Scientists Reveal Inner Workings of Powerful Antibiotic of "Last Resort" That Eliminates Bacteria

The secrets of an antibiotic of "last resort" that mercilessly annihilate bacteria have been divulged.

Researchers from the Imperial College in London, England and the University of Texas also devised a way to make such antibiotic even more powerful, as reported by Phys.org.

Colistin is the considered the "last resort" treatment for infections caused by the most horrible bacteria. While it has been discovered seven decades ago, the way it has killed bacteria has been under wraps. Until now.

Colistin Punches Holes in Bacteria, Making Them Burst

Researchers bared that colistin would punch holes in bacteria, thus making them eventually burst. Their study, "Colistin kills bacteria by targeting lipopolysaccharide in the cytoplasmic membrane," which was published in the eLife journal, also showed a way how to even make the antibiotic even a more effective bacteria killer.

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Colistin was introduced in 1947, and is one of those "elite" drugs that could kill the worst bacteria, such as E. coli, which led to a potentially fatal infection of the bloodstream, Pseudomonas aeruginosa, and Acinetobacter baumanii, which infects the lungs.

These bacteria are composed of two "skins" or membranes. Colistin would pierce both membranes, effectively waylaying the bacteria. Though it was widely known that colistin destroyed the outer membrane by aiming at a chemical called lipopolysaccharide (LPS), how the inner membrane was punctured was not clear, a TechExplorist article said.

Imperial College researchers presented that colistin also attacks LPS in the inner membrane.

Colistin Destroys Both Bacteria Membranes in a Similar Way

According to Dr. Andrew Edwards of the Imperial College Department of Infectious Diseases, it was obvious that colistin would destroy both membranes in a similar way, but it was generally assumed previously that it damaged both membranes in distinctive ways, a Phys.Org report said. With LPS being so small in the inner membrane, damaging the chemical was seemingly impossible. Changing the amounts and chemically modifying LPS in the inner membrane in the lab, researchers were able to reveal that colistin had pierced both membranes in the same way, and this obliterated the bacteria.

Researchers then tried to use the findings to transform colistin into being more efficient in killing bacteria. They concentrated on the bacterium Pseudomonas aeruginosa, which leads to severe lung infections among people suffering from cystic fibrosis. They discovered a novel experimental antibiotic, called murepavadin, caused the growth of LPS in the bacterium's inner membrane, thus making it easier for colistin to pierce and annihilate the bacteria.

Potent Antibiotic Combination to Fight the Worst Diseases

They said that as murepavadin is experimental, it cannot be administered to patients, but clinical trials are set to begin soon. If the trials are successful, murepavadin could be combined with colistin to create a strong treatment for wide range of bacterial infections.

The study's lead author, Akshay Sabnis, who is also from Imperial College Department of Infectious Diseases, said in the same Phys.Org report that as the global crisis of resistance to antibiotics remains prevalent, colistin has become more significant as the last option to save lives. With their discovery of how colistin works, the researchers could devise new ways to make the antibiotic a more effective killer.