DOCSLIB.ORG

University of Cape Town

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
University of Cape Town Town The copyright of this thesis rests with the University of Cape Town. No quotation from it or information derivedCape from it is to be published without full acknowledgement of theof source. The thesis is to be used for private study or non-commercial research purposes only. University Isolation And Molecular CharacterizationTown Of Shiga Toxin Producing Escherichia coli In Cattle, Water And Diarrhoeal Children From The PastoralCape Systems Of Southwesternof Uganda Samuel Majalija UniversityThesis presented for the degree of DOCTOR OF PHILOSOPHY Faculty of Health Sciences UNIVERSITY OF CAPE TOWN February 2009 Town Isolation and Molecular Characterisation of Shiga Toxin Producing Escherichia coli in Cattle, Water and Diarrhoeal Children from the Pastoral Systems of SouthwesternCape Uganda Copyright c Samuel Majalija 2009. of All right reserved. No part of this thesis may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or in any information storage and retrieval system, without permission in writing from the author or the University of Cape Town. Typeset using PDFLATEX as implemented in MIKTEX. Printed in SouthUniversity Africa at: University of Cape Town, Private Bag, 7700, Rondebosch. Cape Town. Specially dedicated to my parents Town Methuselah andCape Glads Majalija of and wife Mabel Majalija University Declaration I...................................................................... declare that the work presented in this thesis is my original work, except where indicated, and that it has not been submitted before for any degree or examination at any university. Town Signed: ........................................... Date: Cape of University Acknowledgements This study was conducted under the supervision of associate Professor Gay B. Elisha and co-supervisor Dr Segal Heidi both of University of Cape Town, and associate Professor Francis Ejobi from Makerere University. I am greatly indebted to Professor Gay B. Elisha for the intellectual guidance, inspiration and patience during the entire study period. I am thankful to Dr Heidi Segal for equipping me with the needed skills in molecular biology and to associate Professor Francis Ejobi for the guidance during field work. Town I am greatly indebted to Universities for Sciences, Humanities and Engineering for Partnership in Africa (USHEPiA) for the generous fellowship to pursue my Ph D studies. The administrators of USHEPiA, Ms. Nan Warner, Mrs. Masego Mogodu, Mrs. Zubaida Hattas and Ms. Norma DerbyCape deserve a mention. Special thanks to Africa Institute for Capacity development (AICAD) for the additional financial support during data collection. of I appreciate Makerere University, my employer, for granting me a study leave and the generous research grant. My work would not have been possible without the permission from the Director of Mbarara regional referral hospital and the cooperation of the medical staff of Rushere Hospital, Kiruhura and Nyakashashara health centres. Thank you very much for the participationUniversity and cooperation. My family has been very dear to me; Martha, Jesse, Joel and Joshua, thank you for your prayers and patience during this time when you needed me most, but I was never around. My dear wife, Mabel Majalija, you are a special God given friend. Your constant love and encouragement motivated me. Thank you for being there for me. The staff in the Department of Veterinary Microbiology, Faculty of Veterinary Medicine Makerere University were very helpful. I am particularly indebted to Mr. Lubowa Musiisi, the