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Colello R, Vélez MV, Farias MVN, Rodríguez M, Montero D, Vidal R, Etcheverría AI, Padola NL. Expression of hes, iha, and tpsA codified in locus of adhesion and autoaggregation and their involvement in the capability of shiga toxin-producing Escherichia coli strains to adhere to epithelial cells. BMC Res Notes 2023; 16:163. [PMID: 37550739 PMCID: PMC10408066 DOI: 10.1186/s13104-023-06433-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 07/17/2023] [Indexed: 08/09/2023] Open
Abstract
OBJECTIVES Shiga toxin-producing Escherichia coli strains LAA-positive are important cause of human infection. The capability to adhere to epithelial cells is a key virulence trait, and genes codified in LAA pathogenicity island could be involved in the adhesion during the pathogenesis of LAA-positive STEC strains. Thus, our objectives were to compare hes-negative and hes-positive STEC strains in their adherence capability to epithelial cells (HEp-2) and to evaluate the expression levels of the hes, iha, and tpsA in the bacteria adhered and non-adhered to HEp-2 cells. These genes are encoded in LAA, and are virulence factors that participate in adhesion and autoaggregation. RESULTS We could not observe differences between the adhesion of strains but also in the expression level of of hes, iha, and tpsA. Genes encoded in LAA contribute to the adhesion phenotype though the expression of STEC adhesins is a coordinated event that depends not only the strain but also on the environment as well as its genetic background. Therefore, the results of this study suggest that LAA ,the most prevalent PAI among LEE-negative STEC strains, plays a role in pathogenesis.
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Affiliation(s)
- Rocío Colello
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), CISAPA, Tandil, Buenos Aires, 7000, Argentina.
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA- CICPBA- CONICET, Tandil, 7000, Argentina.
| | - M Victoria Vélez
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), CISAPA, Tandil, Buenos Aires, 7000, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA- CICPBA- CONICET, Tandil, 7000, Argentina
| | - M Victoria Nieto Farias
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), CISAPA, Tandil, Buenos Aires, 7000, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA- CICPBA- CONICET, Tandil, 7000, Argentina
| | - Marcelo Rodríguez
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), SAMP, Tandil, Buenos Aires, 7000, Argentina
| | - David Montero
- Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, 4030555, Chile
- Centro Integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo O'Higgins, Santiago, 8320000, Chile
| | - Roberto Vidal
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, 8320000, Chile
| | - Analía I Etcheverría
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), CISAPA, Tandil, Buenos Aires, 7000, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA- CICPBA- CONICET, Tandil, 7000, Argentina
| | - Nora Lía Padola
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), CISAPA, Tandil, Buenos Aires, 7000, Argentina
- Centro de Investigación Veterinaria de Tandil (CIVETAN), UNCPBA- CICPBA- CONICET, Tandil, 7000, Argentina
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Bova RA, Lamont AC, Picou TJ, Ho VB, Gilchrist KH, Melton-Celsa AR. Shiga Toxin (Stx) Type 1a and Stx2a Translocate through a Three-Layer Intestinal Model. Toxins (Basel) 2023; 15:toxins15030207. [PMID: 36977098 PMCID: PMC10054274 DOI: 10.3390/toxins15030207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/27/2023] [Accepted: 03/08/2023] [Indexed: 03/12/2023] Open
Abstract
Shiga toxins (Stxs) produced by ingested E. coli can induce hemolytic uremic syndrome after crossing the intact intestinal barrier, entering the bloodstream, and targeting endothelial cells in the kidney. The method(s) by which the toxins reach the bloodstream are not fully defined. Here, we used two polarized cell models to evaluate Stx translocation: (i) a single-layer primary colonic epithelial cell model and (ii) a three-cell-layer model with colonic epithelial cells, myofibroblasts, and colonic endothelial cells. We traced the movement of Stx types 1a and 2a across the barrier models by measuring the toxicity of apical and basolateral media on Vero cells. We found that Stx1a and Stx2a crossed both models in either direction. However, approximately 10-fold more Stx translocated in the three-layer model as compared to the single-layer model. Overall, the percentage of toxin that translocated was about 0.01% in the epithelial-cell-only model but up to 0.09% in the three-cell-layer model. In both models, approximately 3- to 4-fold more Stx2a translocated than Stx1a. Infection of the three-cell-layer model with Stx-producing Escherichia coli (STEC) strains showed that serotype O157:H7 STEC reduced barrier function in the model and that the damage was not dependent on the presence of the eae gene. Infection of the three-layer model with O26:H11 STEC strain TW08571 (Stx1a+ and Stx2a+), however, allowed translocation of modest amounts of Stx without reducing barrier function. Deletion of stx2a from TW08571 or the use of anti-Stx1 antibody prevented translocation of toxin. Our results suggest that single-cell models may underestimate the amount of Stx translocation and that the more biomimetic three-layer model is suited for Stx translocation inhibitor studies.
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Affiliation(s)
- Rebecca A. Bova
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA
- Center for Biotechnology (4DBio3), Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD 20814, USA
- The Geneva Foundation, Tacoma, WA 98402, USA
| | - Andrew C. Lamont
- Center for Biotechnology (4DBio3), Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD 20814, USA
- The Geneva Foundation, Tacoma, WA 98402, USA
| | - Theodore J. Picou
- Center for Biotechnology (4DBio3), Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD 20814, USA
- The Geneva Foundation, Tacoma, WA 98402, USA
| | - Vincent B. Ho
- Center for Biotechnology (4DBio3), Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD 20814, USA
| | - Kristin H. Gilchrist
- Center for Biotechnology (4DBio3), Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD 20814, USA
- The Geneva Foundation, Tacoma, WA 98402, USA
| | - Angela R. Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA
- Correspondence:
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Enterohemorrhagic Escherichia coli and a Fresh View on Shiga Toxin-Binding Glycosphingolipids of Primary Human Kidney and Colon Epithelial Cells and Their Toxin Susceptibility. Int J Mol Sci 2022; 23:ijms23136884. [PMID: 35805890 PMCID: PMC9266556 DOI: 10.3390/ijms23136884] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/07/2022] [Accepted: 06/17/2022] [Indexed: 02/06/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are the human pathogenic subset of Shiga toxin (Stx)-producing E. coli (STEC). EHEC are responsible for severe colon infections associated with life-threatening extraintestinal complications such as the hemolytic-uremic syndrome (HUS) and neurological disturbances. Endothelial cells in various human organs are renowned targets of Stx, whereas the role of epithelial cells of colon and kidneys in the infection process has been and is still a matter of debate. This review shortly addresses the clinical impact of EHEC infections, novel aspects of vesicular package of Stx in the intestine and the blood stream as well as Stx-mediated extraintestinal complications and therapeutic options. Here follows a compilation of the Stx-binding glycosphingolipids (GSLs), globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) and their various lipoforms present in primary human kidney and colon epithelial cells and their distribution in lipid raft-analog membrane preparations. The last issues are the high and extremely low susceptibility of primary renal and colonic epithelial cells, respectively, suggesting a large resilience of the intestinal epithelium against the human-pathogenic Stx1a- and Stx2a-subtypes due to the low content of the high-affinity Stx-receptor Gb3Cer in colon epithelial cells. The review closes with a brief outlook on future challenges of Stx research.
