Figure 1.

Schematic diagram of research process. A cointegrate plasmid (pSL131_IncA/C_IncX3) was transferred by conjugation into Escherichia coli EC600 and Klebsiella pneumoniae YZ6. Analysis of structural polymorphism was conducted after plasmid acquired by EC600. EC600 carrying intact plasmid and YZ6 carrying structural reorganized plasmid were subjected to fitness evaluation and serial passaging under antibiotic-free conditions for 30 days. Yellow circles in different sizes represented changes in cointegrate plasmid size during conjugation.