Abstract: Objective To explore the role of OmpA gene in the pathogenicity of Rodentibacter heylii. Method The homologous recombination technique was used to construct the OmpA gene deletion strain of R. heylii. Its growth characteristics, genetic stability, biochemical characteristics, mass spectrometry characteristics, biological development and effects on mouse lung type Ⅱ epithelial cell line ( MLE-12 cells ) Adhesion; intraperitoneal injection of the OmpA gene-deficient strain to verify its pathogenicity to mice. Result The OmpA gene deletion strain of R. heylii was successfully constructed. The gene deletion strain could be inherited stably. Compared with the wild-type strain, the biochemical characteristics did not change, the mass spectrogram and growth curve were basically the same, and the biofilm formation ability was significantly enhanced ( P<0. 01) ; Adhesion to MLE-12 cells decreased from 43. 9% to 18. 3% (P<0. 001) ; Intraperitoneal challenge to mice, the lethality rate decreased from 100% to 20% ( P < 0. 01 ) . The pathogenicity of the gene deletion strain to mice decreased significantly. Conclusion The deletion of the OmpA gene significantly weakened the pathogenicity of R. heylii, confirming that OmpA plays an important role in the infection process of R. heylii.

Key words: Rodentibacter heylii, OmpA gene, gene deletion mutant, virulence

摘要： 目的 探究外膜蛋白 A(OmpA)基因与海立啮齿杆菌(Rh)致病性的关系。 方法 采用同源重组技术构建海立啮齿杆菌分离株 OmpA 基因缺失株,分析其生长特性、遗传稳定性、生化特征、质谱特征、生物被膜产生能力、对小鼠肺上皮细胞(MLE-12)的黏附力,及对小鼠的致病性。 结果 成功构建海立啮齿杆菌 OmpA 基因缺失株,可稳定遗传。 与野生型菌株相比,生化特征未发生改变,质谱峰图和生长曲线基本一致,生物膜形成能力显著增强( P<0. 01) ;对 MLE-12 细胞的黏附力从 43. 9% 降低至 18. 3% ( P< 0. 001) ;对小鼠腹腔攻毒,致死率从 100% 降至 20%(P<0. 01) ,基因缺失株对小鼠致病力显著下降。 结论 OmpA 基因的缺失致使海立啮齿杆菌的致病性明显减弱,证实 OmpA 在海立啮齿杆菌的感染过程中发挥着重要作用。

关键词: 海立啮齿杆菌, OmpA 基因, 基因缺失株, 毒力