Antibiotic-resistant bacteria found in an ice cave. Is this a threat to public health?

The world’s glaciers are a reservoir of microorganisms trapped in a crystalline matrix thousands of years ago. The latest study by Romanian scientists shows that modern medicine is completely defenseless against some of them. The bacteria discovered in an ice cave pose a serious challenge to humanity, but also an opportunity for progress in pharmacology.

Frozen time capsule

Bacteria are organisms that, through evolution, have adapted to the most hostile conditions on Earth – they can be found in hot deserts and in extremely low temperatures, for example at the poles. Survival strategies in ice vary greatly, from producing antifreeze proteins to completely suspending metabolic functions. The very structure of ice, in which microcapsules of water are often trapped, also helps them survive.

It is therefore not surprising that scientists examining samples from the underground ice cave Scărișoara Ice Cave in Romania discovered the presence of bacteria under the microscope. The age of the ice find is estimated at around 5,000 years, which means that the microorganisms were trapped at a time when pastoral tribes of the late Neolithic inhabited the area around the Black Sea.

Antibiotic resistance older than antibiotics themselves

The results of the study, published on 17 February this year in the scientific journal Frontiers in Microbiology, identify the bacteria from the Romanian ice cave as the strain Psychrobacter SC65A.3. They belong to a genus of aerobic, Gram-negative bacteria that are found in the human body and can cause infections such as endocarditis or peritonitis.

A team of scientists led by Dr. Cristina Purcarea from the Institute of Biology of the Romanian Academy in Bucharest exposed the Psychrobacter SC65A.3 bacteria to 28 antibiotics belonging to 10 classes commonly used today to treat bacterial infections.

It turned out that the microbes from the ice cave are resistant to as many as 10 widely used antibiotics, including rifampicin, vancomycin and ciprofloxacin, used in the treatment of tuberculosis, colitis and urinary tract infections. Moreover, the SC65A.3 strain is the first of the Psychrobacter genus to show resistance to trimethoprim, clindamycin and metronidazole, used to treat lung, skin and blood infections. According to the researchers, bacteria capable of surviving at low temperatures may act as reservoirs of resistance genes, that is specific DNA sequences that help them survive exposure to drugs.

Ice bacteria as a double-edged sword?

The discovery raises serious concerns in the medical community. If melting ice releases these microbes, their genes may spread to modern bacteria, deepening the global problem of antibiotic resistance, warns Dr. Purcarea. In the face of rising air temperatures and the ongoing shrinkage of glaciers, this threat is becoming increasingly real.

But there is another side to the story. In the genome of Psychrobacter SC65A.3, scientists discovered nearly 600 genes of unknown function, including 11 with the potential to combat other bacteria, viruses and fungi. Further research on bacteria from the ice cave may open the door to further breakthroughs in pharmacology and the invention of new, more effective antibiotics.

In 2025, experts from the United Nations Environment Programme warned of the threat associated with melting permafrost and the release of ancient bacteria and viruses at a rate of up to 4 septillion per year. The key question is who will be faster – ancient pathogens spreading under the influence of climate change or scientists trying to tame them.

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Main photo: Mark Olsen/Unsplash

Source:

Paun VI, Itcus C, Lavin P, Chifiriuc MC and Purcarea C (2026) First genome sequence and functional profiling of Psychrobacter SC65A.3 preserved in 5,000-year-old cave ice: insights into ancient resistome, antimicrobial potential, and enzymatic activities. Front. Microbiol. 16:1713017. doi: 10.3389/fmicb.2025.1713017

https://www.unep.org/news-and-stories/story/could-microbes-locked-arctic-ice-millennia-unleash-wave-deadly-diseases