Reorganization of mcr-1-bearing large MDR plasmids resolved by nanopore sequencing

The emergence of plasmid-borne mcr genes among pathogens poses great public concern. Different mcr variants have been identified from various sources and the plasmids encoding mcr genes are diverse and evolve constantly. Plasmid reorganization accelerates the evolution of MDR plasmids and facilitates the generation of large MDR plasmids.

Here, we report the isolation of an mcr-1-bearing Escherichia coli strain from a Père David’s deer in China in 2018. We have characterized the underlying molecular mechanism of the mcr-1-bearing plasmid reorganization responsible and highlight the role of mobile elements such as ISCR2 in the generation of hybrid and cointegrate plasmids.