Ancient Bacteria Found in Romanian Ice Caves Show Antibiotic Resistance
Scientists have made an intriguing discovery: bacteria that have been encased in ice for around 5,000 years are showing resistance to several modern antibiotics. This particular bacterium, identified as Cyclobacter SC65A.3, was unearthed in Romania’s Scalisoara Ice Cave, where researchers extracted a 25-meter ice core. This core represents a frozen history of about 13,000 years, offering a fascinating glimpse into the past.
The findings were documented in the journal Frontiers in Microbiology. To ensure that contamination didn’t occur, the researchers meticulously preserved and transported the ice samples while still frozen. They were able to isolate this ancient bacterial strain and conduct further tests.
Despite its age, this strain was found to be resistant to ten commonly used antibiotics in modern clinical practice, including rifampicin, vancomycin, and ciprofloxacin. Cristina Purcarea, the study’s lead researcher from the Biological Institute of the Romanian Academy in Bucharest, noted that “the ten antibiotics to which we have found resistance are widely used in oral and injectable therapies for various serious bacterial infections.”
The researchers put this ancient strain through tests against 28 antibiotics sourced from ten different drug classes, uncovering over 100 genes associated with antibiotic resistance. Purcarea commented on the implications of these findings, stating that they help reveal how antibiotic resistance developed naturally in the environment long before modern antibiotics were introduced.
Interestingly, the existence of antibiotic resistance in these ancient bacteria suggests that such resistance was already present in nature prior to the development of contemporary medicines.
The strain also demonstrated resistance to additional drugs like trimethoprim, clindamycin, and metronidazole—medications commonly used for treating infections in various areas, including the lungs, urinary tract, skin, and reproductive system.
Limitations of the Study
However, the research has its limitations. It focused solely on one bacterial strain from a single cave sample, and there is currently no evidence that these ancient microbes are causing infections in modern humans. Experts point out that Cyclobacter is primarily an environmental bacterium, lacking established clinical antibiotic breakpoints. This means there’s no clear standard for what constitutes resistance like there is for hospital-acquired infections.
As a result, the resistance levels observed in the lab setting for this environmental bacterium cannot be directly compared to how doctors classify more dangerous superbugs found in healthcare settings.
