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

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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Antibiotic-Mediated Modulations of Outer Membrane Vesicles in Enterohemorrhagic Escherichia coli O104:H4 and O157:H7

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00937-17 ◽

2017 ◽

Vol 61 (9) ◽

Cited By ~ 19

Author(s):

Andreas Bauwens ◽

Lisa Kunsmann ◽

Helge Karch ◽

Alexander Mellmann ◽

Martina Bielaszewska

Keyword(s):

Escherichia Coli ◽

Outer Membrane ◽

Shiga Toxin ◽

Membrane Vesicles ◽

Polymyxin B ◽

Outer Membrane Vesicles ◽

Enterohemorrhagic Escherichia Coli ◽

Content Type ◽

E Coli ◽

Major Virulence Factor

ABSTRACT Ciprofloxacin, meropenem, fosfomycin, and polymyxin B strongly increase production of outer membrane vesicles (OMVs) in Escherichia coli O104:H4 and O157:H7. Ciprofloxacin also upregulates OMV-associated Shiga toxin 2a, the major virulence factor of these pathogens, whereas the other antibiotics increase OMV production without the toxin. These two effects might worsen the clinical outcome of infections caused by Shiga toxin-producing E. coli. Our data support the existing recommendations to avoid antibiotics for treatment of these infections.

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Fate of Salmonella enterica and Enterohemorrhagic Escherichia coli Cells Artificially Internalized into Vegetable Seeds during Germination

Applied and Environmental Microbiology ◽

10.1128/aem.01888-17 ◽

2017 ◽

Vol 84 (1) ◽

Cited By ~ 9

Author(s):

Da Liu ◽

Yue Cui ◽

Ronald Walcott ◽

Jinru Chen

Keyword(s):

Escherichia Coli ◽

Salmonella Enterica ◽

Bacterial Pathogens ◽

Bacterial Species ◽

Enterohemorrhagic Escherichia Coli ◽

Human Pathogens ◽

Gastrointestinal Infections ◽

Tissue Samples ◽

Content Type ◽

Vegetable Seed

ABSTRACTVegetable seeds contaminated with bacterial pathogens have been linked to fresh-produce-associated outbreaks of gastrointestinal infections. This study was undertaken to observe the physiological behavior ofSalmonella entericaand enterohemorrhagicEscherichia coli(EHEC) cells artificially internalized into vegetable seeds during the germination process. Surface-decontaminated seeds of alfalfa, fenugreek, lettuce, and tomato were vacuum-infiltrated with four individual strains ofSalmonellaor EHEC. Contaminated seeds were germinated at 25°C for 9 days, and different sprout/seedling tissues were microbiologically analyzed every other day. The internalization ofSalmonellaand EHEC cells into vegetable seeds was confirmed by the absence of pathogens in seed-rinsing water and the presence of pathogens in seed homogenates after postinternalization seed surface decontamination. Results show that 317 (62%) and 343 (67%) of the 512 collected sprout/seedling tissue samples were positive forSalmonellaand EHEC, respectively. The averageSalmonellapopulations were significantly larger (P< 0.05) than the EHEC populations. Significantly largerSalmonellapopulations were recovered from the cotyledon and seed coat tissues, followed by the root tissues, but the mean EHEC populations from all sampled tissue sections were statistically similar, except in pregerminated seeds. ThreeSalmonellaand two EHEC strains had significantly larger cell populations on sprout/seedling tissues than other strains used in the study.Salmonellaand EHEC populations from fenugreek and alfalfa tissues were significantly larger than those from tomato and lettuce tissues. The study showed the fate of internalized human pathogens on germinating vegetable seeds and sprout/seedling tissues and emphasized the importance of using pathogen-free seeds for sprout production.IMPORTANCEThe internalization of microorganisms into vegetable seeds could occur naturally and represents a possible pathway of vegetable seed contamination by human pathogens. The present study investigated the ability of two important bacterial pathogens,Salmonellaand enterohemorrhagicEscherichia coli(EHEC), when artificially internalized into vegetable seeds, to grow and disseminate along vegetable sprouts/seedlings during germination. The data from the study revealed that the pathogen cells artificially internalized into vegetable seeds caused the contamination of different tissues of sprouts/seedlings and that pathogen growth on germinating seeds is bacterial species and vegetable seed-type dependent. These results further stress the necessity of using pathogen-free vegetable seeds for edible sprout production.

