A team of Romanian scientists has drilled a 25-metre-high ice core from the Scalisoara cave in search of clues for developing new drugs. 5,000-year-old ice yields samples of ancient bacteria.

Laboratory analysis revealed Something noteworthy. These bacteria have been able to thrive in a variety of harsh environments without being disturbed for thousands of years. They thrived in extreme cold and high salinity. Normally, this is a setting that prevents the growth of bacteria.

Scientists also discovered that ancient bacteria had 10 resistances. modern antibioticsThese include powerful broad-spectrum treatments such as ciprofloxacin, a drug designed to kill many types of bacteria. In other words, antibiotics that would normally kill bacteria or stop them from growing had little effect on this strain.

How can bacteria evolve resistance to antibiotics long before scientists create them or doctors prescribe them?

The answer to this obvious conundrum lies in the fact that all modern antibiotics trace their origins back to nature. For billions of years, bacteria have been in an evolutionary struggle with each other. As a result, they have developed formidable chemical attack and defense mechanisms.

A deeper understanding of these mechanisms could help scientists discover new antibiotics to treat dangerous infections. Natural environments are densely populated with bacteria and other microorganisms. There is intense competition for the limited space and nutrients it provides.

Many species produce compounds that kill or suppress nearby rivals. This gives them an advantage in the fight for these resources. However, the protective chemicals they produce facilitate adaptation. Bacteria need to protect themselves from their own toxins. Meanwhile, competitors are also evolving ways to counter it.

Over billions of years, this arms race has produced a vast reservoir of resistance genes and antimicrobial compounds.

Antibiotics can target a limited number of biological processes within bacteria. However, this diversity of natural resistance is so great that some scientists argue that genes resistant to all future antibiotics may already exist in the environment.

Samples recovered from Romanian ice caves provide a powerful example of this idea. Bacteria were isolated from the outside world for 5,000 years. Nevertheless, they were able to show resistance to some important modern drugs. This includes those used to treat serious and potentially fatal infections such as tuberculosis.

There is no evidence that cave microorganisms are harmful to humans. However, bacteria do not exist alone. They have a remarkable ability to share useful traits with each other by exchanging small pieces of DNA, even between unrelated bacterial species. This means that resistance genes that are conserved in environmental bacteria are not necessarily present there. If these genes are transferred to disease-causing bacteria, there is a risk that existing drugs may become less effective.

Rising temperatures are accelerating the melting of global land ice. There is a risk that long-dormant microorganisms and their genetic material may be released into soil and water systems.

If resistance genes that have been conserved over thousands of years re-enter modern microbial communities, they could contribute to the global epidemic of antibiotic resistance. This would make treating both common and serious bacterial infections much more difficult.

nature’s hidden pharmacy

But the same evolutionary pressures that promote resistance also cause microbes to produce molecules that can kill rival bacteria.

In laboratory experiments, chemicals produced from ice cave samples were able to kill or inhibit 14 types of bacteria known to cause human disease. This included several on the World Health Organization’s list of priority pathogens.

These compounds could serve as a starting point for the development of new antibiotics. These may help overcome existing drug resistance in harmful bacteria.

Many of today’s antibiotics were originally discovered through research on natural microorganisms. Penicillin is one example.

Most of the bacteria preserved in ancient environments have not been studied. These may represent an important and largely unexplored source of new antimicrobial compounds.

The DNA of ice cave bacteria also contains a number of genes that have no clearly defined role. These unknown sequences may represent previously uncharacterized biochemical capabilities.

These offer possibilities not only for drug discovery but also for fields as diverse as industrial biotechnology. For example, enzymes that allow bacteria to function in extremely cold environments could be adapted for use in industrial processes that operate at lower temperatures. This can improve energy efficiency and reduce costs.

Bacteria preserved in Romanian ice shows how deeply ingrained antibiotic resistance is in nature. They also show how much of nature’s chemical diversity remains unexplored.

Ancient microorganisms may contain potentially harmful antibiotic resistance genes and require careful monitoring on a global scale. But it also contains a vast reservoir of biochemical tools that could provide us with new medicines.

As antimicrobial resistance continues to increase around the world, understanding these ancient microbial systems may prove increasingly important.