Researchers discover 5,000-year-old bacteria resistant to modern antibiotics

2026-02-17 07:33:00, Shëndeti CNA

A type of bacteria found in a Romanian ice cave is resistant to ten modern antibiotics, according to a new study.

Frozen bacteria kept for 5,000 years in an underground cave have been found to be resistant to modern antibiotics, researchers say.

In the depths of Scarisoara Cave, one of the largest ice caves in Romania, preserved under a 5,000-year-old layer of ice, scientists discovered a strain of Psychrobacter SC65A.3 – bacteria resistant to modern antibiotics.

Bacteria can survive for thousands of years in extreme conditions: under ancient ice sheets, in permafrost, under the sea, or in glacial lakes.

These bacteria play by their own rules, adapting for survival and sustainability over time.

Now, Romanian researchers have discovered that SC65A.3 strains of Psychrobacter - bacteria adapted to cold environments - are resistant to 10 modern antibiotics from 8 different classes.

"The bacterial strain Psychrobacter SC65A.3 isolated from the Scarisoara Ice Cave, despite its ancient origin, shows resistance to many modern antibiotics and carries over 100 genes associated with resistance," said Cristina Purcarea, author of the study and scientist at the Institute of Biology in Bucharest of the Romanian Academy.

The cave's ice block measures 100,000 cubic meters and is approximately 13,000 years old - making it the largest and oldest underground ice block.

The research team drilled an ice cube 25 meters from the area of ??the cave known as the Great Hall. By analyzing ice fragments from this part of the cave, they isolated different bacterial species and sequenced their genomes to determine which genes allow these species to survive in low temperatures and which ones give them antimicrobial resistance.

Purcarea added that the antibiotics to which they found resistance are widely used in oral and injectable therapies used to treat numerous serious bacterial infections in clinical practice, such as tuberculosis, colitis and urinary tract infections (UTIs).

Previous studies have analyzed other types of Psychrobacter bacteria, mainly for their biotechnological potential, but the antibiotic resistance profiles of these bacteria are largely unknown, the study noted.

“The study of microbes such as Psychrobacter SC65A.3 extracted from millennial cave ice deposits reveals how antibiotic resistance evolved naturally in the environment, long before modern antibiotics were ever used,” Purcarea said.

While antimicrobial resistance is a natural phenomenon, it has been accelerated by chronic antibiotic use, driving the diversification and spread of antibiotic resistance genes, the researchers noted.

The results, published in Frontiers in Microbiology, revealed that, with 20 percent of the Earth's surface comprising frozen habitats and low temperatures characterizing much of the biosphere, understanding cold-adapted microbes is increasingly critical amid rapid climate change.

Antimicrobial resistance, a growing concern

Antimicrobial resistance (AMR) causes millions of deaths each year worldwide. In Europe, it is estimated to be the cause of over 35,000 deaths each year - a number that is expected to increase in the coming years.

A small number of factors have created the perfect environment for AMR across the region, the European Centre for Disease Prevention and Control (ECDC) said last year.

Europe's aging population is more vulnerable to infections, drug-resistant pathogens are spreading across borders, doctors and patients are overusing antibiotic medications, and there are critical gaps in infection prevention and control efforts.

One in six bacterial infections worldwide is now resistant to standard treatments, according to the World Health Organization (WHO)./ CNA