What is it about?

Antibiotics have significantly reduced mortality associated with infectious diseases throughout the 20th century, representing a significant advancement in medicine. However, for several years now, the issue of antibiotic resistance has been gaining ground. The transfer resistance amongst bacteria primarily occurs through a gene transfer mechanism known as bacterial conjugation. For a long time, bacterial conjugation was described as a DNA transfer process that could only occur when the donor bacterium was in direct physical contact with the recipient bacterium. Establishing this contact involves a conjugation pilus, a small tubular appendage on the surface of donor bacteria, which facilitates attachment to a recipient bacterium. It was proposed 60 years ago that the extended pilus could also serve as a conduit for the DNA during conjugation between physically distant cells. In this new study, researchers have developed a technique that allows the simultaneous visualisation of DNA transfer and the pilus during conjugation in live cells and in real-time. It provides the first direct evidence of DNA transfer through the extended pilus during bacterial conjugation.

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Why is it important?

This study provides the first direct evidence of DNA transfer through the extended pilus, resolving a 60-year-old debate. It reshapes the prevailing model for F-like plasmids conjugation and significantly advances our understanding of the dissemination of drug resistance and virulence in bacterial communities. This work contributes to a better understanding of the mechanisms of antibiotic resistance dissemination. Indeed, the knowledge that two physically distant bacteria can exchange their DNA suggests that resistance transfers may occur in different environments where direct contact between bacteria is made more difficult by the complexity or viscosity of the medium, as within the intestine, for example. Furthermore, by shedding light on a DNA transfer mechanism that was previously poorly characterised, this work could, in the longer term, pave the way for the development of therapeutic tools aimed at targeting and inhibiting these mechanisms of antibiotic resistance transmission between bacteria.


By uncovering this previously unrecognized mechanism of distant transfer, this study significantly advances our comprehension of how drug resistance and virulence traits are disseminated in bacterial communities. It raises the possibility that transport of the DNA through the extended pilus could be favoured in conditions where tight contact is not favoured. Distant transfer is also expected to escape the activity of exclusion systems that protect against self-transfer. Ultimately, this knowledge may contribute to developing targeted interventions to disrupt the transfer of antibiotic resistance and virulence genes, potentially leading to the design of more effective therapies and preventive measures against bacterial infections.

christian lesterlin
MMSB, CNRS, University of Lyon

Read the Original

This page is a summary of: The F pilus serves as a conduit for the DNA during conjugation between physically distant bacteria, Proceedings of the National Academy of Sciences, November 2023, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2310842120.
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