Plasmids of Distinct IncK Lineages Show Compatible Phenotypes

Area of Science:

• Microbiology and Molecular Biology
• Genetics and Genomics
• Antimicrobial Resistance

Background:

• IncK plasmids are significant vectors for antimicrobial resistance genes, notably blaCTX-M-14 and blaCMY-2.
• These plasmids share considerable genetic similarity with other plasmids within the I complex, including IncB/O plasmids.

Purpose of the Study:

• To investigate the phylogenetic relationships among IncK and IncB/O plasmids.
• To delineate the evolutionary pathways and genetic diversity within the IncK plasmid group.

Main Methods:

• Phylogenetic analysis of 37 newly sequenced IncK and IncB/O plasmids.
• Comparative genomic analysis to identify conserved and variable regions.

Main Results:

• The study identified two distinct and compatible phylogenetic lineages within the IncK plasmid group, designated IncK1 and IncK2.
• Demonstrated that IncK plasmids are not a monolithic group but exhibit significant internal diversification.

Conclusions:

• IncK plasmids represent a complex and evolving plasmid group with at least two distinct evolutionary trajectories (IncK1 and IncK2).
• Understanding these lineages is crucial for tracking the spread of antibiotic resistance genes carried by these plasmids.