Escherichia coli str. K-12 substr. MG1655 Genome sequencing

Bacteria-plasmid coevolution could enhance the persistence of plasmids in bacterial populations and increase antibiotic resistance at reduced cost. However, little is known whether phenotypic and genotypic modifications in the coevolved bacteria-plasmid pairs selected by antibiotics could affect their subsequent colonization in gut microbiota. Here, we investigated the evolutionary footprints of a bacteria-plasmid association consisting of Escherichia coli K-12 MG1655 and plasmid RP4 undergoing a long-term antibiotic stress at sub minimal inhibitory concentration (MIC). We found the coevolved bacteria-plasmid pairs has superior colonization traits compared to the wild-type parent strain. Antibiotic stress is necessary for bacterial evolution and evolved strains mostly exhibit transcriptional modifications to reduce plasmid-related cost in evolutionary adaptations.