Chief technician, who cultured the bacterial isolates. I also thank Mr. Pascal Musoni, Manager Microbiology laboratory Groote Schuur Hospi- tal at the University of Cape Town for providing me with a stock of Escherichia coli O157:H7. v Acknowledgement Special thanks to my parents, Methuselah Majalija (RIP) and Glads Majalija; who treasured education and provided me the opportunity to study not available to themselves. Thank you very much. I can't repay you for what you did. Mukama abahe omugisa. All Africa House has been my home for the past three years. I am grateful to the administrative managers of All Africa House for ensuring my comfort during this period. Similarly, I extend my appreciation to all USHEPiA Fellows, with whom I have shared both social and academic life. I thank Ms. Joanne Evans and Ms. Rachael Jacobs, two of my colleagues I closely worked with in the laboratory. Lastly and most important, special thanks to God, my help and strength. I know it is by your power and favour that I have been able to accomplish this work. What eyes have not seen, ears have not heard or even the mind perceived, that you have prepared for your children. Your name be glorified through Jesus Christ our Lord and Saviour. Amen Town Cape of University vi Table of Contents dedication iii Declaration iv AcknowledgementsTown v Table of Contents vii List of TablesCape xiv of List of Figures xvi Abbreviations and Notations xviii Abstract xxi University 1 General Introduction 1 1.1 Aims of this work: background . 1 1.1.1 Geographic, demographic and climate characteristics of the cattle corridor in Uganda . 1 1.1.2 Pastoral livestock system in Mbarara subregion . 3 1.1.3 Cattle: the source of one of the pathogenic groups of Es- cherichia coli ........................... 3 1.2 E. coli associated with gastrointestinal infections . 6 vii Table of Contents 1.2.1 Enteropathogenic E. coli ..................... 6 1.2.2 Enteroinvasive E. coli ....................... 7 1.2.3 Enterotoxigenic E. coli ...................... 7 1.2.4 Enteroaggregative E. coli ..................... 7 1.2.5 Diffusely adherent E. coli .................... 8 1.2.6 Enterohaemorrhagic E. coli ................... 8 1.3 Shiga toxin containing E. coli ...................... 9 1.3.1 Biology . 9 1.3.2 Serotypes . 9 1.3.3 Virulence factors of Shiga toxin-producingTownE. coli . 10 1.3.3.1 Shiga toxin: Structure and biological properties . 10 1.3.3.2 Systemic uptake of Shiga toxin . 13 1.3.3.3 Role of Shiga toxinCape in the induction of watery diarrhoea 14 1.3.3.4 Role of Shiga toxin in the induction of haemorrhagic colitis in humansof . 14 1.3.3.5 Role of Shiga toxin in the pathogenesis of haemolytic uraemic syndrome . 15 1.3.3.6 The effect of age on the pathogenesis of haemolytic uraemic syndrome . 16 University1.3.3.7 Locus of enterocyte effacement: functional analysis . 17 1.3.3.8 Locus of enterocyte effacement and its role in diarrhoea 20 1.3.3.9 Variants and characteristics of intimin . 20 1.3.3.10 Phylogenetic diversity of intimin . 21 1.4 Evolution of enterohaemorrhagic E. coli . 22 1.5 Epidemiology of Shiga toxin-producing E. coli . 25 1.5.1 Emergence of enterohaemorrhagic E. coli . 25 1.5.2 Worldwide occurrence of Shiga toxin-producing E. coli . 26 viii Table of Contents 1.5.3 Shiga toxin producing E. coli in sub-Sahara Africa . 27 1.5.4 Epidemiology of Shiga toxin producing E. coli in Uganda . 28 2 Isolation and detection of STEC strains from humans, cattle and water sources in the pastoral systems of Nyabushozi county, Kiruhura district 29 2.1 Introduction . 29 2.2 Experimental design . 30 2.2.1 Study area and population . 30 2.2.2 Period of sample collection . 