Within the silent warfare raging beneath our feet are soil-borne bacteria fighting back in battles that could ultimately save millions of human lives. Researchers recently announced that they have discovered an extraordinary megacluster of genes in a common variety of bacterial streptomycetes that features the production of a natural concoction of 4 antibiotics, all acting on separate stages of a vital metabolic process. The combined impact would make it much more difficult for lethal superbugs to develop resistance.
Antibiotic resistance has emerged as one of the most serious health threats we face today. Researchers forecast that ‘drug-resistant infections could cause 39 million deaths between 2025 and 2050 if new solutions are not discovered.’ Antibiotics have traditionally operated by attacking one mere vulnerability within bacteria, providing an opportunity for the pathogen to mutate and escape.
Yet Nature, it would appear, has already constructed a better method: This groundbreaking discovery, reported in a new Nature paper, is actually based on a rediscovery, in the species of bacteria commonly found in the soil Streptomyes, the bacteria that produces the drug streptomycin. A team at McMaster University and colleagues uncovered a huge cluster of genes which synthesizes several compounds targeted at biotin (vitamin B7), a vital molecule involved in cell growth and metabolism of bacteria. By attacking this pathway at many stages at once they have created an antibiotic cocktail that is hard to compete with using the single hit approach.
What is Mostly fascinating about this discovery is that it arose from a system that scientists have been examining for decades. ‘There’s something new in an extensively explored system – it’s just hiding in front of our faces, ‘ said Mark Blaskovich of the University of Queensland, who specializes in antibiotic development. As well as the well known acids acidomycin and the recently identified dapamycins, the cocktail also contains a rather helpful protein.
After billions of years of evolution, this complex blend has been optimized to achieve extremely effective results, providing a template for future research. For patients and clinicians struggling with intractable infections, whether caused by MRSA or other multidrug-resistant bugs, this could be the answer. Attacking several steps along the same pathway would give bacteria a real headache and as microbiologist Brendan Wren points out, it makes it more difficult for them to develop a resistance as “it attacks multiple targets.
” This attack on multiple targets has parallels with some of the most successful modern therapies, but it is derived in this case from nature’s own strategies. Yet, the effects go far wider than just the life sciences. Knwoing about these gene clusters may reveal other, related gene clusters which govern other essential processes in bacteria.
The researchers managed to clone a huge section of DNA from the megalcluster and then express it in laboratorya bacteria with benefits, it worked. Unlike one would have imagined, other streptomycete populations also seem to possess these clusters sharing the same reason because it is evolutionarily conserved. It will still be some time before this discovery is translated to the bedside in the form of medicines. Stability still needs to be optimized, potential side effects minimized, and clinical trials need to be carried out in earnest. Though, the chemical structures, modes of action are now known, giving medicinal chemists something to work on. Right now where new antibiotics are desperately sought this soil cocktail represents an important breakthrough.