B. Gunnlaugsdottir et Bk. Gudmundsdottir, PATHOGENICITY OF ATYPICAL AEROMONAS-SALMONICIDA IN ATLANTIC SALMON COMPARED WITH PROTEASE PRODUCTION, Journal of applied microbiology, 83(5), 1997, pp. 542-551
The pathogenicity of extracellular products (ECPs) from 24 atypical Ae
romonas salmonicida strains was studied with respect to: lethality in
Atlantic salmon, pathogenic effect in muscle, haemolytic activity, cyt
otoxicity in two fish cell lines and proteolytic activities, Furthermo
re, the relationship between lethality of ECPs and mortality caused by
bacterial challenge was examined. Correlation was demonstrated betwee
n the pathogenic properties and proteolytic activities of the ECPs. Cy
tolytic (GCAT) activity comparable with that of the typical reference
strain used (NCMB 1102) was not detected in ECPs of any of the atypica
l strain tested, An extracellular metallo-caseinase, AsaP1, was linked
with lethal toxicity and a strong pathogenic effect. Furuncular-like
lesions were produced by ECPs containing AsaP1 activity. One strain pr
oduced a lethal toxin which was neither caseinolytic nor with GCAT com
parable activity. The examined atypical strains form at least three di
stinct groups based on different virulence mechanisms and extracellula
r proteases.