title: Gene expression in Pseudomonas aeruginosa biofilms.
abstract: 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.
authors.affiliation: Department of Microbiology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
authors.forename: M
authors.initials: M
authors.lastname: Whiteley
authors.forename: M G
authors.initials: MG
authors.lastname: Bangera
authors.forename: R E
authors.initials: RE
authors.lastname: Bumgarner
authors.forename: M R
authors.initials: MR
authors.lastname: Parsek
authors.forename: G M
authors.initials: GM
authors.lastname: Teitzel
authors.forename: S
authors.initials: S
authors.lastname: Lory
authors.forename: E P
authors.initials: EP
authors.lastname: Greenberg
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms; D024881:Drug Resistance, Bacterial; D029968:Escherichia coli Proteins; D010861:Fimbriae, Bacterial / Q000235:genetics; D005407:Flagella / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D020411:Oligonucleotide Array Sequence Analysis; D010933:Plankton; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics* / Q000648:ultrastructure; D012808:Sigma Factor / Q000235:genetics; D014031:Tobramycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; C062093:tolA protein, E coli; D014031:Tobramycin