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McGrath CJ, Laveckis E, Bell A, Crost E, Juge N, Schüller S. Development of a novel human intestinal model to elucidate the effect of anaerobic commensals on Escherichia coli infection. Dis Model Mech 2022; 15:275170. [PMID: 35302159 PMCID: PMC9066490 DOI: 10.1242/dmm.049365] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/10/2022] [Indexed: 01/01/2023] Open
Abstract
The gut microbiota plays a crucial role in protecting against enteric infection. However, the underlying mechanisms are largely unknown owing to a lack of suitable experimental models. Although most gut commensals are anaerobic, intestinal epithelial cells require oxygen for survival. In addition, most intestinal cell lines do not produce mucus, which provides a habitat for the microbiota. Here, we have developed a microaerobic, mucus-producing vertical diffusion chamber (VDC) model and determined the influence of Limosilactobacillus reuteri and Ruminococcus gnavus on enteropathogenic Escherichia coli (EPEC) infection. Optimization of the culture medium enabled bacterial growth in the presence of mucus-producing T84/LS174T cells. Whereas L. reuteri diminished EPEC growth and adhesion to T84/LS174T and mucus-deficient T84 epithelia, R. gnavus only demonstrated a protective effect in the presence of LS174T cells. Reduced EPEC adherence was not associated with altered type III secretion pore formation. In addition, co-culture with L. reuteri and R. gnavus dampened EPEC-induced interleukin 8 secretion. The microaerobic mucin-producing VDC system will facilitate investigations into the mechanisms underpinning colonization resistance and aid the development of microbiota-based anti-infection strategies. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Conor J. McGrath
- Department of Clinical Medicine, Norwich Medical School, University of East Anglia, Norwich NR4 7UQ, UK
| | - Edgaras Laveckis
- Department of Clinical Medicine, Norwich Medical School, University of East Anglia, Norwich NR4 7UQ, UK
| | - Andrew Bell
- Gut Microbes and Health Programme, Quadram Institute Bioscience, Gut Microbes and Health Institute Strategic Programme, Norwich NR4 7UQ, UK
| | - Emmanuelle Crost
- Gut Microbes and Health Programme, Quadram Institute Bioscience, Gut Microbes and Health Institute Strategic Programme, Norwich NR4 7UQ, UK
| | - Nathalie Juge
- Gut Microbes and Health Programme, Quadram Institute Bioscience, Gut Microbes and Health Institute Strategic Programme, Norwich NR4 7UQ, UK
| | - Stephanie Schüller
- Department of Clinical Medicine, Norwich Medical School, University of East Anglia, Norwich NR4 7UQ, UK,Author for correspondence ()
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Allué-Guardia A, Koenig SSK, Martinez RA, Rodriguez AL, Bosilevac JM, Feng† P, Eppinger M. Pathogenomes and variations in Shiga toxin production among geographically distinct clones of Escherichia coli O113:H21. Microb Genom 2022; 8. [PMID: 35394418 PMCID: PMC9453080 DOI: 10.1099/mgen.0.000796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Infections with globally disseminated Shiga toxin-producing Escherichia coli (STEC) of the O113:H21 serotype can progress to severe clinical complications, such as hemolytic uremic syndrome (HUS). Two phylogeographically distinct clonal complexes have been established by multi locus sequence typing (MLST). Infections with ST-820 isolates circulating exclusively in Australia have caused severe human disease, such as HUS. Conversely, ST-223 isolates prevalent in the US and outside Australia seem to rarely cause severe human disease but are frequent contaminants. Following a genomic epidemiology approach, we wanted to gain insights into the underlying cause for this disparity. We examined the plasticity in the genome make-up and Shiga toxin production in a collection of 20 ST-820 and ST-223 strains isolated from produce, the bovine reservoir, and clinical cases. STEC are notorious for assembly into fragmented draft sequences when using short-read sequencing technologies due to the extensive and partly homologous phage complement. The application of long-read technology (LRT) sequencing yielded closed reference chromosomes and plasmids for two representative ST-820 and ST-223 strains. The established high-resolution framework, based on whole genome alignments, single nucleotide polymorphism (SNP)-typing and MLST, includes the chromosomes and plasmids of other publicly available O113:H21 sequences and allowed us to refine the phylogeographical boundaries of ST-820 and ST-223 complex isolates and to further identify a historic non-shigatoxigenic strain from Mexico as a quasi-intermediate. Plasmid comparison revealed strong correlations between the strains' featured pO113 plasmid genotypes and chromosomally inferred ST, which suggests coevolution of the chromosome and virulence plasmids. Our pathogenicity assessment revealed statistically significant differences in the Stx2a-production capabilities of ST-820 as compared to ST-223 strains under RecA-induced Stx phage mobilization, a condition that mimics Stx-phage induction. These observations suggest that ST-820 strains may confer an increased pathogenic potential in line with the strain-associated epidemiological metadata. Still, some of the tested ST-223 cultures sourced from contaminated produce or the bovine reservoir also produced Stx at levels comparable to those of ST-820 isolates, which calls for awareness and for continued surveillance of this lineage.
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Affiliation(s)
- Anna Allué-Guardia
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Sara S. K. Koenig
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Ricardo A. Martinez
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
| | - Armando L. Rodriguez
- University of Texas at San Antonio, Research Computing Support Group, San Antonio, TX, USA
| | - Joseph M. Bosilevac
- U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, NE, USA
| | - Peter Feng†
- U.S. Food and Drug Administration (FDA), College Park, MD, USA
| | - Mark Eppinger
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX, USA
- South Texas Center for Emerging Infectious Diseases (STCEID), San Antonio, TX, USA
- *Correspondence: Mark Eppinger,
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6
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Detzner J, Püttmann C, Pohlentz G, Humpf HU, Mellmann A, Karch H, Müthing J. Primary Human Colon Epithelial Cells (pHCoEpiCs) Do Express the Shiga Toxin (Stx) Receptor Glycosphingolipids Gb3Cer and Gb4Cer and Are Largely Refractory but Not Resistant towards Stx. Int J Mol Sci 2021; 22:ijms221810002. [PMID: 34576167 PMCID: PMC8472147 DOI: 10.3390/ijms221810002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 01/13/2023] Open
Abstract
Shiga toxin (Stx) is released by enterohemorrhagic Escherichia coli (EHEC) into the human intestinal lumen and transferred across the colon epithelium to the circulation. Stx-mediated damage of human kidney and brain endothelial cells and renal epithelial cells is a renowned feature, while the sensitivity of the human colon epithelium towards Stx and the decoration with the Stx receptor glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer, Galα1-4Galβ1-4Glcβ1-1Cer) and globotetraosylceramide (Gb4Cer, GalNAcβ1-3Galα1-4Galβ1-4Glcβ1-1Cer) is a matter of debate. Structural analysis of the globo-series GSLs of serum-free cultivated primary human colon epithelial cells (pHCoEpiCs) revealed Gb4Cer as the major neutral GSL with Cer (d18:1, C16:0), Cer (d18:1, C22:1/C22:0) and Cer (d18:1, C24:2/C24:1) accompanied by minor Gb3Cer with Cer (d18:1, C16:0) and Cer (d18:1, C24:1) as the dominant lipoforms. Gb3Cer and Gb4Cer co-distributed with cholesterol and sphingomyelin to detergent-resistant membranes (DRMs) used as microdomain analogs. Exposure to increasing Stx concentrations indicated only a slight cell-damaging effect at the highest toxin concentration of 1 µg/mL for Stx1a and Stx2a, whereas a significant effect was detected for Stx2e. Considerable Stx refractiveness of pHCoEpiCs that correlated with the rather low cellular content of the high-affinity Stx-receptor Gb3Cer renders the human colon epithelium questionable as a major target of Stx1a and Stx2a.
