Stopping bugs communicating can keep them apart.
Researchers have made a chemical that jams bacterial communication. The finding might help divide and rule troublesome bug collectives that can coat water pipes, medical equipment and body cavities.
The substance - a furanone - is derived from compounds that an Australian seaweed uses to stop its fronds being besieged by bacteria.
Some bacteria build microscopic cities, called biofilms. These mats of cells, punctuated by towers and channels, form on surfaces from rocks to teeth to catheters. Biofilm bacteria secrete a tough, slimy coat of sugar molecules that protects them from our immune system and antibiotics.
"Many persistent infections are caused by biofilm-forming bacteria," says Michael Givskov of the Technical University of Denmark, Lyngby. The main cause of death in cystic fibrosis is groups of the normally innocuous bacterium Pseudomonas aeruginosa clogging patients' lungs.
The furanone that Givskov and his colleagues synthesized blocks receptors on the surface of P. aeruginosa cells so that they cannot receive chemical messages from other bugs. Thus deafened, the bacteria struggle to build and maintain biofilms. This should make them more vulnerable to antibiotics and the immune system.
The furanone could clear P. aeruginosa blockages from water pipes, suggests Paul Williams, who studies bacterial communication at the University of Nottingham, UK. But he is less optimistic about medical applications, pointing out that many different bacteria, with different communication systems, cause biofilm infections.
The furanone's powers are relatively weak, and it has yet to be shown to work on an established biofilm, says microbiologist Barbara Iglewski of the University of Rochester, New York. "To say that this leads to therapy to disrupt biofilms is a pretty long shot," she comments.
Nevertheless, she says, the discovery is a promising first step. "It's a place to start to make something better," she says.
The chemical reduces the bacteria's nastiness without slowing their growth. So there is unlikely to be any evolutionary pressure for bugs to overcome the drugs, says Givskov. "We predict there'll be no resistance."
Preliminary results with a mouse model of cystic fibrosis are also promising
Thefirst applications of furanones might be to prevent biofilms forming, perhaps by coating surgical implants before use, Givskov suggests. The team grew bacteria on glass, a surface similar to that of an implant.
Preliminary results with a mouse model of cystic fibrosis are also promising. Furanones are too toxic for long-term treatment of the disease in humans, but the work illustrates the possibility of designing drugs to target bacterial communication, says Givskov.
Henzer, M. et al.Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound. Microbiology 148, 87 - 102 (2001).
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Whitfield, J. Seaweed inspires antibacterial. Nature (2002). https://doi.org/10.1038/news020107-12