Fighting bacteriophage infection : mechanisms of bacterial resistance

Abstract

In man-made and natural environments, there is a continuous ongoing interaction between phages and their bacterial hosts, a co-evolutionary arms race between two competing organisms which contributes enormously to their diversity. During continuous cycles of co-evolution, phage-resistant bacterial hosts emerge aiming at preservation of their bacterial lineages. For every step in the phage infection cycle, bacteria have evolved various defense mechanisms, passive or active, to evade phage propagation and subsequent spreading of phage progeny in the surrounding environment. However, when facing this selective pressure imposed by the host, phages have developed different strategies to subvert these defense systems in order to thrive in these new bacterial populations. Knowledge of these phage-host dynamics represents a vital tool for phage therapeutic purposes in which the emergence of phage-resistant bacterial pathogen forms a notable disadvantage. In contrast, in the fermentation industries, bacteriophages themselves pose a contamination problem, which can be relieved by selection of phage-insensitive bacterial strains