The Poisoned Arrow
An antibiotic has been created, against which bacteria are powerless
American scientists have discovered a compound that can become a unique new-generation drug that defeats even the most antibiotic-resistant bacteria. The results of the study are published in the journal Cell (Martin II et al., A Dual-Mechanism Antibiotic Kills Gram-Negative Bacteria and Avoids Drug Resistance).
Over the past thirty years, not a single new drug capable of killing gram-negative bacteria has appeared on the market. Their key difference from gram-positive bacteria is that gram-negative bacteria are protected by an outer layer that protects them from most antibiotics.
Scientists from Princeton University has discovered the compound SCH-79797, which has a double effect – it can simultaneously pierce the walls of bacteria and destroy folic acid in their cells. At the same time, bacteria do not develop drug resistance to it.
The head of the study, Professor Zemer Gitai, compares SCH-79797 with a "poisoned arrow" – a combination of two types of weapons – poison and a blade. A weapon that simultaneously attacks from inside and outside can destroy even the strongest opponents – from the widespread Escherichia coli to the powerful Staphylococcus and Gonococcus resistant to all known antibiotics.
"This is the first antibiotic that affects both gram-positive and gram-negative bacteria without resistance. We hope that in the future this will lead to the emergence of new types of antibiotics," Gitai's words are quoted in a press release from the university.
The main problem with antibiotics is that bacteria quickly develop resistance to them. The authors note that they have not observed any development of resistance to the new compound. According to them, it looks like a dream – an antibiotic that is effective against pathogens, does not form resistance and is safe for people at the same time.
"It really looks promising, so we named the compound "irresistin," says the scientist.
Usually, the development of a new antibacterial drug occurs as follows: scientists find a molecule capable of killing bacteria, grow several generations of microorganisms, observing how pathogens develop resistance to it, and then edit the molecule.
But in this case, nothing had to be edited, since resistance was not developed. But the authors faced another task: to prove to their colleagues and experts that no pathogen can really resist SCH-79797.
The researchers exposed the pathogens to the drug over and over again for 25 days. Since bacteria have a new generation about every 20 minutes, the microbes had millions of chances to develop resistance, but they didn't. At the same time, resistance to other antibiotics that scientists used for comparison was developed very quickly.
For their experiments, scientists even received from the vaults of the World Health Organization the most resistant strain of gonococcus Neisseria gonorrhoeae, which is among the top 5 most difficult pathogens to treat. Irresistin defeated him, too.
"Gonorrhea is a huge problem in terms of multidrug resistance," Gitai notes. – Humanity has run out of medicines for gonorrhea. What used to be the last line of defense, a medicine in case of an emergency, is no longer working."
Researchers have demonstrated that irresistin effectively treats mice infected with Neisseria gonorrhoeae.
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