31 2.2.3 Ethical considerations . 31 2.2.4 Human study population . .Town . 31 2.2.5 Demographics and clinical information of diarrhoeal children . 32 2.2.6 Inclusion and exclusion criteria . 32 2.2.7 Collection of stool samplesCape . 33 2.2.8 Selection of cattle andof faecal collection . 33 2.2.9 Selection of valley dams . 33 2.2.10 Water sample collection . 34 2.2.11 Media and buffers . 34 2.2.12 Bacteriological culture . 34 2.2.13University Preparation of genomic DNA . 36 2.2.14 Detection of STEC by polymerase chain reaction (PCR) am- plification . 36 2.2.14.1 Primers and PCR detection of stx . 36 2.2.14.2 Agarose gel electrophoresis . 37 2.2.14.3 Purification of PCR products and quantification of DNA . 37 2.2.14.4 DNA sequencing and computer analysis of sequenc- ing data . 38 ix Table of Contents 2.3 Results . 38 2.3.1 Clinical information on children and isolation of E. coli, Salmonella and Shigella from their faeces . 38 2.3.2 Age and health status of cattle and isolation of E. coli . 39 2.3.3 Information on valley dams . 39 2.3.4 Detection of stx genes in human, bovine and water E. coli isolates using PCR and DNA extracted from a sweep of colonies 40 2.3.5 PCR detection of stx genes in individual E. coli colonies from humans, bovines and water samples . 41 2.3.5.1 Detection of stx genes in human isolates . 41 2.3.5.2 PCR detection of stx genes in individual E. coli colonies from bovines and waterTown samples . 44 2.4 Discussion . 46 3 Molecular typing of STEC strainsCape 50 3.1 Introduction . .of . 50 3.2 Experimental design . 50 3.2.1 Bacterial strains . 50 3.2.2 Pulsed field gel electrophoresis . 51 3.2.2.1 Preparation of DNA . 51 3.2.2.2 Cell lysis and restriction enzyme digest of genomic UniversityDNA . 52 3.2.2.3 Electrophoresis conditions . 52 3.2.2.4 Visualization and photography of the gel . 53 3.2.2.5 Analysis of PFGE data and interpretation of results 53 3.2.2.6 Optimisation of PFGE assays . 54 3.3 Results . 55 3.3.1 Genetic fingerprints of individual clinical STEC colonies from phase 1 . 55 x Table of Contents 3.3.2 Genetic fingerprints of individual clinical STEC colonies from phase 2 . 58 3.3.3 Genetic relatedness of clinical STEC strains in phases 1 and 2 59 3.3.4 Determination and analyses of individual bovine STEC colonies: relatedness to each other and to the clinical STEC .
Load more

Recommended publications
  • Antimicrobial Resistant Escherichia Coli in Alberta's Rural Well Water
    University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2017 Antimicrobial Resistant Escherichia coli in Alberta's Rural Well Water Meyer, Kelsey Meyer, K. (2017). Antimicrobial Resistant Escherichia coli in Alberta's Rural Well Water (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/24938 http://hdl.handle.net/11023/3976 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Antimicrobial Resistant Escherichia coli in Alberta’s Rural Well Water by Kelsey Meyer A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAM IN MICROBIOLOGY AND INFECTIOUS DISEASES CALGARY, ALBERTA JULY, 2017 © Kelsey Meyer 2017 Abstract The consumption of rural well water (RWW) contaminated with antimicrobial resistant (AMR) Escherichia coli has been linked to human carriage of resistance. Our objective was to determine whether AMR and extended spectrum beta lactamase (ESBL) producing E.coli are present in Alberta’s RWW. Resistant isolates were detected with an agar screen on (up to) 20 isolates from each sample, and AMR was measured with NARMS Sensititre™ panels. Disk diffusion assays detected ESBL-producing E.coli, and spatial clusters of AMR E.coli were assessed using ArcGIS (version 10.4.1) and SaTScan™ (version 9.4.4).
