5,000-year-old bacterium found with resistance to modern antibiotics

Researchers recovered a 5,000-year-old Psychrobacter strain from a Romanian ice cave and found laboratory resistance to multiple modern antibiotics; the study noted no evidence the microbe is infecting people.

Scientists report that a 5,000-year-old bacterium was recovered from ice in Scarisoara Ice Cave in Romania. The organism was identified as Psychrobacter SC65A.3 and was isolated from an ancient ice sample. Laboratory testing showed measurable resistance to a number of antibiotics used in modern medicine. The research was published in the journal Frontiers in Microbiology. Key findings: - The bacterium came from an ice core sampled in Scarisoara Ice Cave and was identified as Psychrobacter SC65A.3. - Researchers tested the strain against 28 antibiotics from 10 drug classes and reported laboratory resistance to 10 commonly used antibiotics, including rifampicin, vancomycin and ciprofloxacin, as well as trimethoprim, clindamycin and metronidazole. - The team identified more than 100 genes linked to antibiotic resistance in the strain. - The authors emphasized that Psychrobacter is an environmental bacterium without established clinical breakpoints and that there is no evidence the ancient microbe is currently infecting people or spreading; the study examined a single strain. Summary: The study suggests antibiotic resistance genes existed in the environment long before modern antibiotic use, according to the researchers. Current evidence does not indicate human infection or community spread from this strain. Undetermined at this time.