Organisms that have not been cultured successfully so far is?: (A) Leptospira, (B) Treponema pallidum, (C) Bordetella, (D) Staphylococcus
Answer is B. 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