Genetic diversity of the enterohaemolysin gene (ehxA) in non-O157 Shiga toxin-producing Escherichia coli strains in China

ABSTRACTShiga toxin-producingEscherichia colistrains of serotype O113:H21 have caused severe human diseases, but they are unusual in that they do not produce adherence factors coded by the locus of enterocyte effacement. Here, a PCR microarray was used to characterize 65 O113:H21 strains isolated from the environment, food, and clinical infections from various countries. In comparison to the pathogenic strains that were implicated in hemolytic-uremic syndrome in Australia, there were no clear differences between the pathogens and the environmental strains with respect to the 41 genetic markers tested. Furthermore, all of the strains carried only Shiga toxin subtypes associated with human infections, suggesting that the environmental strains have the potential to cause disease. Most of the O113:H21 strains were closely related and belonged in the same clonal group (ST-223), but CRISPR analysis showed a great degree of genetic diversity among the O113:H21 strains.

Download Full-text

Genetic Diversity of Non-O157 Shiga Toxin-Producing Escherichia coli Recovered From Patients in Michigan and Connecticut

Frontiers in Microbiology ◽

10.3389/fmicb.2020.00529 ◽

2020 ◽

Vol 11 ◽

Cited By ~ 2

Author(s):

Heather M. Blankenship ◽

Rebekah E. Mosci ◽

Quyen Phan ◽

John Fontana ◽

James. T. Rudrik ◽

...

Keyword(s):

Escherichia Coli ◽

Genetic Diversity ◽

Shiga Toxin

Download Full-text

Draft Genome Sequences of 12 Shiga Toxin-Producing Escherichia coli Strains Isolated from Dairy Cattle in Portugal

Microbiology Resource Announcements ◽

10.1128/mra.00790-20 ◽

2020 ◽

Vol 9 (38) ◽

Author(s):

Gregor Fiedler ◽

Andressa Ballem ◽

Erik Brinks ◽

Carina Almeida ◽

Charles M. A. P. Franz ◽

...

Keyword(s):

Escherichia Coli ◽

Genetic Diversity ◽

Dairy Cattle ◽

Shiga Toxin ◽

Draft Genome ◽

Foodborne Pathogen ◽

Genome Sequences ◽

Content Type ◽

The North ◽

Contaminated Food

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen transmitted from animals to humans through contaminated food. Cattle are the main reservoir of STEC, but their genetic diversity is still poorly characterized, especially regarding strains isolated in Portugal. We therefore present the draft genomic sequences of 12 STEC strains isolated from cattle in the north of Portugal.

Download Full-text

Shiga toxin-producing Escherichia coli strains isolated from dairy products — Genetic diversity and virulence gene profiles

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2016.04.032 ◽

2016 ◽

Vol 232 ◽

pp. 52-62 ◽

Cited By ~ 6

Author(s):

T. Douëllou ◽

S. Delannoy ◽

S. Ganet ◽

P. Mariani-Kurkdjian ◽

P. Fach ◽

...

Keyword(s):

Escherichia Coli ◽

Genetic Diversity ◽

Shiga Toxin ◽

Dairy Products ◽

Virulence Gene ◽

Gene Profiles

Download Full-text

Insights into the genome architecture and evolution of Shiga toxin encoding bacteriophages of Escherichia coli

BMC Genomics ◽

10.1186/s12864-021-07685-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Graça Pinto ◽

Marta Sampaio ◽

Oscar Dias ◽

Carina Almeida ◽

Joana Azeredo ◽

...

Keyword(s):

Escherichia Coli ◽

Genetic Diversity ◽

Shiga Toxin ◽

Genetic Material ◽

High Genetic Diversity ◽

Vast Number ◽

Coding Regions ◽

Regulatory Systems ◽

Geographical Regions ◽

Lytic System

Abstract Background A total of 179 Shiga toxin-producing Escherichia coli (STEC) complete genomes were analyzed in terms of serotypes, prophage coding regions, and stx gene variants and their distribution. We further examined the genetic diversity of Stx-converting phage genomes (Stx phages), focusing on the lysis-lysogeny decision and lytic cassettes. Results We show that most STEC isolates belong to non-O157 serotypes (73 %), regardless the sources and geographical regions. While the majority of STEC genomes contain a single stx gene (61 %), strains containing two (35 %), three (3 %) and four (1 %) stx genes were also found, being stx2 the most prevalent gene variant. Their location is exclusively found in intact prophage regions, indicating that they are phage-borne. We further demonstrate that Stx phages can be grouped into four clusters (A, B, C and D), three subclusters (A1, A2 and A3) and one singleton, based on their shared gene content. This cluster distribution is in good agreement with their predicted virion morphologies. Stx phage genomes are highly diverse with a vast number of 1,838 gene phamilies (phams) of related sequences (of which 677 are orphams i.e. unique genes) and, although having high mosaicism, they are generally organized into three major transcripts. While the mechanisms that guide lysis–lysogeny decision are complex, there is a strong selective pressure to maintain the stx genes location close to the lytic cassette composed of predicted SAR-endolysin and pin-holin lytic proteins. The evolution of STEC Stx phages seems to be strongly related to acquiring genetic material, probably from horizontal gene transfer events. Conclusions This work provides novel insights on the genetic structure of Stx phages, showing a high genetic diversity throughout the genomes, where the various lysis-lysogeny regulatory systems are in contrast with an uncommon, but conserved, lytic system always adjacent to stx genes.

