Serological characterization of atypical strains of Edwardsiella tarda isolated from sea breams

The serological relationships between a non-motile variant of Edwardsiella tarda isolated from sea breams, Pagrus major and Evynnis japonica, and typical strains of E. tarda isolated from Japanese eel, Anguilla japonica and Japanese flounder, Paralichthys olivaceus, were studied. Cross-absorption test revealed that all strains shared a similar O-antigen. Agglutination tests showed the presence of heat-labile antigens on the cell surface of the non-motile strains from sea breams. Immunoelectrophoretic analysis demonstrated the relatedness of cell surface antigens among the strains from various fish species. The possibility of usage of a common vaccine for edwardsiellosis among sea breams and other fish species is suggested.