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Cognitive Deficits Found in a Pro-inflammatory State are Independent of ERK1/2 Signaling in the Murine Brain Hippocampus Treated with Shiga Toxin 2 from Enterohemorrhagic Escherichia coli. Cell Mol Neurobiol 2022:10.1007/s10571-022-01298-1. [PMID: 36227397 DOI: 10.1007/s10571-022-01298-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 10/05/2022] [Indexed: 11/03/2022]
Abstract
Shiga toxin 2 (Stx2) from enterohemorrhagic Escherichia coli (EHEC) produces hemorrhagic colitis, hemolytic uremic syndrome (HUS), and acute encephalopathy. The mortality rate in HUS increases significantly when the central nervous system (CNS) is involved. Besides, EHEC also releases lipopolysaccharide (LPS). Many reports have described cognitive dysfunctions in HUS patients, the hippocampus being one of the brain areas targeted by EHEC infection. In this context, a translational murine model of encephalopathy was employed to establish the deleterious effects of Stx2 and the contribution of LPS in the hippocampus. The purpose of this work is to elucidate the signaling pathways that may activate the inflammatory processes triggered by Stx2, which produces cognitive alterations at the level of the hippocampus. Results demonstrate that Stx2 produced depression-like behavior, pro-inflammatory cytokine release, and NF-kB activation independent of the ERK1/2 signaling pathway, while co-administration of Stx2 and LPS reduced memory index. On the other hand, LPS activated NF-kB dependent on ERK1/2 signaling pathway. Cotreatment of Stx2 with LPS aggravated the pathologic state, while dexamethasone treatment succeeded in preventing behavioral alterations. Our present work suggests that the use of drugs such as corticosteroids or NF-kB signaling inhibitors may serve as neuroprotectors from EHEC infection.
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Lodato PB. The effect of two ribonucleases on the production of Shiga toxin and stx-bearing bacteriophages in Enterohaemorrhagic Escherichia coli. Sci Rep 2021; 11:18372. [PMID: 34526533 PMCID: PMC8443680 DOI: 10.1038/s41598-021-97736-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/27/2021] [Indexed: 11/20/2022] Open
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) comprise a group of intestinal pathogens responsible for a range of illnesses, including kidney failure and neurological compromise. EHEC produce critical virulence factors, Shiga toxin (Stx) 1 or 2, and the synthesis of Stx2 is associated with worse disease manifestations. Infected patients only receive supportive treatment because some conventional antibiotics enable toxin production. Shiga toxin 2 genes (stx2) are carried in λ-like bacteriophages (stx2-phages) inserted into the EHEC genome as prophages. Factors that cause DNA damage induce the lytic cycle of stx2-phages, leading to Stx2 production. The phage Q protein is critical for transcription antitermination of stx2 and phage lytic genes. This study reports that deficiency of two endoribonucleases (RNases), E and G, significantly delayed cell lysis and impaired production of both Stx2 and stx2-phages, unlike deficiency of either enzyme alone. Moreover, scarcity of both enzymes reduced the concentrations of Q and stx2 transcripts and slowed cell growth.
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Affiliation(s)
- Patricia B Lodato
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA.