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Affiliation(s)
- Johanna Detzner
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.P.); (G.P.); (A.M.); (H.K.)
| | - Charlotte Püttmann
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.P.); (G.P.); (A.M.); (H.K.)
| | - Gottfried Pohlentz
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.P.); (G.P.); (A.M.); (H.K.)
| | - Hans-Ulrich Humpf
- Institute for Food Chemistry, University of Münster, 48149 Münster, Germany;
| | - Alexander Mellmann
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.P.); (G.P.); (A.M.); (H.K.)
| | - Helge Karch
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.P.); (G.P.); (A.M.); (H.K.)
| | - Johannes Müthing
- Institute for Hygiene, University of Münster, 48149 Münster, Germany; (J.D.); (C.P.); (G.P.); (A.M.); (H.K.)
- Correspondence: ; Tel.: +49-(0)251-8355192
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Koeppel MB, Glaser J, Baumgartner T, Spriewald S, Gerlach RG, von Armansperg B, Leong JM, Stecher B. Scalable Reporter Assays to Analyze the Regulation of stx2 Expression in Shiga Toxin-Producing Enteropathogens. Toxins (Basel) 2021; 13:toxins13080534. [PMID: 34437405 PMCID: PMC8402550 DOI: 10.3390/toxins13080534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/02/2022] Open
Abstract
Stx2 is the major virulence factor of EHEC and is associated with an increased risk for HUS in infected patients. The conditions influencing its expression in the intestinal tract are largely unknown. For optimal management and treatment of infected patients, the identification of environmental conditions modulating Stx2 levels in the human gut is of central importance. In this study, we established a set of chromosomal stx2 reporter assays. One system is based on superfolder GFP (sfGFP) using a T7 polymerase/T7 promoter-based amplification loop. This reporter can be used to analyze stx2 expression at the single-cell level using FACSs and fluorescence microscopy. The other system is based on the cytosolic release of the Gaussia princeps luciferase (gluc). This latter reporter proves to be a highly sensitive and scalable reporter assay that can be used to quantify reporter protein in the culture supernatant. We envision that this new set of reporter tools will be highly useful to comprehensively analyze the influence of environmental and host factors, including drugs, small metabolites and the microbiota, on Stx2 release and thereby serve the identification of risk factors and new therapies in Stx-mediated pathologies.
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Affiliation(s)
- Martin B. Koeppel
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
- Correspondence: (M.B.K.); (B.S.)
| | - Jana Glaser
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - Tobias Baumgartner
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - Stefanie Spriewald
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - Roman G. Gerlach
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054 Erlangen, Germany;
| | - Benedikt von Armansperg
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA 02111, USA;
| | - Bärbel Stecher
- Max-von-Pettenkofer Institute, LMU Munich, Pettenkoferstr. 9a, 80336 Munich, Germany; (J.G.); (T.B.); (S.S.); (B.v.A.)
- German Center for Infection Research (DZIF), Partner Site LMU Munich, 80336 Munich, Germany
- Correspondence: (M.B.K.); (B.S.)
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8
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Ramstad SN, Taxt AM, Naseer U, Wasteson Y, Bjørnholt JV, Brandal LT. Effects of antimicrobials on Shiga toxin production in high-virulent Shiga toxin-producing Escherichia coli. Microb Pathog 2020; 152:104636. [PMID: 33242644 DOI: 10.1016/j.micpath.2020.104636] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 11/10/2020] [Accepted: 11/16/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE Antimicrobial treatment of Shiga toxin-producing Escherichia coli (STEC) infections is controversial because antimicrobials may stimulate Shiga toxin (Stx) production, and thereby increase the risk of developing haemolytic uremic syndrome (HUS). Previous in vitro studies have shown this mainly in infections caused by STEC serotype O157:H7. The aim of this study was to investigate induction of Stx transcription and production in different serotypes of STEC isolated from severely ill patients, following their exposure in vitro to six different classes of antimicrobials. METHODS We investigated Stx transcription and production in 12 high-virulent STEC strains, all carrying the stx2a gene, of six different serotypes following their exposure to six classes of antimicrobials. Liquid cultures of the STEC strains were incubated with sub-inhibitory concentrations of the antimicrobials. We used reverse-transcription quantitative PCR to measure the relative expression of Stx2a mRNA and an enzyme-linked immunosorbent assay to quantify Stx production. RESULTS In general the antibiotics tested showed only minor effects on transcriptional levels of Stx2a. Ciprofloxacin caused an increase of Stx production in all but two strains, while gentamicin, meropenem and azithromycin did not induce Stx production in any of the STEC strains examined. STEC O104:H4 was the serotype that in greatest extent responded to antimicrobial exposure with an increase of stx2a transcription and Stx production. CONCLUSION Gentamicin, meropenem and azithromycin exposure did not result in elevated Stx production. We recommend that this finding is investigated further in the search for candidates for future antimicrobial treatment of STEC.
