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 Giraud, E. Articles by Donnay-Moreno, C. Search for Related Content PubMed PubMed Citation Articles by Giraud, E. Articles by Donnay-Moreno, C. Agricola Articles by Giraud, E. Articles by Donnay-Moreno, C.

Mechanisms of quinolone resistance and clonal relationship among Aeromonas salmonicida strains isolated from reared fish with furunculosis

¹Unité Mixte de Recherche INRA-ENVN Chimiothérapie Aquacole et Environnement, Ecole Nationale Vétérinaire, Atlanpôle, La Chantrerie, BP40706, 44307 Nantes, Cedex 03, France ²Unité de Biodiversité des Bactéries Pathogènes Emergentes, INSERM U 389, Institut Pasteur, 75724 Paris Cedex 15, France

Correspondence Etienne Giraud giraud{at}vet-nantes.fr

Received January 6, 2004
Accepted May 17, 2004

The mechanisms of resistance to quinolone and epidemiological relationships among A. salmonicida strains isolated from diseased fish in French marine farms from 1998 to 2000 were investigated. The quinolone resistance-determining regions of the gyrA and parC genes of 12 clinical A. salmonicida isolates with different levels of quinolone susceptibility were sequenced. MICs were determined in the presence of the efflux pump inhibitor (EPI) Phe-Arg ß-naphthylamide and E_max values (MIC without EPI/MIC in the presence of EPI) were calculated. Isolates fell into two classes: (i) those that had a wild-type gyrA gene with oxolinic acid MIC 0.5, flumequine MIC 1 and ciprofloxacin MIC 0.25 µg ml^–1; and (ii) those that had a single mutation in gyrA encoding Asp-87 Asn with oxolinic acid MIC 2, flumequine MIC 4 and ciprofloxacin MIC 0.125 µg ml^–1. No mutations were found in parC. High E_max values obtained for flumequine and oxolinic acid (up to 16 and 8, respectively, for the most resistant isolates of the two classes) indicated an important contribution of efflux to the resistance phenotype. Flumequine accumulation experiments confirmed that high E_max values were associated with a much lower level of accumulation. PCR/RFLP assays conducted on 34 additional isolates showed the presence of a mutation at codon 87 of gyrA in nearly all the quinolone-resistant isolates. This finding, together with PFGE typing results, strongly suggests a common clonal origin of these quinolone-resistant isolates.

The GenBank accession number for the partial sequence of the parC gene of A. salmonicida ATCC 14174 is AF473701.

This article has been cited by other articles:

				M. Hernould, S. Gagne, M. Fournier, C. Quentin, and C. Arpin Role of the AheABC Efflux Pump in Aeromonas hydrophila Intrinsic Multidrug Resistance Antimicrob. Agents Chemother., April 1, 2008; 52(4): 1559 - 1563. [Abstract] [Full Text] [PDF]

				D. J. Colquhoun, L. Aarflot, and C. F. Melvold gyrA and parC Mutations and Associated Quinolone Resistance in Vibrio anguillarum Serotype O2b Strains Isolated from Farmed Atlantic Cod (Gadus morhua) in Norway Antimicrob. Agents Chemother., July 1, 2007; 51(7): 2597 - 2599. [Abstract] [Full Text] [PDF]

				K. Poole Efflux-mediated antimicrobial resistance J. Antimicrob. Chemother., July 1, 2005; 56(1): 20 - 51. [Abstract] [Full Text] [PDF]