Shiga toxins and stx phages: highly diverse entities.

  title={Shiga toxins and stx phages: highly diverse entities.},
  author={Alejandra Kr{\"u}ger and Paula Mar{\'i}a Alejandra Lucchesi},
  volume={161 Pt 3},
Shiga toxins are the main virulence factors of a group of Escherichia coli strains [Shiga toxin-producing E. coli (STEC)] that cause severe human diseases, such as haemorrhagic colitis and haemolytic-uraemic syndrome. The Shiga toxin family comprises several toxin subtypes, which have been differentially related to clinical manifestations. In addition, the phages that carry the Shiga toxin genes (stx phages) are also diverse. These phages play an important role not only in the dissemination of… 

Tables from this paper

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

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.

Escherichia coli strains producing a novel Shiga toxin 2 subtype circulate in China.

Comparable stx2a expression and phage production levels between Shiga toxin‐producing Escherichia coli strains from human and bovine origin

Evaluated STEC strains with serotypes O26:H11, O91:H21, O145:H‐ (11) and O157:H7, finding a higher stx2a expression in response to mitomycin C in strains isolated from cattle than in those from humans, suggests a higher increase in phage production under induced conditions.

Approaches to treatment of emerging Shiga toxin-producing Escherichia coli infections highlighting the O104:H4 serotype

STEC pathogenicity is highly reliant on the production of one or more Shiga toxins that can inhibit protein synthesis in host cells resulting in a cytotoxicity that may affect various organ systems.

Characterization of Shiga Toxin 2a Encoding Bacteriophages Isolated From High-Virulent O145:H25 Shiga Toxin-Producing Escherichia coli

Phage characteristics associated with high virulence are described and a conserved Stx2a phage among the Norwegian O145:H25 STEC that shared integration site with a shadow phage in all isolates is identified.

Replication Region Analysis Reveals Non-lambdoid Shiga Toxin Converting Bacteriophages

It is shown that Eru1-phages exhibit a less stable lysogenic state than the classical lambdoid Stx phages, which could be used to develop a novel strategy to identify highly virulent EHEC strains for improved risk assessment and management.

Biological and molecular characterization of six Shiga toxin-producing Escherichia coli (STEC) strains encoding the stx2 gene in Colombia

Shiga toxin-producing Escherichia coli (STEC) is a bacterial pathogen that cause diarrhea and severe human diseases. Its principal virulence factor are the Shiga toxins Stx1 and Stx2 which have been

Bacteriophages of Shiga Toxin-Producing Escherichia coli and Their Contribution to Pathogenicity

This work aims to highlight the new insights on the contribution of Stx phages and other STEC phages to pathogenicity.

Pathogenomes and variations in Shiga toxin production among geographically distinct clones of Escherichia coli O113:H21

It is suggested that ST-820 strains may confer an increased pathogenic potential in line with the strain-associated epidemiological metadata, and some of the tested ST-223 cultures sourced from contaminated produce or the bovine reservoir also produced Stx at levels comparable to those of ST- 820 isolates, which calls for awareness and for continued surveillance of this lineage.



Cumulative effect of prophage burden on Shiga toxin production in Escherichia coli.

Investigation of expression profiles of single and double isogenic lysogens of Stx phage 24(B) using quantitative PCR to examine transcription levels, and a reporter gene construct as a proxy for the translation levels of stx transcripts demonstrate that the phenomenon of multiple lysogeny in STEC has the potential to impact upon disease pathology through increased toxin load.

Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

The results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used, and could only observe transient lysogens suggesting that the event of stable stx1-phage acquisition occurs rarely.

Comparative genomics of Shiga toxin encoding bacteriophages

The data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stxphage variants and the subsequent dissemination of shigatoxigenic potential.

Diversity and Host Range of Shiga Toxin-Encoding Phage

Examination of cross-plaquing and lysogeny profiles further substantiated that each phage is distinct; reciprocal patterns of susceptibility and resistance were not observed and it was not possible to define immunity groups.

Nonpathogenic Escherichia coli Can Contribute to the Production of Shiga Toxin

The hypothesis that nonpathogenic E. coli could amplify Stx2 production if infected with the toxin-encoding phage is investigated to suggest the susceptibility of the intestinal flora to the Shiga toxin phage could exert either a protective or an antagonistic influence on the severity of disease by pathogens with phage-encoded Shiga toxins.

Multilocus Characterization Scheme for Shiga Toxin-Encoding Bacteriophages

The design and validation of a PCR-based multilocus typing scheme is reported, designed for database variants of a range of key lambdoid bacteriophage genes, to enable robust and realistically applicable epidemiological studies of Stx phages and their traits.

Comparative Genomics and stx Phage Characterization of LEE-Negative Shiga Toxin-Producing Escherichia coli

A first significant foray into the genome space of this unexplored group of emerging and divergent pathogens is made by comparing the genomes of nine LEE-negative STEC harboring various stx alleles with four complete reference L EE-positive STEC isolates.

Sequence of Shiga Toxin 2 Phage 933W fromEscherichia coli O157:H7: Shiga Toxin as a Phage Late-Gene Product

Evidence is found that the toxin genes are part of a late-phage transcript, suggesting that toxin production may be coupled with, if not dependent upon, phage release during lytic growth, and three novel tRNA genes present in the phage genome may serve to increase the availability of rare tRNA species associated with efficient expression of pathogenicity determinants.

Different Classes of Antibiotics Differentially Influence Shiga Toxin Production

To understand how antibiotics influence Stx production, Stx lysogens were treated with different classes of antibiotics in the presence or absence of phage-sensitive E. coli, and Stx-mediated inhibition of protein synthesis was monitored using luciferase-expressing Vero cells.

Isogenic Lysogens of Diverse Shiga Toxin 2-Encoding Bacteriophages Produce Markedly Different Amounts of Shiga Toxin

The results suggest that the genotype of the Stx2 prophage can influence the level of phage release and toxin expression by host strains and thus may be relevant to STEC pathogenesis.