中国水产科学Issue(4)：698-706,9.DOI:10.3724/SP.J.1118.2015.140508
黄沙鳖源嗜水气单胞菌的致病力与毒力基因型相关性
Studies on the correlation with pathogenicity and virulence genes of Aeromonas hydrophila by Truogx sinensis
摘要
Abstract
This study aims to investigate the correlation of the pathogenicity and virulence genes of Aeromonas hydro-phila isolated from diseased Huangsha soft shelled turtle Truogx sinensis in different areas of Guangxi Zhuang Autonomous Region. An artificial infection test in Huangsha soft shelled turtle T. sinensis and in mice Mus musculus was measured on the pathogenicity of the isolated A. hydrophila strains, including a PCR assay of detecting the bacte-rial strains of 6 kinds of virulence genes including hly, Aer, Alt, Act, ahal and ahp. The results were as follows. Forty seven strains of pathogenic A. hydrophila isolated from diseased Huangsha soft shelled turtle T. sinensis contained 9 kinds of bacterium virulence genotypes in all, including hly+ Aer+ Alt+Act+ ahal+ ahp+, hly+ Aer+ Alt– Act+ ahal+ ahp–, hly+ Aer+ Alt+ ahal+ Act– ahp+, hly+ Aer+ Alt+ Act– ahal– ahp–, hly– Aer– Alt+ Act– ahal+ ahp–, hly+ Aer– Alt+ Act+ahal–ahp+, hly+ Aer– Alt– Act+ ahal– ahp+, hly+ Aer– Alt+ Act– ahal– ahp+ and hly+ Aer– Alt– Act+ ahal– ahp–. Around 48.94 percent of the A. hydrophila strains carried all the 6 kinds of virulence gene detected, and the genotype of hly+ Aer+ Alt+ ahal+ ahp+Act+ was the main virulence genotype. About 95.79 percent of the A. hydrophila strains carried gene hly, and all of them were the virulence strains. Our results also showed that pathogenicity of A. hydrophila to Huangsha soft shelled turtle T. sinensis was the outcome of combined action of multiple virulence genes, among which gene hly and Act were the key virulence genes, gene Alt and ahal of the isolated strains had correlated action with other virulence genes, whereas the absence of gene ahp had no effect on the pathogenicity of the isolated A. hydrophila strains to Huangsha soft shelled turtle T. sinensis or to mice M. musculus based on the artificial infection test. Strain which caused a fatality rate at or above 50 percent in Huangsha soft shelled turtle T. sinensis was determined to be a particularly virulent strain, whereas the one caused a fatality rate below 50 percent was determined to be a low virulent strain. Particularly virulent strains carried at least 4 kinds of virulence genes according to our study, and at the same time hly and Act genes were both pre-sent. Low virulent strains carried only two or three virulence genes besides gene hly. The study found for the first time that strains which carried only Alt and ahal genes have no pathogenicity to mice M. musculus or to Huangsha soft shelled turtle T. sinensis. In the detection of the 6 kinds of virulence genes, genes Alt, ahal and ahp were prone to miss-ing. Among all the virulent strains, the strains with different genotypes varied significantly in causing fatalities rates in Huangsha soft shelled turtle T. sinensis and in mice M. musculus (P<0.01). When any virulence gene is absent, the pathogenicity of the strains with the same genotype contributing to Huangsha soft shelled turtle T. sinensis was signifi-cantly stronger than to mice M. musculus (P<0.01), which indicates that pathogenic A. hydrophila isolated from dis-eased Huangsha soft shelled turtle T. sinensis contributes significantly stronger pathogenicity to Huangsha soft shelled turtle T. sinensis than to mice M. musculus. According to the results of this study, a PCR detection of the virulence gene hly could be recommended to infer whether a strain is virulent or not, and the co-existence of virulence genes hly and Act, as well as two or more virulence genes among Aer, Alt, ahal together with ahp, could be considered as a reasonable predictor of the particularly virulent strains.关键词
黄沙鳖/嗜水气单胞菌/毒力基因/致病力Key words
Truogx sinensis/Aeromonas hydrophila/bacterium virulence genes/pathogenicity分类
农业科技引用本文复制引用
刘杰,植淇业,黄艳华,黄钧,胡大胜,梁静真,彭亚,龙苏,牛志伟,韩书煜..黄沙鳖源嗜水气单胞菌的致病力与毒力基因型相关性[J].中国水产科学,2015,(4):698-706,9.基金项目
广西自然科学基金项目(2011GXNSFA018065) （2011GXNSFA018065）
广西水产畜牧兽医局专项项目(桂渔牧财[2011]52号,桂渔牧财[2012]30号,桂渔牧财[2013]35号) （桂渔牧财[2011]52号,桂渔牧财[2012]30号,桂渔牧财[2013]35号）
南宁市科技局科技计划项目(南科发[2013]46号,合同编号:20132123) （南科发[2013]46号,合同编号:20132123）
