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为探明黄沙鳖(Truogx sinensis)源嗜水气单胞菌(Aeromonas hydrophila)所携带毒力基因种类对其致病力的影响,以从广西各地患病黄沙鳖中分离得到的嗜水气单胞菌为材料,通过对黄沙鳖和小鼠进行人工感染测定试验菌株的致病力,PCR检测供试菌株的hly、Aer、Alt、Act、ahal和ahp 6种毒力基因。结果表明,47株黄沙鳖源嗜水气单胞菌共包含9种毒力基因型,48.94%的菌株携带全部6种毒力基因,基因型为hly+Aer+Alt+Act+ahal+ahp+,是主要的毒力基因型;95.79%的菌株携带hly基因,均为有毒株;嗜水气单胞菌对黄沙鳖的致病力是多个毒力基因共同作用的结果,hly和Act是重要的毒力基因,Alt和ahal基因对菌株的致病力与其他毒力基因之间存在协同作用,ahp基因缺失对菌株的致病力无影响;将对黄沙鳖的致死率达到和超过50%的菌株判定为强毒株,致死率不足50%判定为弱毒株时,强毒株至少携带4种毒力基因,并同时携带有hly和Act基因,弱毒株只携带包括hly在内的2种或3种毒力基因,本研究首次发现只携带Alt和ahal 2种毒力基因的菌株对黄沙鳖和小鼠均无致病力;在所检测的6种毒力基因中,较易缺失的基因主要有Alt、ahal和ahp;在有毒株中,不同基因型的菌株对黄沙鳖和对小鼠的平均致死率差异均为极显著(P<0.01),当存在基因缺失现象时,同一基因型的菌株对黄沙鳖的平均致死率也极显著高于对小鼠的致死率(P<0.01),表明黄沙鳖源嗜水气单胞菌对黄沙鳖的致病力显著强于对小鼠的致病力。根据本研究结果,可将hly基因作为嗜水气单胞菌有毒株的鉴定标准,携带hly和Act基因并同时携带Aer、Alt、ahal、ahp中的2种或2种以上毒力基因作为强毒株的鉴定标准。
In order to investigate the effect of virulence genes of Truogx sinensis on the virulence of pathogenicity, Aeromonas was used as the material to test the pathogenicity of the test strains by artificial infection of the sand turtle and the mice. Six virulence genes of hly, Aer, Alt, Act, ahal and ahp were tested by PCR. The results showed that 47 strains of Aeromonas hydrophila contained 9 virulence genotypes, 48.94% strains carried all 6 virulence genes and the genotypes were hly + Aer + Alt + Act + ahal + ahp + , Is the main genotype of virulence; 95.79% of the strains carry hly gene, are toxic strains; Aeromonas hydrophila on the pathogenicity of sand turtle is a result of multiple virulence genes together, hly and Act Is an important virulence gene, Alt and ahal genes on the virulence of the strains and other virulence genes synergy exists, ahp gene deletion has no effect on the virulence of the strain; the mortality of yellow sand turtle and When more than 50% of the isolates were identified as virulent strains and virulent strains less than 50% of the virulent strains were identified as virulent strains, the virulent strains carried at least 4 virulence genes and carried both hly and Act genes. The attenuated strains contained only hly Two or three virulence genes in this study. For the first time, it was found that none of the virulence genes carrying the two virulence genes, Alt and ahal, had pathogenicity to T. gondii and S.japonicus. Of the six virulence genes tested, The most vulnerable genes were Alt, ahal and ahp. Among the virulent strains, the average lethality of different genotypes to yellow sand turtle and mouse (P <0.01). In the presence of gene deletion, the average lethality of the same genotype strain to sand turtle was also significantly higher than that of mice (P <0.01), indicating that yellow sand Soft-shelled turtle Aeromonas hydrophila pathogenicity of sand turtle was significantly stronger than the virulence of mice. According to the results of this study, the hly gene can be used as the identification standard of Aeromonas hydrophila strains, carrying hly and Act genes and simultaneously carrying two or more virulence genes of Aer, Alt, ahal and ahp as strong Identification of strains.