Piggybacking on Niche Adaptation Improves the Maintenance of Multidrug-Resistance Plasmids

Mol Biol Evol. 2021 Jul 29;38(8):3188-3201. doi: 10.1093/molbev/msab091.


The persistence of plasmids in bacterial populations represents a puzzling evolutionary problem with serious clinical implications due to their role in the ongoing antibiotic resistance crisis. Recently, major advancements have been made toward resolving this "plasmid paradox" but mainly in a nonclinical context. Here, we propose an additional explanation for the maintenance of multidrug-resistance plasmids in clinical Escherichia coli strains. After coevolving two multidrug-resistance plasmids encoding resistance to last resort carbapenems with an extraintestinal pathogenic E. coli strain, we observed that chromosomal media adaptive mutations in the global regulatory systems CCR (carbon catabolite repression) and ArcAB (aerobic respiration control) pleiotropically improved the maintenance of both plasmids. Mechanistically, a net downregulation of plasmid gene expression reduced the fitness cost. Our results suggest that global chromosomal transcriptional rewiring during bacterial niche adaptation may facilitate plasmid maintenance.

Keywords: antibiotic resistance; clinical isolates; experimental evolution; fitness cost; niche adaptation; plasmids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Biological / genetics*
  • Cyclic AMP Receptor Protein / genetics
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / genetics
  • Evolution, Molecular
  • Genes, MDR*
  • Genetic Fitness
  • Klebsiella pneumoniae / genetics*
  • Plasmids*
  • beta-Lactamases / genetics


  • Cyclic AMP Receptor Protein
  • Escherichia coli Proteins
  • crp protein, E coli
  • NDM-1 protein, E coli
  • beta-Lactamases