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Pokharel P, Dhakal S, Dozois CM. The Diversity of Escherichia coli Pathotypes and Vaccination Strategies against This Versatile Bacterial Pathogen. Microorganisms 2023; 11:344. [PMID: 36838308 PMCID: PMC9965155 DOI: 10.3390/microorganisms11020344] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/03/2023] Open
Abstract
Escherichia coli (E. coli) is a gram-negative bacillus and resident of the normal intestinal microbiota. However, some E. coli strains can cause diseases in humans, other mammals and birds ranging from intestinal infections, for example, diarrhea and dysentery, to extraintestinal infections, such as urinary tract infections, respiratory tract infections, meningitis, and sepsis. In terms of morbidity and mortality, pathogenic E. coli has a great impact on public health, with an economic cost of several billion dollars annually worldwide. Antibiotics are not usually used as first-line treatment for diarrheal illness caused by E. coli and in the case of bloody diarrhea, antibiotics are avoided due to the increased risk of hemolytic uremic syndrome. On the other hand, extraintestinal infections are treated with various antibiotics depending on the site of infection and susceptibility testing. Several alarming papers concerning the rising antibiotic resistance rates in E. coli strains have been published. The silent pandemic of multidrug-resistant bacteria including pathogenic E. coli that have become more difficult to treat favored prophylactic approaches such as E. coli vaccines. This review provides an overview of the pathogenesis of different pathotypes of E. coli, the virulence factors involved and updates on the major aspects of vaccine development against different E. coli pathotypes.
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Affiliation(s)
- Pravil Pokharel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Sabin Dhakal
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Charles M. Dozois
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), 531 Boul des Prairies, Laval, QC H7V 1B7, Canada
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Faculté de Médecine Vétérinaire, Université de Montréal Saint-Hyacinthe, Saint-Hyacinthe, QC J2S 2M2, Canada
- Pasteur Network, Laval, QC H7V 1B7, Canada
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Cryoelectron-microscopy structure of the enteropathogenic Escherichia coli type III secretion system EspA filament. Proc Natl Acad Sci U S A 2021; 118:2022826118. [PMID: 33397726 PMCID: PMC7812819 DOI: 10.1073/pnas.2022826118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic Escherichia coli (EHEC) utilize a macromolecular type III secretion system (T3SS) to inject effector proteins into eukaryotic cells. This apparatus spans the inner and outer bacterial membranes and includes a helical needle protruding into the extracellular space. Thus far observed only in EPEC and EHEC and not found in other pathogenic Gram-negative bacteria that have a T3SS is an additional helical filament made by the EspA protein that forms a long extension to the needle, mediating both attachment to eukaryotic cells and transport of effector proteins through the intestinal mucus layer. Here, we present the structure of the EspA filament from EPEC at 3.4 Å resolution. The structure reveals that the EspA filament is a right-handed 1-start helical assembly with a conserved lumen architecture with respect to the needle to ensure the seamless transport of unfolded cargos en route to the target cell. This functional conservation is despite the fact that there is little apparent overall conservation at the level of sequence or structure with the needle. We also unveil the molecular details of the immunodominant EspA epitope that can now be exploited for the rational design of epitope display systems.
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Hotinger JA, May AE. Antibodies Inhibiting the Type III Secretion System of Gram-Negative Pathogenic Bacteria. Antibodies (Basel) 2020; 9:antib9030035. [PMID: 32726928 PMCID: PMC7551047 DOI: 10.3390/antib9030035] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 12/11/2022] Open
Abstract
Pathogenic bacteria are a global health threat, with over 2 million infections caused by Gram-negative bacteria every year in the United States. This problem is exacerbated by the increase in resistance to common antibiotics that are routinely used to treat these infections, creating an urgent need for innovative ways to treat and prevent virulence caused by these pathogens. Many Gram-negative pathogenic bacteria use a type III secretion system (T3SS) to inject toxins and other effector proteins directly into host cells. The T3SS has become a popular anti-virulence target because it is required for pathogenesis and knockouts have attenuated virulence. It is also not required for survival, which should result in less selective pressure for resistance formation against T3SS inhibitors. In this review, we will highlight selected examples of direct antibody immunizations and the use of antibodies in immunotherapy treatments that target the bacterial T3SS. These examples include antibodies targeting the T3SS of Pseudomonas aeruginosa, Yersinia pestis, Escherichia coli, Salmonella enterica, Shigella spp., and Chlamydia trachomatis.
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Mühlen S, Dersch P. Treatment Strategies for Infections With Shiga Toxin-Producing Escherichia coli. Front Cell Infect Microbiol 2020; 10:169. [PMID: 32435624 PMCID: PMC7218068 DOI: 10.3389/fcimb.2020.00169] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 03/31/2020] [Indexed: 01/07/2023] Open
Abstract
Infections with Shiga toxin-producing Escherichia coli (STEC) cause outbreaks of severe diarrheal disease in children and the elderly around the world. The severe complications associated with toxin production and release range from bloody diarrhea and hemorrhagic colitis to hemolytic-uremic syndrome, kidney failure, and neurological issues. As the use of antibiotics for treatment of the infection has long been controversial due to reports that antibiotics may increase the production of Shiga toxin, the recommended therapy today is mainly supportive. In recent years, a variety of alternative treatment approaches such as monoclonal antibodies or antisera directed against Shiga toxin, toxin receptor analogs, and several vaccination strategies have been developed and evaluated in vitro and in animal models. A few strategies have progressed to the clinical trial phase. Here, we review the current understanding of and the progress made in the development of treatment options against STEC infections and discuss their potential.
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Affiliation(s)
- Sabrina Mühlen
- Institute for Infectiology, University of Münster, Münster, Germany.,German Center for Infection Research (DZIF), Associated Site University of Münster, Münster, Germany
| | - Petra Dersch
- Institute for Infectiology, University of Münster, Münster, Germany.,German Center for Infection Research (DZIF), Associated Site University of Münster, Münster, Germany
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5
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Slater SL, Sågfors AM, Pollard DJ, Ruano-Gallego D, Frankel G. The Type III Secretion System of Pathogenic Escherichia coli. Curr Top Microbiol Immunol 2019; 416:51-72. [PMID: 30088147 DOI: 10.1007/82_2018_116] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Infection with enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC), enteroinvasive E. coli (EIEC) and Shigella relies on the elaboration of a type III secretion system (T3SS). Few strains also encode a second T3SS, named ETT2. Through the integration of coordinated intracellular and extracellular cues, the modular T3SS is assembled within the bacterial cell wall, as well as the plasma membrane of the host cell. As such, the T3SS serves as a conduit, allowing the chaperone-regulated translocation of effector proteins directly into the host cytosol to subvert eukaryotic cell processes. Recent technological advances revealed high structural resolution of the T3SS apparatus and how it could be exploited to treat enteric disease. This chapter summarises the current knowledge of the structure and function of the E. coli T3SSs.
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Affiliation(s)
- Sabrina L Slater
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Agnes M Sågfors
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Dominic J Pollard
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - David Ruano-Gallego
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Gad Frankel
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.
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Caetano BA, Rocha LB, Carvalho E, Piazza RMF, Luz D. Immunogenic Domains and Secondary Structure of Escherichia coli Recombinant Secreted Protein Escherichia coli-Secreted Protein B. Front Immunol 2017; 8:477. [PMID: 28484467 PMCID: PMC5402224 DOI: 10.3389/fimmu.2017.00477] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 04/05/2017] [Indexed: 11/24/2022] Open
Abstract
Several pathogenic bacteria are able to induce the attaching and effacing (A/E) lesion. The A/E lesion is caused by effector proteins, such as Escherichia coli-secreted protein B (EspB), responsible together with Escherichia coli-secreted protein D for forming a pore structure on the host cell, which allows the translocation of effector proteins. Different variants of this protein can be found in E. coli strains, and during natural infection or when this protein is injected, this leads to variant-specific production of antibodies, which may not be able to recognize other variants of this bacterial protein. Herein, we describe the production of a hybrid recombinant EspB toxin that comprises all known variants of this protein. This recombinant protein could be useful as an antigen for the production of antibodies with broad-range detection of EspB-bearing bacteria, or as an antigen that could be used in vaccine formulation to generate antibodies against different EspB variants, thereby increasing immunization potential. In addition, the recombinant protein allowed us to analyze its secondary structure, to propose the immunogenic regions of EspB variants, and also to characterize anti-EspB antibodies. Our results suggest that this hybrid protein or a protein composed of the conserved immunogenic regions could be used for a variety of clinical applications.
