Sub-Lethal Dose of Shiga Toxin 2 from Enterohemorrhagic Escherichia coli Affects Balance and Cerebellar Cythoarquitecture

ABSTRACT Using colony blot hybridization with stx 2 and eae probes and agglutination in anti-O157 lipopolysaccharide serum, we isolated stx 2-positive and eae-positive sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:NM (nonmotile) strains from initial stool specimens and stx-negative and eae-positive SF E. coli O157:NM strains from follow-up specimens (collected 3 to 8 days later) from three children. The stx-negative isolates from each patient shared with the corresponding stx 2-positive isolates fliC H7, non-stx virulence traits, and multilocus sequence types, which indicates that they arose from the stx 2-positive strains by loss of stx 2 during infection. Analysis of the integrity of the yecE gene, a possible stx phage integration site in EHEC O157, in the consecutive stx 2-positive and stx-negative isolates demonstrated that yecE was occupied in stx 2-positive but intact in stx-negative strains. It was possible to infect and lysogenize the stx-negative E. coli O157 strains in vitro using an stx 2-harboring bacteriophage from one of the SF EHEC O157:NM isolates. The acquisition of the stx 2-containing phage resulted in the occupation of yecE and production of biologically active Shiga toxin 2. We conclude that the yecE gene in SF E. coli O157:NM is a hot spot for excision and integration of Shiga toxin 2-encoding bacteriophages. SF EHEC O157:NM strains and their stx-negative derivatives thus represent a highly dynamic system that can convert in both directions by the loss and gain of stx 2-harboring phages. The ability to recycle stx 2, a critical virulence trait, makes SF E. coli O157:NM strains ephemeral EHEC that can exist as stx-negative variants during certain phases of their life cycle.

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Cognitive deficits found in a pro-inflammatory state are independent of ERK 1/2 signaling in the murine brain hippocampus treated with Shiga toxin 2 from enterohemorrhagic Escherichia Coli

10.1101/2020.08.24.264929 ◽

2020 ◽

Author(s):

Clara Berdasco ◽

Alipio Pinto ◽

Mariano Blake ◽

Fernando Correa ◽

Nadia A. Longo Carbajosa ◽

...

Keyword(s):

Escherichia Coli ◽

Central Nervous System ◽

Nervous System ◽

Hemolytic Uremic Syndrome ◽

Signaling Pathway ◽

Shiga Toxin ◽

Enterohemorrhagic Escherichia Coli ◽

Shiga Toxin 2 ◽

Uremic Syndrome ◽

The Brain

AbstractShiga toxin 2 (Stx2) from enterohemorrhagic Escherichia coli (EHEC) produces hemorrhagic colitis, hemolytic uremic syndrome (HUS) and acute encephalopathy. The mortality rate in HUS increases significantly when the central nervous system (CNS) is involved. Besides, EHEC also releases lipopolysaccharide (LPS). Many reports have described cognitive dysfunctions in HUS patients, the hippocampus being one of the brain areas targeted by EHEC infection. In this context, a translational murine model of encephalopathy was employed to establish the deleterious effects of Stx2 and the contribution of LPS in the hippocampus. Results demonstrate that systemic administration of a sublethal dose of Stx2 reduced memory index and produced depression like behavior, pro-inflammatory cytokine release and NF-kB activation independent of the ERK 1/2 signaling pathway. On the other hand, LPS activated NF-kB dependent on ERK 1/2 signaling pathway. Cotreatment of Stx2 with LPS aggravated the pathologic state, while dexamethasone treatment succeeded in preventing behavioral alterations. Our present work suggests that the use of drugs such as corticosteroids or NF-kB signaling inhibitors may serve as neuroprotectors from EHEC infection.Author SummaryShiga toxin (Stx) from enterohemorrhagic Escherichia coli (EHEC) is one of the most virulent factors responsible for hemolytic uremic syndrome (HUS). Stx2, the endemic variant targets the brain, among other organs, thus inducing encephalopathies. Central nervous system (CNS) compromise was the main predictor of death in patients with HUS. Stx2 may exert a direct action in the CNS, by disrupting the neurovascular unit. In this context, we investigate the molecular signaling triggered by Stx2 in the murine brain hippocampus involved in inflammatory mechanisms that altered hippocampal-related cognitive behaviors. The present data underscore that the use of drugs such as dexamethasone or those blocking the cascade by preventing NF-kB translocation to the nucleus may serve as effective neuroprotectors with potentially beneficial use in the clinic.

