Clostridium difficile Infections

Po-Ren Hsueh*. Divisions of Clinical Microbiology and Infectious Diseases, Departments of Laboratory, Medicine and Internal Medicine, National Taiwan University Hospital Taipei, Taiwan

Currently, Clostridium difficile rivals methicillin-resistant Staphylococcus aureus (MRSA) as the most common organism to cause healthcare-associated infections in the United States. Incidence of C. difficile infection (CDI) has also increased in Canada, Europe, and other parts of the world. CDI is associated with increased lengths of hospital stay, medical costs, morbidity, and mortality (attributable mortality rate of 6.9% at 30 days after diagnosis and 16.7% at 1 year) among hospitalized patients. Nearly every antibiotic along with gastric acid suppression has been associated with CDI. Among these, cephalosporins, ampicillin, and clindamycin remain important predisposing agents. Fluoroquinolones, previously infrequently associated with CDI, have been found to be one of the primary predisposing antimicrobials in recent studies. A positive result of a test for toxigenic C. difficile and/or its toxins in a patient with diarrhea is considered to be diagnostic for CDI. Most reports of increases in the incidence and severity of CDI have been associated with the BI/NAP1/027 strain of C. difficile. This strain produces more toxins A and B in vitro than do many other strains of C. difficile, produces binary toxin, and is highly resistant to fluoroquinolones. Metronidazole and vancomycin remain the primary options for the treatment of CDI. Several studies suggest that rates of response to treatment of CDI with metronidazole are declining and statistically superior rates of response to vancomycin treatment for severe disease with metronidazole treatment. Two antimicrobials (nitazoxanide and rifaximin) available in the United States have been used successfully for CDI treatment but lack United States Food and Drug Administration approval for this indication. Experimental treatments currently in clinical development include a toxin-binding polymer (tolevamer), two poorly absorbed antimicrobials (OPT-80 [difimicin] and ramoplanin), monoclonal antibodies, and a C. difficile vaccine. General strategies to prevent and reduce the risk of CDI include adherence of antimicrobial usage restriction and stewardship guidelines, preventing the patient from being exposed to C. difficile (disinfection and barrier precautions), and meticulous hand hygiene, and probable implement of probiotics.