• The primary endpoint is the proportion of subjects achieving clinical success, where clinical success is defined as resolution or improvement of baseline signs and symptoms i.e., abdominal pain, fever, diarrhea.
  

• The secondary endpoint will be the proportion of subjects who have a recurrence of CDAD, with recurrence defined as diarrhea and a positive Clostridium difficile stool toxin assay that occurs after initial clinical success.
  

Clostridium difficile is a bacterium that proliferates when normal colonic flora have been altered, most commonly due to antibiotic use. Clostridium difficile is non-invasive and localized to the lumen of the colon. Once established, it produces 2 potent toxins, A and B. The principal reservoir for Clostridium difficile is the hospital environment, with the risk of acquiring Clostridium difficile increasing in direct proportion to the length of hospital stay. Patients with CDAD typically present with profuse watery or mucoid diarrhea and cramping abdominal pain. Additional symptoms include fever, nausea, anorexia, malaise, and bloody stool. More severe cases may be complicated by dehydration, electrolyte disturbances, ileus, and peritonitis. Systemic manifestations may include prerenal azotemia, sepsis syndrome, and toxic colitis. White blood cell counts (WBCs) also may be markedly elevated with a shift to immature forms. Extreme presentation of fulminant colitis may require a colectomy and even result in death. Symptoms of CDAD may begin a few days after initiation of antibiotic therapy or up to 8 weeks after its discontinuation.