engleski

Isolation and molecular characterization of Flavobacterium psychrophilum from reared rainbow trout fry in Croatia

Rainbow trout aquaculture is an important and fast growing sector of food industry in many European countries, including Croatia. Outbreaks of bacterial diseases can impact commercial productivity and cause high economic losses in trout farming. In particular, Flavobacterium psychrophilum, the causative agent of bacterial cold water disease and rainbow trout fry syndrome, can cause significant fish mortality. Due to difficult cultivation of this pathogen, many characteristics of its pathogenesis and epizootiology are still under investigation. The aim of our study was to carry out detailed molecular characterization of F. psychrophilum strain isolated at one Croatian trout farm in 2007. Pools of different organs (spleen, heart, kidney and brain) were sampled from twenty rainbow trout fry. Homogenates were inoculated on cytophaga agar and incubated at 15°C. Yellow pigmented colonies were used for RNA isolation and one step RT-PCR was applied for amplification of partial 16S rRNA, peptidyl-prolyl cis-trans isomerase C (PPIC) and DNA gyrase B subunit (gyrB) genes. Determined sequences were compared to known sequences from different F. psychrophilum strains available at Gen Bank. Comparison with partial 16S rRNA and PPIC nucleotide sequences of F. psychrophilum from Croatia detected in 2005 is currently being undertaken. Our results would be valuable for further epizootiological investigations of F. psychrophilum in Croatia.

: Flavobacterium psychrophilum; 16SrDNA; peptidyl-prolyl cis-trans isomerase C; DNA gyrase B subunit

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