This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Gooderham, W. J.
Right arrow Articles by Hancock, R. E. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gooderham, W. J.
Right arrow Articles by Hancock, R. E. W.

 Previous Article  |  Next Article 

Journal of Bacteriology, August 2008, p. 5624-5634, Vol. 190, No. 16
0021-9193/08/$08.00+0     doi:10.1128/JB.00594-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Induction by Cationic Antimicrobial Peptides and Involvement in Intrinsic Polymyxin and Antimicrobial Peptide Resistance, Biofilm Formation, and Swarming Motility of PsrA in Pseudomonas aeruginosa{triangledown} ,{dagger}

W. James Gooderham, Manjeet Bains, Joseph B. McPhee, Irith Wiegand, and Robert E. W. Hancock*

Center for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada

Received 29 April 2008/ Accepted 5 June 2008

Pseudomonas aeruginosa is an important opportunistic pathogen that causes infections that can be extremely difficult to treat due to its high intrinsic antibiotic resistance and broad repertoire of virulence factors, both of which are highly regulated. It is demonstrated here that the psrA gene, encoding a transcriptional regulator, was upregulated in response to subinhibitory concentrations of cationic antimicrobial peptides. Compared to the wild type and the complemented mutant, a P. aeruginosa PAO1 psrA::Tn5 mutant displayed intrinsic supersusceptibility to polymyxin B, a last-resort antimicrobial used against multidrug-resistant infections, and the bovine neutrophil antimicrobial peptide indolicidin; this supersusceptibility phenotype correlated with increased outer membrane permeabilization by these agents. The psrA mutant was also defective in simple biofilm formation, rapid attachment, and swarming motility, all of which could be complemented by the cloned psrA gene. The role of PsrA in global gene regulation was studied by comparing the psrA mutant to the wild type by microarray analysis, demonstrating that 178 genes were up- or downregulated ≥2-fold (P ≤ 0.05). Dysregulated genes included those encoding certain known PsrA targets, those encoding the type III secretion apparatus and effectors, adhesion and motility genes, and a variety of metabolic, energy metabolism, and outer membrane permeability genes. This suggests that PsrA might be a key regulator of antimicrobial peptide resistance and virulence.

* Corresponding author. Mailing address: Center for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, 232-2259 Lower Mall Research Station, Vancouver, BC, Canada V6T 1Z4. Phone: (604) 822-2682. Fax: (604) 827-5566. E-mail: bob{at}cmdr.ubc.ca

{triangledown} Published ahead of print on 13 June 2008.

{dagger} Supplemental material for this article may be found at http://jb.asm.org/.

Journal of Bacteriology, August 2008, p. 5624-5634, Vol. 190, No. 16
0021-9193/08/$08.00+0     doi:10.1128/JB.00594-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»