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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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Exeni RA, Fernandez-Brando RJ, Santiago AP, Fiorentino GA, Exeni AM, Ramos MV, Palermo MS. Pathogenic role of inflammatory response during Shiga toxin-associated hemolytic uremic syndrome (HUS). Pediatr Nephrol 2018; 33:2057-2071. [PMID: 29372302 DOI: 10.1007/s00467-017-3876-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 11/01/2017] [Accepted: 12/07/2017] [Indexed: 01/22/2023]
Abstract
Hemolytic uremic syndrome (HUS) is defined as a triad of noninmune microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. The most frequent presentation is secondary to Shiga toxin (Stx)-producing Escherichia coli (STEC) infections, which is termed postdiarrheal, epidemiologic or Stx-HUS, considering that Stx is the necessary etiological factor. After ingestion, STEC colonize the intestine and produce Stx, which translocates across the intestinal epithelium. Once Stx enters the bloodstream, it interacts with renal endothelial and epithelial cells, and leukocytes. This review summarizes the current evidence about the involvement of inflammatory components as central pathogenic factors that could determine outcome of STEC infections. Intestinal inflammation may favor epithelial leakage and subsequent passage of Stx to the systemic circulation. Vascular damage triggered by Stx promotes not only release of thrombin and increased fibrin concentration but also production of cytokines and chemokines by endothelial cells. Recent evidence from animal models and patients strongly indicate that several immune cells types may participate in HUS physiopathology: neutrophils, through release of proteases and reactive oxygen species (ROS); monocytes/macrophages through secretion of cytokines and chemokines. In addition, high levels of Bb factor and soluble C5b-9 (sC5b-9) in plasma as well as complement factors adhered to platelet-leukocyte complexes, microparticles and microvesicles, suggest activation of the alternative pathway of complement. Thus, acute immune response secondary to STEC infection, the Stx stimulatory effect on different immune cells, and inflammatory stimulus secondary to endothelial damage all together converge to define a strong inflammatory status that worsens Stx toxicity and disease.
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Affiliation(s)
- Ramon Alfonso Exeni
- Departamento de Nefrología, Hospital Municipal del Niño, San Justo, Provincia de Buenos Aires, Argentina
| | - Romina Jimena Fernandez-Brando
- Laboratorio de Patogénesis e Inmunología de Procesos Infecciosos, Instituto de Medicina Experimental Medicine (IMEX-CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina
| | - Adriana Patricia Santiago
- Departamento de Nefrología, Hospital Municipal del Niño, San Justo, Provincia de Buenos Aires, Argentina
| | - Gabriela Alejandra Fiorentino
- Laboratorio de Patogénesis e Inmunología de Procesos Infecciosos, Instituto de Medicina Experimental Medicine (IMEX-CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina
- Laboratorio, Hospital Municipal del Niño, San Justo, Provincia de Buenos Aires, Argentina
| | - Andrea Mariana Exeni
- Servicio de Nefrología, Hospital Austral, Pilar, Provincia de Buenos Aires, Argentina
| | - Maria Victoria Ramos
- Laboratorio de Patogénesis e Inmunología de Procesos Infecciosos, Instituto de Medicina Experimental Medicine (IMEX-CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina
| | - Marina Sandra Palermo
- Laboratorio de Patogénesis e Inmunología de Procesos Infecciosos, Instituto de Medicina Experimental Medicine (IMEX-CONICET), Academia Nacional de Medicina, Buenos Aires, Argentina.
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Niu S, Paluszynski J, Bian Z, Shi L, Kidder K, Liu Y. LPS-primed CD11b + leukocytes serve as an effective carrier of Shiga toxin 2 to cause hemolytic uremic syndrome in mice. Sci Rep 2018; 8:3994. [PMID: 29507316 PMCID: PMC5838166 DOI: 10.1038/s41598-018-22327-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 02/21/2018] [Indexed: 12/05/2022] Open
Abstract
Shiga toxin (Stx)-induced hemolytic uremic syndrome (HUS) is a life-threatening complication associated with Stx-producing Escherichia coli infection. One critical barrier of understanding HUS is how Stx transports from infected intestine to kidney to cause HUS. Passive dissemination seems unlikely, while circulating blood cells have been debated to serve as the toxin carrier. Employing a murine model of Stx2-induced HUS with LPS priming (LPS-Stx2), we investigate how Stx causes HUS and identify possible toxin carrier. We show that peripheral white blood cells (WBC), but not other blood cells or cell-free plasma, carry Stx2 in LPS-Stx2-treated mice. The capability of WBC binding to Stx2 is confirmed in brief ex vivo Stx2 incubation, and adoptively transferring these Stx2-bound WBC into mice induces HUS. Cell separation further identifies a subpopulation in the CD11b+ myeloid leukocytes not the CD11b− lymphocytes group act as the toxin carrier, which captures Stx2 upon exposure and delivers the toxin in vivo. Interestingly, LPS-induced inflammation significantly augments these leukocytes for binding to Stx2 and enhances HUS toxicity. Our results demonstrate that a specific fraction of circulating leukocytes carry Stx2 and cause HUS in vivo, and that LPS priming enhances the carrier capacity and aggravates organ damage.