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Affiliation(s)
- Silje N Ramstad
- Department of Microbiology, Division of Laboratory Medicine, Oslo University Hospital, PB 4956 Nydalen, 0424, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
| | - Arne M Taxt
- Department of Microbiology, Division of Laboratory Medicine, Oslo University Hospital, PB 4956 Nydalen, 0424, Oslo, Norway
| | - Umaer Naseer
- Department of Infectious Diseases and Prevention, Norwegian Institute of Public Health, Oslo, Norway
| | - Yngvild Wasteson
- Department of Paraclinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Jørgen V Bjørnholt
- Department of Microbiology, Division of Laboratory Medicine, Oslo University Hospital, PB 4956 Nydalen, 0424, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lin T Brandal
- Department of Infectious Diseases and Prevention, Norwegian Institute of Public Health, Oslo, Norway
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Valid Presumption of Shiga Toxin-Mediated Damage of Developing Erythrocytes in EHEC-Associated Hemolytic Uremic Syndrome. Toxins (Basel) 2020; 12:toxins12060373. [PMID: 32512916 PMCID: PMC7354503 DOI: 10.3390/toxins12060373] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023] Open
Abstract
The global emergence of clinical diseases caused by enterohemorrhagic Escherichia coli (EHEC) is an issue of great concern. EHEC release Shiga toxins (Stxs) as their key virulence factors, and investigations on the cell-damaging mechanisms toward target cells are inevitable for the development of novel mitigation strategies. Stx-mediated hemolytic uremic syndrome (HUS), characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal injury, is the most severe outcome of an EHEC infection. Hemolytic anemia during HUS is defined as the loss of erythrocytes by mechanical disruption when passing through narrowed microvessels. The formation of thrombi in the microvasculature is considered an indirect effect of Stx-mediated injury mainly of the renal microvascular endothelial cells, resulting in obstructions of vessels. In this review, we summarize and discuss recent data providing evidence that HUS-associated hemolytic anemia may arise not only from intravascular rupture of erythrocytes, but also from the extravascular impairment of erythropoiesis, the development of red blood cells in the bone marrow, via direct Stx-mediated damage of maturing erythrocytes, leading to “non-hemolytic” anemia.
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10
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Nyong EC, Zaia SR, Allué-Guardia A, Rodriguez AL, Irion-Byrd Z, Koenig SSK, Feng P, Bono JL, Eppinger M. Pathogenomes of Atypical Non-shigatoxigenic Escherichia coli NSF/SF O157:H7/NM: Comprehensive Phylogenomic Analysis Using Closed Genomes. Front Microbiol 2020; 11:619. [PMID: 32351476 PMCID: PMC7175801 DOI: 10.3389/fmicb.2020.00619] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
The toxigenic conversion of Escherichia coli strains by Shiga toxin-converting (Stx) bacteriophages were prominent and recurring events in the stepwise evolution of enterohemorrhagic E. coli (EHEC) O157:H7 from an enteropathogenic (EPEC) O55:H7 ancestor. Atypical, attenuated isolates have been described for both non-sorbitol fermenting (NSF) O157:H7 and SF O157:NM serotypes, which are distinguished by the absence of Stx, the characteristic virulence hallmark of Stx-producing E. coli (STEC). Such atypical isolates either never acquired Stx-phages or may have secondarily lost stx during the course of infection, isolation, or routine subculture; the latter are commonly referred to as LST (Lost Shiga Toxin)-isolates. In this study we analyzed the genomes of 15 NSF O157:H7 and SF O157:NM strains from North America, Europe, and Asia that are characterized by the absence of stx, the virulence hallmark of STEC. The individual genomic basis of the Stx (-) phenotype has remained largely undetermined as the majority of STEC genomes in public genome repositories were generated using short read technology and are in draft stage, posing a major obstacle for the high-resolution whole genome sequence typing (WGST). The application of LRT (long-read technology) sequencing provided us with closed genomes, which proved critical to put the atypical non-shigatoxigenic NSF O157:H7 and SF O157:NM strains into the phylogenomic context of the stepwise evolutionary model. Availability of closed chromosomes for representative Stx (-) NSF O157:H7 and SF O157:NM strains allowed to describe the genomic basis and individual evolutionary trajectories underlying the absence of Stx at high accuracy and resolution. The ability of LRT to recover and accurately assemble plasmids revealed a strong correlation between the strains' featured plasmid genotype and chromosomally inferred clade, which suggests the coevolution of the chromosome and accessory plasmids. The identified ancestral traits in the pSFO157 plasmid of NSF O157:H7 strain LSU-61 provided additional evidence for its intermediate status. Taken together, these observations highlight the utility of LRTs for advancing our understanding of EHEC O157:H7/NM pathogenome evolution. Insights into the genomic and phenotypic plasticity of STEC on a lineage- and genome-wide scale are foundational to improve and inform risk assessment, biosurveillance, and prevention strategies.
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Affiliation(s)
- Emmanuel C. Nyong
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Sam R. Zaia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Anna Allué-Guardia
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Armando L. Rodriguez
- Research Computing Support Group, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Zaina Irion-Byrd
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | - Sara S. K. Koenig
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
| | | | - James L. Bono
- United States Meat Animal Research Center, Agricultural Research Service, United States Department of Agriculture (ARS-USDA), Clay Center, NE, United States
| | - Mark Eppinger
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, United States
- South Texas Center for Emerging Infectious Diseases, San Antonio, TX, United States
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11
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Garimano N, Amaral MM, Ibarra C. Endocytosis, Cytotoxicity, and Translocation of Shiga Toxin-2 Are Stimulated by Infection of Human Intestinal (HCT-8) Monolayers With an Hypervirulent E. coli O157:H7 Lacking stx2 Gene. Front Cell Infect Microbiol 2019; 9:396. [PMID: 31824869 PMCID: PMC6881261 DOI: 10.3389/fcimb.2019.00396] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/05/2019] [Indexed: 11/13/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) strains are responsible for multiple clinical syndromes, including hemolytic uremic syndrome (HUS). E. coli O157:H7 is the most prevalent serotype associated with HUS and produces a variety of virulence factors being Stx2 the responsible of the most HUS severe cases. After intestinal colonization by STEC, Stx2 is released into the intestinal lumen, translocated to the circulatory system and then binds to its receptor, globotriaosylceramide (Gb3), in target cells. Thus, Stx2 passage through the colonic epithelial barrier is a key step in order to produce disease, being its mechanisms still poorly understood. We have previously reported that STEC interaction with the human colonic mucosa enhanced Stx2 production. In the present work, we have demonstrated that infection with O157:H7Δstx2, a mutant unable to produce Stx2, enhanced either Stx2 cytotoxicity on an intestinal cell line (HCT-8), or translocation across HCT-8 monolayers. Moreover, we found that translocation was enhanced by both paracellular and transcellular pathways. Using specific endocytosis inhibitors, we have further demonstrated that the main mechanisms implicated on Stx2 endocytosis and translocation, either when O157:H7Δstx2 was present or not, were Gb3-dependent, but dynamin-independent. On the other hand, dynamin dependent endocytosis and macropinocytosis became more relevant only when O157:H7Δstx2 infection was present. Overall, this study highlights the effects of STEC infection on the intestinal epithelial cell host and the mechanisms underlying Stx2 endocytosis, cytotoxic activity and translocation, in the aim of finding new tools toward a therapeutic approach.
