Enterococcal-phage coevolution

We performed coevolution experiments using a single Enterococcus faecalis strain and two distantly related phages, to determine how phage pressure impacts the evolution of the E. faecalis genome. Whole genome sequencing of E. faecalis following independent continuous exposure to these two phages revealed mutations previously demonstrated to be essential for phage infection. We also identified mutations in several genes previously unreported to be associated with phage infection in E. faecalis. Intriguingly, there was only one shared mutation in the E. faecalis genome that arose in response to each of the two phages tested, demonstrating that infection by two genetically distinct phages results in different host responses. This study shows that infection of the same host by disparate phages leads to evolutionary trajectories that result in distinct genetic changes. This implies that bacteria respond to phage pressure through unique host responses that are tailored to specific phages. This knowledge serves as the basis for the continued study of E. faecalis genome evolution during phage infection and can be used to inform the design of future therapeutics, such as phage cocktails, intended to target MDR E. faecalis.