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': 'All are true about EHEC, except: \nSelect and explain. \nA. Sereny test is positive, B. Ferments sorbitol, C. Causes HUS, D. Elaborates shiga like exotoxin', 'role': 'user'}, {'content': "Answer: A \nExplanation: Sereny Test is given only by EIEC. Ref: Text Book of Microbilogy By Ananthanarayan, 6th Edition, Page 257 ; Harrison's Principles of Internal Medicine, 14th Edition, Page 938 and 15th Edition, Page 955", 'role': 'assistant'}]