This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
[{'content': 'Organisms that have not been cultured successfully so far is? \nSelect and explain. \nA. Leptospira, B. Treponema pallidum, C. Bordetella, D. Staphylococcus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pathogenic Treponemes do not grow in aificial culture media. They require a living organism like a virus for their growth REF: Textbook of microbiology Ananthanarayan, and Paniker. Page no.: 371', 'role': 'assistant'}]