Isolation,identification and virulence gene of atypical Aeromonas salmonicida from cultured turbot Scophthalmus maximus
WANG He, WANG Wenhao, HUANG Hua, LIU Xiaodan, ZHANG Liwen,YANG Tao, HU Lebin, LI Zhanjun*
1.Yantai Marine Economic Research Institute, Yantai 264006, China; 2.Yantai Zongzhe Marine Technology Company Limited, Yantai 264006, China; 3.Shandong Hydrobios Resources Conservation and Management Center, Yantai 264003, China
Abstract: In order to study the characteristics of atypical Aeromonassalmonicida, a dominant strain BHAS-1 was isolated and purified from the spleen of diseasing turbot individuals using conventional methods. The isolated strain BHAS-1 was identified by morphological observation, physiological and biochemical tests, and PCR specific amplification. The virulence gene and antibiotic sensitivity were also detected. The results showed that BHAS-1 strain was gram-negative cocci with β-hemolytic and no motility. The isolated stain BHAS-1 had similar physiological and biochemical properties to the atypical A.salmonicida, but the strain did not produce indole and cannot utilize mannose. After 16S rRNA, gyrB and vapA sequence alignment analysis, BHAS-1 was identified as A.salmonicida subsp. masoucida, and the virulence genotype was aer+-zot+-dna+-ser+-lip+-sp+-alt+-act+-ast+-epa+-fla+-ahyB+, with LD50 of 1.62×108 CFU/mL. The strain BHAS-1 was sensitive to 13 kinds of antibiotics such as enrofloxacin and tetracycline, resistant to 7 kinds of antibiotics such as puromyn and chloramphenicol, and moderately sensitive to ampicillin and streptomycin, with average resistance rate of 31.82%. In this study, we first reported the infection of A.salmonicida subsp. masoucida to cultured turbot in China. The molecular characteristics and drug sensitivity of the strain BHAS-1 were studied to provide reference for the prevention of furunculosis caused by atypical A.salmonicida. The findings indicate that the application of vap gene can effectively identify different subspecies of A.salmonicida.
王鹤, 王文豪, 黄华, 刘晓丹, 张丽文, 杨涛, 胡乐彬, 李战军. 一株大菱鲆源杀鲑气单胞菌非典型株的分离鉴定及毒力基因型[J]. 大连海洋大学学报, 2022, 37(4): 558-567.
WANG He, WANG Wenhao, HUANG Hua, LIU Xiaodan, ZHANG Liwen, YANG Tao, HU Lebin, LI Zhanjun. Isolation,identification and virulence gene of atypical Aeromonas salmonicida from cultured turbot Scophthalmus maximus. Journal of Dalian Ocean University, 2022, 37(4): 558-567.
2022, Vol. 37 
