Evolutionary Adaptation of T7 Bacteriophage to Silver Ion Exposure: Implications for AMR Mitigation
Description
Antimicrobial resistance (AMR) remains a significant global concern, prompting increased exploration of alternative treatments such as bacteriophages and metals like silver ions. While these agents exhibit strong antimicrobial properties, the environmental accumulation of silver nanoparticles raises questions about their influence on microbial and phage evolution. This study examines how T7 bacteriophage adapts to high concentrations of silver ions through experimental evolution. For over 15 generations, ten independent T7 lineages were repeatedly exposed to elevated silver ion levels in Escherichia coli B cultures. The results showed that T7 bacteriophage developed resistance to silver ions, which also enhanced its infectivity of E. coli B. Genomic analysis revealed key mutations, particularly in the tail fiber protein gene (T7P52) and major head protein gene (T7P44), driving these adaptations. The tail fiber is an essential feature that determines the host range and aids the tail in attaching bacteriophage to the host. The major head proteins are essential in virion assembly and release from the bacteria host. These findings highlight the evolutionary flexibility of bacteriophages under selective pressure and suggest potential applications for phage engineering in AMR mitigation efforts.