Host response to the subtilase cytotoxin produced by locus of enterocyte effacement‐negative Shiga‐toxigenic Escherichia coli

2020 ◽  
Vol 64 (10) ◽  
pp. 657-665
Author(s):  
Hiroyasu Tsutsuki ◽  
Kohei Ogura ◽  
Joel Moss ◽  
Kinnosuke Yahiro
Keyword(s):  
Escherichia Coli ◽  
Host Response ◽  
Enterocyte Effacement ◽  
Subtilase Cytotoxin

scholarly journals Subtilase cytotoxin produced by locus of enterocyte effacement‐negative Shiga‐toxigenic Escherichia coli induces stress granule formation

2016 ◽  
Vol 18 (7) ◽  
pp. 1024-1040 ◽  
Author(s):  
Hiroyasu Tsutsuki ◽  
Kinnosuke Yahiro ◽  
Kohei Ogura ◽  
Kimitoshi Ichimura ◽  
Sunao Iyoda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stress Granule ◽  
Granule Formation ◽  
Enterocyte Effacement ◽  
Subtilase Cytotoxin

Subtilase Cytotoxin from Shiga-Toxigenic Escherichia Coli Impairs the Inflammasome and Exacerbates Enteropathogenic Bacterial Infection

2021 ◽  
Author(s):  
Hiroyasu Tsutsuki ◽  
Tianli Zhang ◽  
Kinnosuke Yahiro ◽  
Katsuhiko Ono ◽  
Yukio Fujiwara ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infection ◽  
Subtilase Cytotoxin

scholarly journals Cytotoxic and Apoptotic Effects of Recombinant Subtilase Cytotoxin Variants of Shiga Toxin-Producing Escherichia coli

2015 ◽  
Vol 83 (6) ◽  
pp. 2338-2349 ◽  
Author(s):  
J. Funk ◽  
N. Biber ◽  
M. Schneider ◽  
E. Hauser ◽  
S. Enzenmüller ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Vero Cells ◽  
Toxic Activity ◽  
Content Type ◽  
B Subunits ◽  
Induced Apoptosis ◽  
The Individual ◽  
Apoptotic Effects ◽  
Subtilase Cytotoxin

In this study, the cytotoxicity of the recently described subtilase variant SubAB2-2of Shiga toxin-producingEscherichia coliwas determined and compared to the plasmid-encoded SubAB1and the chromosome-encoded SubAB2-1variant. The genes for the respective enzymatic active (A) subunits and binding (B) subunits of the subtilase toxins were amplified and cloned. The recombinant toxin subunits were expressed and purified. Their cytotoxicity on Vero cells was measured for the single A and B subunits, as well as for mixtures of both, to analyze whether hybrids with toxic activity can be identified. The results demonstrated that all three SubAB variants are toxic for Vero cells. However, the values for the 50% cytotoxic dose (CD50) differ for the individual variants. Highest cytotoxicity was shown for SubAB1. Moreover, hybrids of subunits from different subtilase toxins can be obtained which cause substantial cytotoxicity to Vero cells after mixing the A and B subunits prior to application to the cells, which is characteristic for binary toxins. Furthermore, higher concentrations of the enzymatic subunit SubA1exhibited cytotoxic effects in the absence of the respective B1subunit. A more detailed investigation in the human HeLa cell line revealed that SubA1alone induced apoptosis, while the B1subunit alone did not induce cell death.

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.

scholarly journals Subtilase Cytotoxin-Coding Genes in Verotoxin-Producing Escherichia coli Strains from Sheep and Goats Differ from Those from Cattle

2011 ◽  
Vol 77 (23) ◽  
pp. 8259-8264 ◽  
Author(s):  
José A. Orden ◽  
Pilar Horcajo ◽  
Ricardo de la Fuente ◽  
José A. Ruiz-Santa-Quiteria ◽  
Gustavo Domínguez-Bernal ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Human Disease ◽  
Virulence Genes ◽  
Small Ruminants ◽  
Human Beings ◽  
Content Type ◽  
Sheep And Goats ◽  
E Coli ◽  
Healthy Cattle ◽  
Subtilase Cytotoxin

ABSTRACTSubtilase cytotoxin (SubAB) from verotoxin (VT)-producingEscherichia coli(VTEC) strains was first described in the 98NK2 strain and has been associated with human disease. However, SubAB has recently been found in two VT-negativeE. colistrains (ED 591 and ED 32). SubAB is encoded by two closely linked, cotranscribed genes (subAandsubB). In this study, we investigated the presence ofsubABgenes in 52 VTEC strains isolated from cattle and 209 strains from small ruminants, using PCR. Most (91.9%) VTEC strains from sheep and goats and 25% of the strains from healthy cattle possessedsubABgenes. The presence ofsubABin a high percentage of the VTEC strains from small ruminants might increase the pathogenicity of these strains for human beings. Some differences in the results of PCRs and in the association with some virulence genes suggested the existence of different variants ofsubAB. We therefore sequenced thesubAgene in 12 strains and showed that thesubAgene in most of thesubAB-positive VTEC strains from cattle was almost identical (about 99%) to that in the 98NK2 strain, while thesubAgene in most of thesubAB-positive VTEC strains from small ruminants was almost identical to that in the ED 591 strain. We propose the termssubAB1to describe the SubAB-coding genes resembling that in the 98NK2 strain andsubAB2to describe those resembling that in the ED 591 strain.