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Affiliation(s)
- Bruna Alves Caetano
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, São Paulo, Brazil
| | | | - Eneas Carvalho
- Centro de Biotecnologia, Instituto Butantan, São Paulo, São Paulo, Brazil
| | | | - Daniela Luz
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, São Paulo, Brazil
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Garcia M, Power ML, Moyes KM. Immunoglobulin A and nutrients in milk from great apes throughout lactation. Am J Primatol 2016; 79:1-11. [PMID: 28118501 DOI: 10.1002/ajp.22614] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Differences in macronutrients between human and ape milks appear relatively small, but variation in other components such as immunoglobulins (Ig) may be greater. This study characterized the macronutrient and secretory (sIgA) profiles in milk from gorillas and orangutans throughout lactation. Fifty-three milk samples from four gorillas and three orangutans were collected throughout 48 and 22 months postpartum (MPP), respectively. Samples were grouped in five stages of lactation (0 to 6 months, more than 6 months to 12 months, more than 12 months to 18 months, more than 18 months to 36 months, and more than 36 months to 48 months). Data were analyzed as a complete randomized design. Concentration of sIgA did not change due to species or its interaction with MPP. Crude protein, regardless of MPP, was greater for gorillas compared with orangutans (1.27 vs. 0.85%). Fat, sugar, and gross energy were affected by the interaction of species × MPP. For gorilla milk, concentrations of sIgA were 43 mg/L at 6 MPP increasing to 79 mg/L at 48 MPP. Protein was highest at 48 MPP. Sugar was lowest at 48 MPP. Values for fat and gross energy were the highest 36 MPP. For orangutan milk, concentrations of sIgA were highest at 6 MPP. Sugar decreased with MPP. Protein, dry matter, or fat were unaffected by MPP. Gross energy content was steady during the first 18 MPP but it tended to decrease by 36 MPP. The results indicate that macronutrients are similar between human, published data, and great ape milk, though gorilla milk has higher protein and human milk higher fat (published data). Concentrations of sIgA in ape milk were about 10-fold lower than human values from the literature. Differences between human and ape milk may lie more in bioactive/immune molecules than nutrients. RESEARCH HIGHLIGHTS Milk macronutrients from great apes differed throughout lactation. Milk macronutrients but not IgA from non-human great apes and humans were quite similar. Milk protein was greater in Gorilla compared with Orangutan.
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Affiliation(s)
- Miriam Garcia
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland
| | - Michael L Power
- Nutrition Laboratory, Smithsonian National Zoological Park, Washington, District of Columbia
| | - Kasey M Moyes
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland
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Palmeira P, Carneiro-Sampaio M. Immunology of breast milk. Rev Assoc Med Bras (1992) 2016; 62:584-593. [DOI: 10.1590/1806-9282.62.06.584] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 07/26/2016] [Indexed: 12/14/2022] Open
Abstract
Summary In the critical phase of immunological immaturity of the newborn, particularly for the immune system of mucous membranes, infants receive large amounts of bioactive components through colostrum and breast milk. Colostrum is the most potent natural immune booster known to science. Breastfeeding protects infants against infections mainly via secretory IgA (SIgA) antibodies, but also via other various bioactive factors. It is striking that the defense factors of human milk function without causing inflammation; some components are even anti-inflammatory. Protection against infections has been well evidenced during lactation against, e.g., acute and prolonged diarrhea, respiratory tract infections, including otitis media, urinary tract infection, neonatal septicemia, and necrotizing enterocolitis. The milk’s immunity content changes over time. In the early stages of lactation, IgA, anti-inflammatory factors and, more likely, immunologically active cells provide additional support for the immature immune system of the neonate. After this period, breast milk continues to adapt extraordinarily to the infant’s ontogeny and needs regarding immune protection and nutrition. The need to encourage breastfeeding is therefore justifiable, at least during the first 6 months of life, when the infant’s secretory IgA production is insignificant.
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Abstract
Enterohemorrhagic Escherichia coli (EHEC) is a highly pathogenic bacterial strain capable of causing watery or bloody diarrhea, the latter termed hemorrhagic colitis, and hemolytic-uremic syndrome (HUS). HUS is defined as the simultaneous development of non-immune hemolytic anemia, thrombocytopenia, and acute renal failure. The mechanism by which EHEC bacteria colonize and cause severe colitis, followed by renal failure with activated blood cells, as well as neurological symptoms, involves the interaction of bacterial virulence factors and specific pathogen-associated molecular patterns with host cells as well as the host response. The innate immune host response comprises the release of antimicrobial peptides as well as cytokines and chemokines in addition to activation and/or injury to leukocytes, platelets, and erythrocytes and activation of the complement system. Some of the bacterial interactions with the host may be protective in nature, but, when excessive, contribute to extensive tissue injury, inflammation, and thrombosis, effects that may worsen the clinical outcome of EHEC infection. This article describes aspects of the host response occurring during EHEC infection and their effects on specific organs.
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Impact of Infection Dose and Previous Serum Antibodies against the Locus of Enterocyte Effacement Proteins on Escherichia coli O157:H7 Shedding in Calves following Experimental Infection. BIOMED RESEARCH INTERNATIONAL 2015; 2015:290679. [PMID: 26167480 PMCID: PMC4475743 DOI: 10.1155/2015/290679] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/05/2015] [Accepted: 05/05/2015] [Indexed: 11/26/2022]
Abstract
Escherichia coli O157:H7 is the main causative agent of haemolytic uremic syndrome. Cattle are the main reservoir of these bacteria, and have been shown to develop immune response to colonization. Our aim was to investigate the faecal shedding pattern of E. coli O157:H7 in calves challenged intragastrically with either 108 or 1010 CFU, as well as the ability of specific preexisting antibodies to reduce shedding of the pathogen. Shedding was analysed by direct counting as well as enrichment of rectoanal mucosal swabs. Statistical analysis was performed using a linear model for repeated measures with and without the inclusion of preexisting antibodies against the carboxy-terminal fraction of intimin-γ (γ-intimin C280) as a covariable. Results suggest that there is a statistical difference in the area under the shedding curves between both doses for 14 as well as 28 days after challenge (p = 0.0069 and 0.0209, resp.). This difference is increased when the prechallenge antibodies are taken into account (p = 0.0056 and 0.0185). We concluded that the bacterial dose influences shedding on calves experimentally challenged and that preexisting antibodies against E. coli O157:H7 γ-intimin C280 could partially reduce faecal excretion.
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11
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Hu J, Torres AG. Enteropathogenic Escherichia coli: foe or innocent bystander? Clin Microbiol Infect 2015; 21:729-34. [PMID: 25726041 DOI: 10.1016/j.cmi.2015.01.015] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 01/16/2015] [Accepted: 01/16/2015] [Indexed: 01/27/2023]
Abstract
Enteropathogenic Escherichia coli (EPEC) remain one the most important pathogens infecting children and they are one of the main causes of persistent diarrhoea worldwide. Historically, typical EPEC (tEPEC), defined as those isolates with the attaching and effacement (A/E) genotype (eae(+)), which possess bfpA(+) and lack the stx(-) genes are found strongly associated with diarrhoeal cases. However, occurrence of atypical EPEC (aEPEC; eae(+)bfpA(-)stx(-)) in diarrhoeal and asymptomatic hosts has made investigators question the role of these pathogens in human disease. Current epidemiological data are helping to answer the question of whether EPEC is mainly a foe or an innocent bystander during infection.
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Affiliation(s)
- J Hu
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - A G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA; Department of Pathology and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, USA.
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12
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Abstract
Whereas active immunity refers to the process of exposing the individual to an antigen to generate an adaptive immune response, passive immunity refers to the transfer of antibodies from one individual to another. Passive immunity provides immediate but short-lived protection, lasting several weeks up to 3 or 4 months. Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta or from breast milk to the gut of the infant. It can also be produced artificially, when antibody preparations derived from sera or secretions of immunized donors or, more recently, different antibody producing platforms are transferred via systemic or mucosal route to nonimmune individuals. Passive immunization has recently become an attractive approach because of the emergence of new and drug-resistant microorganisms, diseases that are unresponsive to drug therapy and individuals with an impaired immune system who are unable to respond to conventional vaccines. This chapter addresses the contributions of natural and artificial acquired passive immunity in understanding the concept of passive immunization. We will mainly focus on administration of antibodies for protection against various infectious agents entering through mucosal surfaces.
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Ahmed SF, Shaheen HI, Abdel-Messih IA, Mostafa M, Putnam SD, Kamal KA, Sayed ANE, Frenck RW, Sanders JW, Klena JD, Wierzba TF. The epidemiological and clinical characteristics of diarrhea associated with enteropathogenic, enteroaggregative and diffuse-adherent Escherichia coli in Egyptian children. J Trop Pediatr 2014; 60:397-400. [PMID: 25122630 DOI: 10.1093/tropej/fmu034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
A total of 220 enteroadherent Escherichia coli were identified from 729 Egyptian children with diarrhea using the HEp-2 adherence assay. Enteropathogenic E.coli (EPEC = 38) was common among children <6 months old and provoked vomiting, while diffuse-adhering E.coli (DAEC = 109) induced diarrheal episodes of short duration, and enteroaggregative E.coli (EAEC = 73) induced mild non-persistent diarrhea. These results suggest that EPEC is associated with infantile diarrhea in Egyptian children.
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Affiliation(s)
- Salwa F Ahmed
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | - Hind I Shaheen
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | | | - Manal Mostafa
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | - Shannon D Putnam
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | - Karim A Kamal
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | | | - Robert W Frenck
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | - John W Sanders
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | - John D Klena
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
| | - Thomas F Wierzba
- Research Science Directorate, US Naval Medical Research Unit No. 3, Cairo, Egypt
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Physiopathological effects of Escherichia coli O157:H7 inoculation in weaned calves fed with colostrum containing antibodies to EspB and Intimin. Vaccine 2014; 32:3823-9. [DOI: 10.1016/j.vaccine.2014.04.073] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/18/2014] [Accepted: 04/22/2014] [Indexed: 11/22/2022]
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15
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Croxen MA, Law RJ, Scholz R, Keeney KM, Wlodarska M, Finlay BB. Recent advances in understanding enteric pathogenic Escherichia coli. Clin Microbiol Rev 2013; 26:822-80. [PMID: 24092857 PMCID: PMC3811233 DOI: 10.1128/cmr.00022-13] [Citation(s) in RCA: 895] [Impact Index Per Article: 74.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.
