A new class of antibiotics
Chemists have created an antibiotic capable of killing "super-microbes"
Scientists from Brown University and Harvard have developed a new class of antibiotics capable of destroying staphylococcus, invulnerable to the action of methicillin and a number of other drugs, according to an article published in the journal Nature (Kim et al., A new class of synthetic retinoid antibiotics effective against bacterial persisters).
"Despite all the advantages of retinoid antibiotics, including the rapid nature of their action and the low probability of developing resistance to them, they have one big disadvantage – they are cytotoxic and can kill human cells. We managed to find a variant of them that acted only on bacterial membranes and was particularly effective in fighting long–standing infections," Eleftherios Mylonakis from Brown University and his colleagues write (in a press release, Researchers identify a new class of antibiotics with potential to fight 'superbugs' - VM).
In recent years, the problem of the appearance of so–called "superbugs" - microbes resistant to the action of one or more antibiotics - has become more and more acute for doctors. Among them there are both rare pathogens of infections and very common and dangerous pathogens, such as Staphylococcus aureus or Pneumococcus (Klebsiella pneumoniae). There is a real danger that all antibiotics will lose their effectiveness and medicine will return to the "dark ages".
Milonakis and his colleagues have created the first synthetic antibiotic that can destroy even the most tenacious colonies of "immortal" staphylococcus by experimenting with retinoids, vitamin A analogues that have bactericidal properties.
Such substances, as Milonakis notes, scientists have long been trying to adapt as a means to fight not bacteria, but cancerous tumors, whose cells begin to die en masse when even a small number of retinoid molecules appear in their vicinity.
Relatively recently, scientists have discovered that these same compounds can penetrate the membranes of microbes and turn them inside out, causing their mass death. These discoveries attracted the attention of American chemists, and they tried to find a version of retinoids that would kill staphylococcus, but did not touch animal and human cells, experimenting on nematode worms.
Having created several tens of thousands of "cousins" of vitamin A, scientists infected worms with staphylococcus and tried to cure them with these randomly created antibiotics. They managed to find about two hundred molecules that interfered with the reproduction of microbes, and choose from them two substances, CD437 and CD1530, which coped with this task most effectively and at the same time almost did not touch the cells of the liver, kidneys and other organs.
Further experiments showed that the CD437 molecule and its improved versions, which did not kill human cells in principle, had another interesting and useful property. They were especially effective in destroying those microbes that multiplied slowly and were the cause of the development of chronic and long-standing infections.
Such bacteria do not have "invulnerability genes", but antibiotics have almost no effect on them due to their slow metabolism, and the creation of a cure for them, as Milonakis and his colleagues hope, will help doctors fight hospital epidemics of staphylococcus and allow science to win the arms race with microbes.
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