Scientists find new antibiotic right under our noses

The study demonstrates that this bacterium produces a new peptide antibiotic, named lugdunin, that's part of an entirely new class of antibiotics.

Once scientists grew these Staphylococcus lugdunensis bacteria in a lab dish, they were able to isolate a compound that's lethal to another strain commonly found in the nose that can make us sick - Staphylococcus aureus.

The scientists led by Dr Andreas Peschel, from the University of Tubingen in Germany, wrote: "Lugdunin has apparently evolved for the objective of bacterial elimination in the human organism, implying that it is optimised for efficacy and tolerance at its physiological site of action".

So what happens in the noses of the remaining 70 percent of the human population, who don't carry S. aureus?

The researchers found lugdunin had bacterial activity against many major pathogens and S. aureus isolates had "pronounced susceptibility" to lugdunin in all nasal and clinical samples. Its potential to cure infections was demonstrated on S. aureus skin infections in mice.

At least 2 million people in the USA develop antibiotic-resistant infections each year and 23,000 people die from them, according to the Centers for Disease Control and Prevention.

Dr Peschel said the human body contained a rich ecosystem of bacteria, but that a scientist's normal instinct would be to examine the gut, rather than the nose, for interesting bugs.

In testing the lugdunin on mice that had skin infections caused by staphylococcus aureus, the researchers said some of the infections were completely cleared and others dramatically reduced. S. aureus was present in only 5.9 percent of individuals who also carried S. lugdunensis, compared with 34.7 percent in people without S. lugdunensis.

These were "very unexpected and exciting findings that can be very helpful, we think, for new concepts for the development of antibiotics", Peschel told journalists ahead of the study being published by British journal Nature. Now they're targeting a new location: your nose.

In addition to MRSA, lugdunin killed S. aureus resistant to the antibiotic glycopeptide and vancomycin-resistant Enterococcus spp.

The nasal swabs of 187 hospitalised patients were tested for the presence of S. aureus, S. lugdunensis or both.

It's the first time researchers have been able to definitively connect the production of an antibiotic in a bacterium with the suppresssion of a competitor in a microbiome community, says Kim Lewis, a microbiologist at Northeastern University in Boston, Massachusetts.

Tests to see whether the new antibiotic would work in humans haven't yet been conducted.

The new compound also isn't effective against certain bacteria like E. coli and pseudomonas, which are very risky and claim thousands of lives worldwide every year, says Melinda Pettigrew, a professor of epidemiology at the Yale School of Public Health.

Even if lugdunin never makes it to the clinic, the authors note that the most important takeaway from the new study is that our own microbiomes may be an untapped reserve of antibiotic sources. The study is also a "proof of principle paper" that shows that looking at the human microbiome can successfully lead to finding new antibiotics - and will hopefully inspire other researchers to look a little closer to home in the future.

  • Aubrey Nash