    [Show full text]
  • The Correlation Between Tolerance to Low Water Activity and High Hydrostatic Pressure in Shiga Toxin Producing Escherichia Coli
    The Correlation between Tolerance to Low Water Activity and High Hydrostatic Pressure in Shiga Toxin Producing Escherichia coli BY Fahad Bazaid A Thesis Presented to The University of Guelph In partial fulfillment of requirements for the degree of Doctor of Philosophy in Food Science Guelph, Ontario, Canada © Fahad Bazaid, March 2019 ABSTRACT THE CORRELATION BETWEEN TOLERANCE TO LOW WATER ACTIVITY AND HIGH HYDROSTATIC PRESSURE IN SHIGA TOXIN PRODUCING ESCHERICHIA COLI Fahad Bazaid University of Guelph, 2019 Advisors: Dr. Keith Warriner Dr. Andrew Kropinski Dr. Don Mercer Dr. Tatiana Koutchma High hydrostatic pressure processing (HHP) is extensively applied for the non-thermal pasteurization of foods. One notable feature of HHP mediated inactivation of microbes is the large variation in lethality between strains and the influence of the food matrix. In the following it was hypothesized that the barotolerance of Shiga Toxin producing Escherichia coli could be correlated to tolerance to low water activity environments. The study evaluated the barotolerance of members of the Top 6 STEC serotypes and found variation with O26: H11 and O45: H2 exhibiting higher tolerance to pressure compared to the other bacterial types tested. A negative correlation was found between resistance to high pressure and the NaCl concentration under which E. coli could grow under. For example, E. coli O26: H11 exhibited the highest tolerance to pressure, within 300 MPa, but could only grow under NaCl up to 2.4% w/v. In contrast, E. coli O121: H19 was sensitive to pressure, but could grow in the presence of 6% NaCl. The results suggested ii that the induction of the stress-response was the likely reason for high barotolerance in salt sensitive strains vs resistant.
    [Show full text]
  • Ocorrência De Fatores De Virulência Em Estirpes De Escherichia Coli Isoladas De Fezes De Cães Errantes
    Ocorrência de fatores de virulência em estirpes de Escherichia coli isoladas de fezes de cães errantes. 401 OCORRÊNCIA DE FATORES DE VIRULÊNCIA EM ESTIRPES DE ESCHERICHIA COLI ISOLADAS DE FEZES DE CÃES ERRANTES A.C.M.D.G. von Sydow, J.A. Coogan, A.M. Moreno, P.A. Melville, N.R. Benites Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Departamento de Medicina Veterinária Preventiva e Saúde Animal, Av. Prof. Dr. Orlando Marques de Paiva, 87, CEP 05508-000, São Paulo, SP, Brasil. E-mail: [email protected] RESUMO Escherichia coli pode causar doenças em humanos e animais, tais como infecções do trato urinário, septicemia, meningites e gastroenterites. Cães assintomáticos podem participar da cadeia epidemiológica como reservatório de E. coli patogênica ao homem. Este estudo objetivou avaliar a ocorrência de E. coli patogênica ao homem em fezes de cães errantes sem sintomas de colibacilose e assim averiguar a participação do cão como fonte de infecção de colibacilose humana. Foram coletadas 220 amostras de fezes de animais capturados por diferentes Centros de Controle de Zoonoses do Estado de São Paulo. As amostras foram submetidas a exames microbiológicos sendo isoladas 196 (89,09%) estirpes de E. coli, cujos genes de fatores de virulência foram detectados por PCR. Cento e vinte e três (62,75%) estirpes apresentaram um ou mais dos fatores de virulência estudados. Dezesseis (8,16%) foram positivas para afa, 54 (27,55%) para sfa, 38 (19,38%) para pap, 66 (33,67%) para aer, 31 (15,81%) para cnf, 13 (6,63%) para hly, 1 (0,51%) para VT2 e nenhuma das linhagens foi positiva para LT, STa e STb.
