This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'A 60 year old female patient  complains of diarrhoea and abdominal pain. She  was on antibiotic therapy earlier which comprised of Clindamycin. She is a diabetic and is on oral hypoglycemic. Stool culture  revealed gram positive motile rods. The colonoscopy is done of this patient and the typical structure is revealed. Which of the following microbe is responsible for this? \nSelect and explain. \nA. Clostridium difficile, B. Enteroinvasive E. coli, C. Enteroaggregative E. coli, D. Shiga toxin-producing E. coli', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Enteroinvasive E. coli (EIEC) produce a disease very similar to shigellosis. The disease occurs most commonly in children in developing countries and in travelers to these countries. Similar to Shigella, EIEC strains are nonlactose or late lactose fermenters and are nonmotile. EIEC produce disease by invading intestinal mucosal epithelial cells.\nEnteroaggregative E. coli (EAEC) causes acute and chronic\xa0 diarrhea\xa0 (>14\xa0 days\xa0 in\xa0 duration)\xa0 in\xa0 persons\xa0 in developing countries. These organisms also are the cause of\xa0 foodborne\xa0 illnesses\xa0 in\xa0 industrialized\xa0 countries\xa0 and have been associated with traveler’s diarrhea and persistent diarrhea in patients with HIV. They are characterized by\xa0 their\xa0 specific\xa0 patterns\xa0 of\xa0 adherence\xa0 to\xa0 human\xa0 cells.\nShiga toxin-producing E. coli (STEC) are named for the cytotoxic toxins they produce. STEC has been associated with mild\xa0 non-bloody\xa0 diarrhea,\xa0 hemorrhagic\xa0 colitis,\xa0 a\xa0 severe form of diarrhea, and with hemolytic uremic syndrome, a disease resulting in acute renal failure, microangiopathic hemolytic\xa0 anemia,\xa0 and\xa0 thrombocytopenia.\nC. difﬁcile can be isolated from stool culture in 30% of patients with antibiotic-associated diarrhoea and over 90% of those with pseudomembranous colitis, but also from 5% of healthy adults and up to 20% of elderly patients in residential care. The rectal appearances at sigmoidoscopy may be characteristic, with erythema, white plaques or an adherent pseudomembrane or may resemble ulcerative colitis.', 'role': 'assistant'}]