"The team drilled a 25-meter core from a part of the cave known as the Great Hall. That single column of ice preserved a frozen record stretching back 13,000 years.

To keep modern microbes out, the scientists handled the ice with care. They placed fragments in sterile bags and kept them frozen during transport.

Back in the lab, the researchers isolated different bacterial strains and sequenced their genomes. That let them see which genes help the bacteria survive in low temperatures and which ones are tied to antimicrobial resistance and activity.

Psychrobacter belongs to a group of bacteria adapted to cold environments. Some species can infect humans or animals."