Bacteriophage can promote the emergence of physiologically sub-optimal host phenotypes

Reproduction of bacteria-specific viruses, or bacteriophage, requires the replication and translation machinery of the host cell. As a consequence, phage fitness depends intimately on the physiological state, i.e. growth rate, of the host. We include this dependence of critical phage traits on host growth rate in a mathematical model of a bacteria-phage interaction. This leads to a feedback loop between phage success, host population size, nutrient availability and host growth rate. We find that this feedback allows slow growing bacteria to have a competitive advantage in the presence of phage. Under certain conditions a slow growing host mutant can even drive the phage to extinction. Since in a phage-free environment slow growth is deleterious, the mutant subsequentely dies out as well, constituting a kind of altruistic scenario similar to abortive infections.