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Gavilanes-Parra S, Mendoza-Hernández G, Chávez-Berrocal ME, Girón JA, Orozco-Hoyuela G, Manjarrez-Hernández A. Identification of secretory immunoglobulin A antibody targets from human milk in cultured cells infected with enteropathogenic Escherichia coli (EPEC). Microb Pathog 2013; 64:48-56. [PMID: 24036180 DOI: 10.1016/j.micpath.2013.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 12/27/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) uses a type III secretion system (T3SS) to inject effectors into host cells and alter cellular physiology. The aim of the present study was to identify targets of human secretory immunoglobulin A (sIgA) antibodies from the proteins delivered by EPEC into HEp-2 cells after infection. Bacterial proteins delivered into EPEC-infected cells were obtained in sub-cellular fractions (cytoplasmic, membrane, and cytoskeleton) and probed with sIgA antibodies from human milk and analyzed by Western blotting. These sIgA antibodies reacted with Tir and EspB in the cytoplasmic and membrane fractions, and with intimin in the membrane fraction mainly. The sIgA also identified an EPEC surface-associated Heat-shock protein 70 (Hsp70) in HEp-2 cells infected with EPEC. Purified Hsp70 from EPEC was able to bind to HEp-2 cells, suggesting adhesive properties in this protein. EspC secreted to the medium reacted strongly with the sIgA antibodies. An EPEC 115 kDa protein, unrelated to the EspC protein, was detected in the cytoplasm of infected HEp-2 cells, suggesting that this is a new protein translocated by EPEC. The results suggest that there is a strong host antibody response to Tir and intimin, which are essential proteins for attaching and effacing (A/E) pathogen mediated disease.
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Affiliation(s)
- Sandra Gavilanes-Parra
- Departamento de Salud Publica, Facultad de Medicina, Universidad Nacional Autónoma de México, D. F. 04510, Mexico
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17
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Rabinovitz BC, Gerhardt E, Tironi Farinati C, Abdala A, Galarza R, Vilte DA, Ibarra C, Cataldi A, Mercado EC. Vaccination of pregnant cows with EspA, EspB, γ-intimin, and Shiga toxin 2 proteins from Escherichia coli O157:H7 induces high levels of specific colostral antibodies that are transferred to newborn calves. J Dairy Sci 2012; 95:3318-26. [PMID: 22612965 DOI: 10.3168/jds.2011-5093] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Accepted: 02/05/2012] [Indexed: 01/09/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major cause of intestinal disease and hemolytic uremic syndrome, a serious systemic complication that particularly affects children. Cattle are primary reservoirs for EHEC O157:H7 and the main source of infection for humans. Vaccination of cattle with different combinations of bacterial virulence factors has shown efficacy in decreasing EHEC O157:H7 shedding. It is, therefore, important to demonstrate whether vaccination of pregnant cows with EHEC O157:H7 induces high titers of transferable antibodies to avoid early colonization of calves by the bacteria. In this study we evaluated the ability of EspA, EspB, the C-terminal fragment of 280 amino acids of γ-intimin (γ-intimin C₂₈₀) and inactivated Shiga toxin (Stx) 2 proteins to induce specific antibodies in colostrum and their passive transference to colostrum-fed calves. Friesian pregnant cows immunized by the intramuscular route mounted significantly high serum and colostrum IgG responses against EspB and γ-intimin C₂₈₀ that were efficiently transferred to their calves. Antibodies to EspB and γ-intimin C₂₈₀ were detected in milk samples of vaccinated cows at d 40 postparturition. Significant Stx2-neutralizing titers were also observed in colostrum from Stx2-vaccinated cows and sera from colostrum-fed calves. The results presented showed that bovine colostrum with increased levels of antibodies against EHEC O157:H7 may be obtained by systemic immunization of pregnant cows, and that these specific antibodies are efficiently transferred to newborn calves by feeding colostrum. Hyperimmune colostrum and milk may be an alternative to protect calves from early colonization by EHEC O157:H7 and a possible key source of antibodies to block colonization and toxic activity of this bacterium.
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Affiliation(s)
- B C Rabinovitz
- Instituto de Patobiología, Instituto Nacional de Tecnología Agropecuaria-INTA, Nicolás Repetto y De los Reseros, 1686 Hurlingham, Buenos Aires, Argentina
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Ferreira Oliveira A, Almeida Cardoso S, Bruno dos Reis Almeida F, Licursi de Oliveira L, Pitondo-Silva A, Gomes Soares S, Seixas Hanna E. Oral immunization with attenuated Salmonella vaccine expressing Escherichia coli O157:H7 intimin gamma triggers both systemic and mucosal humoral immunity in mice. Microbiol Immunol 2012; 56:513-22. [DOI: 10.1111/j.1348-0421.2012.00477.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Calderon Toledo C, Arvidsson I, Karpman D. Cross-reactive protection against enterohemorrhagic Escherichia coli infection by enteropathogenic E. coli in a mouse model. Infect Immun 2011; 79:2224-33. [PMID: 21402761 PMCID: PMC3125830 DOI: 10.1128/iai.01024-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 03/06/2011] [Indexed: 11/20/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) are related attaching and effacing (A/E) pathogens. The genes responsible for the A/E pathology are carried on a chromosomal pathogenicity island termed the locus of enterocyte effacement (LEE). Both pathogens share a high degree of homology in the LEE and additional O islands. EHEC prevalence is much lower in areas where EPEC is endemic. This may be due to the development of antibodies against common EPEC and EHEC antigens. This study investigated the hypothesis that EPEC infections may protect against EHEC infections. We used a mouse model to inoculate BALB/c mice intragastrically, first with EPEC and then with EHEC (E. coli O157:H7). Four control groups received either a nonpathogenic E. coli (NPEC) strain followed by EHEC (NPEC/EHEC), phosphate-buffered saline (PBS) followed by EHEC (PBS/EHEC), EPEC/PBS, or PBS/PBS. Mice were monitored for weight loss and symptoms. EPEC colonized the intestine after challenge, and mice developed serum antibodies to intimin and E. coli secreted protein B (encoded in the LEE). Prechallenge with an EPEC strain had a protective effect after EHEC infection, as only a few mice developed mild symptoms, from which they recovered. These mice had an increase in body weight similar to that in control animals, and tissue morphology exhibited mild intestinal changes and normal renal histology. All mice that were not prechallenged with the EPEC strain developed mild to severe symptoms after EHEC infection, with weight loss as well as intestinal and renal histopathological changes. These data suggest that EPEC may protect against EHEC infection in this mouse model.
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Affiliation(s)
- Carla Calderon Toledo
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
- Institute of Molecular Biology and Biotechnology, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - Ida Arvidsson
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Diana Karpman
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
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Vilte DA, Larzábal M, Garbaccio S, Gammella M, Rabinovitz BC, Elizondo AM, Cantet RJ, Delgado F, Meikle V, Cataldi A, Mercado EC. Reduced faecal shedding of Escherichia coli O157:H7 in cattle following systemic vaccination with γ-intimin C280 and EspB proteins. Vaccine 2011; 29:3962-8. [DOI: 10.1016/j.vaccine.2011.03.079] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 03/07/2011] [Accepted: 03/22/2011] [Indexed: 10/18/2022]
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21
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Khare S, Alali W, Zhang S, Hunter D, Pugh R, Fang FC, Libby SJ, Adams LG. Vaccination with attenuated Salmonella enterica Dublin expressing E coli O157:H7 outer membrane protein Intimin induces transient reduction of fecal shedding of E coli O157:H7 in cattle. BMC Vet Res 2010; 6:35. [PMID: 20609252 PMCID: PMC2912257 DOI: 10.1186/1746-6148-6-35] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 07/07/2010] [Indexed: 12/03/2022] Open
Abstract
Background Escherichia coli serogroup O157:H7 has emerged as an important zoonotic bacterial pathogen, causing a range of symptoms from self-limiting bloody diarrhea to severe hemorrhagic colitis and hemolytic-uremic syndrome in humans. Beef and dairy cattle are considered the most important animal reservoirs for this pathogen. One of the important virulence characteristics of E. coli O157:H7 is the eaeA gene encoding the 97 kDa surface protein intimin. Intimin is required for attachment and effacement during the interaction of enterohemorrhagic E. coli with human and bovine neonatal enterocytes. The present study was undertaken to test the hypothesis that an adaptive mucosal immune response directed against intimin will reduce or prevent enteric colonization and fecal shedding of E. coli O157:H7 in cattle. Results Cattle were orally inoculated with either milk (control), milk with live attenuated Salmonella enterica serovar Dublin (vector), or milk with live attenuated recombinant S. Dublin expressing intimin (vaccinated) on days 0, 14 and 28. On day 98, all calves were challenged orally with E. coli O157:H7 to evaluate whether vaccination with the recombinant S. Dublin expressing intimin would reduce the level of E. coli O157:H7 fecal shedding. During the first 28 days, vaccinated calves shed both the vector strain and the intimin-expressing S. Dublin strain at a similar level. The vector strain was shed for a significantly longer period as compared to the level of recombinant vaccine strain. Calves that received the intimin-expressed vaccine ceased shedding S. Dublin from day 28 to day 63. All calves were challenged with E. coli O157:H7 on day 98 to determine the effect on fecal shedding of E. coli O157:H7. The amount of E. coli O157:H7 in feces was measured for 30 days post-challenge. We observed a transient clearance of E. coli O157:H7 from the feces in the vaccinated calves. The magnitude of fecal E. coli O157:H7 shedding did not correlate with the presence of intimin-specific fecal IgA. Conclusion Oral vaccination with live attenuated recombinant S. Dublin expressing intimin reduced enteric colonization and fecal shedding of E. coli O157:H7. However, the transient clearance of E. coli O157:H7 was not associated with an enhanced IgA-mediated mucosal immune response.