    [Show full text]
  • Molecular Evaluation and Antimicrobial Susceptibility Testing of Escherichia Coli Isolates Collected from Various Food Products in Turkey
    MOLECULAR EVALUATION AND ANTIMICROBIAL SUSCEPTIBILITY TESTING OF ESCHERICHIA COLI ISOLATES COLLECTED FROM VARIOUS FOOD PRODUCTS IN TURKEY A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF MIDDLE EAST TECHNICAL UNIVERSITY BY EMMANUEL OWUSU KYERE IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN BIOTECHNOLOGY JULY 2014 ii Approval of the thesis: MOLECULAR EVALUATION AND ANTIMICROBIAL SUSCEPTIBILITY TESTING OF ESCHERICHIA COLI ISOLATES COLLECTED FROM VARIOUS FOOD PRODUCTS IN TURKEY Submitted by EMMANUEL OWUSU KYERE in partial fulfillment of the requirements for the degree of Master of Science in Biotechnology Department, Middle East Technical University by, Prof. Dr. Canan Özgen _____________ Dean, Graduate School of Natural and Applied Sciences Prof. Dr. Filiz Bengü Dilek _____________ Head of Department, Biotechnology Asist. Prof. Dr. Yeşim Soyer _____________ Supervisor, Food Engineering Dept., METU Asist. Prof. Dr. Dilek Avşaroğlu Erkan _____________ Co-supervisor, Agric. Biotech. Dept., Ahi Evran University Examining Committee Members: Assoc. Prof. Dr. Çağdaş Son _____________ Biology Dept., METU Asist. Prof. Dr. Yeşim Soyer _____________ Food Engineering Dept., METU Asist. Prof. Dr. Mecit H. Öztop _____________ Food Engineering Dept., METU Asist. Prof. Dr. Tuba H. Ergüder _____________ Environmental Engineering Dept., METU Asist. Prof. Dr. Umut Yücel _____________ Food Engineering Dept., METU Date: 23.07.2014 iii I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all materials and results that are not original to this work.
    [Show full text]
  • Toxin E. Coli Serogroups on Fresh Produce
    Development of a Phage Cocktail to Control the Top 7 Shiga -toxin E. coli Serogroups on Fresh Produce by Yiran Ding A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfilment of the requirement of the degree of MASTER OF SCIENCE Department of Food and Nutritional Sciences University of Manitoba Winnipeg Copyright © 2018 by Yiran Ding I I hereby declare that I am the sole author of this thesis. I authorize the University of Manitoba to lend this thesis to other institutions or individuals for the purpose of scholarly research. Yiran Ding I further authorize the University of Manitoba to reproduce this thesis by photocopying or by other means in total or in part, at the request of other institutions or individuals for the purpose of scholarly research. Yiran Ding II ACKNOWLEDGMENTS First of all, I want to thank my parents, Luosi Ding and Xu Li, for their encouragements and supports in every way I can think about throughout my life. I would never have been able to achieve anything without their love and care. I also would like to thank my grandparents for believing in me and encouraging me to go through the difficult times. I owe my sincerest gratitude to my relatives back home, for staying in touch and warming my heart in the coldest winter. I am extremely thankful to my Advisor, Dr. Narvaez, for her generous, knowledge, patience, encouragement, and inspiration for me to explore deeper into the topics. She provided me many chances to learn and triggered my passion for food and microbiology.
    [Show full text]
  • Whole Genome Sequence Typing and Analysis of Non-O157 Stec
    WHOLE GENOME SEQUENCE TYPING AND ANALYSIS OF NON-O157 STEC January 2020 1 Scottish E. coli O157/STEC Reference Laboratory Department of Laboratory Medicine Royal Infirmary of Edinburgh Little France Edinburgh EH16 4SA Tel: +44 (0)131 2426013 Main Authors: Lesley Allison, Principal Scientist, Scottish E. coli O157/STEC Reference Laboratory Anne Holmes, Clinical Scientist, Scottish E. coli O157/STEC Reference Laboratory Mary Hanson, Director, Scottish E. coli O157/STEC Reference Laboratory Contributing Author: Melissa Ward, Sir Henry Wellcome Postdoctoral Research Fellowship (WT103953MA), University of Edinburgh (E. coli O26:H11 phylogenetic analysis) 1 CONTENTS 1 Scientific and lay summaries 1.1 Scientific summary 1.2 Lay summary 1.3 Glossary 2 Introduction 2.1 Background 2.1.1 Shiga toxin-producing Escherichia coli (STEC) 2.1.2 Assessment of Pathogenicity 2.1.3 Assigning Pathogenic Potential 2.1.4 Sources of Infection 2.1.5 The Scottish E. coli O157/STEC Reference Laboratory (SERL) 2.1.6 Guidance for Screening for STEC in Scotland 2.1.7 Laboratory Diagnosis 2.1.8 Isolation of STEC 2.1.9 Strain Typing 2.1.10 Prevalence of STEC in Scotland 2.1.11 The Scottish Culture Collection 2.2 Aims of the study 3 Methods 3.1 The Study Group 3.2 DNA extraction, Library Preparation and Sequencing 3.3 Data Analysis 3.4 Phylogenomic Analysis. 