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Dissertation/Thesis Abstract

Optimizing detection and control of Clostridium difficile and its toxins
by Shilling, Michael P., Ph.D., Kent State University, 2013, 199; 3618927
Abstract (Summary)

Clostridium difficile infection (CDI) is a bacterial disease affecting the lower gastrointestinal tract of patients whose normal colonic microbiota are altered, generally by administration of antibiotic therapies. C. difficile produces toxins that cause severe diarrhea, with potentially fatal complications in the immunocompromised. CDI has spread unabated despite the best prevention efforts of clinical practitioners. This dissertation is a broad-based study of several factors of importance in prevention and control CDI. In clinical environments, transport media are used to maintain the integrity of clinical samples for later laboratory testing. A transport medium for enteric bacteria was assessed as a preservative in outpatient fecal samples submitted for CDI testing. The transport medium used preserved C. difficile toxin out to five days. The possible effect of fecal pH and trypsin content on toxin stability was investigated. Fecal pH was ruled out as a factor due to CDI selected samples tending toward neutral pH. Trypsin was found to degrade toxin in controlled experiments; however, results from clinical samples were mixed. Oils and fatty acids, including virgin coconut oil (VCO), have antimicrobial effects on a variety of human pathogens. Use of natural products like VCO may reduce or prevent CDI by killing C. difficile while preserving the protective bowel flora. Virgin coconut oil (VCO) and three of its constituent fatty acids were evaluated for their toxic effect on C. difficile and were found to have bactericidal activity, the most potent of which was lauric acid. The outer surface of C. difficile spores is thought to contain proteins that are critical for attachment of the spores to surfaces, including human hands. This strong attachment assists in transmission of infectious spores; however, the source of this strong attachment in the spore remains unknown. Transmission electron micrography shows that C. difficile lacks a true exosporium, rather, they are coated in the remains of the mother cell. Results from subsequent fluorescence microscopy and ELISA with antibodies raised against spore coat proteins confirm that this residue is not part of the spore coat and can be easily removed by chemical treatment, increasing spore binding to anti-coat antibodies.

Indexing (document details)
Advisor: Woolverton, Christopher J.
Commitee: Gregory, Roger, Johnson, John, Rosenthal, Kenneth, Russell, Mary
School: Kent State University
Department: Biomedical Sciences
School Location: United States -- Ohio
Source: DAI-B 75/08(E), Dissertation Abstracts International
Subjects: Microbiology, Immunology
Keywords: Clostridium difficile, Freeze fracture electron transmission microscopy, Spore coat, Toxin, Transport, Virgin coconut oil
Publication Number: 3618927
ISBN: 978-1-303-87483-3
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