Development of DNA primers to identify a Romet-resistance gene in Aeromonas salmonicida and its subsequent use for epidemiological studies

Furunculosis is a significant cause of disease and mortality to hatchery reared
and wild populations of salmonid fishes, particularly the salmon species. The
disease is caused by Aeromonas salmonicida, a Gram nagative bacterium that is
highly virulent and is readily transmitted horozontally. An asymptomatic form
of the disease occurs, including those individuals that survive epizootics, and
these fish can serve as a source of infection in subsequent outbreaks. The
disease is treated by antimicrobial therapy. Romet, a potentiated sulfonimide,
was approved for use by the FDA in 1986 and is one of only three agents
approved. Since approval of Romet, resistant strains of A. salmonicida have
emerged and this removes treatment with Romet as an alternative. Recent work
has described an R-plasmid mediated resistance in many of the resistant A.
salmonicida strains.