Abstract: A bacterial strain, named as strain TC-1, was isolated from the diseased turtle Trachemysscriptaelegans, and was Gram-staining negative bacterium to investigate the pathogenicity and its biological characteristics of diseased turtle. The 16S rDNA and gyrB sequences of the strain TC-1 were amplified by PCR method, and subcloned into pMD18-T vector, and the products of sequencing were 1503 bp and 989 bp in length. The Blast alignments of the nuclear sequences of 16S rDNA and gyrB showed that the strain TC-1 shared the maximal similarities of 99.60% and 98.80% with Citrobacterfreundiirespectively. Phylogenetic tree analysis showed that the TC-1 strain was clustered into one gourp with C.freundii, thus the TC-1 strain was identified as C.freundii. The antimicrobial susceptibility test indicated that the isolate was sensitive to cefoperazone, ceftazidime, nalidixic acid, norfloxacin, levofloxacin, tetracycline, florfenicol and imipenem, resistant to amoxicillin, cefalexin, bacteresulf and sulfamethoxazole. Artificial infection test showed that clinical signs were consistent with the symptoms of natural infected turtles. The findings will provide a scientific reference with prevention, isolation and identification of C.freundii from turtle.
2019, Vol. 34 