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Affiliation(s)
- Sangeeta Khare
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843 USA.
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22
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Nara JM, Cianciarullo AM, Culler HF, Bueris V, Horton DSPQ, Menezes MA, Franzolin MR, Elias WP, Piazza RMF. Differentiation of typical and atypical enteropathogenic Escherichia coli using colony immunoblot for detection of bundle-forming pilus expression. J Appl Microbiol 2009; 109:35-43. [PMID: 19968733 DOI: 10.1111/j.1365-2672.2009.04625.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
AIMS The aim of study was to develop a colony immunoblot assay to differentiate typical from atypical enteropathogenic Escherichia coli (EPEC) by detection of bundle-forming pilus (BFP) expression. METHODS AND RESULTS Anti-BFP antiserum was raised in rabbits and its reactivity was confirmed by immunoelectron microscopy and by immunoblotting recognizing bundlin, the major pilus repeating subunit. The bacterial isolates tested in the colony immunoblot assay were grown in different media. Proteins from bacterial isolates were transferred to nitrocellulose membrane after treatment with phosphate buffer containing Triton X-100, EDTA and sodium chloride salts. When 24 typical EPEC and 96 isolates including, 72 atypical EPEC, 13 Gram-negative type IV-expressing strains and 11 enterobacteriaceae were cultivated in Dulbecco's Modified Eagle's Medium agar containing fetal bovine serum or in blood agar in the presence of CaCl(2) , they showed a positivity of 92 and 83%, and specificity of 96 and 97%, respectively. CONCLUSION The assay enables reliable identification of BFP-expressing isolates and contributes to the differentiation of typical and atypical EPEC. SIGNIFICANCE AND IMPACT OF THE STUDY The colony immunoblot for BFP detection developed in this study combines the simplicity of an immunoserological assay with the high efficiency of testing a large number of EPEC colonies.
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Affiliation(s)
- J M Nara
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, SP, Brazil
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23
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Ferreira PCD, Campos IB, Abe CM, Trabulsi LR, Elias WP, Ho PL, Oliveira MLS. Immunization of mice with Lactobacillus casei expressing intimin fragments produces antibodies able to inhibit the adhesion of enteropathogenic Escherichia coli to cultivated epithelial cells. ACTA ACUST UNITED AC 2008; 54:245-54. [PMID: 18801043 DOI: 10.1111/j.1574-695x.2008.00471.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) are frequently isolated as a cause of infantile diarrhea in developing countries. Its pathogenicity is distinguished by histopathological alterations at the site of infection, known as attaching and effacing (A/E) lesions, in which bacterial virulence factors and host proteins participate. Intimin, a bacterial adhesin expressed by all EPEC described to date, is responsible for the intimate adherence of the bacteria to host cells and is essential for the formation of A/E lesions. Mucosal vaccination may represent an efficacious intervention to prevent EPEC infection and lower morbidity and mortality rates. Strategies for mucosal vaccinations that use lactic acid bacteria for the delivery of heterologous antigens rely on their safety profile and ability to stimulate the immune system. In the present work, we have constructed Lactobacillus casei strains expressing different fragments of intimin beta, a subtype that is frequently expressed by EPEC strains. Mucosal immunization of mice with L. casei expressing intimin fragments induced specific systemic and mucosal antibodies. These antibodies were able to recognize native intimin on the surface of EPEC and to inhibit in vitro EPEC binding to epithelial cells.
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Bovine colostrum contains immunoglobulin G antibodies against intimin, EspA, and EspB and inhibits hemolytic activity mediated by the type three secretion system of attaching and effacing Escherichia coli. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:1208-13. [PMID: 18562563 DOI: 10.1128/cvi.00027-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) is the main cause of hemolytic-uremic syndrome, an endemic disease in Argentina which had an incidence in 2005 of 13.9 cases per 100,000 children younger than 5 years old. Cattle appear to be a major reservoir of EHEC, and a serological response to EHEC antigens has been demonstrated in natural and experimental infections. In the current study, antibodies against proteins implicated in EHEC's ability to form attaching and effacing lesions, some of which are exported to the host cell via a type three secretion system (TTSS), were identified in bovine colostrum by Western blot analysis. Twenty-seven (77.0%) of the 35 samples examined contained immunoglobulin G (IgG) antibodies against the three proteins assayed in this study: EspA, EspB, and the carboxy-terminal 280 amino acids of gamma-intimin, an intimin subtype associated mainly with O157:H7 and O145:H- serotypes. Every colostrum sample was able to inhibit, in a range between 45.9 and 96.7%, the TTSS-mediated hemolytic activity of attaching and effacing E. coli. The inhibitory effect was partially mediated by IgG and lactoferrin. In conclusion, we found that early colostrum from cows contains antibodies, lactoferrin, and other unidentified substances that impair TTSS function in attaching and effacing E. coli strains. Bovine colostrum might act by reducing EHEC colonization in newborn calves and could be used as a prophylactic measure to protect non-breast-fed children against EHEC infection in an area of endemicity.
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Fernandes PJ, Guo Q, Donnenberg MS. Functional consequences of sequence variation in bundlin, the enteropathogenic Escherichia coli type IV pilin protein. Infect Immun 2007; 75:4687-96. [PMID: 17635860 PMCID: PMC2044524 DOI: 10.1128/iai.00009-07] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The bundle-forming pilus (BFP) of enteropathogenic Escherichia coli (EPEC) is an important virulence factor. We examined the role of divergent alleles of bfpA encoding bundlin, the BFP pilin protein, in pilus biogenesis, pilus interactions, and immune responses. We found that the BFP biogenesis machine from an EPEC strain that expresses one bundlin type is capable of assembling all other bundlin types. Furthermore, we found that EPEC strains expressing divergent bundlin types are capable of forming mixed autoaggregates, suggesting that different pilin types can intertwine. However, we found that there was a marked difference between alleles in immunogenicity in both rabbits and mice of a peptide derived from a region of bundlin undergoing apparent diversifying selection. In addition, despite a high degree of cross-reactivity between divergent bundlin proteins, in both mice and rabbits responses appeared to be stronger against the homologous pilin protein than against the heterologous protein. This result was verified using sera from a volunteer study, which demonstrated that the human antibody responses after an initial challenge with live EPEC were stronger against the homologous bundlin protein than against a divergent bundlin protein. However, a repeat challenge induced equivalent responses. These results are consistent with the hypothesis that human immune responses against bundlin exert selective pressure on bfpA sequence divergence.
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Affiliation(s)
- Paula J Fernandes
- Division of Infectious Diseases, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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26
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Zapata-Quintanilla LB, Palmeira P, Tino-De-Franco M, Amaral JA, Carbonare CB, Carbonare SB. Systemic antibody response to diarrheagenic Escherichia coli and LPS O111, O157 and O55 in healthy Brazilian adults. Scand J Immunol 2007; 64:661-7. [PMID: 17083623 DOI: 10.1111/j.1365-3083.2006.01848.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Enterohaemorrhagic Escherichia coli (EHEC) can cause a variety of human illnesses ranging from uncomplicated diarrhoea to haemorrhagic colitis and haemolytic uremic syndrome. The serotype O157:H7 has been associated with numerous outbreaks worldwide, but in Brazil the infection is rare. Brazilian adults present antibodies reactive with the principal virulence factors of enteropathogenic E. coli (EPEC) that have many genetic and antigenic similarities with EHEC. Lipopolysaccharides (LPS) are components of outer membranes and important virulence factors of Gram-negative bacteria. LPS O111 is present in EPEC and EHEC strains. LPS O157 is found only in EHEC strains, but it has some structural similarities with LPS O55 present in EPEC strains. This study investigates the levels of IgG and IgM seric antibodies reactive with EHEC O157:H7, EHEC O111:H-, EPEC O111:H- and the levels of anti-LPS O111, LPS O157 and LPS O55 antibodies in healthy adults living in São Paulo, Brazil. The antibody levels were determined by an enzyme-linked immunosorbent assay for 100 individual serum samples, and the presence of anti-bacterial and anti-LPS seric antibodies was confirmed. Positive correlations were found among the three kinds of antibodies. The concentrations of IgM anti-LPS were significantly higher than those of IgG, and surprisingly, the concentrations of anti-LPS O157 were high in view of the infrequent isolation of O157 bacteria in Brazil. Our results suggest that there is a cross-reacting immunity to EHEC in the Brazilian population, which may be a result of the immunity to EPEC antigens. Alternatively, Brazilians may be exposed to EHEC more frequently than has previously been thought.
