Via Nature News & Comment: The nose knows how to kill MRSA. Excerpt:
A new antibiotic was right under our noses — or rather, in them. Produced by a bacterium living in the human nose, the molecule kills the potentially deadly methicillin-resistant Staphylococcus aureus (MRSA) in mice and rats.
Staphylococcus aureus resides in the noses of 1 in 3 people without causing a problem. MRSA — an S. aureus strain resistant to many antibiotics — is found in 2 in 100. In a small percentage of cases, the bacterium escapes to the bloodstream, causing infection. MRSA kills 11,000 people annually in the United States alone.
The potential new soldier in the fight against MRSA is a molecule called lugdunin produced by the bacterium Staphylococcus lugdunensis, report Andreas Peschel and colleagues at the University of Tübingen, Germany, on 27 July in Nature.
In a sampling of 187 hospital patients, people whose noses naturally contained S. lugdunensis were six times less likely to have S. aureus than people whose noses lacked S. lugdunensis, Peschel's team found. This suggests that S. lugdunensis is able to combat the growth of the problematic bacterium. That means the antibiotic produced by the bacterium could be developed as a preventive — a nasal spray, for example — to keep S. aureus out of people’s noses in the first place. About 9% of people naturally carry S. lugdunensis.
A new hope
The vast majority of antibiotics are small molecules that attack bacterial enzymes, the proteins that orchestrate chemical reactions inside the cell. The researchers found that lugdunin is unusual in that it’s much larger, with a mode of action involving the cellular membrane that isn’t fully understood. That novel modus operandi could be the reason why bacterial strains of S. aureus were unable to evolve resistance to the antibiotic in a 30-day test tube trial. “We never found spontaneous mutants,” says Peschel.
John Powers, an infectious disease clinician at George Washington University in Washington DC, is hopeful that lugdunin might eventually become a useful antiobitic for human use. But he would like to see how the antibiotic works in humans, as the test tube trials Peschel's team conducted cannot predict whether antibiotic resistance will develop in people.