3.4.1 Core genome (cg) MLST 3.4.2 Reference Based Assembly of E. coli O26:H11 4 Results 4.1 Isolates Confirmed as non-O157 E. coli by Diagnostic Laboratories 4.2 Molecular typing and Characterisation of non-O157 STEC 4.2.1 Species Identification and Serotyping 4.2.2 7-Gene MLST 4.2.3 Shiga Toxin Gene Profile 4.2.4 Virulence Gene Detection 4.2.5 Acquired Antimicrobial Resistance 4.3 Phylogenetic Overview of Non-O157 STEC 4.4 Potential to Cause Clinical Disease – JEMRA Level Assignment 4.5 Predominant, Emerging and Hybrid Strains: a comparison with published data 4.5.1 E.
    [Show full text]
  • Survival of Acid-Adapted Escherichia Coli O157:H7 and Non-O157:H7
    The Pennsylvania State University The Graduate School College of Agricultural Sciences SURVIVAL OF ACID-ADAPTED ESCHERICHIA COLI O157:H7 AND NON-O157:H7 SHIGA TOXIN-PRODUCING E. COLI (STEC) DURING PROCESSING OF DRY, FERMENTED SAUSAGES A Dissertation in Food Science by Minerva Rivera © 2017 Minerva Rivera Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy December 2017 i The dissertation of Minerva Rivera was reviewed and approved* by the following: Catherine N. Cutter Professor of Food Science Food Safety Extension Specialist – Muscle Foods Dissertation Advisor Chair of Committee Jonathan A. Campbell Assistant Professor of Meat Science Extension Meat Specialist Edward G. Dudley Associate Professor of Food Science Sara Milillo Food Science Faculty Director of Math and Science at Bay Path University Robert F. Roberts Professor of Food Science Head of the Department of Food Science *Signatures are on file in the Graduate School ii Abstract Escherichia coli O157:H7 was first recognized as a human pathogen following outbreaks of hemorrhagic colitis in the early 1980s. Due to the infectious dose of E. coli O157:H7, the severity of the disease, and the possibility of lifelong sequalae, the U. S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) declared it as an adulterant in raw ground beef in 1994. In 2012, non-O157:H7 Shiga toxin-producing E. coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145) also were declared adulterants in raw beef products by USDA- FSIS. Until recently, the majority of the research done on interventions used to control STEC has been done on E.
    [Show full text]
  • EURL-Salmonella Newsletter March 2020
    European Union Reference Laboratory for Salmonella Vol. 26 No. 1 March 2020 ISSN 2211-6877 Continuation of Newsletter Community Reference Laboratory for Salmonella ISSN 1572-3836 Newsletter EURL-Salmonella, March 2020 Page 2 of 31 Produced by European Union Reference Laboratory for Salmonella National Institute of Public Health and the Environment P.O. Box 1, 3720 BA Bilthoven, The Netherlands phone: +31 30 274 3537 (Kirsten Mooijman) +31 30 274 4290 (Wilma Jacobs) e-mail: [email protected] [email protected] Newsletter EURL-Salmonella, March 2020 Page 3 of 31 Contents EDITORIAL NOTE ...................................................................................................................... 4 FROM THE LITERATURE ......................................................................................................... 7 Newsletter EURL-Salmonella, March 2020 Page 4 of 31 Editorial Note Bilthoven, 6 April 2020 Dear colleague, Currently we live in strange times. The COVID-19 pandemic has hit us all very hard. It influences our daily live, our work and, most of all, our health. I sincerely hope that you are all healthy and that these difficult times come to an end soon. I wish you all much strength to cope with all difficulties due to this pandemic. In relation to the COVID-19 pandemic, and upon request of EC DG SANTE, we made a short inventory among the NRLs-Salmonella on possible difficulties that the NRLs and/or local laboratories may currently encounter to conduct the Salmonella testing on poultry. I want to express my gratitude for the fact that so many of you could send me a reply within 1,5 (working) days! Very helpful! From the replies it was clear that even in these difficult times the NRLs-Salmonella and/or the local official laboratories do the outmost to ensure the continuity of the important Salmonella analyses.
