Scientists have discovered ancient bacteria trapped in ice that could help us understand antibiotic resistance – or make the problem worse.
That’s according to a study that was recently published in Frontiers in Microbiology, in which Romanian researchers analysed the antibiotic resistance profiles of an ancient bacterial strain.
For 5,000 years, the bacteria – called Psychrobacter SC65A.3 – had been hidden under a thick layer of ice, in Scărişoara Cave, northwest Romania.
“These ancient bacteria are essential for science and medicine, but careful handling and safety measures in the lab are essential to mitigate the risk of uncontrolled spread,” said study author Dr Cristina Purcarea, senior scientist at the Institute of Biology.
As antibiotic resistance grows, so does the possibility that current antibiotics may fail to treat infections or even become obsolete in future.
The problem is often attributed to an overuse of antibiotics, but Purcarea said: “Studying microbes such as Psychrobacter SC65A.3, retrieved from millennia-old cave ice deposits, reveals how antibiotic resistance evolved naturally in the environment, long before modern antibiotics were ever used.”
To retrieve this strain, the scientists drilled a 25-metre ice core that represented a 13,000-year timeline and transported fragments to the lab in sterile bags, while frozen.
Once in the lab, the researchers analysed the DNA of the bacteria in the icy fragments, to study how they managed to survive in such cold conditions and to investigate how it might interact with antibiotics.
The scientists found that Psychrobacter carried more than 100 resistance-related genes.
Then, when they tested it against 28 antibiotics, the bacterium was resistant to 10 – including medicines we currently use to treat infections of the lungs, skin, blood, reproductive system and urinary tract.
“The 10 antibiotics we found resistance to are widely used in oral and injectable therapies that treat a range of serious bacterial infections in clinical practice,” said Purcarea.
The scientists wrote that their findings suggest strains capable of surviving cold environments might act as reservoirs of genes that could help them survive exposure to drugs.
“If melting ice releases these microbes, these genes could spread to modern bacteria, adding to the global challenge of antibiotic resistance,” Purcarea explained.
However, it’s not all bad news. Psychrobacter SC65A.3 also had nearly 600 genes with unknown functions and 11 genes that could kill or stop the growth of other microbes.
That means the strain could be helpful for the development of novel treatments and therapies, including against several major antibiotic-resistant microbes.
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