It is well established that in nature, bacteria are found primarily as residents of surface-associated communities called biofilms. These structures form in a sequential process initiated by attachment of cells to a surface, followed by the formation of matrix-enmeshed microcolonies, and culminating in dispersion of the bacteria from the mature biofilm. In the present study, we have demonstrated that, during growth, Pseudomonas aeruginosa produces an organic compound we have identified as cis-2-decenoic acid, which is capable of inducing the dispersion of established biofilms and of inhibiting biofilm development. When added exogenously to P. aeruginosa PAO1 biofilms at a native concentration of 2.5 nM, cis-2-decenoic acid was shown to induce the dispersion of biofilm microcolonies. This molecule was also shown to induce dispersion of biofilms, formed by Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Streptococcus pyogenes, Bacillus subtilis, Staphylococcus aureus, and the yeast Candida albicans. Active at nanomolar concentrations, cis-2-decenoic acid appears to be functionally and structurally related to the class of short-chain fatty acid signaling molecules such as diffusible signal factor, which act as cell-to-cell communication molecules in bacteria and fungi.
