Subinhibitory concentrations of the cationic antimicrobial peptide colistin induce the pseudomonas quinolone signal in Pseudomonas aeruginosa

• Published in: Microbiology (Society for General Microbiology) Vol. 155; no. 9; pp. 2826 - 2837
• Main Authors: Cummins, Joanne, Reen, F. Jerry, Baysse, Christine, Mooij, Marlies J, O'Gara, Fergal
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.09.2009; Society for General Microbiology
• Subjects: Anti-Bacterial Agents - administration & dosage; Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; Colistin - administration & dosage; DNA, Bacterial - genetics; DNA, Bacterial - metabolism; Dose-Response Relationship, Drug; Gene Expression Profiling; Gene Expression Regulation, Bacterial - drug effects; Genes, Bacterial; Humans; Hydroxyquinolines - metabolism; Medical sciences; Oligonucleotide Array Sequence Analysis; Pharmacology. Drug treatments; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - genetics; Pseudomonas aeruginosa - metabolism; Pseudomonas Infections - drug therapy; Pseudomonas Infections - metabolism; Pyocyanine - biosynthesis; Quinolones - metabolism; Quorum Sensing; Transcriptional Activation; Pseudomonadales; Colistin; Cyclic peptides; Concentration; Gene expression; Biological activity; Antimicrobial agent; Antibiotic; Polypeptide; Bacteria; Pseudomonadaceae; Pseudomonas aeruginosa; Antibacterial agent
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.025643-0

BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland Colistin is an important cationic antimicrobial peptide (CAMP) in the fight against Pseudomonas aeruginosa infection in cystic fibrosis (CF) lungs. The effects of subinhibitory concentrations of colistin on gene expression in P. aeruginosa were investigated by transcriptome and functional genomic approaches. Analysis revealed altered expression of 30 genes representing a variety of pathways associated with virulence and bacterial colonization in chronic infection. These included response to osmotic stress, motility, and biofilm formation, as well as genes associated with LPS modification and quorum sensing (QS). Most striking was the upregulation of Pseudomonas quinolone signal (PQS) biosynthesis genes, including pqsH , pqsB and pqsE , and the phenazine biosynthesis operon. Induction of this central component of the QS network following exposure to subinhibitory concentrations of colistin may represent a switch to a more robust population, with increased fitness in the competitive environment of the CF lung. Correspondence Fergal O'Gara f.ogara{at}ucc.ie Abbreviations: AHQ, 2-alkyl-4-quinolone; CF, cystic fibrosis; MDR, multi-drug resistant; PQS, Pseudomonas quinolone signal; qRT-PCR, quantitative real-time RT-PCR; QS, quorum sensing; RMA, robust multiarray average The microarray data discussed in this study have been deposited in the NCBI Gene Expression Omnibus and are accessible through GEO Series accession number GSE13252 . Three supplementary tables, listing primers used in this study, genes showing significantly altered expression in the colistin-treated sample, and motility in the presence of colistin, are available with the online version of this paper.