Transcriptome analysis of quorum-sensing regulation and virulence factor expression in Pseudomonas aeruginosa

The opportunistic pathogen Pseudomonas aeruginosa possesses two well-studied quorum-sensing (QS) systems (las and rhl) that are important in the production of virulence factors, antibiotic sensitivity, and biofilm development. High-density oligonucleotide microarrays were used to further characterize the las QS system and to investigate the effect of environment (planktonic or biofilm mode of growth, absence or presence of oxygen) and nutritional conditions on detection of transcripts encoding QS-regulated virulence factors. Transcriptome results indicate that the QS system is far more complex than previously proposed. Interestingly, we found that many QS-regulated genes encoding virulence products were expressed in all conditions investigated. (C) 2004 Elsevier Ltd. All rights reserved.