This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Stalactite growth in a ghee broth culture is characteristic of \nSelect and explain. \nA. Bacillus, B. Legionella, C. Yersinia, D. Leptospira', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Yersinia pestis:The plague bacillus is a sho, plump, ovoid gram-negative bacillus.It is aerobic and facultatively anaerobicIt is not nutritionally exacting and grows on ordinary mediaIf grown in a flask of broth with oil or ghee floating on top, a characteristic growth occurs which hangs down into the broth from the surface, resembling stalactites .Ref: Ananthanarayan; 7th edition; Page no: 324', 'role': 'assistant'}]