We all know that antibiotic resistance is a massive problem. According to Dame Sally Davies, the chief medical officer for the UK, antibiotic resistance is “as big of a risk as terrorism,” and as our current antibiotics become less and less useful to treat infections, we may well face a future reminiscent of the 1900s, where even small infections could be deadly.
Why do bacteria become resistant to antibiotics? Well, part of the problem lies in the fact that bacteria are extremely adaptable, can mutate quickly, and can share genes between species—more and more species of bacteria are therefore becoming immune to the drugs we rely on to keep them at bay. New antibiotics are desperately needed, but no new class of antibiotics have been discovered in the last 30 years. Until now.
How new antibiotics are discovered
Antibiotics come cleanly packaged in sterile containers, in perfectly shaped ovals or circles with neatly stamped labels. It’s easy, therefore, to forget that usually antibiotics are discovered rather than created—and far from the hygienic setting of a laboratory, the places in which they are discovered are downright dirty.
Bacteria live everywhere. In the environment, bacteria have to compete with each other for space and resources, just like any other species. To do this more effectively, many species of bacteria and fungus actually produce antibiotics themselves, in order to kill off unfriendly neighbours. Penicillin is an example of one of these antibiotics, as it is produced by the Penecillium fungi. Since its discovery, teams of scientists have been searching through all sorts of filthy environments in an attempt to find more species of bacteria and fungi that produce potentially useful antibiotic drugs. The strategy has been successful on more than one occasion: vancomycin, a powerful antibiotic, was found in a sample of dirt sent from a missionary in Borneo to a friend (who just happened to be an organic chemist at a pharmaceutical company.) The first cephalosporin, an incredibly useful class of antibiotic, was found in a Sardinian sewer.
The search for antibiotics within our own bodies
While scientists have hunted for antibiotics in all sorts of environments, few searches have focused within our own bodies. While we might think of ourselves as generally clean, our own “microbiome”- the sum total of the bacterial, fungal and parasitic cells that live on and within our bodies - actually outnumbers our own human cells on a ratio of ten to one. We already know that one in three of us carries MRSA, the hospital superbug, in our noses. As scientists were trying to work out why some people carried the superbug and others did not, they came across something that they didn’t expect. People who carried a distant relative of MRSA, Staphylococcus lugdunensis, were far less likely to actually carry MRSA. When they investigated further, they found that this second bacteria produced a substance that they named Lugdunin. Initial research has found that Lugdunin is capable of killing multiple species of disease causing bacteria without causing any side effects.
Will Lugdunin be the source of the next big antibiotic?
While is only the beginning of a long road for Lugdunin, and there are many more trials that will be needed, Lugdunin seems very promising as a new class of antibiotic. The method of using the human microbiome as a source for new drug discovery is frankly genius--it is much less likely that these compounds will be dangerous, because we already live with them and they have evolved alongside us. It is an exciting new era for drug discovery, and we just have to hope that current measures to reduce antibiotic resistance can keep us going in the meantime.