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Affiliation(s)
- Shuo Niu
- Program of Immunology & Molecular Cellular Biology, Department of Biology, Center for Diagnostics & Therapeutics, Center of Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA, 30302, USA
| | - John Paluszynski
- Program of Immunology & Molecular Cellular Biology, Department of Biology, Center for Diagnostics & Therapeutics, Center of Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA, 30302, USA
| | - Zhen Bian
- Program of Immunology & Molecular Cellular Biology, Department of Biology, Center for Diagnostics & Therapeutics, Center of Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA, 30302, USA
| | - Lei Shi
- Program of Immunology & Molecular Cellular Biology, Department of Biology, Center for Diagnostics & Therapeutics, Center of Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA, 30302, USA
| | - Koby Kidder
- Program of Immunology & Molecular Cellular Biology, Department of Biology, Center for Diagnostics & Therapeutics, Center of Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA, 30302, USA
| | - Yuan Liu
- Program of Immunology & Molecular Cellular Biology, Department of Biology, Center for Diagnostics & Therapeutics, Center of Inflammation, Immunity and Infection, Georgia State University, Atlanta, GA, 30302, USA.
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ppGpp and cytotoxicity diversity in Shiga toxin-producing Escherichia coli (STEC) isolates. Epidemiol Infect 2017; 145:2204-2211. [PMID: 28587697 DOI: 10.1017/s0950268817001091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a known food pathogen, which main reservoir is the intestine of ruminants. The abundance of different STEC lineages in nature reflect a heterogeneity that is characterised by the differential expression of certain genotypic characteristics, which in turn are influenced by the environmental conditions to which the microorganism is exposed. Bacterial homeostasis and stress response are under the control of the alarmone guanosine tetraphosphate (ppGpp), which intrinsic levels varies across the E. coli species. In the present study, 50 STEC isolates from healthy sheep were evaluated regarding their ppGpp content, cytotoxicity and other relevant genetic and phenotypic characteristics. We found that the level of ppGpp and cytotoxicity varied considerably among the examined strains. Isolates that harboured the stx2 gene were the least cytotoxic and presented the highest levels of ppGpp. All stx2 isolates belonged to phylogroup A, while strains that carried stx1 or both stx1 and stx2 genes pertained to phylogroup B1. All but two stx2 isolates belonged to the stx2b subtype. Strains that belonged to phylogroup B1 displayed on average low levels of ppGpp and high cytotoxicity. Overall, there was a negative correlation between cytotoxicity and ppGpp.
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Moxley RA, Francis DH, Tamura M, Marx DB, Santiago-Mateo K, Zhao M. Efficacy of Urtoxazumab (TMA-15 Humanized Monoclonal Antibody Specific for Shiga Toxin 2) Against Post-Diarrheal Neurological Sequelae Caused by Escherichia coli O157:H7 Infection in the Neonatal Gnotobiotic Piglet Model. Toxins (Basel) 2017; 9:toxins9020049. [PMID: 28134751 PMCID: PMC5331429 DOI: 10.3390/toxins9020049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 12/17/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is the most common cause of hemorrhagic colitis and hemolytic uremic syndrome in human patients, with brain damage and dysfunction the main cause of acute death. We evaluated the efficacy of urtoxazumab (TMA-15, Teijin Pharma Limited), a humanized monoclonal antibody against Shiga toxin (Stx) 2 for the prevention of brain damage, dysfunction, and death in a piglet EHEC infection model. Forty-five neonatal gnotobiotic piglets were inoculated orally with 3 × 109 colony-forming units of EHEC O157:H7 strain EDL933 (Stx1+, Stx2+) when 22–24 h old. At 24 h post-inoculation, piglets were intraperitoneally administered placebo or TMA-15 (0.3, 1.0 or 3.0 mg/kg body weight). Compared to placebo (n = 10), TMA-15 (n = 35) yielded a significantly greater probability of survival, length of survival, and weight gain (p <0.05). The efficacy of TMA-15 against brain lesions and death was 62.9% (p = 0.0004) and 71.4% (p = 0.0004), respectively. These results suggest that TMA-15 may potentially prevent or reduce vascular necrosis and infarction of the brain attributable to Stx2 in human patients acutely infected with EHEC. However, we do not infer that TMA-15 treatment will completely protect human patients infected with EHEC O157:H7 strains that produce both Stx1 and Stx2.
