scholarly journals Prevalence and characterization of Shiga toxin O157 and non-O157 enterohemorrhagic Escherichia coli isolated from different sources in Ismailia, Egypt

2013 ◽  
Vol 7 (21) ◽  
pp. 2637-2645 ◽  
Author(s):  
M EL Alfy Sahar ◽  
F Ahmed Salwa ◽  
A Selim Samy ◽  
H Abdel Aziz Mohamed ◽  
M Zakaria Amira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Enterohemorrhagic Escherichia Coli ◽  
Different Sources

Characterization of enterohemorrhagicEscherichia coliO157:H7 00B015: a Shiga toxin producing but virulence-attenuated isolate

2010 ◽  
Vol 56 (8) ◽  
pp. 651-656 ◽  
Author(s):  
Haiguang Wang ◽  
Jiang Gu ◽  
Shu Yu ◽  
Weijun Zhang ◽  
Yefei Zhu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Actin Polymerization ◽  
Enterohemorrhagic Escherichia Coli ◽  
Wide Range ◽  
Attenuated Isolate

Enterohemorrhagic Escherichia coli (EHEC) causes a wide range of systematic diseases in human and animals in 2 main ways: (1) production of Shiga toxin (Stx) and (2) induction of actin polymerization characterized by attaching and effacing (A/E) lesions. Stx is commonly targeted in the development of drugs and vaccines to control EHEC infection for its indispensible contribution to EHEC pathogenisis. In this study, we isolated a Stx-producing EHEC O157:H7 isolate 00B015 and found that its ability to induce actin polymerization was impaired. In addition, it reduces pathogenicity and decreases mortality in mice. Our results report a Stx-producing but virulence-attenuated EHEC isolate 00B015 and suggest that the formation of actin polymerization may help Stx-induced pathogenesis and have a more important contribution in EHEC infections.

scholarly journals Shiga Toxin (Stx)-Binding Glycosphingolipids of Primary Human Renal Cortical Epithelial Cells (pHRCEpiCs) and Stx-Mediated Cytotoxicity

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 139
Author(s):  
Johanna Detzner ◽  
Elisabeth Krojnewski ◽  
Gottfried Pohlentz ◽  
Daniel Steil ◽  
Hans-Ulrich Humpf ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Epithelial Cells ◽  
Shiga Toxin ◽  
Saturated Fatty Acids ◽  
Human Kidney ◽  
Enterohemorrhagic Escherichia Coli ◽  
Highly Sensitive ◽  
Liquid Ordered ◽  
Uremic Syndrome

Human kidney epithelial cells are supposed to be directly involved in the pathogenesis of the hemolytic–uremic syndrome (HUS) caused by Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli (EHEC). The characterization of the major and minor Stx-binding glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer), respectively, of primary human renal cortical epithelial cells (pHRCEpiCs) revealed GSLs with Cer (d18:1, C16:0), Cer (d18:1, C22:0), and Cer (d18:1, C24:1/C24:0) as the dominant lipoforms. Using detergent-resistant membranes (DRMs) and non-DRMs, Gb3Cer and Gb4Cer prevailed in the DRM fractions, suggesting their association with microdomains in the liquid-ordered membrane phase. A preference of Gb3Cer and Gb4Cer endowed with C24:0 fatty acid accompanied by minor monounsaturated C24:1-harboring counterparts was observed in DRMs, whereas the C24:1 fatty acid increased in relation to the saturated equivalents in non-DRMs. A shift of the dominant phospholipid phosphatidylcholine with saturated fatty acids in the DRM to unsaturated species in the non-DRM fractions correlated with the GSL distribution. Cytotoxicity assays gave a moderate susceptibility of pHRCEpiCs to the Stx1a and Stx2a subtypes when compared to highly sensitive Vero-B4 cells. The results indicate that presence of Stx-binding GSLs per se and preferred occurrence in microdomains do not necessarily lead to a high cellular susceptibility towards Stx.

scholarly journals Whole-genome characterization of hemolytic uremic syndrome-causing Shiga toxin-producing Escherichia coli in Sweden

Virulence ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 1296-1305
Author(s):  
Ying Hua ◽  
Milan Chromek ◽  
Anne Frykman ◽  
Cecilia Jernberg ◽  
Valya Georgieva ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Whole Genome ◽  
Genome Characterization ◽  
Uremic Syndrome

Enterohemorrhagic Escherichia coli Colony Check Assay for the Identification of Serogroups O26, O45, O103, O111, O121, O145, and O157 Colonies Isolated on Plating Media

2014 ◽  
Vol 77 (7) ◽  
pp. 1212-1218 ◽  
Author(s):  
BURTON BLAIS ◽  
MYLÈNE DESCHÊNES ◽  
GEORGE HUSZCZYNSKI ◽  
MARTINE GAUTHIER
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
High Throughput Screening ◽  
Enterohemorrhagic Escherichia Coli ◽  
Test Results ◽  
Bacterial Strains ◽  
Enrichment Broth ◽  
Substrate Solution ◽  
E Coli ◽  
Assay Performance