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Affiliation(s)
- Nicolás Garimano
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Facultad de Medicina, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Marta Amaral
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Facultad de Medicina, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Cristina Ibarra
- Laboratorio de Fisiopatogenia, Departamento de Fisiología, Facultad de Medicina, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Universidad de Buenos Aires, Buenos Aires, Argentina
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12
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To CZ, Bhunia AK. Three Dimensional Vero Cell-Platform for Rapid and Sensitive Screening of Shiga-Toxin Producing Escherichia coli. Front Microbiol 2019; 10:949. [PMID: 31134009 PMCID: PMC6514307 DOI: 10.3389/fmicb.2019.00949] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 04/15/2019] [Indexed: 01/27/2023] Open
Abstract
Shiga-toxin producing Escherichia coli (STEC) is a serious public health concern. Current Vero cell assay, although sensitive, is lengthy and requires 48-72 h to assess STEC presence in a sample. In this study, we investigated if Vero cells in a three-dimensional (3D) platform would provide improved sensitivity for rapid screening of STEC. Vero cells (epithelial kidney cell line) were grown as a monolayer (2D) or in a collagen-matrix (3D) and exposed to Shiga-toxin (Stx) preparation or STEC cells that were pre-exposed to antibiotics (mitomycin C, ciprofloxacin, or polymyxin B) for toxin induction. Lactate dehydrogenase (LDH) release from Vero cells was used as a biomarker for cytotoxicity. Modified tryptic soy broth (mTSB) as enrichment broth containing mitomycin C (2 μg/ml) or ciprofloxacin (100 ng/ml) significantly induced Stx production, which was further confirmed by the dot-immunoblot assay. The 3D Vero platform detected STEC after 6 h post-infection with cytotoxicity values ranging from 33 to 79%, which is considerably faster than the traditional 2D platform, when tested with STEC. The cytotoxicity for non-Stx producing bacteria, Salmonella, Listeria, Citrobacter, Serratia, and Hafnia was found to be below the cytotoxicity cutoff value of 15%. The detection limit for the 3D Vero cell assay was estimated to be 107 CFU/ml for bacteria and about 32 ng/ml for Stx in 6 h. STEC-inoculated ground beef samples (n = 27) resulted in 38-46% cytotoxicity, and the bacterial isolates (n = 42) from ground beef samples were further confirmed to be stx1 and stx2 positive in a multiplex PCR yielding a very low false-positive result. This 3D cell-based screening assay relies on mammalian cell pathogen interaction that can complement other molecular techniques for the detection of cell-free Stx or STEC cells from food samples for early detection and prevention.
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Affiliation(s)
- Celina Z. To
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, United States
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, United States
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States
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13
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Response to Questions Posed by the Food and Drug Administration Regarding Virulence Factors and Attributes that Define Foodborne Shiga Toxin-Producing Escherichia coli (STEC) as Severe Human Pathogens †. J Food Prot 2019; 82:724-767. [PMID: 30969806 DOI: 10.4315/0362-028x.jfp-18-479] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
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- NACMCF Executive Secretariat, * U.S. Department of Agriculture, Food Safety and Inspection Service, Office of Public Health Science, PP3, 9-178, 1400 Independence Avenue S.W., Washington, D.C. 20250-3700, USA
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14
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Ellis SJ, Yasir M, Browning DF, Busby SJW, Schüller S. Oxygen and contact with human intestinal epithelium independently stimulate virulence gene expression in enteroaggregative Escherichia coli. Cell Microbiol 2019; 21:e13012. [PMID: 30673154 PMCID: PMC6563437 DOI: 10.1111/cmi.13012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 12/14/2018] [Accepted: 01/14/2019] [Indexed: 12/22/2022]
Abstract
Enteroaggregative Escherichia coli (EAEC) are important intestinal pathogens causing acute and persistent diarrhoeal illness worldwide. Although many putative EAEC virulence factors have been identified, their association with pathogenesis remains unclear. As environmental cues can modulate bacterial virulence, we investigated the effect of oxygen and human intestinal epithelium on EAEC virulence gene expression to determine the involvement of respective gene products in intestinal colonisation and pathogenesis. Using in vitro organ culture of human intestinal biopsies, we established the colonic epithelium as the major colonisation site of EAEC strains 042 and 17‐2. We subsequently optimised a vertical diffusion chamber system with polarised T84 colon carcinoma cells for EAEC infection and showed that oxygen induced expression of the global regulator AggR, aggregative adherence fimbriae, E. coli common pilus, EAST‐1 toxin, and dispersin in EAEC strain 042 but not in 17‐2. Furthermore, the presence of T84 epithelia stimulated additional expression of the mucinase Pic and the toxins HlyE and Pet. This induction was dependent on physical host cell contact and did not require AggR. Overall, these findings suggest that EAEC virulence in the human gut is modulated by environmental signals including oxygen and the intestinal epithelium.
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Affiliation(s)
- Samuel J Ellis
- Norwich Medical School, University of East Anglia, Norwich, UK.,Quadram Institute Bioscience, Norwich, UK
| | - Muhammad Yasir
- Quadram Institute Bioscience, Norwich, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Douglas F Browning
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Stephen J W Busby
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Stephanie Schüller
- Norwich Medical School, University of East Anglia, Norwich, UK.,Quadram Institute Bioscience, Norwich, UK
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15
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Modulation of Enterohaemorrhagic Escherichia coli Survival and Virulence in the Human Gastrointestinal Tract. Microorganisms 2018; 6:microorganisms6040115. [PMID: 30463258 PMCID: PMC6313751 DOI: 10.3390/microorganisms6040115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 01/05/2023] Open
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) is a major foodborne pathogen responsible for human diseases ranging from diarrhoea to life-threatening complications. Survival of the pathogen and modulation of virulence gene expression along the human gastrointestinal tract (GIT) are key features in bacterial pathogenesis, but remain poorly described, due to a paucity of relevant model systems. This review will provide an overview of the in vitro and in vivo studies investigating the effect of abiotic (e.g., gastric acid, bile, low oxygen concentration or fluid shear) and biotic (e.g., gut microbiota, short chain fatty acids or host hormones) parameters of the human gut on EHEC survival and/or virulence (especially in relation with motility, adhesion and toxin production). Despite their relevance, these studies display important limitations considering the complexity of the human digestive environment. These include the evaluation of only one single digestive parameter at a time, lack of dynamic flux and compartmentalization, and the absence of a complex human gut microbiota. In a last part of the review, we will discuss how dynamic multi-compartmental in vitro models of the human gut represent a novel platform for elucidating spatial and temporal modulation of EHEC survival and virulence along the GIT, and provide new insights into EHEC pathogenesis.
