Edwardsiella ictaluri Infection in Rainbow Trout (Oncorhynchus mykiss)

Abstract

The aim of this study was to isolate Edwardsiella ictaluri from diseased rainbow trout obtained from a commercial farm in the Ankara region, Turkey. Growth of the microorganism after 36 h of incubation was higher and purer at 28 ºC than at 37 ºC on all the organs (liver, spleen, kidney) of the 10 fish examined. Three groups, each consisting of 3 fish were used for experimental infection. All the fish in Group I, which received a pure culture suspension, died after treatment. There were no clinical symptoms of the disease or deaths in Group II treated with 1/50 concentration of the pure culture or in Group III (control group) treated with 0.85% saline. The isolation of E. ictaluri from non-ictalurid fish and the fact that similar bacteria have been isolated from non-ictalurid fish in different countries indicate that the organism is a widespread pathogen. The results from this study show that rainbow trout are susceptible to E. ictaluri and there is a possibility of natural infection.