Investigation of Antibacterial Activities of Ethanol and Methanol Extracts of Some Marine Algae Species on Yersinia ruckeri

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