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16
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Pro-inflammatory capacity of Escherichia coli O104:H4 outbreak strain during colonization of intestinal epithelial cells from human and cattle. Int J Med Microbiol 2018; 308:899-911. [PMID: 29937390 DOI: 10.1016/j.ijmm.2018.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/16/2018] [Indexed: 10/28/2022] Open
Abstract
In 2011, Germany was struck by the largest outbreak of hemolytic uremic syndrome. The highly virulent E. coli O104:H4 outbreak strain LB226692 possesses a blended virulence profile combining genetic patterns of human adapted enteroaggregative E. coli (EAEC), rarely detected in animal hosts before, and enterohemorrhagic E. coli (EHEC), a subpopulation of Shiga toxin (Stx)-producing E. coli (STEC) basically adapted to the ruminant host. This study aimed at appraising the relative level of adaptation of the EAEC/EHEC hybrid strain LB226692 to humans and cattle. Adherence and invasion of the hybrid strain to intestinal (jejunal and colonic) epithelial cells (IEC) of human and bovine origin was compared to that of E. coli strains representative of different pathovars and commensal E. coli by means of light and electron microscopy and culture. Strain-specific host gene transcription profiles of selected cytokines and chemokines as well as host-induced transcription of bacterial virulence genes were assessed. The release of Stx upon host cell contact was quantified. The outbreak strain's immunomodulation was assessed by cultivating primary bovine macrophages with conditioned supernatants from IEC infection studies with E. coli, serving as model for the innate immunity of the bovine gut. The outbreak strain adhered to IEC of both, human and bovine origin. Electron microscopy of infected cells revealed the strain's particular affinity to human small IEC, in contrast to few interactions with bovine small IEC. The outbreak strain possessed a high-level of adhesive power, similar to human-associated E. coli strains and in contrast to bovine-associated STEC strains. The outbreak strain displayed a non-invasive phenotype, in contrast to some bovine-associated E. coli strains, which were invasive. The outbreak strain provoked some pro-inflammatory activity in human cells, but to a lower extent as compared to other pathotypes. In contrasts to bovine-associated E. coli strains, the outbreak strain induced marked pro-inflammatory activity when interacting with bovine host cells directly (IEC) and indirectly (macrophages). Among stx2-positive strains, the human-pathogenic strains (LB226692 and EHEC strain 86-24) released higher amounts of Stx compared to bovine-associated STEC. The findings imply that the outbreak strain is rather adapted to humans than to cattle. However, the outbreak strain's potential to colonize IEC of both host species and the rather mixed reaction patterns observed for all strains under study indicate, that even STEC strains with an unusual genotype as the EHEC O104:H4 outbreak strain, i.e. with an EAEC genetic background, may be able to conquer other reservoir hosts.
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17
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Tran SL, Jenkins C, Livrelli V, Schüller S. Shiga toxin 2 translocation across intestinal epithelium is linked to virulence of Shiga toxin-producing Escherichia coli in humans. MICROBIOLOGY-SGM 2018. [PMID: 29533744 PMCID: PMC5982136 DOI: 10.1099/mic.0.000645] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Shiga toxin-producing Escherichia coli (STEC) are characterized by the release of potent Shiga toxins (Stx), which are associated with severe intestinal and renal disease. Although all STEC strains produce Stx, only a few serotypes cause infection in humans. To determine which virulence traits in vitro are linked to human disease in vivo, 13 Stx2a-producing STEC strains of seropathotype (SPT) A or B (associated with severe human intestinal disease and outbreaks) and 6 strains of SPT D or E (rarely or not linked to human disease) were evaluated in a microaerobic human colonic epithelial infection model. All SPT strains demonstrated similar growth, colonization of polarized T84 colon carcinoma cells and Stx release into the medium. In contrast, Stx translocation across the T84 cell monolayer was significantly lower in SPT group DE compared to SPT group AB strains. Further experiments showed that Stx penetration occurred via a transcellular pathway and was independent of bacterial type III secretion and attaching and effacing lesion formation. These results suggest that the extent of Stx transcytosis across the gut epithelium may represent an important indicator of STEC pathogenicity for humans.
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Affiliation(s)
- Seav-Ly Tran
- Norwich Medical School, University of East Anglia, Norwich, UK.,Gut Health and Food Safety Programme, Quadram Institute Bioscience, Norwich, UK.,Present address: Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Claire Jenkins
- Gastrointestinal Bacteria Reference Unit, Public Health England, London, UK
| | - Valérie Livrelli
- Université Clermont Auvergne, Inserm U1071, M2iSH 'Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte', USC-INRA 2018, Clermont-Ferrand, France.,CHU Clermont-Ferrand, Service de Bactériologie, Parasitologie Mycologie, Clermont-Ferrand, France
| | - Stephanie Schüller
- Norwich Medical School, University of East Anglia, Norwich, UK.,Gut Health and Food Safety Programme, Quadram Institute Bioscience, Norwich, UK
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18
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Kampmeier S, Berger M, Mellmann A, Karch H, Berger P. The 2011 German Enterohemorrhagic Escherichia Coli O104:H4 Outbreak-The Danger Is Still Out There. Curr Top Microbiol Immunol 2018; 416:117-148. [PMID: 30062592 DOI: 10.1007/82_2018_107] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin (Stx) producing bacteria causing a disease characterized by bloody (or non-bloody) diarrhea, which might progress to hemolytic uremic syndrome (HUS). EHEC O104:H4 caused the largest ever recorded EHEC outbreak in Germany in 2011, which in addition showed the so far highest incidence rate of EHEC-related HUS worldwide. The aggressive outbreak strain carries an unusual combination of virulence traits characteristic to both EHEC-a chromosomally integrated Stx-encoding bacteriophage, and enteroaggregative Escherichia coli-pAA plasmid-encoded aggregative adherence fimbriae mediating its tight adhesion to epithelia cells. There are currently still open questions regarding the 2011 EHEC outbreak, e.g., with respect to the exact molecular mechanisms resulting in the hypervirulence of the strain, the natural reservoir of EHEC O104:H4, and suitable therapeutic strategies. Nevertheless, our knowledge on these issues has substantially expanded since 2011. Here, we present an overview of the epidemiological, clinical, microbiological, and molecular biological data available on the 2011 German EHEC O104:H4 outbreak.
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Affiliation(s)
| | - Michael Berger
- Institute of Hygiene, University of Münster, Münster, Germany
| | | | - Helge Karch
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Petya Berger
- Institute of Hygiene, University of Münster, Münster, Germany.
