Shiga Toxin Subtypes and Virulence Genes in &lt;i&gt;Escherichia coli&lt;/i&gt; Isolated from Cattle

Akiyama, Yumi; Futai, Hiroko; Saito, Etsuko; Ogita, Kenichi; Sakae, Hiroshi; Fukunaga, Masaharu; Tsuji, Hidetaka; Chikahira, Masatsugu; Iguchi, Atsushi

doi:10.7883/yoken.jjid.2016.100

Cited by 16 publications

(11 citation statements)

References 30 publications

(40 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Furthermore, the identification of adhesion factors, which are present in addition to or alternatively to the LEE, were of great interest. Here, especially iha and saa , and less often sab , were targets for screening [ 26 , 87 , 88 ].…”

Section: Toxins Of Lee-negative Stecmentioning

confidence: 99%

See 1 more Smart Citation

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Krause

Barth

Schmidt

2018

Toxins

View full text Add to dashboard Cite

Studies on Shiga toxin-producing Escherichia coli (STEC) typically examine and classify the virulence gene profiles based on genomic analyses. Among the screened strains, a subgroup of STEC which lacks the locus of enterocyte effacement (LEE) has frequently been identified. This raises the question about the level of pathogenicity of such strains. This review focuses on the advantages and disadvantages of the standard screening procedures in virulence profiling and summarizes the current knowledge concerning the function and regulation of toxins encoded by LEE-negative STEC. Although LEE-negative STEC usually come across as food isolates, which rarely cause infections in humans, some serotypes have been implicated in human diseases. In particular, the LEE-negative E. coli O104:H4 German outbreak strain from 2011 and the Australian O113:H21 strain isolated from a HUS patient attracted attention. Moreover, the LEE-negative STEC O113:H21 strain TS18/08 that was isolated from minced meat is remarkable in that it not only encodes multiple toxins, but in fact expresses three different toxins simultaneously. Their characterization contributes to understanding the virulence of the LEE-negative STEC.

show abstract

Section: Toxins Of Lee-negative Stecmentioning

confidence: 99%

“…A schematic overview of the transport and target sites of Stx, SubAB, Cdt, and EHEC-Hly are presented in Figure 1 . These toxins are frequently found in LEE-negative STEC and sparked great interest to understand their potential virulence [ 23 , 85 , 87 , 88 , 89 ].…”

Section: Toxins Of Lee-negative Stecmentioning

confidence: 99%

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Krause

Barth

Schmidt

2018

Toxins

View full text Add to dashboard Cite

show abstract

“…It is important to note that STEC strains producing different Stx2 subtypes can be associated with different animal reservoirs. The E. coli strains producing Stx2a, Stx2c and to a lesser extent Stx2d, are mainly isolated from the bovine reservoir (Januszkiewicz and Rastawicki, 2016;Akiyama et al, 2017;Jajarmi et al, 2017;Tostes et al, 2017;Cha et al, 2018;Rahman et al, 2018;Dehdashti et al, 2019). Other subtypes, such as the Stx2b and Stx2g, can be also found in STEC isolated from ruminants but with a lower prevalence (Januszkiewicz and Rastawicki, 2016;Akiyama et al, 2017;Jajarmi et al, 2017;Dehdashti et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Evolution of Shiga Toxin-Converting Phages Based on Whole Genome Sequencing

et al. 2020

View full text Add to dashboard Cite

Bacteriophages are pivotal elements in the dissemination of virulence genes. The main virulence determinants of Shiga Toxin producing E. coli, Shiga Toxins (Stx), are encoded by genes localized in the genome of lambdoid bacteriophages. Stx comprise two antigenically different types, Stx1 and Stx2, further divided into subtypes. Among these, certain Stx2 subtypes appear to be more commonly occurring in the most severe forms of the STEC disease, haemorrhagic colitis and haemolytic uremic syndrome (HUS). This study aimed at obtaining insights on the evolution of Stx2 bacteriophages, due to their relevance in public health, and we report here on the analysis of the genomic structure of Stx2 converting phages in relation with the known reservoir of the E. coli strains harboring them. Stx2-converting phages conveying the genes encoding different stx2 subtypes have been isolated from STEC strains and their whole genomes have been sequenced, analyzed and compared to those of other Stx2 phages available in the public domain. The phages' regions containing the stx2 genes have been analyzed in depth allowing to make inference on the possible mechanisms of selection and maintenance of certain Stx2 phages in the reservoir. The "stx regions" of different stx2 gene subtypes grouped into three different evolutionary lines in the comparative analysis, reflecting the frequency with which these subtypes are found in different animal niches, suggesting that the colonization of specific reservoir by STEC strains could be influenced by the Stx phage that they carry. Noteworthy, we could identify the presence of nanS-p gene exclusively in the "stx regions" of the phages identified in STEC strains commonly found in cattle. As a matter of fact, this gene encodes an esterase capable of metabolizing sialic acids produced by submaxillary glands of bovines and present in great quantities in their gastrointestinal tract.

show abstract

“…elegans is likely to be protective in mammals because they suppress the expression of bacterial virulence genes and shiga toxin at high concentrations [ 40 ]. Moreover, our findings suggest that STEC strains possessing the toxin-producing gene [ 41 – 42 ] reduce the life span of C . elegans ( Fig 3 ).…”

Section: Discussionmentioning

confidence: 91%

In vivo screening platform for shiga toxin-producing Escherichia coli (STEC) using Caenorhabditis elegans as a model

et al. 2018

View full text Add to dashboard Cite

Shiga toxin-producing Escherichia coli (STEC) strains are the main cause of bacillary dysentery, although STEC strains generally induce milder disease symptoms compared to Shigella species. This study aimed to determine the virulence of STEC using the nematode Caenorhabditis elegans as a model host. Worm killing, fertility and bacterial colonisation assays were performed to examine the potential difference in the virulence of STEC strains compared to that of the control E. coli OP50 strains on which worms were fed. A statistically significant difference in the survival rates of C. elegans was observed in that the STEC strains caused death in 8–10 days and the E. coli OP50 strains caused death in 15 days. STEC strains severely reduced the fertility of the worms. The intestinal load of bacteria in the adult stage nematodes harbouring the E. coli OP50 strains was found to be 3.5 log CFU mL-1. In contrast, the STEC strains E15, E18 and E22 harboured 4.1, 4.2 and 4.7 log CFU ml−1 per nematode, respectively. The heat-killed STEC strains significantly increased the longevity of the worms compared to the non-heated STEC strains. In addition, PCR-based genomic profiling of shiga toxin genes, viz., stx1 and stx2, identified in selected STEC strains revealed that these toxins may be associated with the virulence of the STEC strains. This study demonstrated that C. elegans is an effective model to examine and compare the pathogenicity and virulence variation of STEC strains to that of E. coli OP50 strains.

show abstract

Shiga Toxin Subtypes and Virulence Genes in <i>Escherichia coli</i> Isolated from Cattle

Cited by 16 publications

References 30 publications

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Toxins of Locus of Enterocyte Effacement-Negative Shiga Toxin-Producing Escherichia coli

Investigation on the Evolution of Shiga Toxin-Converting Phages Based on Whole Genome Sequencing

In vivo screening platform for shiga toxin-producing Escherichia coli (STEC) using Caenorhabditis elegans as a model

Contact Info

Product

Resources

About