Classification of fish-pathogenic vibrios based on comparative 16S rRNA analysis

• Main Authors: Ragnhild Wiik, Erko Stackebrandt, Olav Valle, Frida Lise Daae, Odd Magne, Rddseth, Kari Andersen
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1995
• Subjects: Atlantic salmon; Turbot
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.322.5807; http://ijs.sgmjournals.org/content/45/3/421.full.pdf

No systematic classification of fish-pathogenic vibrios has been accomplished previously despite the use of serological, physiological, and genetical classification systems. In this study, a comparative 16s rRNA analysis of 34 strains (representing seven species) of fish-pathogenic vibrios was performed. The 16s rRNA sequences were obtained by using reverse transcriptase. Nearly complete sequences were obtained for nine strains. On the basis of the results of this analysis, the remaining strains were investigated by analyzing selected stretches containing a total of 560 nucleotides. With the exception of a few strains, including ATCC 43313 (serovar 09), our comparative 16s rRNA analysis confirmed that strains preliminarily identified as Vibrio anguillamm were phylogenetically closely related. Strains of V. anguiUamm could be divided into groups, with the main group containing serotype 01 and 02 strains isolated from Atlantic salmon, rainbow trout, turbot, cod, and saithe. The other distinctive group was represented by type strain NCMB 6. This strain was nearly indistinguishable from the type strains of Vibrio ordalii and Vibrio damsela on the basis of the 16s rRNA stretches compared. The results of a comparative 16s rRNA analysis justified the status of Vibrio sulmonicidu as a distinct species. Originally, this species was characterized biochemically as a very homogeneous species. However, two strains, which were isolated from diseased halibut and from the intestines of healthy cod, could not be distinguished from V. sulmonicida strains phylogenetically, although they differed from the original species description in