    [Show full text]
  • Detection of Shigella and Enteroinvasive Escherichia Coli, the Causative Agents of Bacillary Dysentery from Environmental and Clinical Samples
    EVELYN DÓRA SZAKÁL Detection of Shigella and enteroinvasive Escherichia coli, the causative agents of bacillary dysentery from environmental and clinical samples Ph.D. DISSERTATION PTE AOK Faculty of Medicine, University of Pécs Department of Clinical Microbiology and Immunology Hungary Pécs 2003 EVELYN DÓRA SZAKÁL Detection of Shigella and enteroinvasive Escherichia coli, the causative agents of bacillary dysentery from environmental and clinical samples Ph.D. DISSERTATION Title of PhD Programme: Molecular pathogenesis of infectious diseases Programme leader: Professor Levente Emődy, M.D., Ph.D., D.Sc. Supervisor: Professor Tibor Pál, M.D., Ph.D., D.Sc. PTE AOK Faculty of Medicine, University of Pécs Department of Clinical Microbiology and Immunology Hungary Pécs 2003 To my brother, my parents and my grandparents CONTENTS ABBREVIATIONS........................................................................................................8 1 INTRODUCTION ......................................................................................................9 2 REVIEW OF THE LITERATURE ........................................................................11 2.1. THE SIGNIFICANCE OF BACILLARY DYSENTERY IN THE PAST AND TODAY.............11 2.2. THE CAUSATIVE AGENTS OF BACILLARY DYSENTERY, BIOCHEMICAL AND SEROLOGICAL CHARACTERISTICS ........................................................................13 2.3. CLINICAL FEATURES OF BACILLARY DYSENTERY .................................................16 2.4. IMMUNITY............................................................................................................18
    [Show full text]
  • Shiga Toxin-Producing Escherichia Coli (STEC) and Food: Attribution, Characterization, and Monitoring
    31 ISSN 1726-5274 Shiga toxin-producing Escherichia coli (STEC) infections are a substantial health issue worldwide. Circa 2010, foodborne STEC caused > 1 million human illnesses, 128 deaths, and ~ 13,000 Disability Adjusted Life Years (DALYs). Targeting interventions to address this hazard relies on identifying those STEC strains of greatest risk to human health and determining the food vehicles for such infections. This report brings together the review and analysis of existing information on the burden, source attribution, hazard characterization and monitoring of STEC. It proposes a set of criteria for categorizing the potential risk of severity of characterisation, and monitoring Shiga toxin-producing illness associated with the presence of a STEC in food, for consideration by risk managers, as part of a risk-based approach to control STEC in foods. It presents the initial results on source attribution of foodborne STEC, highlighting that while ruminants and other land animals are considered the main reservoirs Shiga toxin-producing for STEC, largescale outbreaks have also been linked to other foods, such as fresh produce. It also provides a review of monitoring programmes and meth- odology for STEC, which can serve as a reference for countries planning to Escherichia coli (STEC) develop such programmes. Escherichia coli ( and food: attribution, This work was undertaken in response to a request from the Codex Alimentarius to support the development of international standards on foodborne STEC. The advice herein is useful for both
    [Show full text]
  • Escherichia Coli ISOLADAS DE ÁGUA DE CONSUMO: CARACTERIZAÇÃO FENOTÍPICA E GENOTÍPICA DAS PROPRIEDADES DE VIRULÊNCIA”
