Different threats posed by two major mobilized colistin resistance genes - mcr-1.1 and mcr-3.1 - revealed through comparative genomic analysis.

Based on high horizontal transferability, mcr-1.1 could play a major role on colistin resistance propagation. On the other hand, mcr-3.1 could be transmitted with MDR and have dual pathways mediated by plasmid transfer (horizontal transmission) and chromosomal insertion (vertical transmission), enabling it to proliferate stably despite its lower horizontal transferability.