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Vitamin K Analogs Influence the Growth and Virulence Potential of Enterohemorrhagic Escherichia coli

Applied and Environmental Microbiology ◽

10.1128/aem.00583-20 ◽

2020 ◽

Vol 86 (24) ◽

Author(s):

Anne Kijewski ◽

Ingun Lund Witsø ◽

Hildegunn Iversen ◽

Helene Thorsen Rønning ◽

Trine L'Abée-Lund ◽

...

Keyword(s):

Escherichia Coli ◽

Vitamin K ◽

Bacterial Growth ◽

Shiga Toxin ◽

Treatment Options ◽

Inhibitory Effect ◽

Enterohemorrhagic Escherichia Coli ◽

Lytic Cycle ◽

Content Type ◽

Negative Effect

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) causes serious foodborne disease worldwide. It produces the very potent Shiga toxin 2 (Stx2). The Stx2-encoding genes are located on a prophage, and production of the toxin is linked to the synthesis of Stx phages. There is, currently, no good treatment for EHEC infections, as antibiotics may trigger lytic cycle activation of the phages and increased Stx production. This study addresses how four analogs of vitamin K, phylloquinone (K1), menaquinone (K2), menadione (K3), and menadione sodium bisulfite (MSB), influence growth, Stx2-converting phage synthesis, and Stx2 production by the EHEC O157:H7 strain EDL933. Menadione and MSB conferred a concentration-dependent negative effect on bacterial growth, while phylloquinone or menaquinone had little and no effect on bacterial growth, respectively. All four vitamin K analogs affected Stx2 phage production negatively in uninduced cultures and in cultures induced with either hydrogen peroxide (H2O2), ciprofloxacin, or mitomycin C. Menadione and MSB reduced Stx2 production in cultures induced with either H2O2 or ciprofloxacin. MSB also had a negative effect on Stx2 production in two other EHEC isolates tested. Phylloquinone and menaquinone had, on the other hand, variable and concentration-dependent effects on Stx2 production. MSB, which conferred the strongest inhibitory effect on both Stx2 phage and Stx2 production, improved the growth of EHEC in the presence of H2O2 and ciprofloxacin, which could be explained by the reduced uptake of ciprofloxacin into the bacterial cell. Together, the data suggest that vitamin K analogs have a growth- and potential virulence-reducing effect on EHEC, which could be of therapeutic interest. IMPORTANCE Enterohemorrhagic E. coli (EHEC) can cause serious illness and deaths in humans by producing toxins that can severely damage our intestines and kidneys. There is currently no optimal treatment for EHEC infections, as antibiotics can worsen disease development. Consequently, the need for new treatment options is urgent. Environmental factors in our intestines can affect the virulence of EHEC and help our bodies fight EHEC infections. The ruminant intestine, the main reservoir for EHEC, contains high levels of vitamin K, but the levels are variable in humans. This study shows that vitamin K analogs can inhibit the growth of EHEC and/or production of its main virulence factor, the Shiga toxin. They may also inhibit the spreading of the Shiga toxin encoding bacteriophage. Our findings indicate that vitamin K analogs have the potential to suppress the development of serious disease caused by EHEC.

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Is Shiga Toxin-Negative Escherichia coli O157:H7 Enteropathogenic or Enterohemorrhagic Escherichia coli? Comprehensive Molecular Analysis Using Whole-Genome Sequencing

Journal of Clinical Microbiology ◽

10.1128/jcm.01899-15 ◽

2015 ◽

Vol 53 (11) ◽

pp. 3530-3538 ◽

Cited By ~ 30

Author(s):

Mithila Ferdous ◽

Kai Zhou ◽

Alexander Mellmann ◽

Stefano Morabito ◽

Peter D. Croughs ◽

...

