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 Dacanay, A. Articles by Reith, M. Search for Related Content PubMed PubMed Citation Articles by Dacanay, A. Articles by Reith, M. Agricola Articles by Dacanay, A. Articles by Reith, M.

Contribution of the type III secretion system (TTSS) to virulence of Aeromonas salmonicida subsp. salmonicida

National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada

Correspondence
A. Dacanay
andrew.dacanay{at}cnrc-nrc.gc.ca

The recently described type III secretion system (TTSS) of Aeromonas salmonicida subsp. salmonicida has been linked to virulence in salmonids. In this study, three TTSS effector genes, aexT, aopH or aopO, were inactivated by deletion, as was ascC, the gene encoding the outer-membrane pore of the secretion apparatus. Effects on virulence were assayed by live challenge of Atlantic salmon (Salmo salar). The ascC mutant strain was avirulent by both intraperitoneal (i.p.) injection and immersion, did not appear to establish a clinically inapparent infection and did not confer protection from subsequent rechallenge with the parental strain. ¹H NMR spectroscopy-based metabolite profiling of plasma from all fish showed significant differences in the metabolite profiles between the animals exposed to the parental strain or ascC. The experimental infection by immersion with aopO was indistinguishable from that of the parental strain, that of aexT was delayed, whilst the virulence of aopH was reduced significantly but not abolished. By i.p. injection, aexT, aopH and aopO caused an experimental disease indistinguishable from that of the parental strain. These data demonstrate that while the TTSS is absolutely essential for virulence of A. salmonicida subsp. salmonicida in Atlantic salmon, removal of individual effectors has little influence on virulence but has a significant effect on colonization. The ascC i.p. injection data also suggest that in addition to host invasion there is a second step in A. salmonicida pathogenesis that requires an active TTSS.

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]

				J. M. Boyd, A. Dacanay, L. C. Knickle, A. Touhami, L. L. Brown, M. H. Jericho, S. C. Johnson, and M. Reith Contribution of Type IV Pili to the Virulence of Aeromonas salmonicida subsp. salmonicida in Atlantic Salmon (Salmo salar L.) Infect. Immun., April 1, 2008; 76(4): 1445 - 1455. [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]