Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse

Clostridium difficile is the leading cause of health care associated diarrhoea and remains a burden for the NHS. Disease symptoms can range from mild diarrhoea through to fulminant pseudomembranous colitis, resulting in mortality for some patients. Recurrence is a major problem and estimates are t...

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Main Author: Lister, Michelle M.
Format: Thesis (University of Nottingham only)
Language:English
Published: 2018
Online Access:https://eprints.nottingham.ac.uk/53216/
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author Lister, Michelle M.
author_facet Lister, Michelle M.
author_sort Lister, Michelle M.
building Nottingham Research Data Repository
collection Online Access
description Clostridium difficile is the leading cause of health care associated diarrhoea and remains a burden for the NHS. Disease symptoms can range from mild diarrhoea through to fulminant pseudomembranous colitis, resulting in mortality for some patients. Recurrence is a major problem and estimates are that 20% of all patients with disease will either relapse (with the same strain) or have a re-infection (with a different strain). Arguably, the main virulence factors are toxins A (TcdA) and toxin B (TcdB) which cause disease symptoms. The genes encoding TcdA and TcdB are located within the pathogenicity locus (PaLoc) along with three accessory genes; tcdR, tcdE and tcdC. The regulatory network has been studied but we aimed to add to this knowledge by using two under investigated strains R20291 a so-called hypervirulent strain and VPI 10463 a strain known to produce higher levels of toxin. Two different methods of investigation were employed during this study to improve our understanding of both the regulation of TcdA / TcdB but also the genetic mechanisms behind clinical relapse. These methods were; using forward and reverse genetic analysis to assess phenotypic differences and using bioinformatics to identify genes and / or single nucleotide variants (SNP) that may play a role. Using a combination these methods we have identified potential regulators of toxin production in both strains. We have also identified unique genes and SNPs that might provide a fitness benefit to strains of C. difficile that were isolated from patients who had suffered relapse episodes.
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spelling nottingham-532162025-02-28T12:06:38Z https://eprints.nottingham.ac.uk/53216/ Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse Lister, Michelle M. Clostridium difficile is the leading cause of health care associated diarrhoea and remains a burden for the NHS. Disease symptoms can range from mild diarrhoea through to fulminant pseudomembranous colitis, resulting in mortality for some patients. Recurrence is a major problem and estimates are that 20% of all patients with disease will either relapse (with the same strain) or have a re-infection (with a different strain). Arguably, the main virulence factors are toxins A (TcdA) and toxin B (TcdB) which cause disease symptoms. The genes encoding TcdA and TcdB are located within the pathogenicity locus (PaLoc) along with three accessory genes; tcdR, tcdE and tcdC. The regulatory network has been studied but we aimed to add to this knowledge by using two under investigated strains R20291 a so-called hypervirulent strain and VPI 10463 a strain known to produce higher levels of toxin. Two different methods of investigation were employed during this study to improve our understanding of both the regulation of TcdA / TcdB but also the genetic mechanisms behind clinical relapse. These methods were; using forward and reverse genetic analysis to assess phenotypic differences and using bioinformatics to identify genes and / or single nucleotide variants (SNP) that may play a role. Using a combination these methods we have identified potential regulators of toxin production in both strains. We have also identified unique genes and SNPs that might provide a fitness benefit to strains of C. difficile that were isolated from patients who had suffered relapse episodes. 2018-12-13 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/53216/1/Lister_Genetics%20of%20Clostridium%20difficile%20toxin%20and%20recurrence.pdf Lister, Michelle M. (2018) Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse. PhD thesis, University of Nottingham.
spellingShingle Lister, Michelle M.
Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse
title Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse
title_full Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse
title_fullStr Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse
title_full_unstemmed Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse
title_short Understanding the genetic mechanisms of Clostridium difficile toxin regulation and clinical relapse
title_sort understanding the genetic mechanisms of clostridium difficile toxin regulation and clinical relapse
url https://eprints.nottingham.ac.uk/53216/