Sequencing of gyrB and Their Application in the Identification of Flavobacterium psychrophilum by PCR

Flavobacterium psychrophilum (formerly Cytophaga psychrophila and Flexibacter psychrophilus) is the causative agent of bacterial cold water disease (BCWD) and rainbow trout fry syndrome (RTFS). The PCR assay for the identification or detection of F. psychrophilum has been described previously. However, it has also been reported that some 16S rDNA based primers for F. psychrophilum amplify non-specific PCR products under some conditions. The present study, therefore, aims to develop a new PCR for identifying F. psychrophilum by designing primers based on the sequences of gyrB encoding the subunit B protein of DNA gyrase. DNA gyrase is the enzyme that regulates supercoiling of doubled-stranded DNA, and is necessary for DNA replication.