A new class of antibiotics — an exciting discovery but no substitute for antimicrobial stewardship

Last week, an article in Nature highlighted some progress in antibiotic discovery—a new antibiotic, named teixobactin, has been unearthed which could help in the treatment of resistant infections from bacteria like MRSA and antibiotic resistant M. tuberculosis.

It was discovered in a soil bacterium that has never been studied before and the discovery hints at the potential for other new antibiotics. Using new technology, scientists are now able to mine for new compounds (and potential antibiotics) like teixobactin from a vast population of microbes that was previously untapped. It is certainly cause for excitement, but it is important to keep some perspective. It's not a magic wand for the problem of antibiotic resistance. Here are a few points to keep in mind about the new discovery:

• Teixobactin has only been tested in mice and against some strains of bacteria. There is still a lot more work that needs to be done to establish it is safe for humans and the range of human bacterial infections it can address.
• We know that Teixobactin can work against some antibiotic resistant bacteria, including also bacteria that have been associated with animal agriculture. For example, teixobactin was effective against gram positive bacteria including antibiotic resistant MRSA and Enterococci. MRSA and resistant forms of Enterococci have also been found in poultry and meat products. However, Teixobactin doesn't work on gram negative bacteria such as resistant E. coli and Salmonella, which can be found on poultry and livestock. Importantly, it is gram negative bacteria (i.e. Kleibsiella, E. coli) that are increasingly resistant to all available antibiotics and are considered an urgent threat by the CDC.
• Teixobactin works by attacking a fundamental building block of a bacterium's cell wall, which is something that the bacterium can't easily change to evade the antibiotic. However, even the authors and other microbiologists admit that while resistance might be slower in emerging, microbes will eventually figure out how to overcome this antibiotic too. (Microbiologists know not to underestimate the evolutionary power of microbes!)

All this is a reminder of the continued importance of antibiotic stewardship. Even with potential new antibiotics in the pipeline, antimicrobial stewardship is necessary to slow the tide of antibiotic resistance. Antibiotics are essential medicines that are needed now to treat infections and to ensure that surgeries and treatments like chemotherapy can continue. So, antibiotics should be used judiciously, whether in hospitals or in animal agriculture. In human medicine, it means prescribing antibiotics for infections and not for colds. In animal agriculture, that means not using antibiotics for routine disease prevention or as a substitute for better management practices. Antimicrobial stewardship is important so that all antibiotics, the ones we have and use now as well as the ones waiting to be discovered, last for as long as possible.