Romanian Bacteria from Icy Undergrounds Show Unique Qualities 0 9

Romanian scientists studied the antibiotic resistance of a strain of bacteria that was recently found in a 5,000-year-old layer of ice in an underground cave. The results showed that such microorganisms could help in developing new approaches to combat antibiotic resistance and in understanding how it forms and spreads in nature. The researchers reported their findings in the journal Frontiers in Microbiology.

Psychrobacter SC65A.3 is a strain of the genus Psychrobacter, microorganisms adapted to life in cold environments. Some representatives of this genus can cause infections in humans and animals. Although Psychrobacter are considered promising from a biotechnological perspective, their antibiotic resistance has not been sufficiently studied. According to the scientists, studying such microorganisms extracted from millennia-old ice deposits helps understand how the mechanisms of antibiotic resistance formed in nature long before the advent of modern medicines.

The researchers drilled a 25-meter ice core in a part of the cave called the Great Hall, covering a period of approximately 13,000 years. To avoid contamination, the ice samples were placed in sterile bags and transported frozen. In the laboratory, the researchers isolated bacterial strains and sequenced their genomes to identify the genes responsible for survival at low temperatures and for resistance to antimicrobial agents.

The SC65A strain was tested for sensitivity to 28 antibiotics from 10 different classes widely used in medicine. The list included drugs for which genes or mutations conferring resistance had previously been identified. This allowed the researchers to verify whether the proposed mechanisms indeed lead to real resistance. Resistance was found to ten antibiotics that are actively used in clinical practice for treating serious bacterial infections. Among them are drugs used for tuberculosis, colitis, and urinary tract infections, such as rifampicin, vancomycin, and ciprofloxacin.

SC65A.3 became the first known Psychrobacter strain found to exhibit resistance to a number of antibiotics, including trimethoprim, clindamycin, and metronidazole. These drugs are prescribed for infections of the urinary tract, respiratory tract, skin, blood, and reproductive system. The obtained data suggest that psychrophilic bacteria may serve as natural reservoirs of resistance genes—DNA segments that allow microorganisms to survive under the influence of drugs.

In the genome of Psychrobacter SC65A.3, scientists identified about 600 genes with yet unknown functions, indicating significant, yet undisclosed potential for discovering new biological mechanisms. Additionally, the analysis revealed the presence of 11 genes that may potentially suppress the growth or destroy other bacteria, fungi, and viruses. Such potential becomes especially important in light of the growing global problem of antibiotic resistance. The study of ancient genomes and their hidden capabilities emphasizes that the natural environment played a key role in the formation and spread of antibiotic resistance long before the advent of modern medicine.