New class of antibiotics could help in battle against superbugs

Scientists have discovered a new antibiotic which could kill a broad range of bacterial pathogens, including methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant enterococci (VRE).

Called teixobactin, the antibiotic is the result of a research partnership between the University of Bonn in Germany; Northeastern University, in Boston, MA, US; and NovoBiotic Pharmaceuticals, a US developer of antibiotics.

Details of the breakthrough are reported in the journal Nature (Ling et. al. 2015).

Laboratory tests have shown that teixobactin can kill some bacteria as quickly as established antibiotics and can cure laboratory mice suffering from bacterial infections with no toxic side-effects.

Most antibiotics are derived from soil bacteria, which make the chemicals to kill competing microbes. NovoBiotic has extended this approach with technology that enables researchers to grow species that would not survive in traditional laboratory cultures.

Teixobactin’s dual mode of action and binding to non-peptidic regions suggest that resistance will be very difficult to develop

The scientists developed a device called an iChip to simultaneously isolate and grow uncultured bacteria. A sample of soil was diluted so that approximately one bacterial cell was delivered to a given channel, after which the device was covered with two semi-permeable membranes and placed back in the soil where the microbes grew into colonies. Screening identified a previously unknown species of Elephtheria terrae, which the scientists called teixobactin.

Teixobactin quickly kills Gram-positive bacteria, including Clostridium difficile, Mycobacterium tuberculosis and Staphylococcus aureus, which are often the cause of hospital-acquired infections.

It works in a unique way by binding to the fatty lipids that form the building blocks used by bacteria to manufacture their cell walls, a mode of action similar to vancomycin, which doctors sometimes use as an antibiotic of last resort to treat drug-resistant infections.

‘The need for new antibiotics is acute due to the global problem of pathogen drug resistance. Teixobactin’s dual mode of action and binding to non-peptidic regions suggest that resistance will be very difficult to develop,’ said Dr Kim Lewis, co-founder of NovoBiotic.

Lewis said the first clinical trials in humans could start in two years and, if successful, the drug could be in widespread use in 10 years.

Although the discovery and methods used were described as ‘the tip of the iceberg’ by Mark Woolhouse, Professor of Infectious Disease Epidemiology at the University of Edinburgh, and he suggested that many more antibiotics could be found using such techniques, Dr Angelika Gruendling, reader in Molecular Microbiology at Imperial College London, said teixobactin does not work on other drug-resistant pathogens such as E.coli, and that testing in humans might show that it is not as effective as hoped and there could be unforeseen side-effects.