Bacteria in Rainbow Trout (Oncorhynchus mykiss) in the Southern Black Sea Region of Turkey - A Survey

Thirty-two freshwater rainbow trout (Oncorhynchus mykiss) farms, two rain- bow trout marine cages, and one research station in the Black Sea region of Turkey were surveyed for bacterial pathogens and diseases in 2006- 2008. Forty bacterial isolates were phenotypically identified in 558 fish. Yersiniosis, furunculosis, vibriosis, motile Aeromonas septicemia, bacterial cold water disease, and Pseudomonas infection were recorded. Infections caused by Yersinia ruckeri, A. hydrophila, and A. salmonicida occurred most frequently, but one or two outbreaks of P. putida, Flavobacterium psy- chrophilum, and P. luteola infection were also recorded. Most of the bacte- ria were isolated in spring and summer rather than fall and winter. Susceptibility to antibiotics was fairly consistent regardless of geographic area or year of isolation. Fifty percent or more of the bacteria were resistant to ampicillin, cephalothin, erythromycin, neomycin, sulfamethoxazole, tetra- cycline, and O/129. The most effective antibiotics were oxolinic acid and flo- refenicol