Citrobacter freundii: a Causative Agent for Tail Rot Disease in Freshwater Cultured Japanese Eel Anguilla japonica

Abstract

Tail rot disease causes significant economic damage in freshwater farmed Japanese eel Anguilla japonica, yet information on Citrobacter freundii as a possible causal agent for this disease is scarce. In this study, a virulent strain, temporarily named MINA, was isolated from diseased A. japonica suffering from tail rot disease. It was identified through phylogenetic analysis and phenotypic characteristics and thus compared to other known isolates. Isolate MINA has developed multiple resistances to penicillin, quinolones and sulfonamide antibiotics as well as to amide alcohols, cephalosporin, glycopeptide and macrolide drugs used in aquaculture when screened against a range of common antibiotics. To the best of our knowledge, this is the first report of tail rot disease caused by C. freundii in freshwater farmed A. japonica.