STREPTOCOCCOSIS AND ANTIBIOTIC RESISTANCE IN INFECTED RAINBOW TROUT (ONCORHYNCHUS MYKISS ) FARMS IN GUILAN PROVINCE

Background and Aim:The aim of this study was to investigate the incidence of streptococcosis and its antibiotic resistance in Guilan province Streptococcosis is one of the most causes of mortality in rainbow trout farms in Guilan provinceMethods:The infected fish (168 with an average weight of 25-50 g) with clinical signs such as blurry, exophthalmic eyes and bleeding in the eyes, skin, fins fish were sampled . Samples were taken from the liver, kidney, spleen and some parts of the brain and transferred to the Blood Agar and TSA Agar.Results:The incidence of Streptococcosis in this study was 39.29%. The streptococcal bacteria were isolated S. iniae (33.3%), S. agalactia (39.4%) and E. faecalis (27.3% ) respectivelyConclusion:antibiotic resistance of bacteria in rainbow trout showed the highest resistance to Bacitracin and lincomycin. (92% -100%).

Keywords:

Streptococcosis , Rainbow trout , bacteria