Download

Download Full Text (165 KB)

Description

We subjected Escherichia coli B to 35 days of experimental evolution under elevated iron(III) sulfate and T4 phage stress, performing genomic, phenotypic, and cross-resistance analyses. Ten replicate populations were grown in LB broth with or without 1500 mg/L iron(III), with or without phage. All populations underwent daily transfers, ensuring consistent selective pressures. Whole genome sequencing revealed mutations that reached fixation or sweeping frequency. Iron(III)-selected strains showed enhanced tolerance at 1000–1750 mg/L iron but experienced reduced susceptibility thresholds to sulfanilamide, silver nitrate, and copper(II) sulfate, highlighting significant trade-offs. Conversely, iron(III) adaptation conferred cross- resistance to iron(II) and gallium(III) salts, likely reflecting overlapping uptake and detoxification pathways. Phage-mediated selection further shaped these trade-offs, occasionally increasing resistance to certain antibiotics while diminishing metal tolerance. Convergent mutations in hchA (C→A at position 144564) emerged across multiple regimes, implying a broad adaptive role in stress response and protein quality control. Large deletions in phage receptor-related genes appeared consistently under phage pressure, underscoring receptor modifications for phage resistance. These findings clarify how metals, phages, and antibiotics can jointly influence evolutionary trajectories, offering insights into effectively countering multidrug resistance.

Publication Date

4-1-2025

Keywords

Antibiotic, resistance, evolution, Iron(III) sulfate

Investigating Evolutionary Pressures: Uncovering Adaptive Trade-offs of Iron Stress and Phage Resistance in E. coli B

Share

COinS