Researchers from the Romanian Academy have discovered a bacterial strain that had been frozen for 5,000 years in the Romanian ice cave Scărișoara Ice Cave. Carefully isolating the sample, the researchers tested it against 10 common antibiotics, including those used to treat tuberculosis, colitis, and urinary tract infections.
The results showed that this strain, despite originating from five millennia ago, is already resistant to all 10 tested antibiotics. What is concerning is that researchers predict the bacterium could cause serious consequences if it manages to emerge from the ice.
As global temperatures continue to rise, this frightening possibility is becoming more realistic every day.
“The bacterial strain psychrobacter SC65A.3 isolated from the Scărișoara Ice Cave, despite its ancient origin, shows resistance to multiple modern antibiotics and carries more than 100 genes associated with resistance,” said the study’s author, Dr. Kristina Purkarea.
“If melting ice releases these microorganisms, these genes could spread to modern bacteria, further worsening the global problem of antibiotic resistance,” the doctor explained.
From the International Space Station to the acidic soil around volcanoes, bacteria have evolved to survive almost everywhere. In the new study, the team sought to understand how bacteria adapted to cold environments.
The team drilled a 25-meter-deep ice core, representing a period of 13,000 years, from a section of the Scărișoara Ice Cave known as the Great Hall.
To avoid contamination, ice fragments were placed in sterile bags and kept frozen during transport to the laboratory.
There, researchers isolated different bacterial strains and sequenced their genome to determine which genes enable survival in icy conditions. The most interesting isolated strain is psychrobacter SC65A.3.
Previous research has shown that other strains from this genus can cause infections in humans as well as in animals.
To test the strain’s resistance, researchers exposed it to 28 antibiotics from 10 classes regularly used in humans.
Alarmingly, it was shown to be resistant to all 10, including trimethoprim, clindamycin, and metronidazole.
These antibiotics are routinely used to treat urinary tract infections, as well as infections of the lungs, skin, blood, or reproductive system.
“The ten antibiotics to which we detected resistance are widely used in therapies for treating various serious bacterial infections in clinical practice,” said Dr. Purkarea.
The researchers then sequenced the bacterium’s genome and discovered 11 genes that could potentially destroy or stop the growth of other bacteria, fungi, and viruses.
In addition, they identified nearly 600 genes with unknown function.
According to experts, this indicates that this superbug represents “an untapped source for discovering new biological mechanisms.”
Although most pandemics have been caused by viruses, scientists have previously warned that the next one could be triggered by an antibiotic-resistant bacterium like this.
“These ancient bacteria are of great importance to science and medicine, but careful handling and laboratory safety measures are essential to reduce the risk of uncontrolled spread,” concluded Dr. Purkarea.
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Source: RTS; Foto: Wikimedia Creative Commons