et al, 2011;Zhang et al, 2010;Ziebell et al, 2008). In addition, several epidemiological studies supported the growing evidence of substantial variability in the virulence of E. coli O157 : H7 genotypes implicated in different outbreaks and variation in patient symptoms (Besser et al, 2008;Grant et al, 2008;Manning et al, 2008).…”

Section: Introductionmentioning

confidence: 97%

Genetic diversity of Shiga toxin-producing Escherichia coli O157 : H7 recovered from human and food sources

et al. 2015

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The aim of this study was to identify an epidemiological association between Shiga toxinproducing Escherichia coli O157 : H7 strains associated with human infection and with food sources. Frequency distributions of different genetic markers of E. coli O157 : H7 strains recovered from human and food sources were compared using molecular assays to identify E. coli O157 : H7 genotypes associated with variation in pathogenic potential and host specificity. Genotypic characterization included: lineage-specific polymorphism assay (LSPA-6), clade typing, tir (A255T) polymorphism, Shiga toxin-encoding bacteriophage insertion site analysis and variant analysis of Shiga toxin 2 gene (stx 2a and stx 2c ) and antiterminator Q genes (Q 933 and Q 21 ). The intermediate lineage (LI/II) dominated among both food and human strains. Compared to other clades, clades 7 and 8 were more frequent among food and human strains, respectively. The tir (255T) polymorphism occurred more frequently among human strains than food strains. Q 21 and Q 933+Q21 were found at significantly higher frequencies among food and human strains, respectively. Moreover, stx 2a and stx 2a+c were detected at significantly higher frequencies among human strains compared to food strains. Bivariate analysis revealed significant concordance (P,0.05) between the LSPA-6 assay and the other typing methods. Multivariable regression Abbreviations: HP, hairpin; HUS, haemolytic uraemic syndrome; LSPA-6, lineage-specific polymorphism assay; SBI, Shiga toxin bacteriophage insertion; STEC, Shiga toxin-producing Escherichia coli; stx 1 , Shiga toxin 1; stx 2 , Shiga toxin 2.Five supplementary tables are available with the online Supplementary Material.

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Biased distribution of IS629 among strains in different lineages of enterohemorrhagic Escherichia coli serovar O157

Cited by 29 publications

References 25 publications

Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

Different IS 629 Transposition Frequencies Exhibited by Escherichia coli O157:H7 Strains in the Stepwise Evolutionary Model

Genetic diversity of Shiga toxin-producing Escherichia coli O157 : H7 recovered from human and food sources

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