Phage-resistant mutations in Escherichia coli strain C

Our study describes how exposure to bacteriophages results in mutations conferring phage-resistance in E. coli, and this resistance is conferred to related phages that the bacteria were never exposed. This phage-resistance carryover results from a correlated response to selection due to mutations in virus receptors and absorption pathway. Trade-offs resulting from phage-resistance were determined via antibiotic challenge. We discovered phage-resistant mutations that resulted in greater antibiotic susceptibility compared to wild-type; however, challenge to a particular antibiotic resulted in synergistic pleiotropy where mutants gained greater antibiotic resistance. This work explores the genetic architecture underlying evolutionary trade-offs and pay-offs, and has implications in development of therapeutic strategies to combat multidrug-resistant pathogens.