Phage spread dynamics in clonal bacterial populations is depending on features of the founder cell

Plate-cultured bacterial colonies are intriguing models to study host-paras ite interactions in senescent populations. During the growth of bacteriopha ge-infected colonies there is a synchronous prophage induction episode amon g lysogenic eels that allows a dramatic but time-restricted amplification o f viral particles. We report here that the dynamics of phage spread depends on the history of the lysogenic cell that establishes the clonal populatio n, the duration of the pre-burst period being shorter when the founder, inf ected cell derives from older colonies. These results offer a physiologic e xplanation for the self-contained progression of the viral spread in closed environments, that ensures both viral dissemination but also survival of m ost of the host cells.