A plasmid-encoded genetic switch orchestrates the bacterial virulence-fitness trade-off to drive antibiotic resistance dissemination.

A plasmid-encoded protein, T1FR, suppresses bacterial virulence and enhances plasmid transmission, facilitating the spread of antibiotic resistance in Enterobacteriaceae.

• Why it matters: Understanding how resistance plasmids balance bacterial fitness and pathogenicity is crucial for developing strategies to combat multidrug-resistant infections and limit resistance dissemination.
• What they did: Researchers identified T1FR, a novel IncFII plasmid protein, and studied its role in repressing fimbriae production and reprogramming metabolism through molecular binding and transcriptional regulation, revealing its dual function.
• The result: The T1FR system modulates the virulence-fitness trade-off, promoting plasmid spread while reducing bacterial pathogenicity, and presents a potential target for anti-adhesion therapies to control resistance without promoting further antibiotic resistance.