Outbreak of Shiga Toxin–Producing Escherichia coli (STEC) O104:H4 Infection in Germany Causes a Paradigm Shift with Regard to Human Pathogenicity of STEC Strains

2012 ◽  
Vol 75 (2) ◽  
pp. 408-418 ◽  
Author(s):  
LOTHAR BEUTIN ◽  
ANNETT MARTIN
Keyword(s):  
Escherichia Coli ◽  
Hemolytic Uremic Syndrome ◽  
Shiga Toxin ◽  
Outbreak Strain ◽  
Fenugreek Seeds ◽  
E Coli ◽  
Aggregative Adherence ◽  
Uremic Syndrome ◽  
Enterocyte Effacement ◽  
The Way

An outbreak that comprised 3,842 cases of human infections with enteroaggregative hemorrhagic Escherichia coli (EAHEC) O104:H4 occurred in Germany in May 2011. The high proportion of adults affected in this outbreak and the unusually high number of patients that developed hemolytic uremic syndrome makes this outbreak the most dramatic since enterohemorrhagic E. coli (EHEC) strains were first identified as agents of human disease. The characteristics of the outbreak strain, the way it spread among humans, and the clinical signs resulting from EAHEC infections have changed the way Shiga toxin–producing E. coli strains are regarded as human pathogens in general. EAHEC O104:H4 is an emerging E. coli pathotype that is endemic in Central Africa and has spread to Europe and Asia. EAHEC strains have evolved from enteroaggregative E. coli by uptake of a Shiga toxin 2a (Stx2a)–encoding bacteriophage. Except for Stx2a, no other EHEC-specific virulence markers including the locus of enterocyte effacement are present in EAHEC strains. EAHEC O104:H4 colonizes humans through aggregative adherence fimbrial pili encoded by the enteroaggregative E. coli plasmid. The aggregative adherence fimbrial colonization mechanism substitutes for the locus of enterocyte effacement functions for bacterial adherence and delivery of Stx2a into the human intestine, resulting clinically in hemolytic uremic syndrome. Humans are the only known natural reservoir known for EAHEC. In contrast, Shiga toxin–producing E. coli and EHEC are associated with animals as natural hosts. Contaminated sprouted fenugreek seeds were suspected as the primary vehicle of transmission of the EAHEC O104:H4 outbreak strain in Germany. During the outbreak, secondary transmission (human to human and human to food) was important. Epidemiological investigations revealed fenugreek seeds as the source of entry of EAHEC O104:H4 into the food chain; however, microbiological analysis of seeds for this pathogen produced negative results. The survival of EAHEC in seeds and the frequency of human carriers of EAHEC should be investigated for a better understanding of EAHEC transmission routes.

scholarly journals Mutational Analysis of the Locus of Enterocyte Effacement-Encoded Regulator (Ler) of Enteropathogenic Escherichia coli

2008 ◽  
Vol 190 (23) ◽  
pp. 7808-7818 ◽  
Author(s):  
Gal Yerushalmi ◽  
Chen Nadler ◽  
Tatiana Berdichevski ◽  
Ilan Rosenshine
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Mutational Analysis ◽  
Bacterial Colonization ◽  
Point Mutations ◽  
Dominant Negative ◽  
Compensatory Mechanism ◽  
Dependent Manner ◽  
Enterocyte Effacement ◽  
Related Proteins

ABSTRACT The locus of enterocyte effacement (LEE) pathogenicity island of enterohemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC, respectively) comprises a cluster of operons encoding a type III secretion system and related proteins, all of which are essential for bacterial colonization of the host intestines. The LEE1 operon encodes Ler, which positively regulates many EPEC and EHEC virulence genes located in the LEE region and elsewhere in the chromosome. In addition, Ler is a specific autorepressor of LEE1 transcription. To better understand the function of Ler, we screened for Ler mutants defective in autorepression. We isolated 18 different point mutations in Ler, rendering it defective in autorepression and in DNA binding. Among these mutants were those defective in positive regulation as well as in autorepression, dominant-negative mutants, and a mutant deficient in oligomerization. Importantly, a group of Ler autorepression mutants complemented an EPEC ler deletion mutant for transcription activation in a dosage-dependent manner, suggesting that Ler and possibly other autorepressors have an intrinsic compensatory mechanism that enables them to sustain mutations. In addition, the phenotypes of the different mutants identified by the screen define a novel domain in Ler that is required for oligomerization.

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

Toxins ◽  
2018 ◽  
Vol 10 (6) ◽  
pp. 241 ◽  
Author(s):  
Maike Krause ◽  
Holger Barth ◽  
Herbert Schmidt
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Enterocyte Effacement
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