Antibiotic kills superbug

Researchers followed their noses to discover a new bacteria-fighter inside our nasal cavities which may help in the fight against superbugs.

The antibacterial compound, named lugdunin, comes from a bacterium that occurs naturally in our noses called Staphylococcus lugdunensis.

According to researchers at the University of Tübingen in Germany led by Alexander Zipperer and Martin Konnerth, the new antibacterial can be used to treat bacterial skin infections in mice, including golden staph – one of the most common causes of hospital infections worldwide.

Importantly, the antibiotic doesn’t seem to provoke mutations in the bacteria it fights.

Antibiotics, drugs which fight bacterial infections, often comprise naturally occurring compounds. But since the rise in antibiotics, some infection-causing bacteria evolved resistance to our antibacterial defenses.

An example of this is the well-known bacterium golden staph (Staphylococcus aureus), which is found in around 30% of the population. It colonises the human nose and can lead to nasty infections of the skin and respiratory system.

Since doctors have been treating S. aureus with antibiotics, resistant strains have emerged, including methicillin-resistant S. aureus (MRSA).

So the researchers wanted to find out why 70% of the population were naturally free of the S. aureus bacterium. They identified lugdunin – the first in a new class of peptide antibiotics – which is secreted by a bacterium in our noses and has the ability to fight the resistant strain of golden staph.

Our own bodies are abundant sources of antibacterials thanks to the high concentration of diverse microorganisms, known as our body’s microbiota. This study suggests that many sites on the body – not just our gut – could be fertile ground for the microorganisms that help fight infections.

Once developed, lugdunin was used on mice infected with MRSA. The researchers found it fought or killed the bacteria within 72 hours, and similar results were seen against a range of other harmful bacteria.

“Lugdunin treatment led to a strong reduction or even complete eradication of viable S. aureus on the surface and in the deeper layers of the skin,” the paper reads.

The researchers also tested the nose microbiome of 187 hospital patients. Interestingly, among those carrying the main bacterium present with lugdunin, only 6% had colonisation by S. aureus compared with 35% of patients without lugdunin.

Perhaps most significantly, the researchers saw lugdunin appeared not to be “prone to causing development of resistance in S. aureus” – meaning a lugdinin-resistant strain of golden staph isn’t likely to develop any time soon.

New types of antibiotics should be sourced from the human microbiota, the researchers write – but “it will be a challenge for future research to elucidate the identity, variability, activity and ecological roles of such compounds and to exploit them for the development of new drugs”.

The findings were published in the journal Nature.