The vast majority of chronic bacterial infections involve the formation of biofilms. On their own, individual bacteria tend not to represent much of a threat when met with the average human’s immune arsenal. 

However, some types of bacteria have developed a particularly effective defensive strategy.  By grouping together into slimy aggregate colonies, otherwise known as biofilms, bacteria can make themselves virtually impervious to destruction through conventional means. Once a biofilm forms, an infection may become chronic, or even fatal.

Luckily for us, researchers at the University of Washington, Seattle have developed a new method to turn bacteria’s best defensive strategy against them.
Credit: ACS Sustainable Chem. Eng.

In order to form a biofilm, bacteria secrete polysaccerides and proteins which in turn form an extracellular matrix. As a consequence, their external environment becomes unusually saturated with dissolved salts and sugar, resulting in increased osmotic pressure on the cells. In order to compensate, bacteria fill their internal cytoplasm with small molecules called, unsurprisingly, osmoprotectants.

Researchers have focused their attention on these osmoprotectants. By synthesizing artificial analogs in the lab, they have been able to investigate various compounds that might interfere with their effectiveness. Ethylcoline appeared to be the most promising. It reduced biomass by 70%, and was the only compound tested that produced substantial effects without inhibiting bacterial growth.

Strange as it may seem, the fact that this approach doesn’t directly kill the bacteria is actually what makes it so appealing. By leaving the cells alive, selective pressure is minimized, making it incredibly difficult for the bacteria to adapt. 


Madhusoodanan, J. (2014). Simple Molecules Block Bacterial Biofilms | Chemical & Engineering News. [online] Available at: [Accessed 15 Oct. 2014].