<prompt> Which of the following is not associated with pseudomembranous colitis?Toxin A is responsible for clinical manifestationToxin B is responsible for clinical manifestationGross blood in stools is commonSummit lesion is early histopathological finding  <response>: Clostridium difficile produce 5 toxins, toxin A and B are most studied and both causes pseudo membranous colitis. The Summit or volcano lesions are seen due to mucosal micro ulceration. Diarrhea is soft to watery or mucoid in consistency but never with gross blood 