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Franzolin MR, Alves RCB, Keller R, Gomes TAT, Beutin L, Barreto ML, Milroy C, Strina A, Ribeiro H, Trabulsi LR. Prevalence of diarrheagenic Escherichia coli in children with diarrhea in Salvador, Bahia, Brazil. Mem Inst Oswaldo Cruz 2005; 100:359-63. [PMID: 16113883 DOI: 10.1590/s0074-02762005000400004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We report the frequency of the different diarrheagenic Escherichia coli (DEC) categories isolated from children with acute endemic diarrhea in Salvador, Bahia. The E. coli isolates were investigated by colony blot hybridization with the following genes probes: eae, EAF, bfpA, Stx1, Stx2, ST-Ih, ST-Ip, LT-I, LT-II, INV, and EAEC, as virulence markers to distinguish typical and atypical EPEC, EHEC/STEC, ETEC, EIEC, and EAEC. Seven of the eight categories of DEC were detected. The most frequently isolated was atypical EPEC (10.1%) followed by ETEC (7.5%), and EAEC (4.2%). EHEC, STEC, EIEC, and typical EPEC were each detected once. The strains of ETEC, EAEC, and atypical EPEC belonged to a wide variety of serotypes. The serotypes of the others categories were O26:H11 (EHEC), O21:H21 (STEC), O142:H34 (typical EPEC), and O:H55 (EIEC). We also present the clinical manifestations and other pathogenic species observed in children with DEC. This is the first report of EHEC and STEC in Salvador, and one of the first in Brazil.
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Hanson LÅ, Korotkova M, Telemo E. Human Milk: Its Components and Their Immunobiologic Functions. Mucosal Immunol 2005. [DOI: 10.1016/b978-012491543-5/50108-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Palmeira P, Carbonare SB, Amaral JA, Tino-De-Franco M, Carneiro-Sampaio MMS. Colostrum from healthy Brazilian women inhibits adhesion and contains IgA antibodies reactive with Shiga toxin-producing Escherichia coli. Eur J Pediatr 2005; 164:37-43. [PMID: 15549380 DOI: 10.1007/s00431-004-1561-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Accepted: 09/13/2004] [Indexed: 10/26/2022]
Abstract
UNLABELLED Although Shiga toxin-producing Escherichia coli (STEC) has been isolated in Brazil, severe manifestations of the infection, such as haemorrhagic colitis and haemolytic-uraemic syndrome, are extremely rare in our population. Enteropathogenic Escherichia coli (EPEC) is the main aetiological agent of acute infantile diarrhoea in Brazil. There are many similarities between STEC and EPEC, such as the ability to produce attaching and effacing (A/E) lesions and some virulence-associated factors. Our aim was to investigate the presence of anti-STEC antibodies in healthy people living in an EPEC endemic area. Colostrum samples collected from 51 women living in low socio-economic conditions were analysed. Two STEC strains: O111:H- (Stx1) and O157:H7 (Stx2), and one EPEC strain (O111:H-) were used in the bacterial adhesion assays to HEp-2 cells, in the Stx1 and Stx2 cytotoxicity assays on Vero cells, in immunoblotting and in ELISA assays. All the samples strongly inhibited the adhesion of the three strains and contained SIgA antibodies reactive with antigens of EPEC O111:H-, STEC O111:H- and STEC O157:H7, mainly STEC and EPEC 94 kDa adhesin intimin. High titres of anti-LPS O111 antibodies were found in many samples. Nevertheless, the cytotoxic effect of both Stx1 and Stx2 on Vero cells was not neutralised by any sample. CONCLUSION Our results suggest that Brazilian people may be exposed to Shiga toxin-producing Escherichia colimore frequently than previously thought or alternatively there may be a cross reactive immunity between enteropathogenic Escherichia coliand Shiga toxin-producing Escherichia coli.
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Affiliation(s)
- Patricia Palmeira
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Ochoa TJ, Noguera-Obenza M, Ebel F, Guzman CA, Gomez HF, Cleary TG. Lactoferrin impairs type III secretory system function in enteropathogenic Escherichia coli. Infect Immun 2003; 71:5149-55. [PMID: 12933858 PMCID: PMC187368 DOI: 10.1128/iai.71.9.5149-5155.2003] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) is an important cause of infant diarrhea in developing countries. EPEC uses a type III secretory system to deliver effector proteins into the host cell. These proteins cause the characteristic attaching and effacing lesion on enterocytes. Lactoferrin, a glycoprotein present in human milk, inhibits EPEC adherence to mammalian cells. To determine the effect of lactoferrin on the initial host cell attachment step that is mediated by the type III secretory system, we focused on EPEC-induced actin polymerization in HEp2 cells, on the hemolytic activity, and on measurement of E. coli secreted proteins A, B, and D (EspABD). Lactoferrin blocked EPEC-mediated actin polymerization in HEp2 cells and blocked EPEC-induced hemolysis. The mechanism of this inhibition was lactoferrin-mediated degradation of secreted proteins necessary for bacterial contact and pore formation, particularly EspB. The proteolytic effect of lactoferrin was prevented by serine protease inhibitors. This disruption of the type III secretory system implies that lactoferrin could provide broad cross protection against the enteropathogens that share this mechanism.
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Affiliation(s)
- Theresa J Ochoa
- Division of Pediatric Infectious Diseases, University of Texas-Houston Medical School, Houston, Texas 77040, USA
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Boullier S, Nougayrède JP, Marchès O, Tasca C, Boury M, Oswald E, De Rycke J, Milon A. Genetically engineered enteropathogenic Escherichia coli strain elicits a specific immune response and protects against a virulent challenge. Microbes Infect 2003; 5:857-67. [PMID: 12919854 DOI: 10.1016/s1286-4579(03)00175-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Enteropathogenic Escherichia coli (EPEC), a major cause of severe disease with diarrhea in infants, is also involved in weaned rabbit colibacillosis. EPEC O103 is frequent in rabbit-fattening units of Western Europe. It causes high mortality and growth retardation, leading to substantial economic losses. We report here the construction by allelic exchange of an EPEC O103 strain mutated in espB and tir, two essential virulence genes. Upon live oral administration to weaned rabbits, the E22DeltaTir/EspB mutant strain efficiently colonized the intestinal tract without any adverse consequences. The rabbits were challenged with the highly pathogenic parental strain E22. The mutant provided complete protection to rabbits and total resistance to intestinal colonization by E22. In addition, E22DeltaTir/EspB strain induced a specific humoral response against the bacterial adhesin AF/R2. These Abs prevent bacterial attachment to epithelial cells in vitro. These results open the way for the development of an efficient vaccine strategy against rabbit EPEC infections.
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Affiliation(s)
- Séverine Boullier
- UMR 1225, Institut National de la Recherche Agronomique, Ecole Nationale Vétérinaire de Toulouse, 31076 Toulouse cedex 3, France.
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Carbonare CB, Carbonare SB, Carneiro-Sampaio MMS. Early acquisition of serum and saliva antibodies reactive to enteropathogenic Escherichia coli virulence-associated proteins by infants living in an endemic area. Pediatr Allergy Immunol 2003; 14:222-8. [PMID: 12787303 DOI: 10.1034/j.1399-3038.2003.00028.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) is the most common etiological agent of acute diarrhea among infants living in poor social conditions in Brazil and other developing countries. This infection is rare in breast-fed infants, as well as in children older than 2 years. Over the past few years, our group has attempted to identify antibodies to EPEC virulence proteins in human milk and to establish the in vitro protective role of these antibodies. In the present study, we report the identification of antibodies to EPEC virulence proteins in sera and saliva from children of different ages, living in slums in the city of São Paulo, Brazil. Using EPEC and bacterial constructs (pET) for immunoblotting (IB) analysis, antibodies reacting to the main adhesins (intimin, bundle-forming pilli) and cell-signaling proteins (EPEC secreted proteins - Esp A, Esp B) were detected in sera from adults and children older than 1 year. Almost all children older than 1 year presented recognition patterns similar to those of adults in IB assays for serum IgG and secretory IgA antibodies, using EPEC outer membrane and other antigenic preparations. As previously observed for human milk, all samples from adults and older children recognized the 94 kDa molecular weight adhesin intimin strongly. In most children, previous EPEC symptomatic diarrhea could not be confirmed; however, almost all of them have presented one or more diarrhea episodes during their lifetime. These results suggest that reduction of EPEC infection frequency after 2 years of age may be associated with the development of anti-EPEC antibody repertoires.
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Affiliation(s)
- Cristiane Barros Carbonare
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, and Instituto Butantan, São Paulo, Brazil.
