In this study, the diseased fish samples were collected from fish farms in the nine different dam lakes during the summer months between July 2014 and September 2018. It is isolated twenty-two bacteria from diseased rainbow trout (Oncorhynchus mykiss) eyes showing exophthalmos symptoms. All isolates identification was carried out by using conventional biochemical tests, API 20 Strep test kit and PCR test. ATCC 43921 reference strain of the Lactococcus garvieae was used as a positive control. The PCR test was confirmed by using the pLG-1 and pLG-2 reference genes (16S rRNA) specific for the L. garvieae species. As a result of this study, all of the twenty-two isolates isolated from the eyes of diseased rainbow trout were confirmed as L. garvieae by PCR test. According to the results of antibiotic susceptibility test, all of the L. garvieae isolates were resistant to streptomycin, sulfamethoxazole, and sulfamethoxazole/trimethoprim. The same isolates have been determined to be resistant to ampicillin (94.2%), oxytetracycline (72.5%), erythromycin (55.07%), oxolinic acid (43.5%), enrofloxacin (26.09%), doxycycline (20.3%), amoxicillin and florfenicol (8,7%) as well. Thus, florfenicol, amoxicillin, doxycycline, and enrofloxacin were found as the most effective antibiotics.

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Aeromonas hydrophila is known to be causative agent of an infection named as Bacterial haemorrhagic septicaemia or red pest in freshwater fish. The aim of this study was to develop and validate the glycoprotein-based fish vaccine against Aeromonas hydrophila. For this aim, after identification and characterization of A. hydrophila isolates from fish farms, one A. hydrophila isolate was selected as vaccine strain. Antigenic glycoproteins of this vaccine strain were determined by Western blotting and glycan detection kit. The connection types of these glycoproteins were examined by glycoprotein differentiation kit. Two glycoproteins, molecular weights of 19 and 38 kDa, with SNA connection type were selected for use in vaccination trials. After their purification by SNA-specific lectin and size-exclusion chromatography, protection studies with purified proteins were performed. For challenge trials, four experimental fish groups were designated: Group I (with montanide), Group II (with montanide and ginseng), Group III [with Al(OH)3 ] and Group IV [with Al(OH)3 and ginseng]. The survival ratings of fish were determined, and protection was calculated as 21.56%, 29.41%, 69.83% and 78.88% in groups I, II, III and IV, respectively. In conclusion, A. hydrophila glycoproteins with Al(OH)3 and ginseng could be used as a safe and effective vaccine for fish.