HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Burr, S. E. Articles by Frey, J. Search for Related Content PubMed PubMed Citation Articles by Burr, S. E. Articles by Frey, J. Agricola Articles by Burr, S. E. Articles by Frey, J.

Attenuated virulence of an Aeromonas salmonicida subsp. salmonicida type III secretion mutant in a rainbow trout model

¹ Institute of Veterinary Bacteriology, University of Berne, Länggass-Strasse 122, Postfach, CH-3001 Berne, Switzerland
² Centre for Fish and Wildlife Health, Institute of Animal Pathology, University of Berne, Länggass-Strasse 122, Postfach, CH-3001 Berne, Switzerland

Correspondence
Joachim Frey
joachim.frey{at}vbi.unibe.ch

Aeromonas salmonicida subsp. salmonicida is the causative agent of furunculosis, a severe systemic disease affecting salmonid fish. This bacterium contains a type III protein secretion system that is responsible for the secretion and translocation of the ADP-ribosylating toxin, AexT, into the cytosol of fish cells. This study showed that inactivation of the type III secretion system by marker-replacement mutagenesis of the gene ascV, which encodes an inner-membrane component of the type III secretion system, attenuated virulence in a rainbow trout model. The isogenic ascV deletion mutant was phagocytosed by peripheral blood leukocytes but the wild-type (wt) A. salmonicida subsp. salmonicida isolate was not. Histological examination of fish experimentally infected with the wt bacterium revealed extensive tissue necrosis and bacterial aggregates in all organs examined, including the heart, kidney and liver, indicating that the isolate established a systemic infection. Cumulative mortality of fish experimentally infected with the wt bacterium reached 88 %. In contrast, no mortality was observed among fish infected with the same dose of the ascV mutant, and histological examination of fish infected with this strain revealed healthy organs. The results indicate that the type III secretion system of A. salmonicida subsp. salmonicida is required to establish systemic infection.

The GenBank/EMBL/DDBJ accession number for the nucleotide sequence of the complete A. salmonicida subsp. salmonicida type III secretion locus in strain JF2267 is AJ616218.

This article has been cited by other articles:

				M. Najimi, M. L. Lemos, and C. R. Osorio Identification of Siderophore Biosynthesis Genes Essential for Growth of Aeromonas salmonicida under Iron Limitation Conditions Appl. Envir. Microbiol., April 15, 2008; 74(8): 2341 - 2348. [Abstract] [Full Text] [PDF]

				D. Fehr, S. E. Burr, M. Gibert, J. d'Alayer, J. Frey, and M. R. Popoff Aeromonas Exoenzyme T of Aeromonas salmonicida Is a Bifunctional Protein That Targets the Host Cytoskeleton J. Biol. Chem., September 28, 2007; 282(39): 28843 - 28852. [Abstract] [Full Text] [PDF]

				R. Froquet, N. Cherix, S. E. Burr, J. Frey, S. Vilches, J. M. Tomas, and P. Cosson Alternative Host Model To Evaluate Aeromonas Virulence Appl. Envir. Microbiol., September 1, 2007; 73(17): 5657 - 5659. [Abstract] [Full Text] [PDF]

				D. Fehr, C. Casanova, A. Liverman, H. Blazkova, K. Orth, D. Dobbelaere, J. Frey, and S. E. Burr AopP, a type III effector protein of Aeromonas salmonicida, inhibits the NF-{kappa}B signalling pathway. Microbiology, September 1, 2006; 152(Pt 9): 2809 - 2818. [Abstract] [Full Text] [PDF]

				A. Dacanay, L. Knickle, K. S. Solanky, J. M. Boyd, J. A. Walter, L. L. Brown, S. C. Johnson, and M. Reith Contribution of the type III secretion system (TTSS) to virulence of Aeromonas salmonicida subsp. salmonicida Microbiology, June 1, 2006; 152(6): 1847 - 1856. [Abstract] [Full Text] [PDF]