Keyword(s):

Escherichia Coli ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Shiga Toxin ◽

Enterohemorrhagic Escherichia Coli ◽

Cellular Damage ◽

Whole Genome ◽

Content Type ◽

E Coli ◽

Treatment And Prevention

The ability ofEscherichia coliO157:H7 to induce cellular damage leading to disease in humans is related to numerous virulence factors, most notably thestxgene, encoding Shiga toxin (Stx) and carried by a bacteriophage. Loss of the Stx-encoding bacteriophage may occur during infection or culturing of the strain. Here, we collectedstx-positive andstx-negative variants ofE. coliO157:H7/NM (nonmotile) isolates from patients with gastrointestinal complaints. Isolates were characterized by whole-genome sequencing (WGS), and their virulence properties and phylogenetic relationship were determined. Because of the presence of theeaegene but lack of thebfpAgene, thestx-negative isolates were considered atypical enteropathogenicE. coli(aEPEC). However, they had phenotypic characteristics similar to those of the Shiga toxin-producingE. coli(STEC) isolates and belonged to the same sequence type, ST11. Furthermore, EPEC and STEC isolates shared similar virulence genes, the locus of enterocyte effacement region, and plasmids. Core genome phylogenetic analysis using a gene-by-gene typing approach showed that the sorbitol-fermenting (SF)stx-negative isolates clustered together with an SF STEC isolate and that one non-sorbitol-fermenting (NSF)stx-negative isolate clustered together with NSF STEC isolates. Therefore, thesestx-negative isolates were thought either to have lost the Stx phage or to be a progenitor of STEC O157:H7/NM. As detection of STEC infections is often based solely on the identification of the presence ofstxgenes, these may be misdiagnosed in routine laboratories. Therefore, an improved diagnostic approach is required to manage identification, strategies for treatment, and prevention of transmission of these potentially pathogenic strains.

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

Frontiers in Microbiology ◽

10.3389/fmicb.2016.00133 ◽

2016 ◽

Vol 7 ◽

Cited By ~ 3

Author(s):

Luciana D’Alessio ◽

Alipio Pinto ◽

Adriana Cangelosi ◽

Patricia A. Geoghegan ◽

Carla Tironi-Farinati ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Lethal Dose ◽

Enterohemorrhagic Escherichia Coli ◽

Shiga Toxin 2

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Basic Reproduction Number and Transmission Dynamics of Common Serogroups of Enterohemorrhagic Escherichia coli

Applied and Environmental Microbiology ◽

10.1128/aem.00815-16 ◽

2016 ◽

Vol 82 (18) ◽

pp. 5612-5620 ◽

Cited By ~ 4

Author(s):

Shi Chen ◽

Michael W. Sanderson ◽

Chihoon Lee ◽

Natalia Cernicchiaro ◽

David G. Renter ◽

...

Keyword(s):

Escherichia Coli ◽

Basic Reproduction Number ◽

Shiga Toxin ◽

Reproduction Number ◽

Enterohemorrhagic Escherichia Coli ◽

Transmission Dynamics ◽

Cross Sectional ◽

Content Type ◽

Group Data ◽

Reproduction Numbers

ABSTRACTUnderstanding the transmission dynamics of pathogens is essential to determine the epidemiology, ecology, and ways of controlling enterohemorrhagicEscherichia coli(EHEC) in animals and their environments. Our objective was to estimate the epidemiological fitness of common EHEC strains in cattle populations. For that purpose, we developed a Markov chain model to characterize the dynamics of 7 serogroups of enterohemorrhagicEscherichia coli(O26, O45, O103, O111, O121, O145, and O157) in cattle production environments based on a set of cross-sectional data on infection prevalence in 2 years in two U.S. states. The basic reproduction number (R0) was estimated using a Bayesian framework for each serogroup based on two criteria (using serogroup alone [the O-group data] and using O serogroup, Shiga toxin gene[s], and intimin [eae] gene together [the EHEC data]). In addition, correlations between external covariates (e.g., location, ambient temperature, dietary, and probiotic usage) and prevalence/R0were quantified.R0estimates varied substantially among different EHEC serogroups, with EHEC O157 having anR0of >1 (∼1.5) and all six other EHEC serogroups having anR0of less than 1. Using the O-group data substantially increasedR0estimates for the O26, O45, and O103 serogroups (R0> 1) but not for the others. Different covariates had distinct influences on different serogroups: the coefficients for each covariate were different among serogroups. Our modeling and analysis of this system can be readily expanded to other pathogen systems in order to estimate the pathogen and external factors that influence spread of infectious agents.IMPORTANCEIn this paper we describe a Bayesian modeling framework to estimate basic reproduction numbers of multiple serotypes of Shiga toxin-producingEscherichia coliaccording to a cross-sectional study. We then coupled a compartmental model to reconstruct the infection dynamics of these serotypes and quantify their risk in the population. We incorporated different sensitivity levels of detecting different serotypes and evaluated their potential influence on the estimation of basic reproduction numbers.

