Trapped within the ice, microbes pulse with life. Researchers venture into dark caves and bitter cold, looking for resilient microorganisms and their vast bioactive potential.
This group includes Cristina Purcarea, a microbiologist at the Institute of Biology Bucharest of the Romanian Academy, who aimed to isolate bacteria from cave ice and characterize their antibiotic resistance and other potential biotechnology uses.
In a new study, published in Frontiers in Microbiology, she and her team isolated a strain of Psychrobacter from a 5,000-year-old layer of ice in the Scărișoara Ice Cave.1 Using whole genome sequencing, the researchers found that this ancient bacterium harbored resistance to modern antibiotics, along with resistance-related genes and genes with the potential to kill other “superbugs.” These findings suggest that ancient genomes may help scientists gain deeper insights into the mechanisms behind antibiotic resistance.
The researchers traveled to the Scărișoara Ice Cave, where they drilled a 25-meter ice core. From this ancient ice sample, the team observed an orange- and pink-pigmented bacterial colony emerge, which they later purified and identified as Psychrobacter strain SC65A.3.
Genomic analysis revealed that the novel bacterium carried 45 genes associated with adaptation to low-temperature environments, enabling it to survive in the extreme cold. When the researchers examined its antibiotic resistance profile, they found that SC65A.3 was resistant to 10 of the 28 modern antibiotics tested. In total, the genome contained over 100 resistance-related genes.
“Studying microbes such as Psychrobacter SC65A.3 retrieved from millennia-old cave ice deposits reveals how antibiotic resistance evolved naturally in the environment, long before modern antibiotics were ever used,” said Purcarea in a press release.
Beyond resistance, the researchers also investigated the bacterium’s potential to produce unique enzymes and antimicrobial compounds. Notably, they identified nearly 600 genes with unknown functions, suggesting a vast, untapped reservoir of novel biological mechanisms. The genome also contained 11 genes that may inhibit or kill other bacteria, fungi, and viruses.
Based on these findings, the researchers emphasized the potential of studying microbes from extreme environments, such as ice caves. “These ancient bacteria are essential for science and medicine,” Purcarea said.
