Isolation and identification of Citrobacter freundii from diseased giant salamander, Andrias davidianus
患病大鲵中弗氏柠檬酸杆菌的分离与鉴定

Objective]To determine the pathogenic bacterium infecting giant salamander(Andrias davidianus).Methods]Bacterium was isolated from the liver of diseased Chinese giant salamander and identified by the Biolog Microbial Identification System and molecular biology method.Healthy Chinese giant salamander and crucian carp were used for experimental infection with bacterial suspension.Results]A bacterial strain JZ01 was isolated and identified from diseased giant salamander.Infection with the bacterial suspension to healthy giant salamander could reproduce the diseased symptoms as occurred naturally and the same bacterium could be recovered from these infected giant salamanders.The isolated bacterium also has certain pathogenicity to crucian carp.Identification by the Biolog Microbial Identification System,and further 16S rDNA sequence and phylogenetic analysis demonstrated that the bacterium isolated from diseased giant salamander was Citrobacter freundii.The susceptibility test to antibiotics demonstrated that the bacterial strain JZ01 was susceptible to aztreonam,cefepime and cefotamine.Conclusion]Citrobacter freundii is a pathogen for cultured Chinese giant salamander.