Exclusion systems preserve host cell homeostasis and fitness, ensuring successful dissemination of conjugative plasmids and associated resistance genes.

ABSTRACT: Plasmid conjugation is a major driver of antibiotic resistance dissemination in bacteria. In addition to genes required for transfer and maintenance, conjugative plasmids encode exclusion systems that prevent host cells from acquiring identical or redundant plasmids. Despite their ubiquity, the biological impact of these systems remains poorly understood. Here, we investigate the importance of the exclusion mechanism for plasmid dynamics and bacterial physiology at the single-cell level. Using real-time microscopy, we directly visualize how the absence of exclusion results in plasmid unregulated self-transfer, causing continuous and repeated plasmid exchange among host cells. This runaway conjugation severely compromises cell integrity, viability, and fitness, a largely undescribed phenome

SUBMITTER: Couturier A 

PROVIDER: S-EPMC12445648 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature