Pseudomonas aeruginosa detachment from surfaces via a self-made small molecule

J Biol Chem. 2021 Jan-Jun:296:100279. doi: 10.1016/j.jbc.2021.100279. Epub 2021 Jan 12.


Pseudomonas aeruginosa is a significant threat in both healthcare and industrial biofouling. Surface attachment of P. aeruginosa is particularly problematic as surface association induces virulence and is necessary for the ensuing process of biofilm formation, which hampers antibiotic treatments. Previous efforts have searched for dispersal agents of mature biofilm collectives, but there are no known factors that specifically disperse individual surface-attached P. aeruginosa. In this study, we develop a quantitative single-cell surface-dispersal assay and use it to show that P. aeruginosa itself produces factors that can stimulate its dispersal. Through bioactivity-guided fractionation, mass spectrometry, and nuclear magnetic resonance, we elucidated the structure of one such factor, 2-methyl-4-hydroxyquinoline (MHQ). MHQ is an alkyl quinolone with a previously unknown activity and is synthesized by the PqsABC enzymes. Pure MHQ is sufficient to disperse P. aeruginosa, but the dispersal activity of natural P. aeruginosa conditioned media requires additional factors. Whereas other alkyl quinolones have been shown to act as antibiotics or membrane depolarizers, MHQ lacks these activities and known antibiotics do not induce dispersal. In contrast, we show that MHQ inhibits the activity of Type IV Pili (TFP) and that TFP targeting can explain its dispersal activity. Our work thus identifies single-cell surface dispersal as a new activity of P. aeruginosa-produced small molecules, characterizes MHQ as a promising dispersal agent, and establishes TFP inhibition as a viable mechanism for P. aeruginosa dispersal.

Keywords: Pseudomonas aeruginosa; bacterial adhesion; bioactivity-guided fractionation; microbiology; natural product; surface detachment; type IV pili.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aniline Compounds / chemistry
  • Biofilms / drug effects*
  • Fimbriae, Bacterial / drug effects
  • Fimbriae, Bacterial / genetics
  • Gene Expression Regulation, Bacterial
  • Humans
  • Hydroxyquinolines / pharmacology*
  • Pseudomonas Infections / drug therapy*
  • Pseudomonas Infections / microbiology
  • Pseudomonas Infections / pathology
  • Pseudomonas aeruginosa / genetics*
  • Pseudomonas aeruginosa / pathogenicity
  • Quinolones / pharmacology
  • Single-Cell Analysis
  • Virulence / drug effects


  • Aniline Compounds
  • Hydroxyquinolines
  • Quinolones
  • 2-methyl-4-methoxyaniline
  • 2-hydroxyquinoline