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AnIn VitroCombined Antibiotic-Antibody Treatment Eliminates Toxicity from Shiga Toxin-Producing Escherichia coli

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00763-15 ◽

2015 ◽

Vol 59 (9) ◽

pp. 5435-5444 ◽

Cited By ~ 7

Author(s):

Craig Skinner ◽

Guodong Zhang ◽

Stephanie Patfield ◽

Xiaohua He

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Shiga Toxin ◽

Neutralizing Antibodies ◽

Vero Cells ◽

Antibody Treatment ◽

Gastrointestinal Infections ◽

Content Type ◽

Life Threatening ◽

Uremic Syndrome

ABSTRACTTreating Shiga toxin-producingEscherichia coli(STEC) gastrointestinal infections is difficult. The utility of antibiotics for STEC treatment is controversial, since antibiotic resistance among STEC isolates is widespread and certain antibiotics dramatically increase the expression of Shiga toxins (Stxs), which are some of the most important virulence factors in STEC. Stxs contribute to life-threatening hemolytic uremic syndrome (HUS), which develops in considerable proportions of patients with STEC infections. Understanding the antibiotic resistance profiles of STEC isolates and the Stx induction potential of promising antibiotics is essential for evaluating any antibiotic treatment of STEC. In this study, 42 O157:H7 or non-O157 STEC isolates (including the “big six” serotypes) were evaluated for their resistance against 22 antibiotics by using an antibiotic array. Tigecycline inhibited the growth of all of the tested STEC isolates and also inhibited the production of Stxs (Stx2 in particular). In combination with neutralizing antibodies to Stx1 and Stx2, the tigecycline-antibody treatment fully protected Vero cells from Stx toxicity, even when the STEC bacteria and the Vero cells were cultured together. The combination of an antibiotic such as tigecycline with neutralizing antibodies presents a promising strategy for future STEC treatments.

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Phenethyl Isothiocyanate Inhibits Shiga Toxin Production in Enterohemorrhagic Escherichia coli by Stringent Response Induction

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02515-13 ◽

2014 ◽

Vol 58 (4) ◽

pp. 2304-2315 ◽

Cited By ~ 12

Author(s):

Dariusz Nowicki ◽

Monika Maciąg-Dorszyńska ◽

Wioletta Kobiela ◽

Anna Herman-Antosiewicz ◽

Alicja Węgrzyn ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Stringent Response ◽