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Boullier S, Tasca C, Milon A. New flow cytometric method to quantify the inhibition of enteropathogenic Escherichia coli adhesion by anti-adhesin antibodies. Cytometry A 2003; 53:79-87. [PMID: 12766969 DOI: 10.1002/cyto.a.10042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Pathogenesis of enteropathogenic Escherichia coli (EPEC) infections can be divided in three stages. The first one is the intestinal colonization mediated by bacterial adhesins. The second and third stages are characterized by an intimate attachment of bacteria to the enterocytes. Little information is available on the specific immune response against EPEC. Here, we describe and validate a new approach to quantify the function of anti-EPEC adhesin antibodies (Abs). METHODS We developed a new method to quantify the function of anti-adhesin Abs by flow cytometry. We used pEGFP-E22 (a rabbit EPEC E22 strain expressing the GFP protein) and HeLa cells. The adhesion of E22 bacteria to HeLa cells is mediated by AF/R2, the specific E22 adhesin. We performed short-time interaction (30 min) between pEGFP-E22 and HeLa cells. After extensive washes, 10,000 HeLa cells were acquired by flow cytometry and bacterial adhesion was quantified. Different sera were used to inhibit bacterial adhesion and recombinant MPB-Afr2G (Afr2G is the main AF/R2 subunit) was also tested in this system. RESULTS We first verified that GFP expression by E22 did not modify bacterial adhesion. We then showed that this flow cytometry approach allowed easy quantification of bacterial adhesion and inhibition mediated by a specific anti-AF/R2 serum. Moreover, recombinant AF/R2 protein reversed the effect of the anti-AF/R2 serum. Finally, we validated our method using sera from E22 orally infected rabbits. We detected and quantified with this method functional specific anti-AF/R2 Abs in their sera. In addition, we correlated our results with an anti-AF/R2 enzyme-linked immunosorbent assay. CONCLUSIONS We have developed a new method to detect and quantify specific anti-EPEC adhesin Abs by flow cytometry. This method is easy to use and highly reproducible. Its development could be extended to the search of specific anti-adhesin Abs in human EPEC infections.
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Affiliation(s)
- Séverine Boullier
- UMR 1225 Intéractions Hôtes-Agents Pathogènes, Institut National de la Recherche Agronomique-Ecole Nationale Vétérinaire de Toulouse, 23 chemin des Capelles, F-31076 Toulouse Cédex 3, France.
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Noguera-Obenza M, Ochoa TJ, Gomez HF, Guerrero ML, Herrera-Insua I, Morrow AL, Ruiz-Palacios G, Pickering LK, Guzman CA, Cleary TG. Human milk secretory antibodies against attaching and effacing Escherichia coli antigens. Emerg Infect Dis 2003; 9:545-51. [PMID: 12737737 PMCID: PMC2972756 DOI: 10.3201/eid0905.020441] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Secretory immunoglobulin A (sIgA) is a primary factor responsible for preventing attachment of enteropathogens to gut epithelium in breastfeeding infants. We compared the frequency of sIgA to major surface antigens of enterohemorrhagic Escherichia coli (EHEC) in milk of 123 women from the United States and Mexico to determine whether regional differences existed in the frequency of antibodies to these surface antigens. In both groups of women, milk commonly has sIgA against various EHEC lipopolysaccharides, EspA, EspB, intimin, and less frequently against Shiga toxin. The study suggests that persons living in the United States are exposed to attaching/effacing enteropathogens more frequently than is generally assumed. The low frequency of antibodies to Stx1 (in 12% of Mexican and in 22% of U.S. samples) suggests that the rare appearance of hemolytic uremic syndrome in adults is not due to neutralization of toxin at the gut level. Only anti-EspA is found in most milk samples from both populations of women. EspA may represent a useful target for an immunization strategy to prevent EHEC disease in humans.
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Affiliation(s)
| | | | - Henry F. Gomez
- University of Texas-Houston Medical School, Houston, Texas, USA
| | - M. Lourdes Guerrero
- Instituto Nacional de la Nutricion “Salvador Zubiran,” México City, México, D. F
| | | | | | | | | | - Carlos A. Guzman
- GBF-German National Research Centre for Biotechnology, Braunschweig, Germany
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de Souza Campos Fernandes RC, Quintana Flores VM, Sousa de Macedo Z, Medina-Acosta E. Coproantibodies to the enteropathogenic Escherichia coli vaccine candidates BfpA and EspB in breastfed and artificially fed children. Vaccine 2003; 21:1725-31. [PMID: 12639496 DOI: 10.1016/s0264-410x(02)00525-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A diagnostic test was developed to discriminate active from past enteropathogenic Escherichia coli (EPEC) infection, which uses the affinity-purified recombinant proteins BfpA (bundle-forming pilus (BFP) structural repeating subunit A) and EspB (pore-forming secreted protein B) as reliable markers of virulence to detect antigen-specific coproantibodies by immunoblot analysis, and verification of active typical EPEC infection by gene-specific (bfpA and espB) PCR amplification using DNA extracted directly from specimens and/or culture-enriched preparations. To begin addressing the potential protective role of anti-EPEC antibodies at early age, the prevalence of IgA coproantibodies to these antigens was determined in either breastfed or artificially fed children <2 years of age hospitalized for watery diarrhea.
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de Souza Campos Fernandes RC, Quintana Flores VM, Medina-Acosta E. Prevalent transfer of human colostral IgA antibody activity for the enteropathogenic Escherichia coli bundle-forming pilus structural repeating subunit A in neonates. Diagn Microbiol Infect Dis 2002; 44:331-6. [PMID: 12543537 DOI: 10.1016/s0732-8893(02)00463-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The frequency of IgA antibody activity to the structural protein subunit BfpA of the enteropathogenic Escherichia coli bundle-forming pilus was determined in 40 mother-infant pairs by immunoblot analysis using affinity purified recombinant BfpA to monitor for IgA in maternal colostrum and in feces of the neonates. Fecal samples were collected from exclusively breastfed term infants < 24-h after the first breastmilk feeding and colostral samples from their mothers. Infants were monitored prospectively with monthly visits to ascertain dietary practices and diarrheal illnesses. The percentage of colostral anti-BfpA IgA positive patients that were also coproantibody positive was 67.5%. The median duration of lactation was 108 days and the incidence of infantile diarrheal disease was 7.5%. Thus, colostral anti-BfpA IgA antibody activity survives passage through the gut of breastfed neonates, persisting in their feces. It is suggested that oral passive immunotherapy may be used to prevent and/or treat typical EPEC infection during infancy.
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Noguera-Obenza M, Cleary TG. The role of human milk secretory IgA in protecting infants from bacterial enteritis. ADVANCES IN NUTRITIONAL RESEARCH 2002; 10:213-29. [PMID: 11795042 DOI: 10.1007/978-1-4615-0661-4_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Affiliation(s)
- M Noguera-Obenza
- University of Texas-Houston Health Science Center, Department of Pediatrics, Infectious Diseases Division, 6431 Fannin, JFB 1.739, Houston, Texas 77030, USA
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Fitzhenry RJ, Reece S, Trabulsi LR, Heuschkel R, Murch S, Thomson M, Frankel G, Phillips AD. Tissue tropism of enteropathogenic Escherichia coli strains belonging to the O55 serogroup. Infect Immun 2002; 70:4362-8. [PMID: 12117946 PMCID: PMC128144 DOI: 10.1128/iai.70.8.4362-4368.2002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Four enteropathogenic Escherichia coli (EPEC) strains belonging to the O55 serogroup (G21 and G30 [both O55:H6], G35 [O55:H-], and G58 [O55:H7]) were tested for their tissue tropism by using human intestinal in vitro organ culture. Strains showed restricted adhesion with attaching-and-effacing activity to follicle-associated epithelium of Peyer's patches, with no apparent adhesion to duodenum or colon. G35 and G58 express intimin gamma and show a similar tropism to intimin gamma-expressing enterohemorrhagic E. coli (EHEC) O157:H7. However, strains G21 and G30 were unusual because they expressed intimin alpha and had a restricted tissue tropism of intimin gamma phenotype. The amino acid sequence of the carboxy-terminal 280 amino acids of intimin from G21 was determined. Comparison with the prototype intimin alpha from strain E2348/69 (O127:H6) showed a single amino acid difference (corresponding to Val907 and Ala907 in the whole intimins). This mutation was reproduced by site-directed mutagenesis in an intimin alpha plasmid template, pCVD438, with the hypothesis that it may induce a change in tropism. However, when the mutated plasmid was placed in both EPEC and EHEC backgrounds, duodenal adhesion in a manner similar to strain E2348/69 was evident upon in vitro organ culture. Thus, additional factor(s) unrelated to intimin exist in the O55:H6 genome that influence human intestinal tissue tropism.
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Affiliation(s)
- R J Fitzhenry
- Centre for Paediatric Gastroenterology, Royal Free Hospital and University College Medical School, London, United Kingdom
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39
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Amaral JA, Tino De Franco M, Carneiro-Sampaio MMS, Carbonare SB. Anti-enteropathogenic Escherichia coli immunoglobulin Y isolated from eggs laid by immunised Leghorn chickens. Res Vet Sci 2002; 72:229-34. [PMID: 12076119 DOI: 10.1053/rvsc.2002.0551] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
IgY, the egg yolk immunoglobulin, equivalent to the IgG from mammals, has been used in veterinary practice for passive immunisation against bacterial or viral infectious diseases. Enteropathogenic Escherichia coli (EPEC) is the main etiological agent of infantile diarrhoea in Brazil and other developing countries. Our aims were to isolate immunoglobulin IgY from egg yolk laid by EPEC -immunised Leghorn chickens and to study its reactivity to the antigens from this pathogen, including some virulence factors. Leghorn chickens were immunised with a bacterial suspension intramuscularly (three hens) or intravenously (three hens) or with PBS (two hens). Eggs were collected over a period of 17 weeks. IgY isolation procedures were carried out by salt precipitation (ammonium sulphate, in solid form) followed by centrifugations and dialysis. Final preparations were submitted to sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS - PAGE), enzyme-linked immunosorbent assay (ELISA) and immunoblotting. All immunised animals developed good levels of antibodies reactive to whole bacteria or lipopolysaccharide (LPS), in contrast to the control ones. Immunoblottings allowed the recognition of several antigenic fractions of bacterial antigens, some of which had a molecular weight compatible with bacterial virulence factors, confirming the efficacy of the immunisation and the adequacy of the method.
