In this study, a disease case caused with 15% mortality on gilthead sea bream (Sparus aurata) which was cultured in the Antalya Bay in the Mediterranean coast of Turkey was investigated in July 2015. Lethargy, loss of equilibrium, petechae on the operculums and the dorsal part of the body, pillar of the gills were recorded in the diseased fish. Internally, ascites, splenomegaly and hemorrhages on the intestinal tissue and muscle were observed. Occurrence of parasite was not detected. According to the results of phenotypical test and 16S rDNA sequencing analysis, the isolated bacterial species was identified as Staphylococcus hominis. Histopathologically, hyperplasia of primary lamellae, lamellar telangiectasia, edema and hemorrhages on the gill arch, numerous melanomacrophage centers (MMCs) in the spleen tissue, vacuoler degeneration, necrose and hemorrhages in the liver, multifocal necrosis, and numerous MMC in the kidney were determined and hemorrhages in the tunica propria region of the intestine were observed. It was determined that he isolates showed different susceptibility against antimicrobial agents.

The aim of this study is to inform isolations of Shewanella putrefaciens, Aeromonas sobria and Aeromonas veronii from the silver European eel fish (Anguilla anguilla) caught from the Gulf of Antalya, Turkey. Three silver eel fish samples as freshly dead (mean weight 75 g) were obtained by a local fisherman. For presumptive identification of the bacterial strains, the strains were identified using a variety of phenotypic characteristics. The further identification of the strains was performed with PCR. Clinically, the silver eel samples showed pale gills, losses of scale, necrotic lesions on dorsal, hemorrhagies on the jaws, lateral and ventral sides of the body and around the anus and hemoragic anal fin. At necropsy, the fish had enlarged and pale spleen and the gastrointestinal tract was empty. After 72 hours, 10 bacterial strains were isolated. 6 strains as Shewanella putrefaciens, 2 strains as Aeromonas sobria and 2 strains as Aeromonas veronii were identified according to the phenotypical characteristics and PCR study results. The eel fish stocks in natural conditions are decreasing and this problem may be multifactorial such as disease, migration and overhunting. As a result of this study, Aeromonas veronii was first isolated from Anguilla anguilla.

In this study, antibacterial activities of extracts of Liagora ceranoides (Rhodophyta), Halopteris scoparia (Ocrophyta), Padina pavonica (Ocrophyta) and Sargassum vulgare (Ocrophyta) on Yersinia ruckeri strains isolated from sick rainbow trout (Oncorhynhus mykiss) were evaluated. Also, susceptibilities of the strains against various antibiotics were studied. The strains isolated from the sick fish were identified as Yersinia ruckeri according to the results of the phenotypic tests, the API 20E rapid diagnostic kit and PCR. In the study, it was found that the methanol extracts of L. ceranoides, H. scoparia, P. pavonica and S. vulgare did not show antibacterial activity against Y. ruckeri. The ethanol extract of P. pavonica showed low antibacterial activity against Y. ruckeri. The ethanol extracts of L. ceranoides, H. scoparia and S. vulgare macroalgae did not show antibacterial activity against the bacterium. According to the results of the antibiogram test, it was found that the strains were sensitive against ampicillin, flumequine, oxytetracycline and trimethoprime. The strains showed intermediate resistance against erythromycine. In conclusion, although it was reported that algae had antibacterial activities, it was understood that every algae species could not exhibit antibacterial activity.