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Affiliation(s)
- Rodney A Moxley
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
| | - David H Francis
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD 57007, USA.
| | - Mizuho Tamura
- Teijin Pharma Limited, Pharmacology Research Department, 4-3-2 Asahigaoka, Hino, Tokyo 191-8512, Japan.
| | - David B Marx
- Department of Statistics, University of Nebraska-Lincoln, Lincoln, NE 68583, USA.
| | - Kristina Santiago-Mateo
- Canadian Food Inspection Agency, Lethbridge Laboratory, Box 640 TWP Rd 9-1, Lethbridge, AB T1J 3Z4, Canada.
| | - Mojun Zhao
- Valley Pathologists, Inc., 1100 South Main Street, Suite 308, Dayton, OH 45409, USA.
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Steil D, Bonse R, Meisen I, Pohlentz G, Vallejo G, Karch H, Müthing J. A Topographical Atlas of Shiga Toxin 2e Receptor Distribution in the Tissues of Weaned Piglets. Toxins (Basel) 2016; 8:toxins8120357. [PMID: 27916888 PMCID: PMC5198551 DOI: 10.3390/toxins8120357] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 01/08/2023] Open
Abstract
Shiga toxin (Stx) 2e of Stx-producing Escherichia coli (STEC) is the primary virulence factor in the development of pig edema disease shortly after weaning. Stx2e binds to the globo-series glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer, Galα1-4Galβ1-4Glcβ1-1Cer) and globotetraosylceramide (Gb4Cer, GalNAcβ1-3Galα1-4Galβ1-4Glcβ1-1Cer), the latter acting as the preferential Stx2e receptor. We determined Stx receptor profiles of 25 different tissues of a male and a female weaned piglet using immunochemical solid phase binding assays combined with mass spectrometry. All probed tissues harbored GSL receptors, ranging from high (category I) over moderate (category II) to low content (category III). Examples of Gb4Cer expression in category I tissues are small intestinal ileum, kidney pelvis and whole blood, followed by colon, small intestinal duodenum and jejunum belonging to category II, and kidney cortex, cerebrum and cerebellum as members of category III organs holding true for both genders. Dominant Gb3Cer and Gb4Cer lipoforms were those with ceramides carrying constant sphingosine (d18:1) and a variable C16:0, C22:0 or C24:1/C24:0 fatty acid. From the mapping data, we created a topographical atlas for Stx2e receptors in piglet tissues and organs, which might be helpful to further investigations on the molecular and cellular mechanisms that underlie infections of Stx2e-producing STEC in pigs and their zoonotic potential for humans.
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Affiliation(s)
- Daniel Steil
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.
| | - Robert Bonse
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.
| | - Iris Meisen
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.
| | | | - German Vallejo
- Veterinary practice Dr. med. vet. K. Nolte and Dr. med. vet. G. Vallejo, D-48329 Havixbeck, Germany.
| | - Helge Karch
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.
| | - Johannes Müthing
- Institute for Hygiene, University of Münster, D-48149 Münster, Germany.
