Bilateral Exophthalmos: The Most Important Sign of Lactococcosis in Rainbow Trout (Oncorhynchus mykiss)

In this study, we aimed to investigate rapidly isolation and identification of Lactococcus garvieae from rainbow trout ( Oncorhynchus mykiss ), reared Black Sea Region, Turkey. The fish with bilateral exophthalmos were collected from a commercial trout farm. The bacteria were identified as L. garvieae based on some biochemical tests and Polymerase Chain Reaction (PCR) assay. Following identification, the antibacterial susceptibility of bacteria was also determined for five different antibiotics by the disk diffusion method. All isolates were sensitive to florfenicol and amoxicillin-clavulanate and resistant to trimethoprim+sulfamethoxazole and enrofloxacin. Overall this study revealed that the bilateral exophthalmos may be considered as a pathognomonic symptom for lactococcosis in rainbow trout.