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 heavy mortalities in carp farms during spring and summer in iran. objectives: the aim of this study was to detect phenotypic and genotypic characterization of motile aeromonas species isolated from diseased carps in some northern and southern provinces of iran. methods: a number of 40 samples from 22 fish farms were collected. the identified motile aeromonas species were sequenced and phylogenetic tree was drawn by mega6 using upgma analysis. results: a number of 19 bacterial isolates were identified as motile aeromonas sp. by biochemical tests, and the dna segments of 16s rrna gene of all these strains gave 1200 bp after running on 1% agarose electrophorus gel. also, the sequencing results showed that the bacterial samples were determined as a. hydrophila and a. veronii biovar veronii. conclusions: phylogenetic analysis revealed that motile aeromonas strains in this study were separated in two clusters and four genogroups with high similarities.