Evolutionary dynamics and genomic diversification of the mcr-9.1 region in Cronobacter sakazakii across four decades
This study reconstructs the 43-year evolutionary history of the mcr-9.1 region in *Cronobacter sakazakii*, revealing a conserved core structure that has evolved into a complex, semi-mobile genomic module predominantly associated with the chromosome in early isolates but increasingly linked to plasmids in recent years through clonal expansion and horizontal gene transfer.