1992/03/01 by M. YADAV, G. INDIRA, A. ANSARY
paper · doi:10.1111/j.1365-2761.1992.tb00652.x
Abstract. Twenty‐eight strains of A. Hydeophila, 18 from fish with epizootic ulcerative syndrome (EUS) and 10 from apparently normal fish, were examined for their ability to produce cylotoxins and haemolysins. Bacterial culture supernantants were tested for cytotoxin elaborated using the visual cell damage technique and a novel clorimetric method. Two types of target cells were used and the WEHI cells were reproducibly more sensitive than Vero cells in both the cytotoxin assays. Cytotoxin‐producer strains were more frequently associated with EUS‐infected fish compared to normal fish. Haemolysin‐producing strains were equally present in healthy and EUS‐positive fish, and the haemolysin was not correlated with cytotoxin production. It appears that the progression of pathogenicity of EUS may be linked with the presence of cytotoxic strains of A. hydrophila in the EUS lesions.