Fighting biofilms by messing with the language of bacteria
If you've ever had a vase of flowers develop a stinky slimy film inside, then you're familiar with biofilms. While these organized gangs of bacteria are unpleasant in such a situation, in medical setting like hospitals, they can be downright dangerous. Biofilms are notoriously difficult to dispatch (think about how hard it is to clean that vase), so researchers at Germany's Kiel University, in cooperation with colleagues at the Hamburg University of Technology, figured it might be best to stop them from growing in the first place. They focussed their attention on the communication mechanism inside the colony.
Specifically, the researchers looked at the way in which bacteria communicate with each other to organize themselves into a biofilm. The organisms send out the call to have other bacteria join their community through signal molecules called autoinducers in a process known as quorum sensing (QS). If those signal molecules could be blocked, the researchers reasoned, then the biofilm wouldn't be able to form. It's akin to keeping people from forming a mob in the dark by not letting them shout out their location.
The proteins that can shut down quorum sensing are known as quorum quenching (QQ) proteins and, to learn more about them, the researchers turned to the natural world, taking samples from sources including seawater, glaciers and jellyfish. What they found was that there's a large number of QQ proteins in marine environments – more than what they found on land.
"As the oldest ecosystem, the marine system – including the oceans, water or algae – is incredibly rich in new, undiscovered substances," said said Ruth Schmitz-Streit, a professor from the Institute of General Microbiology at Kiel University." It offers a huge potential regarding biological activities and QQ mechanisms."
In particular, the researchers identified a QQ protein known as QQ-2 as an especially effective communication disruptor.
"This protein is very robust and can prevent many different types of biofilms," said Kiel's Nancy Weiland-Bräuer.
Whereas previous research had found QQs to quelch very specific bacterial communication molecules, QQ-2 was found to be more of a generalist. "The QQ-2 protein is orientated towards a 'universal language,' and can disrupt the communication of different bacteria," added Weiland-Bräuer. "This makes it a 'general troublemaker.'"
The researchers hope that their work can lead to the development of biofilm-busting techniques that can help keep medical facilities clear of disease-causing slime.
Their work has been published in the journal Frontiers in Microbiology.
Source: Kiel University