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Obata F, Hippler LM, Saha P, Jandhyala DM, Latinovic OS. Shiga toxin type-2 (Stx2) induces glutamate release via phosphoinositide 3-kinase (PI3K) pathway in murine neurons. Front Mol Neurosci 2015; 8:30. [PMID: 26236186 PMCID: PMC4501177 DOI: 10.3389/fnmol.2015.00030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 06/29/2015] [Indexed: 01/17/2023] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) can cause central nervous system (CNS) damage resulting in paralysis, seizures, and coma. The key STEC virulence factors associated with systemic illness resulting in CNS impairment are Shiga toxins (Stx). While neurons express the Stx receptor globotriaosylceramide (Gb3) in vivo, direct toxicity to neurons by Stx has not been studied. We used murine neonatal neuron cultures to study the interaction of Shiga toxin type 2 (Stx2) with cell surface expressed Gb3. Single molecule imaging three dimensional STochastic Optical Reconstruction Microscopy—Total Internal Reflection Fluorescence (3D STORM-TIRF) allowed visualization and quantification of Stx2-Gb3 interactions. Furthermore, we demonstrate that Stx2 increases neuronal cytosolic Ca2+, and NMDA-receptor inhibition blocks Stx2-induced Ca2+ influx, suggesting that Stx2-mediates glutamate release. Phosphoinositide 3-kinase (PI3K)-specific inhibition by Wortmannin reduces Stx2-induced intracellular Ca2+ indicating that the PI3K signaling pathway may be involved in Stx2-associated glutamate release, and that these pathways may contribute to CNS impairment associated with STEC infection.
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Affiliation(s)
- Fumiko Obata
- Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA ; Department of Molecular Pathology, Graduate Faculty of Interdisciplinary of Research, Graduate School, University of Yamanashi Chuo, Japan
| | - Lauren M Hippler
- Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Progyaparamita Saha
- Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Dakshina M Jandhyala
- Department of Molecular Biology and Microbiology, Tufts University Boston, MA, USA
| | - Olga S Latinovic
- Department of Microbiology and Immunology, University of Maryland School of Medicine Baltimore, MD, USA ; Institute of Human Virology, University of Maryland School of Medicine Baltimore, MD, USA
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Sacerdoti F, Amaral M, Aisemberg J, Cymeryng C, Franchi A, Ibarra C. Involvement of hypoxia and inflammation in early pregnancy loss mediated by Shiga toxin type 2. Placenta 2015; 36:674-80. [DOI: 10.1016/j.placenta.2015.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 03/04/2015] [Accepted: 03/06/2015] [Indexed: 10/23/2022]
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Kaper JB, O'Brien AD. Overview and Historical Perspectives. Microbiol Spectr 2014; 2:10.1128/microbiolspec.EHEC-0028-2014. [PMID: 25590020 PMCID: PMC4290666 DOI: 10.1128/microbiolspec.ehec-0028-2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Indexed: 12/16/2022] Open
Abstract
In this overview, we describe the history of Shiga toxin (Stx)-producing Escherichia coli (STEC) in two phases. In phase one, between 1977 and 2011, we learned that E. coli could produce Shiga toxin and cause both hemorrhagic colitis and the hemolytic-uremic syndrome in humans and that the prototype STEC-E. coli O157:H7-adheres to and effaces intestinal epithelial cells by a mechanism similar to that of enteropathogenic E. coli. We also recognized that the genes for Stx are typically encoded on a lysogenic phage; that STEC O157:H7 harbors a large pathogenicity island that encodes the elements needed for the characteristic attaching and effacing lesion; and that the most severe cases of human disease are linked to production of Stx type 2a, not Stx type 1a. Phase two began with a large food-borne outbreak of hemorrhagic colitis and hemolytic-uremic syndrome in Germany in 2011. That outbreak was caused by a novel strain consisting of enteroaggregative E. coli O104:H4 transduced by a Stx2a-converting phage. From this outbreak we learned that any E. coli strain that can adhere tightly to the human bowel (either by a biofilm-like mechanism as in E. coli O104:H4 or by an attaching and effacing mechanism as in E. coli O157:H7) can cause severe diarrheal and systemic illness when it acquires the capacity to produce Stx2a. This overview provides the basis for the review of current information regarding these fascinating and complex pathogens.
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Affiliation(s)
- James B Kaper
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21122
| | - Alison D O'Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
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