Detection and identification of the bacterial kidney disease (BKD) organism by the indirect fluorescent antibody technique.
The bacteria was isolated from infected rainbow trout kidney, cultured on agar for ten days and injected into a rabbit to obtain BKD antiserum. Two different strains isolated from trout in Canada and 3 isolated in Scotland were also tested. The specificity of the test was examined using 2 gram positive bacteria isolated from mammalian sources, Corynebacterium pyogenes and Listeria monocytogenes, and two gram negative bacteria isolated from rainbow trout. A comparison was made between the sensitivity of the indirect fluorescent antibody technique (FAT) and gram staining using randomly selected BKD bacteria. All strains of BKD showed bright fluorescence and no fluorescence was seen with the other 4 bacteria. The indirect FAT was more effective in identifying BKD in kidney smears than gram staining which was less sensitive and required experience in interpretation.