Harnessing plasmid structures to track their movement and evolution

Plasmid evolution is shaped by the actions of translocatable elements (TEs) such as insertion sequences and transposons. TEs can drastically alter plasmid structures through insertion, deletion, inversion or cointegration events, or by serving as substrates for homologous recombination. These actions leave detectable fingerprints in plasmid structures. It is therefore possible to trace the evolution of a plasmid lineage by performing detailed structural annotations and comparative analyses of complete sequences. The increasing accessibility of long-read sequencing technologies has seen rapid growth in the numbers of publicly available plasmid sequences this decade. The volume of data has re-shaped our ability to explore plasmid structures, providing new insights into emergent phenomena and raising fascinating questions about the molecular events that drive them. By understanding their evolution, we can harness structural information for surveillance of plasmid lineages that drive the spread of antibiotic resistance and other accessory genes contributing to bacterial pathogenicity.