DAO 39:109-119 (2000)  -  doi:10.3354/dao039109

Genetic diversity of the fish pathogen Aeromonas salmonicida demonstrated by random amplified polymorphic DNA and pulsed-field gel electrophoresis analyses

Bronagh O¹hIci1, Gilles Olivier2, Richard Powell1,*

1Department of Microbiology, National University of Ireland, Galway, Ireland
2Department of Fisheries and Oceans, Gulf Fisheries Centre, PO Box 5030, Moncton, New Brunswick E1C 9K1, Canada
*Corresponding author. E-mail:

ABSTRACT: The current taxonomy of Aeromonas salmonicida includes 4 subspecies. A. salmonicida subsp. salmonicida is associated with salmonid furunculosis, and A. salmonicida subsp. achromogenes, A. salmonicida subsp. masoucida, and A. salmonicida subsp. smithia are strains that show variation in some biochemical properties. This classification does not readily encompass isolates from a wide range of fish hosts currently described as atypical A. salmonicida. This study examined 17 typical strains, 39 atypical strains and 3 type A. salmonicida subspecies strains for genetic similarity using the random amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE) techniques. On the basis of RAPD- and PFGE-derived profiles, similarity matrices and dendrograms were constructed. The results showed that species A. salmonicida constituted a genetically heterogeneous group of strains, encompassing within an homogeneous or clonal lineage comprised solely of typical strains and the A. salmonicida subsp. salmonicida type strain.

KEY WORDS: Aeromonas salmonicida · Fish pathogens · Taxonomy · RAPD · PFGE

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