Enterohemorrhagic Escherichia Coli ◽

Negative Regulator ◽

Phenethyl Isothiocyanate ◽

Prophage Induction ◽

Content Type ◽

E Coli ◽

Stimulation Of

ABSTRACTThe pathogenicity of enterohemorrhagicEscherichia coli(EHEC) depends on production of Shiga toxins, which are encoded bystxgenes located in the genomes of lambdoid prophages. Efficient expression of these genes requires prophage induction and lytic development of phages. Treatment of EHEC infections is problematic due to not only the resistance of various strains to antibiotics but also the fact that many antibiotics cause prophage induction, thus resulting in high-level expression ofstxgenes. Here we report thatE. coligrowth, Shiga toxin-converting phage development, and production of the toxin by EHEC are strongly inhibited by phenethyl isothiocyanate (PEITC). We demonstrate that PEITC induces the stringent response inE. colithat is mediated by massive production of a global regulator, guanosine tetraphosphate (ppGpp). The stringent response induction arises most probably from interactions of PEITC with amino acids and from amino acid deprivation-mediated activation of ppGpp synthesis. In mutants unable to synthesize ppGpp, development of Shiga toxin-converting phages and production of Shiga toxin are significantly enhanced. Therefore, ppGpp, which appears at high levels in bacterial cells after stimulation of its production by PEITC, is a negative regulator of EHEC virulence and at the same time efficiently inhibits bacterial growth. This is in contrast to stimulation of virulence of different bacteria by this nucleotide reported previously by others.

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Highly Virulent Non-O157 Enterohemorrhagic Escherichia coli (EHEC) Serotypes Reflect Similar Phylogenetic Lineages, Providing New Insights into the Evolution of EHEC

Applied and Environmental Microbiology ◽

10.1128/aem.01921-15 ◽

2015 ◽

Vol 81 (20) ◽

pp. 7041-7047 ◽

Cited By ~ 27

Author(s):

Inga Eichhorn ◽

Katrin Heidemanns ◽

Torsten Semmler ◽

Bianca Kinnemann ◽

Alexander Mellmann ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Enterohemorrhagic Escherichia Coli ◽

Toxin Gene ◽

Content Type ◽

E Coli ◽

Healthy Humans ◽

Uremic Syndrome ◽

Enterocyte Effacement ◽

Phylogenetic Lineages

ABSTRACTEnterohemorrhagicEscherichia coli(EHEC) is the causative agent of bloody diarrhea and extraintestinal sequelae in humans, most importantly hemolytic-uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Besides the bacteriophage-encoded Shiga toxin gene (stx), EHEC harbors the locus of enterocyte effacement (LEE), which confers the ability to cause attaching and effacing lesions. Currently, the vast majority of EHEC infections are caused by strains belonging to five O serogroups (the “big five”), which, in addition to O157, the most important, comprise O26, O103, O111, and O145. We hypothesize that these four non-O157 EHEC serotypes differ in their phylogenies. To test this hypothesis, we used multilocus sequence typing (MLST) to analyze a large collection of 250 isolates of these four O serogroups, which were isolated from diseased as well as healthy humans and cattle between 1952 and 2009. The majority of the EHEC isolates of O serogroups O26 and O111 clustered into one sequence type complex, STC29. Isolates of O103 clustered mainly in STC20, and most isolates of O145 were found within STC32. In addition to these EHEC strains, STC29 also includedstx-negativeE. colistrains, termed atypical enteropathogenicE. coli(aEPEC), yet another intestinal pathogenicE. coligroup. The finding that aEPEC and EHEC isolates of non-O157 O serogroups share the same phylogeny suggests an ongoing microevolutionary scenario in which the phage-encoded Shiga toxin genestxis transferred between aEPEC and EHEC. As a consequence, aEPEC strains of STC29 can be regarded as post- or pre-EHEC isolates. Therefore, STC29 incorporates phylogenetic information useful for unraveling the evolution of EHEC.

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Presence of Enterohemorrhagic Escherichia coli ST678/O104:H4 in France Prior to 2011

Applied and Environmental Microbiology ◽

10.1128/aem.06524-11 ◽

2011 ◽

Vol 77 (24) ◽

pp. 8784-8786 ◽

Cited By ~ 28

Author(s):

Stefan Monecke ◽

Patricia Mariani-Kurkdjian ◽

Edouard Bingen ◽

François-Xavier Weill ◽

Charlotte Balière ◽

...

Keyword(s):

Escherichia Coli ◽

Enterohemorrhagic Escherichia Coli ◽

Content Type

ABSTRACTTwo isolates of enterohemorrhagicEscherichia coli(EHEC) O104:H4 were isolated in France in 2004 and 2009. Both were characterized and compared to the strain which caused the German outbreak in 2011 and to other O104:H4 strains. This suggests that different O104:H4 EHEC strains were present several years prior to the 2011 outbreak.

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