Researchers from NovoBiotic Pharmaceuticals have identified a revolutionary new antibiotic called teixobactin[1], which kills a broad panel of bacteria. And more importantly, the researchers have not yet found any mutants of Staphylococcus aureus or Mycobacterium tuberculosis resistant to the antibiotic.
Teixobactin was isolated from an extract of Eleftheria terrae which was previously not known to produce antibiotics. Eleftheria terrae is a Gram-negative bacterium that lives in soil and cann’t be cultured in the lab using standard techniques.
Many antibiotics were originally isolated from bacteria. However, 99% of bacteria can’t be cultured in the lab, greatly limiting the discovery of new antibiotics. The researchers applied a high-throughput device called iChip to isolate and grow uncultured bacteria from soil.
Teixobactin had excellent activity against Gram-positive bacteria including superbugs. The researchers tested teixobactin in mice with MRSA and showed that 0.2 mg/kg of teixobactin compares favourably to 2.75 mg/kg of vancomycin.
Teixobactin inhibits cell wall synthesis by binding to lipid II and lipid III. Vancomycin has a similar mechanism, but teixobactin has a wider spectrum of activity against lipid II variants. Because teixobactin is produced by an uncommon Gram-negative bacterium targets lipid molecules, resistance may take a long time to appear.
[1] Nature. 2015, doi:10.1038/nature14098.
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