It looked increasingly bleak so far. Bacteria evolve rapidly and are rapidly becoming resistant to antibiotics. With the discovery of teixobactin, the first of a completely new class of antibiotics, the odds seem to have turned. Do we finally have a devastating weapon against some of the worst diseases ever?
In new research, Professor Kim Lewis and his research group succeeded in developing an antibiotic that eliminates pathogens without making them resistant. Something that is impossible according to certain well-established microbiological theories. Lewis even achieved the holy grail for scientists: a publication in the top journal Nature. Teixobactin was discovered when Lewis and his team developed a new method to cultivate previously unreportable soil bacteria. For billions of years, bacteria have regularly waged a biochemical war to the death with each other, and Lewis managed to discover one of their weapons. And not just any weapon. An antibiotic that succeeds in killing previously untreatable pathogens such as tubercle bacilli and MRSA.
Hidden antibiotics in the soil
Soil bacteria have provided the majority of all known antibiotics, which is no wonder: the vast majority of bacteria live in the soil, at billions per gram, but only 1% of the soil bacteria can be grown in the lab. This limited population had already been completely combed through in the 1960s. Time to explore the remaining 99%, and this is what Lewis and his team did. They developed new methods to grow these bacteria in the lab and placed them in the biotech company NovoBiotic. Their company developed the iChip, a miniature culture environment developed by Epstein's team, Novobiotic has now examined 50,000 lines of previously uncultured bacteria and found 25 new antibiotics in this process. Of these, teixobactin is the most recent and also the most promising, said Lewis.
Teixobactin was discovered during a routine examination of microbial material. Lewis then tested the drug for resistance to development and found no mutated MRSA and Mycobacterium tuberculosum that had become resistant to teixobactin. Teixobactin, it seems, acts on several important biochemical production routes in the bacterial cell, with which the bacterium produces components for the thick, protective cell wall. Until 2015, no antibiotic has been found that did not produce resistance. Teixobactin is unique in this respect.
How does teixobactin work?
Teixobactin does not attack proteins, but bacterial lipids (fats). A double layer of phospholipids forms the cell membrane in species such as humans. Bacteria and plants also have a thick cell wall. Because teixobactin attaches to the precursors for these lipids, bacteria cannot grow and divide themselves. This ensures that our immune system can make short work of the bacteria. This, presumably, also explains why the extremely persistent bacteria S. aureus and M. tuberculosum failed to develop resistance even after 27 days of exposure to sublethal doses of teixobactin.
Can we finally save lives now?
Obviously, it will be a lot of research before teixobactin can be used as an effective therapy, if ever. Some potential antibiotics are toxic to humans or have serious side effects. Teixobactin is only effective against gram-positive bacteria, not gram-negative bacteria, which include many other pathogens. On the other hand, if teixobactin does not induce resistances, there are probably more undiscovered antibiotics with the same property. Pharmaceutical giants are reluctant to invest in new antibiotics as they are unlikely to be prescribed much. This prevents the development of resistance. This is another excellent argument why universities, international governments and non-profit organizations should take over the development of medicines from pharmaceuticals. We must not let the survival of human lives depend on grab managers and short-sighted shareholders. and declare all-out war on poverty, disease and death.
Lewis has made a medical breakthrough before. He discovered a means to disable the 'dormant persistors' of MR staphylococcus aureus, the reason why this pathogen is so persistently resistant to antibiotics.
1. Newly discovered antibiotic kills pathogens without resistance, Northwestern University, 2014
2. Kim Lewis et al., A new antibiotic kills pathogens without detectable resistance, Nature, 2015