Bacteria hidden up people's noses produce an antibiotic which could herald a new age in the fight against superbugs.
The new drug, lugdunin, is made naturally by Staphylococcus lugdunensis, one of a number of different kinds of microbe bedding in alongside people's nasal hair.
Just under one third of people carry the bacteria Staphylococcus aureus in their noses, which can cause fatal infection if it enters the blood stream and lead to superbug strain methicillin-resistant S. aureus (MRSA).
Nine per cent of people naturally carry S. lugdunensis in their noses and were six times less likely to have S. aureus than those without it, nasal swabs from 187 hospital patients showed.
New antibiotics are urgently needed as doctors struggle to protect against superbugs such as MRSA, which have developed resistance to existing drugs.
Professor Andreas Peschel from the University of Tubingen in Germany told the BBC: "Lugdunin may be the first example of such an antibiotic. We have started a screening programme."
The human body has so far yielded few antibiotics, which are usually derived from bacteria living in the soil.
The vast majority of antibiotics are small molecules that attack bacterial enzymes. Lugdunin is unusual in that it is much larger, and operates in a new way involving the cell membrane that scientists do not yet fully understand.
This could explain why, in a 30-day test tube trial, the S. aureus strains were unable to develop resistance to the new antibiotic. However, scientists have warned this might not necessarily be the case in the human body.
Writing in the journal Nature, researchers said the results showed it may be "particularly difficult for bacteria to develop resistance to lugdunin".
This indicates it has "apparently evolved for the purpose of bacterial elimination in the human organism" and "shows promise as a potential drug for inhibiting growth of S. aureus in the nares (nostrils) and potentially other body sites."
The team is talking to companies interested in developing the antibiotic as a drug for human use. One idea is that it could be used as a nasal spray to keep S. aureus out of people's noses in the first place.
Dr Peschel told the Telegraph: "If I was a bacteria I wouldn't go to the nose. There's nothing - it's simply salty liquid and a tiny amount of nutrients."