    Universidade Estadual de Campinas Daniela Alves Ribeiro “Escherichia coli ISOLADAS DE ÁGUA DE CONSUMO: CARACTERIZAÇÃO FENOTÍPICA E GENOTÍPICA DAS PROPRIEDADES DE VIRULÊNCIA” Dissertação apresentada ao Instituto de Biologia para obtenção do Título de Mestre em Genética e Biologia Molecular na área de Microbiologia. Orientador: Prof. Dr. Tomomasa Yano Co-orientador: Profa. Dra. Maria Célia S. Lanna Campinas 2006 “A verdadeira vida não é constituída de currículos e conquistas que aumentam nosso intelecto, mas de essência humana. A maior mensagem que podemos deixar cravada na nossa vida é maneira pela qual vamos vivê-la. N ossa vida será nossa mensagem”. iv Dedico este trabalho ao meu namorado, Edmar, pois sem o seu apoio, incentivo e amor nada disso se concretizaria. v Agradecimentos A Deus, por estar sempre presente em minha vida e pela sua imensa bondade, permitindo-me a conquista de tantas coisas. Aos meus pais e irmãos, que compreenderam a minha ausência, me apoiaram e, principalmente, pelo amor que sempre me deram. Ao meu namorado, que na ocasião não encontro palavras para agradecer tudo que fez por mim. Você é o grande responsável por esta conquista. Agradeço enormemente ao meu orientador, Prof. Dr. Tomomasa Yano, pela exímia orientação, por toda confiança e apoio e pela grande pessoa que é. Ao senhor, toda a minha admiração. À Profa. Dra. Silvia Gatti, pelos seus valiosos ensinamentos, não apenas na ocasião da pré-banca, mas em todo o decorrer deste trabalho, pela participação em banca examinadora e, principalmente, por ser um exemplo de profissional. A Dr. Cleide Catani, pela amizade, pelas sugestões em todo decorrer deste trabalho e pelos importantes comentários em exame de pré-banca.
    [Show full text]
  • Use of Comparative Genomics As a Tool to Assess the Clinical and Public Health Significance of Emerging Shiga Toxin-Producing Escherichia Coli Serotypes
    MEAT SCIENCE Meat Science 71 (2005) 62–71 www.elsevier.com/locate/meatsci Review Use of comparative genomics as a tool to assess the clinical and public health significance of emerging Shiga toxin-producing Escherichia coli serotypes Mohamed A. Karmali * Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, 110 Stone Road West, Guelph, Ont., Canada N1G 3W4 Abstract Shiga toxin (Stx)-producing Escherichia coli (STEC) cause sporadic or epidemic food- or water-borne illness whose clinical spec- trum includes diarrhea, hemorrhagic colitis, and the potentially fatal hemolytic uremic syndrome (HUS). Over 200 STEC serotypes have now been implicated in human disease. Serotype O157:H7 is associated most outbreaks and most cases of HUS. Other sero- types are also associated with outbreaks and HUS but less commonly than serotype O157:H7, and some cause HUS but are typically non-epidemic. Many STEC serotypes have been associated with diarrhea, but not with outbreaks or HUS, while others, isolated from cattle, have never been linked to human disease. The only proven virulence strategies for STEC are Stx production and, in some strains, a characteristic attaching and effacing cytopathology on enterocyte that is mediated by factors encoded on a patho- genicity island (PAI) known as the locus of enterocyte effacement (LEE). But Stx subtypes and LEE cannot fully explain the appar- ent differences in virulence between STEC subgroups. However, publication of the genome sequences of two E. coli O157:H7 strains has revealed new candidate PAIs and has stimulated the use of novel approaches for assessing differences in virulence potential between groups of strains.
    [Show full text]