Host responses to phage infection
The discovery of phage-targeted host pathways could reveal potential antibacterial therapeutic targets. This is considering that many phage targeted host pathways and mechanisms of phage resistance can lead to bacterial fitness defects (Mangalea and Duerkop 2020). We are performing genome-wide temporal transcriptomic, proteomic, and transposon profiling of phage infected Enterococcus faecalis to identify factors involved in phage bacterial interactions (Chatterjee et al. 2020). We have discovered several previous unknown enterococcal physiological responses to phage infection. Notably, phage mediated membrane damage activates a stress response leading to the induction of the type VII secretion system (Chatterjee, Willett, et al. 2021). The type VII secretion system secretes polymorphic toxins that are antibacterial. Phage infection induced type VII secretion system activity leads to the inhibition of bacteria that are not phage targets. This work suggests that phages may have off target effects on bacteria other than their target host.