肠炎沙门氏菌鸡源株ompR基因缺失株的构建及生物学特性与亲本株的比较

Construction and characterization of an ompR gene deletion mutant from Salmonella enteritidis

【目的】为了探讨ompR基因在肠炎沙门氏菌生物被膜形成及毒力中的作用。【方法】以肠炎沙门氏菌作为母本,运用自杀性载体pGMB151构建了ompR基因缺失株,结晶紫染色法和扫描电镜观察测定缺失株的生物被膜形成能力,细胞的吸附和侵入及小鼠攻毒试验测定缺失株的毒力。【结果】RT-PCR和蛋白表达证明了ompR基因缺失株构建成功;该缺失株不表达纤维素和菌毛,不形成生物被膜;上皮细胞吸附和侵入试验表明缺失株与野生株具有相同的吸附和侵入率;BALB/c鼠腹腔感染性试验表明,缺失株的半数致死量为106.67CFU,而野生株的半数致死量小于2 CFU。【结论】ompR基因既是肠炎沙门氏菌生物膜形成的调控基因,又是重要的毒力基因。

[Objective] To investigate the role of ompR gene from Salmonella enteritidis in biofilm formation and virulence.[Methods] We constructed an ompR mutant of Salmonella enteritidis by suicide plasmid pGMB151.Biofilm forming ability of the mutant was detected by crystal violet assay and scanning electron micrography.Virulence of the mutant was determined by assay of adherence to and invasion of epithelial cells,and mouse challenge experiments.[Results] The ompR mutant was confirmed by RT-PCR and the pattern of outer membrane protein.The mutant did not produce cellulose,curli,and biofilm,and showed similar adherence percentage to and invasion percentage of epithelial cells as wild type strain.In addition,intraperitoneal challenge of bacteria in BALB/c mice revealed that LD50 of the mutant strain was 106.67 CFU,while that of the wild type strain was less than 2 CFU.[Conclusion] These data indicate that the ompR gene is involved in both biofilm formation and virulence in Salmonella enteritidis.