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Environmental Cues Modulate Microglial Cell Behavior Upon Shiga Toxin 2 From Enterohemorrhagic Escherichia coli Exposure

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2019.00442 ◽

2020 ◽

Vol 9 ◽

Author(s):

Clara Berdasco ◽

Maite Duhalde Vega ◽

María Victoria Rosato-Siri ◽

Jorge Goldstein

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Microglial Cell ◽

Enterohemorrhagic Escherichia Coli ◽

Cell Behavior ◽

Environmental Cues ◽

Shiga Toxin 2

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The Shiga toxin 2 production level in enterohemorrhagic Escherichia coli O157:H7 is correlated with the subtypes of toxin-encoding phage

Scientific Reports ◽

10.1038/srep16663 ◽

2015 ◽

Vol 5 (1) ◽

Cited By ~ 49

Author(s):

Yoshitoshi Ogura ◽

Shakhinur Islam Mondal ◽

Md Rakibul Islam ◽

Toshihiro Mako ◽

Kokichi Arisawa ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Enterohemorrhagic Escherichia Coli ◽

Production Level ◽

Escherichia Coli O157 ◽

Shiga Toxin 2

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PCR Detection of Enterohemorrhagic Escherichia coli O145 in Food by Targeting Genes in the E. coli O145 O-Antigen Gene Cluster and the Shiga Toxin 1 and Shiga Toxin 2 Genes

Foodborne Pathogens and Disease ◽

10.1089/fpd.2008.0254 ◽

2009 ◽

Vol 6 (5) ◽

pp. 605-611 ◽

Cited By ~ 42

Author(s):

Pina M. Fratamico ◽

Chitrita DebRoy ◽

Takahisa Miyamoto ◽

Yanhong Liu

Keyword(s):

Escherichia Coli ◽

Gene Cluster ◽

Shiga Toxin ◽

Pcr Detection ◽

Enterohemorrhagic Escherichia Coli ◽

E Coli ◽

Antigen Gene ◽

O Antigen ◽

Shiga Toxin 2

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A Comparison of Shiga-Toxin 2 Bacteriophage from Classical Enterohemorrhagic Escherichia coli Serotypes and the German E. coli O104:H4 Outbreak Strain

PLoS ONE ◽

10.1371/journal.pone.0037362 ◽

2012 ◽

Vol 7 (5) ◽

pp. e37362 ◽

Cited By ~ 40

Author(s):

Chad R. Laing ◽

Yongxiang Zhang ◽

Matthew W. Gilmour ◽

Vanessa Allen ◽

Roger Johnson ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Enterohemorrhagic Escherichia Coli ◽

Outbreak Strain ◽

E Coli ◽

Shiga Toxin 2

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The Serine 31 Residue of the B Subunit of Shiga Toxin 2 Is Essential for Secretion in Enterohemorrhagic Escherichia coli

Infection and Immunity ◽

10.1128/iai.01546-06 ◽

2007 ◽

Vol 75 (5) ◽

pp. 2189-2200 ◽

Cited By ~ 16

Author(s):

Takeshi Shimizu ◽

Satomi Kawakami ◽

Toshio Sato ◽

Terumi Sasaki ◽

Masato Higashide ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Enterohemorrhagic Escherichia Coli ◽

