中文摘要：

【目的】了解致病岛-2（Salmonella Pathogenicity Island 2,SPI-2）对鸡白痢沙门菌致病性的影响,初步探讨研制安全有效的鸡白痢沙门菌减毒株的可行性。【方法】采用λ-red同源重组系统构建鸡白痢沙门菌S06004株的SPI-2（约40 kb）缺失株S06004ΔSPI2。并与野生型相比较,对该缺失株的生长特性、生化特性、遗传稳定性和致病性等基本生物学特性进行鉴定。【结果】成功构建SPI-2缺失株S06004ΔSPI2,SPI-2的缺失不影响鸡白痢沙门菌的生长特性和生化特性,且该缺失株具有良好的遗传稳定性,其对2日龄雏鸡的LD50是野生株的252倍。【结论】SPI-2的缺失引起鸡白痢沙门菌毒力的明显下降,这为进一步研究鸡白痢沙门菌SPI-2的功能及制备减毒疫苗奠定了基础。

英文摘要：

[ Objective] To research the pathogenicity of Salmonella Pathogenicity Island 2 （SPI-2） deletion mutant of Salmonella Pullorum and preliminary explore the feasibility of developing safe attenuated Salmonella Pullorum candidate vaccine strain. [ Methods] TheSPI-2 （ -40 kb） deletion mutant of Salmonella Pullorum S06004 was constructed using the h-red recombinant system. Then the biological characteristics such as growth rate, biochemical properties, genetic stability and virulence were evaluated between the deletion mutant strain S06004ASPI2 and its parent strain S06004. [ Results] S06004ASPI2 was successfully constructed. The growth rate and biochemical properties of S06004ASPI2 were consistent with those of its parent strain S06004. The mutant was stable with the deletion of SPI-2. Chicken lethal test showed that the LD50 of S06004ASPI2 was 252 times higher than the parent strain S06004. [ Conclusion] The virulence of S06004ASPI2 was obviously attenuated. This study provided basic data for further study of the functions of SPI-2, and implied its potential to develop attenuated Salmonella vaccine.