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
Stalactite growth in a ghee broth culture is characteristic of 
Select and explain. 
A. Bacillus, B. Legionella, C. Yersinia, D. Leptospira
C: Yersinia
Answer: C: Yersinia 
Explanation: 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