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Chapter 16 : Clostridium difficile Disease
Category: Clinical Microbiology
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This chapter reviews the salient features of infection caused by Clostridium difficile. C. difficile inhabits the lumen of the colon and is not invasive. Nearly all strains produce toxins A and B, although some strains that produce only toxin B have been shown to cause disease. The genes tcdA and tcdB, which encode toxins A and B, respectively, are downregulated by the gene tcdC. C. difficile colitis was originally recognized exclusively as a nosocomial infection and, subsequently, as a problem in extended care facilities. Strains of C. difficile have been identified by restriction enzyme analysis (REA), pulsed-field gel electrophoresis (PFGE), restriction fragment length polymorphism analysis of the pathogenicity locus that includes genes for toxin production (toxinotyping), and PCR for tcdC, which encodes a binary toxin. Using these techniques, many distinct strains have been identified in patients with C. difficile disease (CDD). In the epidemiologic setting of hospitalization with prior antimicrobial and/or chemotherapy, the clinical syndrome of CDD is usually easy to recognize. Abdominal discomfort and diarrhea, generally > 3 loose or watery bowel movements per day, develop over a period of a few days. Oral vancomycin was used to treat ‘‘staphylococcal enterocolitis’’ and clindamycin-associated diarrhea before the discovery that C. difficile was responsible. Rifaximin is only minimally absorbed in the gastrointestinal tract after oral administration. Use of hypochlorite solution as a disinfectant and disposable rectal thermometers are also effective.
Key Concept Ranking
- Restriction Fragment Length Polymorphism
Dendrogram showing 22 C. difficile isolates from the Michael E. DeBakey Veterans Affairs Medical Center during the prolonged outbreak of severe CDAD. Four of 22 isolates were NAP 1. The isolates were selected randomly and submitted to the Centers for Disease Control and Prevention for study. The photo was graciously provided by C. Kilgore and A. Thompson of the Centers for Disease Control and Prevention.
Factors contributing to the recent increase in C. difficile disease
Treatments for C. difficile colitis