Phage-Mediated Iron Acquisition by Pseudomonas aeruginosa

Abstract

Iron acquisition is critical to bacterial growth and pathogenesis. Here, we describe a previously unrecognized mechanism by which the major human pathogen Pseudomonas aeruginosa acquires iron through a unique partnership with bacteriophages (phages). Pf is a filamentous phage that infects P. aeruginosa and is associated with chronic infections. We reveal that Pf contributes to P. aeruginosa pathogenesis by promoting iron uptake. We demonstrate that Pf phage is highly induced under iron-deplete growth conditions and that once induced, Pf virions directly bind and locally concentrate free iron. Pf-bound iron is more efficiently utilized by P. aeruginosa than unbound iron, enhancing bacterial growth. We further demonstrate that Pf-mediated iron acquisition depends on type IV pili, which facilitate Pf attachment and confers strain selective uptake of phage-bound iron, providing a competitive fitness advantage in polymicrobial settings. Together, these findings identify an unrecognized role for filamentous phages in mediating iron acquisition and reveal a novel phage-bacterium partnership that operates through selective kin cooperation.