沙门菌果蝇感染致死模型构建及其评价

目的为了比较不同沙门菌对果蝇致死毒力,建立果蝇沙门菌肠道感染模型,并进行模型评价。方法将鼠伤寒沙门菌SL1344、14028S和肠炎沙门菌C50041及其突变株C50041ΔspiC,以OD₆₀₀为100的高浓度菌液通过饲喂法和针刺法,分别感染30只CS型果蝇和yw型果蝇,每隔3 h观察活果蝇数,计算存活率,分析沙门菌毒力。结果肠炎沙门菌C50041和C50041ΔspiC饲喂果蝇,120小时后CS型果蝇存活率0%,yw型果蝇的存活率低于20%,而针刺法感染CS型果蝇和yw型果蝇存活率则高于80%;鼠伤寒沙门菌饲喂法感染CS型果蝇和yw型果蝇,其存活率均高于90%。针刺法存活率均高于60%。比较分析显示,鼠伤寒沙门菌肠道感染耐受和肠炎沙门菌肠道感染敏感,存在明显的差异;肠炎沙门菌对果蝇肠道感染模式的毒力明显高于非肠道感染模式,不同果蝇品系之间则无明显的差异。结论本研究中,果蝇沙门菌肠道感染模型被成功建立,并能够评价不同沙门菌的毒力,其中肠炎沙门菌C50041果蝇肠道感染呈高度敏感,为后续肠炎沙门菌功能基因鉴定研究奠定基础,便于深入研究沙门菌致病机理。

Construction of drosophila Salmonella death model and its assessment

To compare the virulence of different Salmonella in the Drosophila, construction of Drosophila/Salmonella infection model and its assessment were made. S.typhimurium SL1344, 14028S and S.enteritidis C50041 and its mutant strain C50041ΔspiC infected 30 CS and yw drosophilas, respectively, at an OD₆₀₀ of 100 by feeding or acupuncture, live Drosophilas were numbered every 3 hours for survival rate to compare Salmonella virulence. The results showed that after being infected S.enteritidis C50041 and C50041 ΔspiC by feeding for 120 h, the survival rate of 30 CS Drosophilas was 0%, and the survival rate of yw Drosophilas was less than 20%, but the survival rate of CS and yw drosophilas infected S.enteritidis by acupuncture were over 80%; the survival rate of CS and yw drosophilas infected S.typhimurium by feeding was over 90%, the survival rate of that by acupuncture is over 60%. Comparative analysis showed that S.typhimurium intestinal-infection was resistant and S.enteritidis intestinal-infection was sensitive to drosophilas, there were significant differences; S.enteritidis virulence by intestinal infection was significantly higher than that by the non-intestinal infection to drosophilas, there was no significant difference between CS and yw drosophilas. In this study, Drosophila/Salmonella infection model was constructed successfully and could assess the virulence of different Salmonella, the sensitive intestinal-infection model of S.enteritidis C50041 by feeding Drosophila will provide a basis for the subsequent identification of the functional genes of S.enteritidis for its pathogenic mechanism.