大口鲇致病菌的分离鉴定、系统发育分析及相关特性的研究  

Isolation,identification,phylogenetic analysis and related properties of a pathogen in Silurus meridionalis Chen

作　　者：曹海军[1] 李永文[1] 雷雨[1] 吴江[2] 徐恒[1] 张涛[1] 张学俊[1] 

机构地区：[1]四川大学生命科学学院生物资源与生态环境教育部重点实验室,成都610064 [2]成都通威水产科技有限公司,成都610081

出　　处：《微生物学报》2007年第1期1-6,共6页Acta Microbiologica Sinica

基　　金：四川省科技攻关项目(05NG002-002-4);通威股份科技发展项目~~

摘　　要：从四川鲶科鱼类养殖场濒死的大口鲇(Silurus meridionalis Chen)体内分离到3株优势菌,人工感染试验表明菌株TWN3致病性最强。通过形态学观察、生理生化测定,结合DNA的G+Cmol%、16S rDNA序列同源性和系统发育分析,确定TWN3为普通变形杆菌(Proteus vulgaris)。再根据生理生化特性,可进一步确定TWN3属于普通变形杆菌(Proteus vulgaris)中的P.vulgarisBG3。该菌株不溶血;对庆大霉素等4种药物敏感;对小鼠有较强的致病性。生长特性研究表明,该菌最适生长温度37℃、最适pH6.0、37℃时盐度1.5%生长最适。普通变形杆菌致病性广泛,但作为养殖大口鲇的致病菌国内外未见报道。另外,对该菌的分类学研究、生长特性、感染途径及防治进行了讨论。In October 2005, a large number of adults of Silurus meridionalis Chen died in the mud fish farming of Sichuan province. Later, three predominate strains of bacteria were isolated from the body of moribund fish. By artificial infection tests, strain TWN3 was confirmed to be the pathogen of the disease. Based on the characteristics of morphology, physiology and biochemistry tests, TWN3 was initially identified as Proteus vulgaris, and its G＋ C content of DNA is 39.1%. After being amplified, the sequence of its 16S rDNA was analyzed in the database of NCBI and it showed that TWN3 had the highest similarity to P. vulgaris, with 99.52% identity. By constructing the molecular phylogenetic dendrogram with Minimum Evolution method in Mega3.1, it was revealed that TWN3 was in the same branch with P. vulgaris. Based on all the results above, TWN3 is identified as P. vulgaris. However, the result of one biochemistry test, growth in KCN, deviates from the description in Bergey＇s Manual of Systematic Bacteriology. With reference to the Manual above, Proteus vulgaris is divided into two groups, P. vulgaris BG2 and 3. According to the specific biochemical properties, TWN3 is classified as a member of P. vulgaris BG3. Relevant tests of biological properties were also conducted, which showed that this strain has no haemolysis and is sensitive to four kinds of antibiotic such as gentamicin. Moreover, it can strongly cause diseases to mice. The research on the growth property of strain TWN3 indicated that its growth temperature ranges from 10℃ to 43℃, optimum 37℃ ; growth pH ranges from 4 to 11, optimum 6. Its optimum salinity varies under different temperatures, and it grows best under 1.5 % salinity while 37 ℃. The aim of these researches is to provide an evidence for the prevention and cure of TWN3. According to the appearance of the diseased Silurus meridionalis Chen and results of artificial infection test on crucian carps, it is considered that Silurus meridionalis Chen is infected through digestive system

关 键 词：普通变形杆菌 大口鲇 致病菌 16S RDNA 系统发育分析 生长特性 

分 类 号：S943[农业科学—水产养殖]