New antibiotic kills pathogens without resistance

A newly discovered antibiotic eliminates pathogens without encountering any detectable resistance, a finding that may lead to treatments for chronic infections such as tuberculosis and MRSA.
For years, pathogens' resistance to antibiotics has put them one step ahead of researchers, which is causing a public health crisis, according to Northeastern University Distinguished Professor Kim Lewis.
The pioneering work to develop a novel method for growing uncultured bacteria led to the discovery of the antibiotic, called teixobactin, and Lewis' lab played a key role in analysing and testing the compound for resistance from pathogens.
Lewis said this marks the first discovery of an antibiotic to which resistance by mutations of pathogens have not been identified.

The research team says teixobactin's discovery presents a promising new opportunity to treat chronic infections caused by staphylococcus aureus, or MRSA, that are highly resistant to antibiotics, as well as tuberculosis, which involves a combination of therapies with negative side effects.
Lewis and biology professor Slava Epstein tapped into a new source of antibiotics beyond those created by synthetic means: uncultured bacteria, which make up 99 per cent of all species in external environments.

They developed a novel method for growing uncultured bacteria in their natural environment.
Their approach involves the iChip, a miniature device Epstein's team created that can isolate and help grow single cells in their natural environment and thereby provides researchers with much improved access to uncultured bacteria.

Researchers have 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 MRSA 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. This challenges the dogma that we've operated under that bacteria will always develop resistance. Well, maybe not in this case," Lewis said.