How can polyvalent phage shape bacterial dynamics?

A new paper published in J. Virology, “A polyvalent phage shapes bacterial dynamics“

Phages are the most abundant biological entity on the planet, but polyvalent phages that infect multiple bacterial species are poorly understood. Here, we investigated how the polyvalent phage PSA39 affects two susceptible but unrelated bacterial hosts (Pseudomonas aeruginosa and Stenotrophomonas maltophilia). During co-cultures with S. maltophilia, P. aeruginosa quickly develops resistance to this virus and has an antagonistic effect on its bacterial competitor. We find that both bacterial species evolve mutations in Type IV pili genes to resist PSA39 lysis. Our study provides novel insights into the impact that polyvalent phages can have on susceptible bacteria, such as those from natural environments or from infections.