Culture- and Polymerase Chain Reaction-Based Detection of Flavobacterium Psychrophilum in Naturally Infected Rainbow Trout (Oncorhynchus mykiss walbaum, 1792) from Trout Farms

Abstract

The present study aimed to detect Flavobacterium psychrophilum in fish samples collected from rainbow trout (Oncorhynchus mykiss Walbaum 1792) farms in the Southeastern Anatolia region of Türkiye by means of bacteriological culture and polymerase chain reaction and to investigate the antibiotic susceptibility of the causative bacteria. A total of 40 trout farms located in Diyarbakır, Adıyaman, Şanlıurfa, and Batman provinces were visited, and 1200 samples were examined. During January and February 30 fish with an average live weight of 200–250 g were collected from each farm. Samples were obtained from the liver, spleen, kidneys, and tissues following macroscopic laboratory examination of the specimens. Antibiotic treatment is the treatment of choice owing to the lack of an effective vaccine in the control of the disease. Therefore, it is important to rapidly identify the bacterial species and investigate its susceptibility to antibiotics. In this study, the causative bacteria were detected in 5 out of 40 farms. The causative bacteria infected the liver, kidney, and tissues. The sensitivity of Enrofloxacin (5 microgram (µg)), Florfenicol (30µg), Neomycin (5µg), Amoxicillin (25µg), Oxytetracycline (30µg), Erythromycin (10µg), Gentamycin (5µg), Streptomycin (5µg) and Nalidixic acid (10µg) were defined at chancing ratios. In conclusion, these bacteria were detected in regional farms, which should minimize the stress factors by avoiding overstocking and following the required hygiene rules.