The Other ◽

Supernatant Fraction ◽

Isogenic Mutant ◽

B Subunit ◽

Related Information ◽

Other Hand ◽

Shiga Toxin 2

ABSTRACT Shiga toxins produced by enterohemorrhagic Escherichia coli (EHEC) include Shiga toxin 1 (Stx1) as well as Shiga toxin 2 (Stx2). Stx1 is cell associated, whereas Stx2 is localized to the culture supernatant. We have analyzed the secretion of Stx2 by generating histidine-tagged StxB (StxB-H). Although neither StxB1-H nor StxB2-H was secreted in StxB-H-overexpressed EHEC, StxB2-H-overexpressed EHEC showed inhibited Stx2 secretion. On the other hand, StxB1-H-overexpressed EHEC showed no alteration of Stx2 secretion. B-subunit chimeras of Stx1 and Stx2 were used to identify the specific residue of StxB2 that the Stx2 secretory system recognizes. Alteration of the serine 31 residue to an asparagine residue (S31N) in StxB2-H enabled the recovery of Stx2 secretion. On the other hand, alteration of the asparagine 32 residue to a serine residue (N32S) in StxB1-H caused the partial secretion of a point-mutated histidine-tagged B subunit in EHEC. Based on the evidence, it appeared possible that this residue might contain secretion-related information for Stx2 secretion. To investigate this hypothesis, we constructed an isogenic mutant EHEC (Stx1B subunit, N32S) strain and an isogenic mutant EHEC (Stx2B subunit, S31N) strain. Although the mutant Stx2 was cell associated in isogenic mutant EHEC, mutant Stx1 was not extracellular. However, when we used plasmids for the expression of the mutant holotoxins, the overexpressed mutant Stx1 was found in the supernatant fraction, and the overexpressed mutant Stx2 was found in the cell-associated fraction in mutant holotoxin gene-transformed EHEC. These results indicate that the serine 31 residue of the B subunit of Stx2 contains secretion-related information.

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Retinoid Levels Influence Enterohemorrhagic Escherichia coli Infection and Shiga Toxin 2 Susceptibility in Mice

Infection and Immunity ◽

10.1128/iai.02191-14 ◽

2014 ◽

Vol 82 (9) ◽

pp. 3948-3957 ◽

Cited By ~ 6

Author(s):

Gabriel Cabrera ◽

Romina J. Fernández-Brando ◽

María Jimena Abrey-Recalde ◽

Ariela Baschkier ◽

Alipio Pinto ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Lethal Dose ◽

Absolute Number ◽

Enterohemorrhagic Escherichia Coli ◽

Polymorphonuclear Cells ◽

Intestinal Damage ◽

Gastrointestinal Infections ◽

Systemic Complications ◽

Content Type

ABSTRACTEnterohemorrhagicEscherichia coli(EHEC) is a food-borne pathogen that produces Shiga toxin (Stx) and causes hemorrhagic colitis. Under some circumstances, Stx produced within the intestinal tract enters the bloodstream, leading to systemic complications that may cause the potentially fatal hemolytic-uremic syndrome. Although retinoids like vitamin A (VA) and retinoic acid (RA) are beneficial to gut integrity and the immune system, the effect of VA supplementation on gastrointestinal infections of different etiologies has been controversial. Thus, the aim of this work was to study the influence of different VA status on the outcome of an EHEC intestinal infection in mice. We report that VA deficiency worsened the intestinal damage during EHEC infection but simultaneously improved survival. Since death is associated mainly with Stx toxicity, Stx was intravenously inoculated to analyze whether retinoid levels affect Stx susceptibility. Interestingly, while VA-deficient (VA-D) mice were resistant to a lethal dose of Stx2, RA-supplemented mice were more susceptible to it. Given that peripheral blood polymorphonuclear cells (PMNs) are known to potentiate Stx2 toxicity, we studied the influence of retinoid levels on the absolute number and function of PMNs. We found that VA-D mice had decreased PMN numbers and a diminished capacity to produce reactive oxygen species, while RA supplementation had the opposite effect. These results are in line with the well-known function of retinoids in maintaining the homeostasis of the gut but support the idea that they have a proinflammatory effect by acting, in part, on the PMN population.

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