|Staphylococcus aureus at work|
If you’ve ever spent some quality time with a staph infection, then you have some idea of the brute force of it. It’s an old, primitive killer of human beings, and new research is painting a picture of the bacteria's mechanism that somehow makes the whole thing all the more sinister. Researchers at Ecole Polytechnique Fédérale de Lausanne have meticulously deconstructed the nanoscale killing machine of the infamous Staphylococcus aureus, finding that the bacteria does its dirty work by unleashing volleys of tiny darts at its target, often a healthy cell somewhere in a human body. The dart tears open the cell’s membrane, killing it. The team’s paper, out in this week’s issue of Nature Chemical Biology delivers a crucial insight into a pathogen that’s increasingly becoming resistant to our antibiotics.
The bacteria’s mechanism of attack gets even a bit weirder. First off, it’s an entirely mechanical process—there’s nothing chemical about it, though we're talking about molecular scales here and such classifications get a bit more difficult. Basically, the aggressor sidles up to your healthy cell and attaches a package of proteins resembling a cowboy spur. In time, seven proteins arranged in a ring unfurl outwards, with each molecule presenting a deadly weapon. The trigger works like this: when in the presence of the target cell, a small organic molecule detaches from the pre-spur arrangement, which then shifts itself into the spikey shape that then pierces the bacterium’s prey.
Describing the staph machine with this kind of precision opens a doorway to new ways of preventing infections, particularly in hospitals. "We could imagine catheters coated with substitute peptides," co-author Gisou Van der Goot says. "They could prevent the formation of the ring and, thus, the spur. We would avoid many hospital infections." So, the trigger peptide would detach and there would be another one right there to take its place, thus avoiding the attack and, hopefully, overall infection.