A Mixed Frigoribacterium faeni and Lactococcus garvieae Infection in Cultured Rainbow Trout (O. mykiss)

The aim of this study was to diagnose the bacterial pathogens of moribund rainbow trout (Oncorhynchus mykiss) reared in a dam-lake cage farm located in the Black Sea Region of Turkey and to determine their antibiotic susceptibility and histopathological effects by using routine bacteriological, histopathological and molecular methods. Besides possibility of the use of two probiotics against these pathogens for the prevention of further infections was investigated. In this study, a mixed bacterial infection case caused by Frigoribacterium faeni and Lactococcus garvieae was diagnosed in rainbow trout samples of 100-250 g with general clinical and histopathological symptoms of bacterial hemorrhagic septicemia. Pathogens were found to be resistant against most of the antibiotics tested and the possibility of the use of Bacillus subtilis as a probiotic to prevent diseases caused by these pathogens was proposed.