Methicillin-resistant Staphylococcus aureus (MRSA) infection has gotten a lot of attention. It is caused by a strain of staph bacteria that's become resistant to the antibiotics commonly used to fight it, but antibiotic resistance is not new. For as long as antibiotics have been manufactured (and nature shows evidence of it well before that) resistance evolves.
Science has to stay a step ahead in the interests of public health and a new paper details a newly discovered antibiotic that eliminates pathogens without encountering any detectable resistance, which holds great promise for treating chronic infections like tuberculosis and those caused by MRSA.
A novel method for growing uncultured bacteria led to the discovery of the antibiotic, called teixobactin. Northeastern University Distinguished Professor Kim Lewis, the paper's lead author, said this marks the first discovery of an antibiotic to which resistance by mutations of pathogens have not been identified.
Teixobactin's discovery presents a promising new opportunity to treat chronic infections caused by staphylococcus aureus, or MSRA, that are highly resistant to antibiotics, as well as tuberculosis, which involves a combination of therapies with negative side effects.
The screening of soil microorganisms has produced most antibiotics, but only 1 percent of them will grow in the lab, and this limited resource was overmined in the 1960s, Lewis explained. He and colleagues spent years seeking to address this problem by tapping into a new source of antibiotics beyond those created by synthetic means: uncultured bacteria, which make up 99 percent of all species in external environments.
They developed a novel method for growing uncultured bacteria in their natural environment, which led to the founding of NovoBiotic. Their approach involves the iChip, a miniature device that can isolate and help grow single cells in their natural environment and thereby provides researchers with much improved access to uncultured bacteria. NovoBiotic has since assembled about 50,000 strains of uncultured bacteria and discovered 25 new antibiotics, of which teixobactin is the latest and most interesting, Lewis said.
The antibiotic was discovered during a routine screening for antimicrobial material using this method. Lewis then tested the compound for resistance development and did not find mutant MSRA or Mycobacterium tuberculosis resistant to teixobactin, which was found to block several different targets in the cell wall synthesis pathway.
"Our impression is that nature produced a compound that evolved to be free of resistance," Lewis said. "This challenges the dogma that we've operated under that bacteria will always develop resistance. Well, maybe not in this case."
Going forward, the research team hopes to develop teixobactin into a drug.
Published in Nature.
Lewis and Northeastern biology professor Slava Epstein co-authored the paper with colleagues from the University of Bonn in Germany, NovoBiotic Pharmaceuticals in Cambridge, Massachusetts, and Selcia Limited in the United Kingdom.