A new study has confirmed that a sophisticated genetic system known as integron plays a key role in accelerating resistance and gives bacteria an “incredible opportunity” to evolve in response to antibiotic treatment.
The new research, by scientists at the University of Oxford and Universidad Complutense de Madrid, highlights both the danger posed by integrons and the need to develop tools to counter their influence. The study suggests that new drugs given alongside antibiotics could limit an integron’s ability to accelerate bacterial evolution.
Lead author Dr Célia Souque of Oxford’s Department of Zoology said, “Antibiotic resistance is one of the biggest threats to modern medicine. As resistance grows, it will become harder to treat common infections such as food poisoning or pneumonia, or even to perform minor surgeries – and all parts of the world will be affected”. He stressed the urgent need not only to develop new antibiotics, but to increase the understanding of how bacteria develop resistance to these treatments.
To probe experimentally for the first time the role played in resistance by integrons, the researchers inserted a customized integron carrying several resistance genes into a bacterium called Pseudomonas aeruginosa, which can cause pneumonia and blood infections in humans.
The scientists found that when confronted with antibiotics, the P. aeruginosa bacteria with functioning integrons were able to survive longer than those without.
Dr Souque said that bacteria have multiple mechanisms to evolve resistance. They might mutate certain genes to dodge the effects of antibiotics, or acquire new genes that help produce antibiotic-destroying enzymes.
The integron is a remarkable genetic structure that is unique to bacteria. It provides them with a kind of Swiss army knife of antibiotic resistance genes that they can rapidly alter in response to our treatments, according to senior study author Craig Maclean, who is Professor at Oxford’s Department of Zoology.
“Understanding the benefits that integrons provide to bacteria gives us insights into potential future treatment strategies to limit or counteract the evolution of antibiotic resistance,” Prof. Maclean added. In his opinion, antibiotics could be combined with molecules that inhibit integrase activity to reduce bacteria’s gene-shuffling ability and thus the evolution of higher levels of resistance.
The research paper is published in eLife.
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