In the Bacterium Yersinia Pestis, Which Causes Bubonic Plague, Loss

Short Answer

In the bacterium Yersinia pestis, which causes bubonic plague, loss of an operon that is normally responsible for iron storage diminishes the ability of the cells to form biofilms and colonize inside the iron-rich gut of infected fleas. Would you expect the efficiency of transmission of plague to increase (I), decrease (D), or remain unchanged (U) as a result of this mutation? Write down I, D, or U as your answer.