Antibiotics from the computer
Scientists have found a new super-powerful antibiotic inside the human body
Computer analysis of the DNA of bacteria living on our skin and in the intestines helped scientists identify two powerful antibiotics – humimycin A and humimycin B, which will help fight the so-far invulnerable "superbugs", according to an article published in the journal Nature Chemical Biology (Chu et al., Discovery of MRSA active antibiotics using primary sequence from the human microbiome).
"These antibiotics can work as a kind of "booster" for other drugs. Their effect on the synthesis chains of vital substances in microbes can be compared to if you took a hose and squeezed it in two places. Neither the first nor the second compression can completely stop the flow of water by themselves, but their combination gradually stops the flow," says Sean Brady from Rockefeller University (in a press release, Researchers discover new antibiotics by sifting through the human microbiome).
The emergence of antibiotic resistance in bacteria forces pharmacists to create more and more new types of medicines. However, microorganisms mutate very quickly, so strains that are invulnerable to dangerous drugs appear among them quite quickly. If humanity stops inventing new antibacterial drugs, existing antibiotics will soon become simply useless.
The problem of antibiotic resistance is being dealt with by really advanced scientific centers all over the world, but this is not an easy matter. Playing tag with microbes – you're a new antibiotic to them, they're resistant to you after a while - is not cheap: the development of a new antibiotic today costs from 800 million to a billion dollars, and it usually takes 8-10 years.
Brady and his colleagues have significantly reduced the cost and accelerated this process by developing an unusual technique for computer analysis of genes, which allows you to find sequences in the virtual DNA of microbes and multicellular living beings that may be associated with the production of molecules capable of destroying pathogenic bacteria.
The scientists tested the work of this algorithm on the most studied set of bacterial genomes – the human microbiome, a collection of DNA of microorganisms living in our intestines and on the surface of the skin.
After analyzing thousands of genomes of bacteria living in our body, Brady and his colleagues identified six dozen genes, the "reading" of which should force the cell to synthesize molecules similar in composition and shape to antibiotics. Having selected the most successful half of them, the scientists synthesized proteins whose assembly instructions were contained in these genes, and tested their work on colonies of E. coli, Staphylococcus aureus and other dangerous microbes.
As it turned out, two of them, named humimycin A and humimycin B, were especially effective in the fight against bacteria, destroying not only "ordinary" strains of staphylococcus, streptococcus and E. coli, but also their versions resistant to the action of conventional antibiotics. Both of these proteins destroy microbes by suppressing the enzymes they use to "fix" and build their cell walls.
Scientists tested the effectiveness of these antibiotics by infecting several mice with a lethal dose of staphylococcus resistant to conventional drugs. Rodents that then received portions of medicine based on humimycins and traditional antibiotics successfully survived the infection, while all individuals from the control group died.
Interestingly, the rhodococcus bacteria in which these substances were found "hide" them in natural conditions and do not synthesize these antibiotics when they are grown in a test tube. In the near future, Brady and his colleagues plan to continue searching for such molecules in the DNA of other microbes, hoping to replenish our "arsenal" in the arms race against diseases.
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16.11.2016