Loss of mcr Genes Mediated by Plasmid Elimination and IS Apl1

We characterized the stability of a plasmid pCP53-mcr1_3 encoding and with and without colistin exposure during cultural passages via S1-pulsed-field gel electrophoresis (PFGE) and nanopore MinION sequencing. Both and were missing in certain subclones, mediated by genetic excision (IS ), and deletions of large multidrug resistance (MDR) regions confirmed by IS and plasmid elimination. Without colistin exposure, the eradication of genes is feasible, while the factors influencing the elimination processes warrant further study.