Modeling gene associations for virulence classification of verocytotoxin-producing E. coli (VTEC) from patients and beef

Andersson, Tom; Nilsson, C.; Kjellin, Eva; Toljander, Jonas; Welinder‐Olsson, Christina; Lindmark, Hans

doi:10.4161/viru.2.1.14861

Cited by 9 publications

(8 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, stx 2a and stx 2c were detected at significantly higher frequencies among human clinical and food strains, respectively. These results supported recent epidemiological studies that demonstrated higher association between stx 2a and clinical outcome, as compared to stx 2c (Andersson et al, 2011;Beutin et al, 2007;Persson et al, 2007). In the present study, a strong correlation between stx 2a /stx 2c genotypes and LSPA-6 genotypes was observed, supporting a recent postulation that both lineage types, together with stx genotype, may be informative surrogate markers for epidemiological and evolutionary investigations (Stanton et al, 2014).…”

Section: Discussionsupporting

confidence: 81%

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

et al. 2015

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionsupporting

confidence: 81%

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

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Similar patterns were reported by recent Norwegian (18) and Japanese (26) studies. Epidemiological studies have revealed that stx 2a is more strongly associated with clinical isolates and causes more severe symptoms than stx 2c (1,4,21,36). In addition, the effective dose to inhibit protein synthesis in Vero cells has been reported to be 100 times lower for stx 2a than stx 2c , which correlated with a 50% lethality dose for mice 154 times lower than that for stx 2a (16).…”

Section: Discussionmentioning

confidence: 93%

Genetic Features Differentiating Bovine, Food, and Human Isolates of Shiga Toxin-Producing Escherichia coli O157 in The Netherlands

et al. 2012

View full text Add to dashboard Cite

The frequency of Escherichia coli O157 genotypes among bovine, food, and human clinical isolates from The Netherlands was studied. Genotyping included the lineage-specific polymorphism assay (LSPA6), the Shiga-toxin-encoding bacteriophage insertion site assay (SBI), and PCR detection and/or subtyping of virulence factors and markers [stx1, stx 2a /stx 2c , q21/Q933, tir(A255T), and rhsA(C3468G)]. LSPA6 lineage II dominated among bovine isolates (63%), followed by lineage I/II (35.6%) and lineage I (1.4%). In contrast, the majority of the human isolates were typed as lineage I/II (77.6%), followed by lineage I (14.1%) and lineage II (8.2%). Multivariate analysis revealed that the tir(A255T) SNP and the stx 2a /stx 2c gene variants were the genetic features most differentiating human from bovine isolates. Bovine and food isolates were dominated by stx 2c (86.4% and 65.5%, respectively). Among human isolates, the frequency of stx 2c was 36.5%, while the frequencies of stx 2a and stx 2a plus stx 2c were 41.2% and 22.4%, respectively. Bovine isolates showed equal distribution of tir(255A) (54.8%) and tir(255T) (45.2%), while human isolates were dominated by the tir(255T) genotype (92.9%). LSPA6 lineage I isolates were all genotype stx 2c and tir(255T), while LSPA6 lineage II was dominated by tir(255A) (86.4%) and stx 2c (90.9%). LSPA6 lineage I/II isolates were all genotype tir(255T) but showed more variation in stx 2 types. The results support the hypothesis that in The Netherlands, the genotypes primarily associated with human disease form a minor subpopulation in the bovine reservoir. Comparison with published data revealed that the distribution of LSPA6 lineages among bovine and human clinical isolates differs considerably between The Netherlands and North America. Shiga toxin-producing Escherichia coli (STEC) O157 is considered a serious pathogen due to its low infectious dose, the severe clinical symptoms (especially among children), and the potential for food-and waterborne outbreaks (7,22,35). STEC O157 can be transmitted to humans by direct contact with the ruminant reservoir or indirectly via ingestion of contaminated food or water (33). STEC O157 has several virulence genes that play a crucial role in the development of clinical symptoms. These include the Shiga toxin genes 1 and 2 (stx 1 and stx 2 ), several genes located on the chromosomal locus of enterocyte effacement (LEE), which codes for a specialized epithelium attachment system responsible for the characteristic attaching and effacing (A/E) phenotype, and (putative) virulence factors encoded on various genomic pathogenicity islands (20,25).In The Netherlands, the prevalences of STEC O157 at the herd level are on average 8% for dairy herds and 13% for veal herds (2), with seasonal peaks from 30% to 70% during the summer months (12,19). The notification rates of STEC O157 disease cases in The Netherlands (including outbreaks) for 2007, 2008, and 2009 were 0.50, 0.27, and 0.34 cases per 100,000 inhabitants per year, respectively (14). It can be cons...

show abstract

“…In this analysis, the relation of each genetic marker has been analyzed separately, without investigating the interaction effects of genes in correlation with the infection outcome. This simple approach may lead to biased estimation of the role of collective genotypes in disease pathogenesis by neglecting the confounding effects of other genetic markers (Andersson et al, 2011). Therefore, it seems justifiable that the most appropriate assessment of E. coli O157:H7 genotypes for their associations with clinical outcome should result from integration of all data generated from characterization of various genotypes (Whitworth et al, 2010).…”

Section: Resultsmentioning

confidence: 99%

“…The last category represents individuals who tested positive for E. coli O157:H7 but showed no apparent symptoms. Both HUS and BD were considered as severe symptoms of human illness (Andersson et al, 2011). Clinical data were provided by referring clinical hospitals when sending strains in the frame of the public health mission of the National Reference Centre.…”

Section: Bacterial Strains and Their Genetic Characteristicsmentioning

confidence: 99%

“…However, these studies examined the distribution of each genotype separately, without accounting for potential linkage between different genotypes (Andersson et al, 2011). Consistent with this approach, a multivariate logistic regression model was previously assigned to correlate between different strains, patient factors, and E. coli O157:H7-induced illness, and this study suggested that eae and stx 2 genes, somatic group, and increasing age are potential risk factors for BD, while presence of the stx 2 and eae genes, being a child, and having BD are potential risk factors for HUS (Ethelberg et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Model-based clustering of Escherichia coli O157:H7 genotypes and their potential association with clinical outcome in human infections

Elhadidy

Elkhatib

Piérard³

et al. 2015

Diagnostic Microbiology and Infectious Disease

View full text Add to dashboard Cite

Modeling gene associations for virulence classification of verocytotoxin-producing E. coli (VTEC) from patients and beef

Abstract: (2011) Modeling gene associations for virulence classification of verocytotoxin-producing E. coli (VTEC) from patients and beef, Virulence, 2:1, 41-53,

Cited by 9 publications

References 46 publications

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

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

Genetic Features Differentiating Bovine, Food, and Human Isolates of Shiga Toxin-Producing Escherichia coli O157 in The Netherlands

Model-based clustering of Escherichia coli O157:H7 genotypes and their potential association with clinical outcome in human infections

Contact Info

Product

Resources

About