Scientists identify key evolutionary catalyst for antibiotic resistance

A new study led by scientists at the University of Oxford has found that small DNA molecules known as plasmids are one of the key culprits in spreading the major global health threat of antibiotic resistance. Using a novel experimental model, the international team of researchers show that plasmids, which live inside bacteria and are known to be a vehicle for transferring antibiotic resistance genes, can accelerate the evolution of new forms of resistance - making them more important to the process than previously thought. The study is published in the journal Nature Ecology and Evolution . Senior author Professor Craig MacLean, a Wellcome Trust Research Fellow in Oxford's Department of Zoology, said: 'The discovery of antibiotics revolutionised medicine by making it much simpler to treat bacterial infections, and this had a big impact on human health and longevity. For example, the use of penicillin led to a 90% decrease in mortality caused by some forms of pneumonia. Unfortunately, few new antibiotics have been discovered over the last 30 years, and resistance to existing antibiotics has spread steadily because antibiotics are used heavily in medicine. This is leading to a crisis in medicine, as we have lost the ability to treat bacterial infections that can have life-threatening consequences.' An influential report from the O'Neill Commission predicts that antibiotic resistance will lead to 10 million deaths per year by 2050, surpassing cancer as a source of human mortality.