Phenotypic and Genotypic Studies of Pseudomonas anguilliseptica Strains Isolated from Farmed European Eels (Anguilla anguilla) in France

Abstract

Several bacterial strains were isolated in France from diseased European eels (Anguilla anguilla) reared in freshwater. The resemblance of these isolates to the known eel pathogen Pseudomonas anguilliseptica led to the comparative study of two of them with the type strain NCIMB 1949^T and with four reference strains from different geographical origins. Morphological, physiological and biochemical characteristics of the seven strains proved to be very similar. DNA base composition was in the same range (60 to 62 mol % G+C) for the four strains tested. Comparison of the DNA by the S1 nuclease DNA-DNA hybridization method showed that the seven strains formed a tight genomic species with DNA relatedness above 85 %. This is the first identification of this fish pathogen in France. As its pathogenicity for salmonids has been demonstrated in Finland, this bacterium may prove a potential hazard, not only for the small eel farming industry in France, but also for the trout and salmon farming which is of much greater economical significance in this country.