Download Full-text

Greater Diversity of Shiga Toxin-Encoding Bacteriophage Insertion Sites among Escherichia coli O157:H7 Isolates from Cattle than in Those from Humans

Applied and Environmental Microbiology ◽

10.1128/aem.01035-06 ◽

2006 ◽

Vol 73 (3) ◽

pp. 671-679 ◽

Cited By ~ 86

Author(s):

Thomas E. Besser ◽

Nurmohammad Shaikh ◽

Nicholas J. Holt ◽

Phillip I. Tarr ◽

Michael E. Konkel ◽

...

Keyword(s):

Escherichia Coli ◽

Genetic Diversity ◽

Shiga Toxin ◽

Insertion Site ◽

Reservoir Host ◽

Clinical Isolates ◽

Escherichia Coli O157 ◽

Human Pathogen ◽

E Coli ◽

Insertion Sites

ABSTRACT Escherichia coli O157:H7, a zoonotic human pathogen for which domestic cattle are a reservoir host, produces a Shiga toxin(s) (Stx) encoded by bacteriophages. Chromosomal insertion sites of these bacteriophages define three principal genotypes (clusters 1 to 3) among clinical isolates of E. coli O157:H7. Stx-encoding bacteriophage insertion site genotypes of 282 clinical and 80 bovine isolates were evaluated. A total of 268 (95.0%) of the clinical isolates, but only 41 (51.3%) of the bovine isolates, belonged to cluster 1, 2, or 3 (P < 0.001). Thirteen additional genotypes were identified in isolates from both cattle and humans (four genotypes), from only cattle (seven genotypes), or from only humans (two genotypes). Two other markers previously associated with isolates from cattle or with clinical isolates showed similar associations with genotype groups within bovine isolates; the tir allele sp-1 and the Q 933W allele were under- and overrepresented, respectively, among cluster 1 to 3 genotypes. Stx-encoding bacteriophage insertion site typing demonstrated that there is broad genetic diversity of E. coli O157:H7 in the bovine reservoir and that numerous genotypes are significantly underrepresented among clinical isolates, consistent with the possibility that there is reduced virulence or transmissibility to humans of some bovine E. coli O157:H7 genotypes.

Download Full-text

Genetic diversity of the intimin gene (eae) in non-O157 Shiga toxin-producing Escherichia coli strains in China

Scientific Reports ◽

10.1038/s41598-020-60225-w ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Xi Yang ◽

Hui Sun ◽

Ruyue Fan ◽

Shanshan Fu ◽

Ji Zhang ◽

...

Keyword(s):

Public Health ◽

Escherichia Coli ◽

Genetic Diversity ◽

Shiga Toxin ◽

Great Risk ◽

Critical Role ◽

Foodborne Pathogen ◽

Different Sources

AbstractShiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen. The increasing incidence of non-O157 STEC has posed a great risk to public health. Besides the Shiga toxin (Stx), the adherence factor, intimin, coded by eae gene plays a critical role in STEC pathogenesis. In this study, we investigated the prevalence and polymorphisms of eae gene in non-O157 STEC strains isolated from different sources in China. Among 735 non-O157 STEC strains, eae was present in 70 (9.5%) strains. Eighteen different eae genotypes were identified in 62 eae-positive STEC strains with the nucleotide identities ranging from 86.01% to 99.97%. Among which, seven genotypes were newly identified in this study. The eighteen eae genotypes can be categorized into five eae subtypes, namely β1, γ1, ε1, ζ3 and θ. Associations between eae subtypes/genotypes and serotypes as well as origins of strains were observed in this study. Strains belonging to serotypes O26:H11, O103:H2, O111:H8 are associated with particular eae subtypes, i.e., β1, ε1, θ, respectively. Most strains from diarrheal patients (7/9, 77.8%) carried eae-β1 subtype, while most isolates from cattle (23/26, 88.5%) carried eae-ζ3 subtype. This study demonstrated a genetic diversity of eae gene in non-O157 STEC strains from different sources in China.

Download Full-text