Experimental evolution with HGT under antibiotic-free conditions. Credit: Ecology and evolution of nature (2024). DOI: 10.1038/s41559-023-02269-5
In a scientific breakthrough, Monash University researchers have discovered a revolutionary “U-turn” in the evolution of antibiotic resistance, challenging the widely accepted notion that traits once developed are irreversible.
The discovery, published in Ecology and evolution of nature has far-reaching implications in the fight against antibiotic resistance, a global health crisis threatening the effectiveness of medicines.
Dollo’s Law, considered a fundamental principle of evolutionary biology, posits that traits, once lost, cannot be regained.
“Our study challenges this idea by uncovering the first known example of reverse molecular evolution of antibiotic resistance,” said the study’s lead author, Associate Professor Mike McDonald, from the Faculty of Biological Sciences at Monash University.
The study explores the possibility of overriding harmful traits, such as antibiotic resistance, through a mechanism called horizontal gene transfer (HGT).
The bacterium Helicobacter pylori was the focus of the experiment due to its ability to exchange DNA through HGT. The research team tracked and sequenced genetic alterations in real time in independent bacterial populations.
In some of these groups, they found that the antibiotic-resistant gene variant had reverted to its original susceptible form, marking a groundbreaking discovery in the field of evolutionary biology.
“Imagine a scenario in which infections lose their harmful characteristics, such as antibiotic resistance, and effectively revert to their original state,” Associate Professor McDonald said.
“This research opens new possibilities in our fight against antibiotic resistance and reinforces the importance of antibiotic stewardship, our approach to antibiotic and insecticide stewardship.”
The study also highlights the role of recombination, mixing and exchange of genetic material, in facilitating this evolutionary turnaround. Populations with lower recombination rates developed a hyper-recombination phenotype, accelerating the rate at which bacteria exchange DNA and reversing antibiotic resistance.
To better understand the dynamics of natural selection and HGT, the researchers constructed a population genetic model. Mathematical simulations revealed that although the costs of resistance are substantial, moderate to high levels of HGT could make antibiotic-resistant populations susceptible again.
The study challenges conventional wisdom about irreversible traits and presents a new path to combating antibiotic resistance.
“This research could redefine our strategies against antibiotic resistance, offering hope for a future in which we can mitigate the spread of harmful traits and potentially restore the effectiveness of antimicrobial drugs,” Associate Professor McDonald said.
More information:
An NT Nguyen et al, Horizontal gene transfer facilitates reverse molecular evolution of antibiotic susceptibility in experimental populations of H. pylori, Ecology and evolution of nature (2024). DOI: 10.1038/s41559-023-02269-5
Provided by Monash University
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