Isolation, phenotypic and molecular characterization of motile Aeromonas species, the cause of bacterial hemorrhagic septicemia in affected farmed carp in Iran

Background: Motile Aeromonas species cause heavymortalities in carp farms during spring and summer in Iran. Objectives: The aim of this study was to detect phenotypicand genotypic characterization of motile Aeromonas species isolated fromdiseased carps in some northern and southern provinces of Iran. Methods: A number of 40 samples from 22 fish farms werecollected. The identified motile Aeromonas species were sequenced andphylogenetic tree was drawn by MEGA6 using UPGMA analysis. Results: A number of 19 bacterial isolates wereidentified as motile Aeromonas sp. by biochemical tests, and the DNAsegments of 16S rRNA gene of all these strains gave 1200 bp after running on 1%agarose electrophorus gel. Also, the sequencing results showed that thebacterial samples were determined as A. hydrophila and A. veroniibiovar veronii. Conclusions: Phylogenetic analysis revealed that motile Aeromonasstrains in this study were separated in two clusters and four  genogroups with high similarities