Characterization of Vibrio strains isolated from turbot (Scophthalmus maximus) culture by phenotypic analysis, ribotyping and 16S rRNA gene sequence comparison.

Abstract

The aim of the present study was to clarify the taxonomic status of Vibrio strains isolated from an aquaculture system and to compare the results of the identifications made by phenotypic and molecular methods. Fifty-one Vibrio strains isolated from a turbot (Scophthalmus maximus) aquaculture system were characterized by ribotyping and 16S rRNA gene sequencing. The strains had been identified phenotypically in a previous numerical taxonomy analysis as Vibrio anguillarum, V. mediterranei, V. splendidus, V. aestuarianus, V. ordalii, V. fischeri and V. scophthalmi. Cluster analysis of ribotype patterns showed that the strains were separated into two main groups: V. splendidus-V. lentus and V. scophthalmi groups. The use of 16S rRNA gene sequence allowed differentiation among V. splendidus biovar I and V. lentus strains. The molecular methods identified strains of V. splendidus biovar I, V. lentus and V. scophthalmi, showing discrepancies with phenotypic characterization. The molecular methods, as 16S rRNA gene sequence analysis, are necessary for the identification of phenotypically close species to avoid mis-identifications. Interestingly, this is the first report of V. lentus strains associated to turbot culture.