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19
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Böhnlein C, Kabisch J, Meske D, Franz CMAP, Pichner R. Fitness of Enterohemorrhagic Escherichia coli (EHEC)/Enteroaggregative E. coli O104:H4 in Comparison to That of EHEC O157: Survival Studies in Food and In Vitro. Appl Environ Microbiol 2016; 82:6326-6334. [PMID: 27542931 PMCID: PMC5066349 DOI: 10.1128/aem.01796-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/10/2016] [Indexed: 11/20/2022] Open
Abstract
In 2011, one of the world's largest outbreaks of hemolytic-uremic syndrome (HUS) occurred, caused by a rare Escherichia coli serotype, O104:H4, that shared the virulence profiles of Shiga toxin-producing E. coli (STEC)/enterohemorrhagic E. coli (EHEC) and enteroaggregative E. coli (EAEC). The persistence and fitness factors of the highly virulent EHEC/EAEC O104:H4 strain, grown either in food or in vitro, were compared with those of E. coli O157 outbreak-associated strains. The log reduction rates of the different EHEC strains during the maturation of fermented sausages were not significantly different. Both the O157:NM and O104:H4 serotypes could be shown by qualitative enrichment to be present after 60 days of sausage storage. Moreover, the EHEC/EAEC O104:H4 strain appeared to be more viable than E. coli O157:H7 under conditions of decreased pH and in the presence of sodium nitrite. Analysis of specific EHEC strains in experiments with an EHEC inoculation cocktail showed a dominance of EHEC/EAEC O104:H4, which could be isolated from fermented sausages for 60 days. Inhibitory activities of EHEC/EAEC O104:H4 toward several E. coli strains, including serotype O157 strains, could be determined. Our study suggests that EHEC/EAEC O104:H4 is well adapted to the multiple adverse conditions occurring in fermented raw sausages. Therefore, it is strongly recommended that STEC strain cocktails composed of several serotypes, instead of E. coli O157:H7 alone, be used in food risk assessments. The enhanced persistence of EHEC/EAEC O104:H4 as a result of its robustness, as well as the production of bacteriocins, may account for its extraordinary virulence potential. IMPORTANCE In 2011, a severe outbreak caused by an EHEC/EAEC serovar O104:H4 strain led to many HUS sequelae. In this study, the persistence of the O104:H4 strain was compared with those of other outbreak-relevant STEC strains under conditions of fermented raw sausage production. Both O157:NM and O104:H4 strains could survive longer during the production of fermented sausages than E. coli O157:H7 strains. E. coli O104:H4 was also shown to be well adapted to the multiple adverse conditions encountered in fermented sausages, and the secretion of a bacteriocin may explain the competitive advantage of this strain in an EHEC strain cocktail. Consequently, this study strongly suggests that enhanced survival and persistence, and the presumptive production of a bacteriocin, may explain the increased virulence of the O104:H4 outbreak strain. Furthermore, this strain appears to be capable of surviving in a meat product, suggesting that meat should not be excluded as a source of potential E. coli O104:H4 infection.
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Affiliation(s)
- Christina Böhnlein
- Department of Microbiology and Biotechnology, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Kiel, Germany
| | - Jan Kabisch
- Department of Microbiology and Biotechnology, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Kiel, Germany
| | - Diana Meske
- Department of Microbiology and Biotechnology, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Kiel, Germany
| | - Charles M A P Franz
- Department of Microbiology and Biotechnology, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Kiel, Germany
| | - Rohtraud Pichner
- Department of Microbiology and Biotechnology, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Kiel, Germany Department of Nutritional, Food, and Consumer Sciences, University of Applied Sciences, Fulda, Germany
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20
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Cordonnier C, Thévenot J, Etienne-Mesmin L, Alric M, Livrelli V, Blanquet-Diot S. Probiotic and enterohemorrhagic Escherichia coli: An effective strategy against a deadly enemy? Crit Rev Microbiol 2016; 43:116-132. [PMID: 27798976 DOI: 10.1080/1040841x.2016.1185602] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are major food-borne pathogens that constitute a serious public health threat. Currently, there is no specific treatment available for EHEC infections in human creating an urgent need for the development of alternative therapeutic strategies. Among them, one of the most promising approaches is the use of probiotic microorganisms. Even if many studies have shown the antagonistic effects of probiotic bacteria or yeast on EHEC survival, virulence, adhesion on intestinal epithelium or pathogen-induced inflammatory responses, mechanisms mediating their beneficial effects remain unclear. This review describes EHEC pathogenesis and novel therapeutic strategies, with a particular emphasis on probiotics. The interests and limits of a probiotic-based approach and the way it might be incorporated into global health strategies against EHEC infections will be discussed.
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Affiliation(s)
- Charlotte Cordonnier
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France.,b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France
| | - Jonathan Thévenot
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France.,b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France
| | - Lucie Etienne-Mesmin
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France.,b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France
| | - Monique Alric
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France
| | - Valérie Livrelli
- b M2iSH, "Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte" , UMR Inserm/Université d'Auvergne U1071, USC-INRA 2018, Centre de Recherche en Nutrition Humaine Auvergne, Université d'Auvergne , Clermont-Ferrand , France.,c Service de Bactériologie , CHU Clermont-Ferrand , Clermont-Ferrand , France
| | - Stéphanie Blanquet-Diot
- a EA 4678 CIDAM, "Conception, Ingénierie et Développement de l'Aliment et du Médicament", Centre de Recherche en Nutrition Humaine Auvergne , Université d'Auvergne , Clermont-Ferrand , France
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21
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Wallace N, Zani A, Abrams E, Sun Y. The Impact of Oxygen on Bacterial Enteric Pathogens. ADVANCES IN APPLIED MICROBIOLOGY 2016; 95:179-204. [PMID: 27261784 DOI: 10.1016/bs.aambs.2016.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bacterial enteric pathogens are responsible for a tremendous amount of foodborne illnesses every year through the consumption of contaminated food products. During their transit from contaminated food sources to the host gastrointestinal tract, these pathogens are exposed and must adapt to fluctuating oxygen levels to successfully colonize the host and cause diseases. However, the majority of enteric infection research has been conducted under aerobic conditions. To raise awareness of the importance in understanding the impact of oxygen, or lack of oxygen, on enteric pathogenesis, we describe in this review the metabolic and physiological responses of nine bacterial enteric pathogens exposed to environments with different oxygen levels. We further discuss the effects of oxygen levels on virulence regulation to establish potential connections between metabolic adaptations and bacterial pathogenesis. While not providing an exhaustive list of all bacterial pathogens, we highlight key differences and similarities among nine facultative anaerobic and microaerobic pathogens in this review to argue for a more in-depth understanding of the diverse impact oxygen levels have on enteric pathogenesis.
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Affiliation(s)
- N Wallace
- University of Dayton, Dayton, OH, United States
| | - A Zani
- University of Dayton, Dayton, OH, United States
| | - E Abrams
- University of Dayton, Dayton, OH, United States
| | - Y Sun
- University of Dayton, Dayton, OH, United States
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22
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Kunsmann L, Rüter C, Bauwens A, Greune L, Glüder M, Kemper B, Fruth A, Wai SN, He X, Lloubes R, Schmidt MA, Dobrindt U, Mellmann A, Karch H, Bielaszewska M. Virulence from vesicles: Novel mechanisms of host cell injury by Escherichia coli O104:H4 outbreak strain. Sci Rep 2015; 5:13252. [PMID: 26283502 PMCID: PMC4539607 DOI: 10.1038/srep13252] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/22/2015] [Indexed: 12/27/2022] Open
Abstract
The highly virulent Escherichia coli O104:H4 that caused the large 2011 outbreak of diarrhoea and haemolytic uraemic syndrome secretes blended virulence factors of enterohaemorrhagic and enteroaggregative E. coli, but their secretion pathways are unknown. We demonstrate that the outbreak strain releases a cocktail of virulence factors via outer membrane vesicles (OMVs) shed during growth. The OMVs contain Shiga toxin (Stx) 2a, the major virulence factor of the strain, Shigella enterotoxin 1, H4 flagellin, and O104 lipopolysaccharide. The OMVs bind to and are internalised by human intestinal epithelial cells via dynamin-dependent and Stx2a-independent endocytosis, deliver the OMV-associated virulence factors intracellularly and induce caspase-9-mediated apoptosis and interleukin-8 secretion. Stx2a is the key OMV component responsible for the cytotoxicity, whereas flagellin and lipopolysaccharide are the major interleukin-8 inducers. The OMVs represent novel ways for the E. coli O104:H4 outbreak strain to deliver pathogenic cargoes and injure host cells.
