Flavobacterial diseases in fish are caused by multiple bacterial species within the family Flavobacteriaceae and are responsible for devastating losses in wild and farmed fish stocks around the world. With the recent advances in molecular biology, several novel genera within the family Flavobacteriaceae (e.g., Chryseobacterium, Elizabethkingia and Tenacibaculum) have emerged that encompass pathogens of fish, amphibians, reptiles, birds, and mammals, including humans.1 Members of the genus Chryseobacterium have emerged as serious fish pathogens on multiple continents. During the last ten years alone, numerous novel Chryseobacterium spp., including C. piscicola,2 C. chaponense,3 C. viscerum,4 and C. oncorhynchi5 were described and recovered from systemically infected fishes exhibiting clinical disease signs worldwide.1 The objective of this study was to identify and genotyping of C. aquaticum isolates in rainbow trout. Herein, twenty-seven, C. aquaticum isolates recovered from farmed rainbow trout exhibiting clinical signs such as darkening of skin color, exophthalmia, and caudal fin root. The identification of the isolates was performed through biochemical tests and 16S rRNA sequence analysis with using 27F and 1387R universal primers. The isolates were compared through a phylogenetic analysis with C. aquaticum sequences accessed in GenBank which were isolated from rainbow trout in Iran and water isolates in New Zealand and South Korea.6 We report that our C. aquaticum isolates were found to have close relationship between each other. Also, the isolates of Iran and South Korea showed 99.5% similarity with our isolates.
In conclusion, this is the first report of C. aquaticum recovered from rainbow trout in Turkey. Its pathogenicity was not assessed previously.1 Further research is needed to determining the virulence mechanisms and pathogenesis of C. aquaticum.
This research was supported by The Research Fund of the Erciyes University. Project Number: TCD-2018-8586.
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