Plasmid streamlining drives the extinction of antibiotic resistance plasmids under selection for horizontal transmission.

ABSTRACT: Conjugative plasmids carrying antimicrobial resistance (AMR) genes are critical for the spread of AMR, due to their ability to transmit horizontally between bacterial hosts. We previously observed that during experimental evolution in the presence of abundant susceptible Escherichia coli hosts, the AMR plasmid R1 rapidly evolves variants with increased horizontal transmission due to mutations causing increased plasmid copy number. Yet AMR was progressively lost from the evolving populations. Here, we show that AMR loss was associated with evolution of streamlined plasmids in which the AMR region is spontaneously deleted, making plasmid carriage undetectable by plating on selective antibiotic-containing media. These plasmids transmit both vertically and horizontally more efficiently than th

SUBMITTER: Matthews AC 

PROVIDER: S-EPMC12711027 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature