Isolation, genetic characterization, and virulence profiling of different species recovered from moribund hybrid catfish ( spp.).

BACKGROUND AND AIM

The high diversity of spp. results in various pathogenicity levels. This group of bacteria causes a serious disease named motile septicemia (MAS) in catfish ( spp.). This study aimed to characterize the species and virulence gene diversity of spp. isolated from diseased catfish.

MATERIALS AND METHODS

Nine spp. were isolated from infected catfish cultivated in Java, Indonesia, and they were identified at the phenotypic and molecular levels (16S rDNA). The virulence genes assessed included , , , , , and .

RESULTS

Phylogenetic analysis identified nine isolates of spp.: (11.11%), (11.11%), bv. (44.44%), and (33.33%). Virulence genes, such as , , , , , and , were detected in all isolates at frequencies of approximately 100%, 66.67%, 88.89%, 100%, 55.56%, and 66.67%, respectively. This study is the first report on recovered from an Indonesian catfish culture. Furthermore, our study revealed the presence of . bv , a biovar that has not been reported before in Indonesia.

CONCLUSION

This finding confirms that MAS was caused by multiple species of , notably and . bv , within Indonesian fish culture. The presence of these species with multiple virulence genes poses a significant threat to the freshwater aquaculture industry.