Wed. Mar 22nd, 2023
Bacteria fighting over boogers in your nose can have life-saving antibiotics

I’m sorry, kids. You may try your best to stick your finger in your nose and dig tirelessly. But it seems scientists are the ones who found gold.

By sifting through the bacteria that inhabit our cavernous snouts, researchers came up with one that produces a new antibiotic — one unlike any other bacteria-destroying drug known to modern medicine. That prized chemical nugget can be deadly Staphylococcus aureus strains, including the dastardly methicillin-resistant strain called MRSA, plus other drug-resistant foes. While it’s still unclear exactly how the new drug kills nasal rivals, scientists hope the compound will prove useful in treating deadly MRSA infections and even clearing S aureus out of the nose before it has a chance to cause an infection.

“No one has found anything like this before,” Bernhard Krismer, a bacteriologist at the University of Tübingen in Germany and a lead scientist for the study, said in a news conference. The drug, along with its bacterial maker, has “a huge impact on the composition of the microbiota,” Krismer added. The full results of the nose excavation appear in the July 28 issue of Nature.

Krismer and colleagues began a search for new antibiotics in the nose, based on the simple fact that those booger-crusted cavities are barren landscapes for germs. Any wannabe nasal colonizer who blows periodically in Schnozville has to fight quite a bit for scarce resources. And some of the best weapons bacteria have to fight each other are antibiotics. So the researchers filtered through all the staphylococci known to take up residence in the human nose, and grew them all in the presence of S aureus. Then they noticed S. lugdunensisthose obvious outward elbows S aureus when they shared a petri dish full of food.

S. lugdunensis seemed to make something pushing back S aureus. TTo find out what it was, the researchers made a stack of mutated versions of it S.lugdunensis, each with a different segment of its DNA broken. The researchers hoped to be able to independently break down each part of the bacteria’s genome to find the stretch responsible for the S. aureuschemical slaughter. They examined all the mutants and found one that could no longer fight S aureus, which led them to a group of broken genes that looked a bit like an antibiotic coding cluster. With a little genetic engineering, the researchers created one S. lugdunensis strain that mass-produced what that group of genes also had the blueprints for — an antibiotic they then isolated and named lugdunin, it turned out.

Lugdunin has a chemical structure different from other antibiotic researchers, an unusual cyclic peptide containing five amino acids. But as weird as it looked, the chemical did great in lab tests in killing S aureus and other drug-resistant human pathogens, including Enterococci isolates resistant to a last resort antibiotic called vancomycin.

On the injured backs of shaved mice, a smear of lugdunin might ward off S aureus, which caused no infection – except in two mice that apparently licked all their lugdunin. When the researchers ask S. lugdunensis And S aureus together in the noses of rats, S. lugdunensis won.

Those results mirrored what researchers found when they peered into the dark holes of the noses of 187 hospital patients. Although less than 10 percent of patients had S. lugdunensis in their nose, the speed of S aureus colonization in those patients was 5.9 times lower than in patients who did not S. lugdunensis in their nose.

Based on the results, the researchers are optimistic that not only can lugdunin be used to treat MRSA and other infections, but that S. lugdunensis can be used as a probiotic. If people purposefully put the drug-guzzling bug up their noses, they could keep it S aureus never get your foot in the door. This can be very helpful since about 30 percent of the population naturally carry around S aureus in their nose. While S aureus only causes infections when the opportunity arises, wearing it definitely increases the chance of a person getting an infection.

Scientists say the study also suggests that our microbiomes — the microbes our bodies share with us — may be an untapped source of new antibiotics. Or, in more drug development terms, they “could serve as leads for drug discovery,” according to Northeastern University microbiologists and antibiotic researchers Kim Lewis and Philip Strandwitz, who were not involved in the study. Such new antibiotics are desperately needed to combat the rising number of highly resistant bacteria.

Nature2016. DOI: 10.1038/nature18634 (About DOIs).

By akfire1

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