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Affiliation(s)
- J A Amaral
- Laboratório de Imunogenética, Instituto Butantan, São Paulo, Brazil
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Quintana Flores VM, Campos de Souza Fernandes RC, Sousa de Macedo Z, Medina-Acosta E. Expression and purification of the recombinant enteropathogenic Escherichia coli vaccine candidates BfpA and EspB. Protein Expr Purif 2002; 25:16-22. [PMID: 12071694 DOI: 10.1006/prep.2001.1604] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BfpA, the structural repeating protein subunit A of the bundle-forming pilus and EspB, a type-III-secreted pore-forming protein of enteropathogenic Escherichia coli (EPEC), both virulence factors central for EPEC pathogenesis, were overexpressed in E. coli DH5alpha and M15 laboratory strains, respectively, using the pQE-30 cloning expression system, as chimeric fusions to a NH(2)-terminal histidine hexapeptide (His(6)-tag) sequence. After isopropyl beta-d-thiogalactoside induction, the expression levels achieved were 11 and 40% of total soluble protein for BfpA and EspB, respectively. The His(6)-tagged recombinant proteins were purified (up to 98% homogeneity) by Ni-agarose affinity chromatography and produced yields varying from 0.65 to 3.1 mg of recombinant protein per gram of wet weight cells. The immunogenicity and antigenicity of the final products were tested in rabbits and using fecal specimens obtained from children suffering from acute watery diarrhea, respectively. The recombinant products correspond to antigenically authentic protein standards, useful in future epidemiological and neonatal vaccinology studies.
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Vieira da Silva J, Garcia AB, Vieira Flores VMQ, Sousa de Macedo Z, Medina-Acosta E. Phytosecretion of enteropathogenic Escherichia coli pilin subunit A in transgenic tobacco and its suitability for early life vaccinology. Vaccine 2002; 20:2091-101. [PMID: 11972978 DOI: 10.1016/s0264-410x(02)00057-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
A plant expression cassette system was engineered to efficiently target proteins to the default secretory pathway, allowing the expression of DNA inserts in three frames as fusion proteins containing a synthetic tobacco calreticulin cleavable signal peptide sequence, with the advantage of producing the recombinant proteins by phytosecretion. As one approach to develop a vaccine to enteropathogenic Escherichia coli (EPEC) infection, the oral immunogenicity of phytosecreted BfpA, the structural subunit A of the bundle-forming pilus, expressed at high levels (7.7% of soluble protein) in transgenic tobacco tissues, was demonstrated in BALB/c mice by the induction and detection of fecal anti-BfpA antibodies.
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Affiliation(s)
- Jeferson Vieira da Silva
- Plant Biotechnology Section, Laboratory of Biotechnology, Center for Biosciences and Biotechnology, Universidade Estadual do Norte Fluminense, Avenida Alberto Lamego 2000, Horto, Campos dos Goytacazes, RJ CEP 28015-620, Brazil
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Abstract
Typical and atypical enteropathogenic Escherichia coli (EPEC) strains differ in several characteristics. Typical EPEC, a leading cause of infantile diarrhea in developing countries, is rare in industrialized countries, where atypical EPEC seems to be a more important cause of diarrhea. For typical EPEC, the only reservoir is humans; for atypical EPEC, both animals and humans can be reservoirs. Typical and atypical EPEC also differ in genetic characteristics, serotypes, and virulence properties. Atypical EPEC is more closely related to Shiga toxin-producing E. coli (STEC), and like STEC these strains appear to be emerging pathogens.
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Affiliation(s)
- Luiz R Trabulsi
- Laboratório Especial de Microbiologia, prédio novo, 2nd andar, Instituto Butantan, Av. Vital Brasil, 1500 São Paulo, Brazil, CEP:05503-900.
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de Araújo AN, Giugliano LG. Lactoferrin and free secretory component of human milk inhibit the adhesion of enteropathogenic Escherichia coli to HeLa cells. BMC Microbiol 2001; 1:25. [PMID: 11690544 PMCID: PMC59506 DOI: 10.1186/1471-2180-1-25] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2001] [Accepted: 10/09/2001] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Diarrhoea caused by Escherichia coli is an important cause of infant morbidity and mortality in developing countries. Enteropathogenic Escherichia coli (EPEC) is considered one of the major causes of diarrhoea in children living in developing countries. The ability of diarrhoeagenic strains of E. coli to adhere to and colonize the intestine is the first step towards developing the disease. EPEC strains adhere to enterocytes and HeLa cells in a characteristic pattern known as localized adherence. Many epidemiological studies of diarrhoea have shown that breast-feeding protects infants from intestinal infections. Both immunoglobulin and non-immunoglobulin elements of human milk are thought to contribute to the protection from diarrhoeal agents. RESULTS The effects of human milk and its protein components on the localized adherence of EPEC were investigated. Non-immunoglobulin components of human milk responsible for the inhibition of EPEC adhesion to HeLa cells were isolated by chromatographic fractionation of human whey proteins. Besides secretory immunoglobulin A, which has been previously reported to affect the adhesion of EPEC, free secretory component (fSC) and lactoferrin (Lf) were isolated. Even in concentrations lower than those usually found in whole milk, fSC and Lf were able to inhibit the adhesion of EPEC. alpha-lactalbumin was also isolated, but showed no activity on EPEC adhesion. CONCLUSIONS This study demonstrated that the immunoglobulin fraction, the free secretory component and lactoferrin of human milk inhibit EPEC adhesion to HeLa cells. These results indicate that fSC and Lf may be important non-specific defence factors against EPEC infections.
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Affiliation(s)
- Andréa Nascimento de Araújo
- Laboratório de Microbiologia, Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, 70910-900, Brasília DF, Brazil
| | - Loreny Gimenes Giugliano
- Laboratório de Microbiologia, Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, 70910-900, Brasília DF, Brazil
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Fernandes RM, Carbonare SB, Carneiro-Sampaio MM, Trabulsi LR. Inhibition of enteroaggregative Escherichia coli adhesion to HEp-2 cells by secretory immunoglobulin A from human colostrum. Pediatr Infect Dis J 2001; 20:672-8. [PMID: 11465839 DOI: 10.1097/00006454-200107000-00007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Enteroaggregative Escherichia coli (EAEC) is an important agent of the persistent diarrhea among low socioeconomic level children in developing countries that may be associated with chronic undernourishment. Breast-feeding is effective in protecting infants against diarrhea and other infectious diseases. The aim of the study is to verify the ability of human colostrum to inhibit aggregative adhesion of EAEC to HEp-2 cells and the presence of antibodies reactive to antigenic fractions of EAEC in colostrum samples. METHODS Enzyme-linked immunosorbent assay, immunoblotting and adhesion assays of EAEC to HEp-2 cells were done with pooled or individual colostrum samples (n = 35). Assays were performed with a well-known EAEC strain, 044:H18 E. coli (strain 042). Colostral IgA was isolated by affinity chromatography in Sepharose anti-human alpha chain column. RESULTS Total colostrum and isolated IgA inhibited EAEC adhesion, and this ability was associated with the presence of IgA antibodies against a 15-kDa band, compatible with the subunits of aggregative adherence fimbrial adhesin II, characteristic of the 042 strain, absent in its plasmid-cured isogenic strain, that was used as control. Individual colostrum samples also inhibited adhesion, showed variable antibody titles against EAEC antigens in enzyme-linked immunosorbent assay and recognized many antigenic fractions in immunoblotting assays, including the 15-kDa band. CONCLUSIONS These results confirm that IgA from human colostrum inhibits adhesion of EAEC to HEp-2 cells and suggest that colostrum IgA antibodies reactive to EAEC antigens may play a role in protection of infants against diarrhea caused by these bacteria.
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Affiliation(s)
- R M Fernandes
- Department of Microbiology and Parasitology, Santa Maria Federal University, Brazil
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45
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Abstract
Mammalian colostrum offers passive protection to the newborn against a variety of microbial pathogens, in the form of specific immunoglobulin A, G and M antibodies. Sharing maternal immunological memory is in many cases vital for the infant, but may have disastrous consequences, such as involuntary transfer of disease and disturbance of the developing immune system. In most published studies, immune milk preparations are reported to be effective in the prevention of various gastroenteric infections, but not in the treatment of an established infection.
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Affiliation(s)
- E M Lilius
- Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland.
