以患有腐皮综合征的度夏仿刺参(Apostichopus japonicus)为对象,从其体壁病灶处分离纯化获得一株病原细菌.通过传统细菌鉴定方法对病原菌的形态学、生理生化特征和培养特征进行研究;以16S rRNA基因测序为基础,结合基质辅助激光解析电离飞行时间质谱技术(MALDI-TOF MS)进行鉴定,结果表明该菌株在分类上属于伯麦罗氏弧菌(Vibriopomeroyi);人工感染实验验证了不论是注射感染还是浸浴感染,该菌株均能导致仿刺参发病甚至死亡.此外,将本次实验获得的伯麦罗氏弧菌菌株SUS(V.pomeroyi SUS)与伯麦罗氏弧菌的其他菌株,如Vpomeroyi LMG20537T(典型菌株)、Vpomeroyi 929进行比较,探讨了来自不同海域的菌株生理生化特征与环境因子之间的关系.研究结果显示:伯麦罗氏弧菌为南移度夏仿刺参腐皮综合征的病原菌,而且表明MALDI-TOF MS技术结合微生物数据库MALDI Biotyper系统的鉴定方法准确、便捷、重复性高,非常适合于传统鉴定方法易混淆的种类鉴别,这为南移仿刺参的疾病检查和预防奠定了基础.
The sea cucumber,Apostichopus japonicus (Selenka, 1867),is a major aquaculture species along the coastline of northern China.Because of increasing demand of the profitable species, culture of A.japonicus has expanded towards to the southern region of China including Fujian,Guangdong Provinces. However, as a temperate species,A.japonicus is more easily infected by environmental bacteria during aestivation,and skin ulcer syndrome is proved to be the major disease of sea cucumber.In this study,a dominant bac- terium strain was isolated from the body wall of diseased cultured sea cucumber(A.japonicus)infected with skin ulcer syndrome. Phenotypic characterization of the bacteria was investigated with traditional biochemical tests.Genotypic characterization was evalua- ted by 16S rRNA gene sequencing technique,along with matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS).The phenotypic and genotypic characterization proved that the pathogen was Vibrio pomeroyi. Meanwhile, the artificial infection test proved that V. pomeroyi could cause severe infections and even death whether injection or immersion. Addi- tionally,comparing V. pomeroyi SUS isolated from China with other strains of V. pomeroyi ,including LMG 20537T (type strain) i- solated from Brazil and V. pomeroyi 929 isolated from Peter the Great Bay showed distinctly different tolerance pattern with envi- ronmental factors, e.g. salinity and temperature.For the first time this paper reported the isolation of the pathogen of A.japonicus with skin ulcer syndrome during aestivation in southern China and MALDI-TOF MS analysis was proved to be an accurate and rapid method for identification and differentiation of common pathogens.