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Affiliation(s)
- Lisa Kunsmann
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, 48149 Münster, Germany
| | - Christian Rüter
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149 Münster, Germany
| | - Andreas Bauwens
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, 48149 Münster, Germany
| | - Lilo Greune
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149 Münster, Germany
| | - Malte Glüder
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, 48149 Münster, Germany
| | - Björn Kemper
- Biomedical Technology Center, University of Muenster, 48149 Münster, Germany
| | - Angelika Fruth
- National Reference Center for Salmonella and Other Enteric Pathogens, Robert Koch Institute, Branch Wernigerode, 38855 Wernigerode, Germany
| | - Sun Nyunt Wai
- Department of Molecular Biology, Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, S-90187 Umeå, Sweden
| | - Xiaohua He
- Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture (USDA), Albany, CA 94710, USA
| | - Roland Lloubes
- Laboratoire d'Ingenierie des Systemes Macromoleculaires UMR7255, CNRS-Aix-Marseille Université, 13402 Marseille cedex 20, France
| | - M Alexander Schmidt
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149 Münster, Germany
| | - Ulrich Dobrindt
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, 48149 Münster, Germany
| | - Alexander Mellmann
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, 48149 Münster, Germany
| | - Helge Karch
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, 48149 Münster, Germany
| | - Martina Bielaszewska
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, 48149 Münster, Germany
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23
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Boisen N, Hansen AM, Melton-Celsa AR, Zangari T, Mortensen NP, Kaper JB, O'Brien AD, Nataro JP. The presence of the pAA plasmid in the German O104:H4 Shiga toxin type 2a (Stx2a)-producing enteroaggregative Escherichia coli strain promotes the translocation of Stx2a across an epithelial cell monolayer. J Infect Dis 2014; 210:1909-19. [PMID: 25038258 DOI: 10.1093/infdis/jiu399] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND A Shiga toxin type 2a (Stx2a)-producing enteroaggregative Escherichia coli (EAEC) strain of serotype O104:H4 caused a large outbreak in 2011 in northern Europe. Pathogenic mechanisms for this strain are unclear. We hypothesized that EAEC genes encoded on the pAA virulence plasmid promoted the translocation of Stx2a across the intestinal mucosa. METHODS We investigated the potential contribution of pAA by using mutants of Stx-EAEC strain C227-11, either cured of the pAA plasmid or deleted for individual known pAA-encoded virulence genes (ie, aggR, aggA, and sepA). The resulting mutants were tested for their ability to induce interleukin 8 (IL-8) secretion and translocation of Stx2a across a polarized colonic epithelial (T84 cell) monolayer. RESULTS We found that deletion of aggR or aggA significantly reduced bacterial adherence and (independently) translocation of Stx2a across the T84-cell monolayer. Moreover, deletion of aggR, aggA, sepA, or the Stx2a-encoding phage from C227-11 resulted in reduced secretion of IL-8 from the infected monolayer. CONCLUSIONS Our data suggest that the AggR-regulated aggregative adherence fimbriae I enhance inflammation and enable the outbreak strain to both adhere to epithelial cells and translocate Stx2a across the intestinal epithelium.
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Affiliation(s)
- Nadia Boisen
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville
| | - Anne-Marie Hansen
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore
| | - Angela R Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Tonia Zangari
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Ninell Pollas Mortensen
- Technology for Industry and the Environment, Discovery-Science-Technology, RTI International, Research Triangle Park, North Carolina Biological and Nanoscale Systems, BioSciences Division, Oak Ridge National Laboratory, Tennessee
| | - James B Kaper
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore
| | - Alison D O'Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - James P Nataro
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville
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24
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Hostetter SJ, Helgerson AF, Paton JC, Paton AW, Cornick NA. Therapeutic use of a receptor mimic probiotic reduces intestinal Shiga toxin levels in a piglet model of hemolytic uremic syndrome. BMC Res Notes 2014; 7:331. [PMID: 24890228 PMCID: PMC4049369 DOI: 10.1186/1756-0500-7-331] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 05/26/2014] [Indexed: 12/31/2022] Open
Abstract
Background Hemolytic uremic syndrome (HUS) is a systemic and potentially fatal complication of gastroenteritis secondary to Shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) infection characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal damage. Shiga toxin (Stx), the toxin principle in HUS, is produced locally within the gut following EHEC colonization and is disseminated via the vasculature. Clinical development of HUS currently has no effective treatment and is a leading cause of renal failure in children. Novel post-exposure therapies are currently needed for HUS; therefore, the purpose of this study was to investigate the efficacy of a Stx receptor mimic probiotic in a porcine model of HUS. Edema disease, an infection of swine caused by host adapted Shiga toxin-producing Escherichia coli (STEC) and mediated by Shiga toxin 2e (Stx2e), shares many pathogenic similarities to HUS. In this study, three-week old piglets were inoculated with STEC and 24 hours later treated twice daily with a probiotic expressing an oligosaccharide receptor mimic for Stx2e to determine if the probiotic could reduce intestinal toxin levels. Methods Piglets were orally inoculated with 1010 CFU of STEC strain S1191 eight days after weaning. Beginning day 1 post-inoculation, piglets were treated orally twice daily with 5 × 1011 CFU of either the receptor mimic probiotic or a sham probiotic for 10 days. Intestinal Stx2e levels were assessed daily via Vero cell assay. The efficacy of the probiotic at reducing intestinal Stx2e, vascular lesions, and clinical disease was evaluated with repeated measures ANOVA and Fisher’s exact test as appropriate. Results The probiotic significantly reduced intestinal Stx2e, as reflected by decreased fecal toxin titers on days 3–8 post-inoculation (p < 0.01). Despite this reduction in intestinal toxin levels, however, the probiotic failed to reduce the incidence of vascular necrosis in target organs and had no effect on clinical disease. Conclusions The data suggest that post-exposure treatment with a Stx-binding probiotic is effective in reducing intestinal toxin burden. Future studies could target this approach for possible development of post-exposure interventions.
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Affiliation(s)
- Shannon J Hostetter
- Department of Veterinary Pathology, Iowa State University, 1600 S, 16th Street, Ames, IA 50011-1250, USA.
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