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46
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Nagao AT, Friedlander-Del Nero D, Arslanian C, Carneiro-Sampaio MM. Elevated levels and different repertoire profile of colostral anti-LPS antibodies may have a significant role in compensating newborn immunity. Scand J Immunol 2001; 53:602-9. [PMID: 11422909 DOI: 10.1046/j.1365-3083.2001.00921.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A high prevalence of systemic infections caused by enterobacteria such as Escherichia coli is observed during the neonatal period. Lipopolysaccharide (LPS) is one of the major factors responsible for septic shock caused by these Gram-negative bacteria. We have recently demonstrated the presence of anti-LPS immunoglobulin (Ig)G antibodies in cord blood with a repertoire identical to that found in maternal serum. In the present study, we analyzed anti-LPS O111 antibody isotypes in maternal serum and colostrum from mothers and in cord serum from their respective full-term (n = 30) and preterm (n = 13) neonate infants. The main isotype found in serum samples from mothers of term infants was IgM (range between 28 and 54 mg/l), followed by IgA (1-2 mg/l) and IgG (2-3 mg/l). The range of IgG antibody concentrations in cord blood was between 2 and 3 mg/l, as a result of placental transfer. A novel observation in our study was that the LPS bands recognized by colostral antibodies were completely different from those recognized by IgG in serum. Colostral IgA antibodies recognized several bands not bound by serum IgG antibodies from the respective maternal serum, independently of the antibody quantity. In addition, we verified the pattern of LPS recognition by serum IgA and colostral IgA antibodies was identical, what suggested that the antibody isotype found in serum could probably be derived from differentiated IgA-positive cells which were homing to the mucosa through the mucosal homing mechanism. Identical pattern of recognition was obtained comparing the IgA and IgM isotypes in colostrum. Slight differences in the pattern of recognition were found between colostral and serum IgM antibodies. The fact that colostral antibodies recognize much more bands than serum antibodies may be important for the host to mount an effective immune response in the intestinal lumen, in order to prevent excessive absorption of LPS, reducing possible systemic effects caused by the molecule.
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Affiliation(s)
- A T Nagao
- Department of Immunology, University of São Paulo, SP, Brazil.
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Reece S, Simmons CP, Fitzhenry RJ, Matthews S, Phillips AD, Dougan G, Frankel G. Site-directed mutagenesis of intimin alpha modulates intimin-mediated tissue tropism and host specificity. Mol Microbiol 2001; 40:86-98. [PMID: 11298278 DOI: 10.1046/j.1365-2958.2001.02371.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The hallmark of enteropathogenic (EPEC) and enterohaemorrhagic (EHEC) Escherchia coli adhesion to host cells is intimate attachment leading to the formation of distinctive 'attaching and effacing' lesions. This event is mediated, in part, by binding of the bacterial adhesion molecule intimin to a second bacterial protein, Tir, delivered by a type III secretion system into the host cell plasma membrane. The receptor-binding activity of intimin is localized to the C-terminal 280 amino acids (Int280) and at least five distinct intimin types (alpha, beta, gamma, delta and epsilon) have been identified thus far. In addition to binding to Tir, intimin can also bind to a component encoded by the host. The consequence of latter intimin-binding activity may determine tissue tropism and host specificity. In this study we selected three amino acids in intimin, which are implicated in Tir binding, for site-directed mutagenesis. We used the yeast two-hybrid system and gel overlays to study intimin-Tir protein interaction. In addition, the biological consequences of the mutagenesis was tested using a number of infection models (cultured epithelial cells, human intestinal explants and a mouse model). We report that while an I237/897A substitution (positions numbered according to Int280alpha/whole intimin alpha) in intimin alpha did not have any affect on its biological activity, a T255/914A substitution attenuated intimin activity in vivo. In contrast, the mutation V252/911A affected tissue targeting in the human intestinal explant model and attenuated the biological activity of intimin in the mouse model. This study provides the first clues of the molecular basis of how intimin mediates tissue tropism and host specificity.
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Affiliation(s)
- S Reece
- Centre for Molecular Microbiology and Infection, Department of Biochemistry, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK
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Goosney DL, Gruenheid S, Finlay BB. Gut feelings: enteropathogenic E. coli (EPEC) interactions with the host. Annu Rev Cell Dev Biol 2001; 16:173-89. [PMID: 11031234 DOI: 10.1146/annurev.cellbio.16.1.173] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) is a gram-negative bacterial pathogen that adheres to human intestinal epithelial cells, resulting in watery, persistent diarrhea. It subverts the host cell cytoskeleton, causing a rearrangement of cytoskeletal components into a characteristic pedestal structure underneath adherent bacteria. In contrast to other intracellular pathogens that affect the actin cytoskeleton from inside the host cytoplasm, EPEC remains extracellular and transmits signals through the host cell plasma membrane via direct injection of virulence factors by a "molecular syringe," the bacterial type III secretion system. One injected factor is Tir, which functions as the plasma membrane receptor for EPEC adherence. Tir directly links extracellular EPEC through the epithelial membrane and firmly anchors it to the host cell actin cytoskeleton, thereby initiating pedestal formation. In addition to stimulating actin nucleation and polymerization in the host cell, EPEC activates several other signaling pathways that lead to tight junction disruption, inhibition of phagocytosis, altered ion secretion, and immune responses. This review summarizes recent developments in our understanding of EPEC pathogenesis and discusses similarities and differences between EPEC pedestals, focal contacts, and Listeria monocytogenes actin tails.
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Affiliation(s)
- D L Goosney
- The Biotechnology Laboratory and the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
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Blank TE, Zhong H, Bell AL, Whittam TS, Donnenberg MS. Molecular variation among type IV pilin (bfpA) genes from diverse enteropathogenic Escherichia coli strains. Infect Immun 2000; 68:7028-38. [PMID: 11083828 PMCID: PMC97813 DOI: 10.1128/iai.68.12.7028-7038.2000] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Typical enteropathogenic Escherichia coli (EPEC) strains produce bundle-forming pili (BFP), type IVB fimbriae that have been implicated in EPEC virulence, antigenicity, autoaggregation, and localized adherence to epithelial cells (LA). BFP are polymers of bundlin, a pilin protein that is encoded by the bfpA gene found on a large EPEC plasmid. Striking sequence variation has previously been observed among type IV pilin genes of other gram-negative bacterial pathogens (e.g., Pseudomonas and Neisseria spp.). In contrast, the established sequences of bfpA genes from two distantly related prototype EPEC strains vary by only a single base pair. To determine whether bundlin sequences vary more extensively, we used PCR to amplify the bfpA genes from 19 EPEC strains chosen for their various serotypes and sites and years of isolation. Eight different bfpA alleles were identified by sequencing of the PCR products. These alleles can be classified into two major groups. The alpha group contains three alleles derived from strains carrying O55, O86, O111, O119, O127, or O128 somatic antigens. The beta group contains five alleles derived from strains carrying O55, O110, O128ab, O142, or nontypeable antigens. Sequence comparisons show that bundlin has highly conserved and variable regions, with most of the variation occurring in the C-terminal two-thirds of the protein. The results of multilocus enzyme electrophoresis support the hypothesis that bfpA sequences have spread horizontally across distantly related clonal lineages. Strains with divergent bundlin sequences express bundlin protein, produce BFP, and carry out autoaggregation and LA. However, four strains lack most or all of these phenotypes despite having an intact bfpA gene. These results have important implications for our understanding of bundlin structure, transmission of the bfp gene cluster among EPEC strains, and the role of bundlin variation in the evasion of host immune system responses.
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Affiliation(s)
- T E Blank
- Division of Infectious Diseases, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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50
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Casswall TH, Sarker SA, Faruque SM, Weintraub A, Albert MJ, Fuchs GJ, Alam NH, Dahlström AK, Link H, Brüssow H, Hammarström L. Treatment of enterotoxigenic and enteropathogenic Escherichia coli-induced diarrhoea in children with bovine immunoglobulin milk concentrate from hyperimmunized cows: a double-blind, placebo-controlled, clinical trial. Scand J Gastroenterol 2000; 35:711-8. [PMID: 10972174 DOI: 10.1080/003655200750023372] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Enterotoxigenic Escherichia coli (ETEC) and enteropathogenic Escherichia coli (EPEC) are important causes of diarrhoea in young children and are associated with significant mortality rates. Passive immunization with antibodies from immunized cows has previously been shown to be effective as prophylaxis against E. coli-induced diarrhoea and therapeutically against rotavirus and cryptosporidia-induced diarrhoea. METHODS We tested the therapeutic efficacy of an oral bovine immunoglobulin milk concentrate (BIC) from cows hyperimmunized with ETEC and EPEC strains, in a randomized, placebo-controlled study in children with E. coli-induced diarrhoea. Eighty-six children between 4-24 months of age attending the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B) with E. coli-induced diarrhoea (63 EPEC/ETEC and 23 with other diarrhoeagenic E. coli) were randomly assigned to receive orally administered BIC (20 g) containing anti-ETEC/EPEC antibodies or a placebo preparation daily for 4 consecutive days. Daily stool output, intake of oral rehydration solution (ORS), stool frequency, and presence of diarrhoeagenic E. coli strains in the stool were monitored for 4 days. RESULTS Children in the treatment group tolerated the BIC with no side effects. There were no significant differences between the two groups with regard to ORS intake, stool output, frequency of diarrhoea, or clearance of pathogen. Nor was there any significant alteration in the duration of diarrhoea. CONCLUSIONS In contrast to the prophylactic efficacy of anti-E. coli BIC and the therapeutic efficacy of a similarly prepared anti-rotavirus BIC, antibodies from hyperimmunized cows appear to have no significant therapeutic benefit in the treatment of acute diarrhoea due to EPEC/ETEC.
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Affiliation(s)
- T H Casswall
- Dept. of Clinical Science, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden
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