Scientists Crack Chemical Code that Controls Bacterial Swarms

By Clay Dillow Posted 06.22.2010 at 1:55 pm 5 Comments

Bacterial Swarm The visible concentric circles show evidence of bacteria swarm as the colony starts and stops its forward progress. Universitat Autònoma de Barcelona

Spanish researchers have discovered a key component of infectious bacteria's battle plan, identifying a protein that tells bacteria in a colony to halt their forward march when antibiotics are present, waiting until the coast is clear before resuming the infection. The finding shows how bacteria outmaneuver antibiotics in the body to continue infecting an organ even after treatment, but it also pinpoints a vulnerability that researchers may be able to exploit to make antibiotics more effective.

When infecting tissue in the body, bacteria swarm collectively across the surface like an 18th-century army on the march, growing into a massive colony that produces toxins that cause damage to the tissue. The mechanism by which bacteria organize this mass movement has remained a mystery to researchers, but now scientists at the Universitat Autònoma de Barcelona (UAB) have identified the chemical courier that makes this possible.

A protein called CheW is essential for swarming, catalyzing the mass movement of bacteria across the surface of an organ. But when bacteria encounter antibiotics, the drugs initiate a DNA repair system in bacteria known as SOS response, which is supposed to stop the infection. But the Spanish researchers found that when SOS response kicks in, levels of another protein known as RecA begin to increase. RecA interferes with CheW, causing the colony to stop moving forward. As a result, only the front line of the colony is affected by the antibiotics; the rest of the colony stops marching until the concentration of antibiotics decreases, at which point RecA concentrations fall and the colony starts attacking again.

It's a clever play by the bacteria, but it could open up new treatment options to deal with bacterial infections. If antibiotics could be augmented with something that stops RecA from halting the forward progress of the swarm, current drugs could become more effective in neutralizing infections.

[American Society For Microbiology]

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5 Comments

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Petudy

06/22/10 at 5:09 pm

Interesting but, what is the goal? Are scientist's trying to eradicate every form of disease, virus, bacterial infection? That is extremely short-sighted...

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JohnnyH

06/22/10 at 7:24 pm

The point is that the more we know about how something works the better. They aren't trying to eradicate all bacteria, but perhaps this will lead to new ways to deal with bacterial infections.

And I find it cool to learn the mechanisms involved in how bacteria communicate across a colony.

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rpenri

06/22/10 at 10:31 pm

@ Petudy

Seriously? The goal is to protect human life, maybe even yours one day.

Your comment makes as much sense as someone saying: What's the point of modern medicine? To kill every disease out there?

Infections used to be the number one killer of soldiers in warfare until antibiotics were discovered.

Well, since then, antibiotics have saved millions and millions of people...but overuse has led to some "superbugs" that are resistant to most forms of treatment.

With this new information, we change the dynamic in which we attack the bacteria...instead of a frontal assault which causes the bacteria to dig in and wait out the bombing, this new information can be used to subvert their normal defensive measures and wipe them clear from a patient's body.

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phildo

06/23/10 at 8:24 am

you idiots. He was joking when he said that was short sighted.

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lilpete_45

02/12/12 at 10:17 pm

i like this article, but now is "What's next?" What are scientists going to do know? It's been two years now, have they done anything? I'd defenately like to know.

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