For the future of medicine and treatment of infections, it is scary news. A pair of scientists, Catriona Harkins and Matthew Holden at the University of St. Andrews, have now determined bacteria can evolve resistance to antibiotics that the bacteria has never seen or interacted with.
According to an article in The Atlantic, the duo sequenced the DNA of 209 samples of methicillin-resistant Staphylococcus aureus, or MRSA, that were collected between 1960 and 1989. They discovered that “methicillin use was not the original driving factor in the evolution of MRSA as previously thought.” Instead, it was penicillin. According to the research, when penicillin became popular, it likely helped the rise of staph strains that carried mecA, and were already resistant to methicillin.
This revelation makes MRSA even more frightening than previously thought. In 1959, Margaret Patricia Jevons had isolated three strains of methicillin-resistant Staphylococcus aureus, or MRSA, which has since become a global problem. The bacteria had become a cautionary tale for how quickly bacteria can quickly evolve to resist popular drugs, especially when overprescribed.
But a few questions remained. MRSA appeared in India and some Eastern European countries before the countries had started using the antibiotic methicillin. So how did the bacteria evolve to resist a drug it had never encountered before?
This new study provides an answer, and many new consequences. According to MRSA researcher Hsu Li Yang, from the National University of Singapore, it demonstrates that “antibiotic resistance is a web of unintended consequences, rather than a simplistic cause-effect model that we often find (too much) comfort in.”
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