A group of researchers from the Romanian Academy isolated a cold-adapted bacterium, called Psychrobacter SC65A.3, from approximately 5,000-year-old ice.
In laboratory tests, this bacterium proved resistant to 10 out of 28 modern antibiotics commonly used for serious infections of the lungs, skin, blood, urinary tract and reproductive system, writes Eco News.
To get to the bacterium, the researchers extracted a 25-meter ice core from the Great Hall of the Scarișoara cave, a true frozen “archive” covering approximately 13,000 years.
From the 5,000-year-old layer, they isolated SC65A.3, sequenced its genome and identified the genes that allow it to withstand extreme cold, lack of nutrients and even some modern antibiotics.
When they exposed the bacterium to antibiotics used in hospitals, it resisted 10 drugs from eight different classes, including rifampicin, vancomycin, ciprofloxacin, trimethoprim, clindamycin and metronidazole.
The bacterium is the first example of its group with such a high level of resistance, suggesting that cold-adapted microorganisms can retain such genes long-term.
Its genome contains more than 100 genes associated with antibiotic resistance and about 600 with as yet unknown roles, some of which may produce substances that affect other microbes. In the laboratory, SC65A.3 was able to inhibit dangerous bacteria such as Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae.
Cristina Purcarea, co-author of the research, describes the discovery as “double-edged”: the bacterium is resistant to several antibiotics, but it also has useful potential for the development of new treatments.
The discovery shows that antibiotic resistance evolved naturally in the environment long before humans used drugs, and that ancient ice can preserve these genes for thousands of years.
The World Health Organization already warns that bacterial antimicrobial resistance directly caused about 1.27 million deaths in 2019 and contributed to nearly 5 million globally.
If antibiotics become less effective, seemingly trivial problems like a urinary tract infection or minor surgery can become much more risky.
