Gene expression in Pseudomonas aeruginosa biofilms

Nature. 2001 Oct 25;413(6858):860-4. doi: 10.1038/35101627.


Bacteria often adopt a sessile biofilm lifestyle that is resistant to antimicrobial treatment. Opportunistic pathogenic bacteria like Pseudomonas aeruginosa can develop persistent infections. To gain insights into the differences between free-living P. aeruginosa cells and those in biofilms, and into the mechanisms underlying the resistance of biofilms to antibiotics, we used DNA microarrays. Here we show that, despite the striking differences in lifestyles, only about 1% of genes showed differential expression in the two growth modes; about 0.5% of genes were activated and about 0.5% were repressed in biofilms. Some of the regulated genes are known to affect antibiotic sensitivity of free-living P. aeruginosa. Exposure of biofilms to high levels of the antibiotic tobramycin caused differential expression of 20 genes. We propose that this response is critical for the development of biofilm resistance to tobramycin. Our results show that gene expression in biofilm cells is similar to that in free-living cells but there are a small number of significant differences. Our identification of biofilm-regulated genes points to mechanisms of biofilm resistance to antibiotics.

Publication types

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

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / genetics
  • Biofilms*
  • Drug Resistance, Bacterial
  • Escherichia coli Proteins*
  • Fimbriae, Bacterial / genetics
  • Flagella / genetics
  • Gene Expression Regulation, Bacterial* / drug effects
  • Oligonucleotide Array Sequence Analysis
  • Plankton
  • Pseudomonas aeruginosa / drug effects
  • Pseudomonas aeruginosa / genetics*
  • Pseudomonas aeruginosa / ultrastructure
  • Sigma Factor / genetics
  • Tobramycin / pharmacology


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Sigma Factor
  • sigma factor KatF protein, Bacteria
  • tolA protein, E coli
  • Tobramycin