Diagnosis of bacterial fish diseases and classification of serotypes with slide agglutination method

Bacterial fish pathogens cause significant losses in rainbow trout farms. In fish farms, bacterial pathogens cause threatening diseases which has made it necessary to develop rapid methods for disease diagnosis. Serological techniques which are applied with a small amount of antiserum and sample, are preferred for the rapid diagnosis of fish diseases. In this study, formalin-killed antigens prepared from reference strains of Lactococcus garvieae, Yersinia ruckeri, and Vibrio (Listonella) anguillarum were injected intravenously in consecutive doses to New Zealand rabbits. One week after the last injection, the sera separated to use in the slide agglutination tests. A total of 42 strains were studied, including Y. ruckeri (18 isolates), V. anguillarum (14 isolates), and L. garvieae (7 isolates) and 3 references (ATCC 43305, ATCC 29473, ATCC 49156) strains. Serotype O1 determined the predominant serotype (86%) in V. anguillarum and Y. ruckeri (84%) strains examined by the slide agglutination method. L. garvieae strains did not react against Japanese antisera but positively reacted against Turkish L. garvieae antisera.