Many publications about pathogenicity mechanisms have resulted from the examination of single isolates, often of questionable authenticity. The usefulness of such approaches to the understanding of pathogenicity of bacterial species is doubtful. Also, the value of studies involving bacterial subcellular components produced on agar plates or in broth cultures at explaining disease mechanisms in situ is unclear. Nevertheless, an interesting development concerns the potential role of quorum-sensing signal molecules (= acylated homoserine lactones [AHLs]) in the regulation of some virulence factors, with work revealing that AHLs are produced by some Gram-negative bacterial fish pathogens, notably Aer. hydrophila, Aer. salmonicida, V. salmonicida, V. splendidus, V. vulnificus and Y. ruckeri, but not in Fla. psychrophilum, Moritella viscosa or Ph. damselae (Bruhn et al., 2005).
KeywordsRainbow Trout Atlantic Salmon Brown Trout Striped Bass Chinook Salmon
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