Scientists searching for ways to combat antibiotic-resistant bacterial infections say they have found a new potential weapon in an unexpected place: the human nose.
The promising compound is produced by a nose-dwelling bacterium, and is able to kill a disease-causing, antibiotic-resistant superbug, the researchers said in a paper published on Wednesday by the journal Nature.
"It was completely unexpected to find a human-associated bacterium to produce a real antibiotic," said study co-author Andreas Peschel of the University of Tubingen in Germany.
"We have started a larger screening programme and we are sure there will be many additional antibiotics that can be discovered from these sources."
In the past, most new antibiotics have been discovered by sifting through soil samples. The last new class of the drugs to reach patients was discovered in the 1980s.
The scientists found Staphylococcus aureus bacteria in the noses of about 30 percent of people, raising the question why the other 70 percent were not beset by this staph bacterium. A hardened variety, known as methicillin-resistant Staphylococcus aureus, or MRSA, is among the superbugs that pose a growing health problem worldwide.
The researchers said that another in-nose bacterium - called Staphylococcus lugdunensis - appeared to be keeping the rival staph at bay in some people by producing its own antibiotic.
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Peschel and his colleagues isolated the new antibiotic, which they called lugdunin, and tested it on mice whose skin had been infected with Staphylococcus aureus. They found it was effective in clearing the bacteria in most cases.
Tests to see whether the new antibiotic would work in humans have not yet been conducted.
Finding one that works against MRSA would be a great success because more people are expected to die from infections with resistant bacteria than from cancer in 10 years' time, said Peschel.
So far, staph does not seem to be able to adapt to lugdunin. "For whatever reason it seems to be very, very difficult for Staphylococcus aureus to become resistant to lugdunin, which is interesting," Peschel said.
However, Kim Lewis and Philip Strandwitz, two scientists at Northeastern University in Boston who were not involved in the study, warned that lugdunin itself might not be a safe treatment because it appeared likely that the antibiotic could be harmful to human cells.
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But in a commentary published alongside the original paper, they said the approach taken by Peschel and his colleagues could lead to further antibiotics discoveries.
Peschel said he did not believe lugdunin was particularly toxic but noted that research is only just the beginning.
Even if the new antibiotic turns out not to be suitable it might be possible to adapt the bacterium or transfer key genes to innocuous germs that could then be used to fight MRSA.