Rhamnolipids mediate detachment of Pseudomonas aeruginosa from biofilms

Mol Microbiol. 2005 Sep;57(5):1210-23. doi: 10.1111/j.1365-2958.2005.04743.x.


The process of detachment, through which bacteria use active mechanisms to leave biofilms and return to the planktonic (free-living) state, is perhaps the least understood aspect of the biofilm life cycle. Like other stages of biofilm development, detachment is a dynamic, regulated process, controlled by specific genes, and induced by particular environmental cues. In previous work we discovered Pseudomonas aeruginosa variants that exhibit accelerated biofilm detachment. These hyper-detaching variants arise spontaneously from biofilms at a high frequency, and they exhibit robust detachment under different biofilm growth conditions. Here we show that these variants detach by a mechanism requiring the biosurfactant rhamnolipid and that this detachment mechanism rapidly restores antibiotic sensitivity to separating bacteria. We also show that rhamnolipids can bring about detachment in wild-type P. aeruginosa biofilms. These findings raise the possibility that this detachment mechanism may be useful as a treatment to disrupt established biofilms. Interestingly, the rhamnolipid-mediated detachment mechanism involves the formation of cavities within the centre of biofilm structures. Our data suggest a model to explain detachment that occurs via this pattern.

MeSH terms

  • Bacterial Adhesion
  • Biofilms / growth & development*
  • Glycolipids / genetics
  • Glycolipids / metabolism*
  • Phenotype
  • Pseudomonas aeruginosa / cytology
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / physiology*


  • Glycolipids
  • rhamnolipid