This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Haemophilus, Yersinia, Spirochaetes, Ricketssia, Chlamydia, Mycoplasma and Miscellaneous Bacteria), Subject name: Microbiology
[{'content': 'Following is true of T. pallidum except - \nSelect and explain. \nA. Can be maintained in rabbit testis, B. Motile by peritrichate flagella, C. To visualise, dark ground microscopy is used, D. TPI test is very-useful', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Option 1 Culture: - Pathogenic treponemes cannot be grown in aificial culture media but are maintained rabbit testes. - However, nonpathogenic treponemes (e.g. Reiter treponemes) can be cultured in Smith Noguchi media Option 2 - It is actively motile. Endoflagella are responsible for motility of the bacteria. Option 3 Direct Microscopy: - Dark field microscopy - Direct IF staining from sample (DFA-TP) - Silver impregnation method Option 4 - TPI : Specific Treponemal test for diagnosis of Syphilis.', 'role': 'assistant'}]