A simple immunoenzymatic enterohemorrhagic Escherichia coli (EHEC) colony check (ECC) assay was developed for the presumptive identification of priority EHEC colonies isolated on plating media from enrichment broth cultures of foods. With this approach, lipopolysaccharide extracted from a colony is spotted on the grid of a polymyxin-coated polyester cloth strip, and bound E. coli serogroup O26, O45, O103, O111, O121, O145, and O157 antigens are subsequently detected by sequential reactions with a pool of commercially available peroxidase-conjugated goat antibodies and tetramethylbenzidine substrate solution. Each strip can accommodate up to 15 colonies, and test results are available within 30 min. Assay performance was verified using colonies from a total of 73 target EHEC isolates covering the range of designated priority serogroups (all of which were reactive), 41 nontarget E. coli isolates including several nontarget Shiga toxin–producing E. coli serogroups (all unreactive), and 33 non–E. coli strains (all unreactive except two bacterial strains possessing O-antigenic structures in common with those of the priority EHEC). The ECC assay was reactive with target colonies grown on several types of selective and nonselective plating media designed for their cultivation. These results support the use of the ECC assay for high-throughput screening of colonies isolated on plating media for detecting priority EHEC strains in foods.

scholarly journals Comparative Genomics and Characterization of the Late Promoter pR’ from Shiga Toxin Prophages in Escherichia coli

Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 595 ◽  
Author(s):  
Ling Zhang ◽  
David Simpson ◽  
Lynn McMullen ◽  
Michael Gänzle
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Toxin Production ◽  
Late Promoter ◽  
Regulatory Systems ◽  
Human Illness ◽  
Late Transcription ◽  
Native Strains ◽  
Native Host

Shiga-toxin producing Escherichia coli (STEC) causes human illness ranging from mild diarrhea to death. The bacteriophage encoded stx genes are located in the late transcription region, downstream of the antiterminator Q. The transcription of the stx genes is directly under the control of the late promoter pR’, thus the sequence diversity of the region between Q and stx, here termed the pR’ region, may affect Stx toxin production. Here, we compared the gene structure of the pR’ region and the stx subtypes of nineteen STECs. The sequence alignment and phylogenetic analysis suggested that the pR’ region tends to be more heterogeneous than the promoter itself, even if the prophages harbor the same stx subtype. Furthermore, we established and validated transcriptional fusions of the pR’ region to the DsRed reporter gene using mitomycin C (MMC) induction. Finally, these constructs were transformed into native and non-native strains and examined with flow cytometry. The results showed that induction levels changed when pR’ regions were placed under different regulatory systems. Moreover, not every stx gene could be induced in its native host bacteria. In addition to the functional genes, the diversity of the pR’ region plays an important role in determining the level of toxin induction.

scholarly journals EDL933 Strains of Escherichia coli O157 can Demonstrate Genetic Diversity and Differential Adherence to Bovine Recto-Anal Junction Squamous Epithelial Cells

2021 ◽  
Vol 15 (1) ◽  
pp. 129-138
Author(s):  
Raegan S. Hoefler ◽  
Indira T. Kudva
Keyword(s):  
Escherichia Coli ◽  
Wild Type ◽  
Cell Adherence ◽  
O157 Strain ◽  
Shiga Toxins ◽  
The Us ◽  
Strain Type ◽  
Enterocyte Effacement ◽  
Different Sources

Background: Differences between Escherichia coli O157 (O157) strains are well-established with some of these strains being associated with major outbreaks in the US. EDL933 is one such O157 strain that caused a multistate outbreak in 1982 and has since been used as a prototype in various O157-related experiments. Objective: As O157 can readily acquire genetic mutations, we sought to determine if the genetic and phenotypic profiles of EDL933 strains from different sources would be consistent. Methods: We evaluated wild-type O157 strains stocked as EDL933 from three different laboratories, in the strain typing Polymorphic Amplified Typing Sequence (PATS) and the bovine rectal-anal junction squamous epithelial (RSE) cell- and HEp-2 cell- adherence assays. In addition, we also verified if Shiga toxins (Stx), the Locus of Enterocyte Effacement (LEE) or curli fimbriae contributed to the adherence phenotypes observed using mutant and wild-type EDL933 isolates. Results: Our results showed differences in PATS profiles and RSE cell-adherence phenotype, with no influence from the Stx or LEE genes, between EDL933 from different sources. Interestingly, the EDL933 strain that demonstrated the most contrasting diffuse adherence phenotype on RSE cells, EDL933-T, had decreased curli production that may have contributed to this phenotype. Conclusion: Our observations suggest that a comprehensive characterization of bacterial isolates, even if assigned to the same strain type prior to use in experiments, is warranted to ensure consistency and reproducibility of results.

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