Prehistoric ‘superbug’ discovered in 5,000-year-old-ice after scientists drilled too deep

Boffins have uncovered antibiotic-resistant bacteria in an ancient underground Romanian cave that they say could pose new health risks if released by the melting ice

Scientists who drilled through 25 metres of ice discovered an ancient strain of bacteria resistant to multiple types of antibiotics.

The germs had laid hidden and undisturbed under layers of ice for 5,000 years in the core of the Scarisoara underground cave in Romania. The experts found out the bacteria could thrive in extreme cold and high salt levels, both environments that would usually stop bugs from growing at all.

Drugs which would normally kill off germs were found to be inactive against the strain, according to evidence published in Frontiers in Microbiology.

“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.

Dubbed Psychrobacter SC65A.3, the bacteria were found to be resistant to 10 kinds of modern antibiotics, including ciprofloxacin – what’s known as a broad-spectrum antibiotic, created to destroy many types of bacteria.

As antibiotic resistance continues to surge, the prospect grows that today’s life-saving drugs could one day fail to tackle infections or become useless down the line.

The issue is frequently blamed on antibiotic overuse, but Purcarea explained: “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 extract this particular strain, the research team bored a 25-metre ice core spanning a 13,000-year period and carried samples back to their laboratory in sterile containers, keeping them frozen throughout.

Back in the lab, the team examined the DNA of bacteria within the frozen specimens to understand how they managed to endure such harsh, frigid conditions and to explore their potential interactions with antibiotics.

The researchers discovered that Psychrobacter harboured more than 100 genes linked to resistance.

When they subsequently exposed it to 28 different antibiotics, the microbe proved resistant to 10 of them – including drugs currently deployed to combat infections affecting the lungs, skin, blood, reproductive organs and urinary system.

“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.

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