副溶血弧菌ompA基因缺失株的生物学特性及致病性分析

Biological characteristics and pathogenicity of an ompA mutant of Vibrio parahaemolyticus

[目的]外膜蛋白Omp A是一个多功能蛋白,在很多革兰氏阴性菌的环境适应性和致病性过程中发挥重要作用,而副溶血弧菌Omp A的功能尚未见报道。本试验旨在研究omp A基因(VPA1186)对副溶血弧菌生物学特性及致病性的影响。[方法]通过构建副溶血弧菌SH112株的omp A基因缺失株和互补株,开展对该基因在细菌生长特性、生物被膜形成、运动性、血清杀菌、细胞黏附、细胞毒性,组织载量以及小鼠致病性等相关生物学特性和致病性的影响研究。[结果]omp A的缺失不影响副溶血弧菌的生长速度、生物被膜形成能力和运动性。野生株和Δomp A的黏附和抗血清试验结果无显著差异。但Δomp A对Caco-2细胞的毒性作用显著低于野生株。小鼠染毒验结果显示,与感染野生株的小鼠相比,感染Δomp A的小鼠症状明显减轻,存活率更高,Δomp A在小鼠血液和肝脏中的带菌量显著低于野生株,而互补株的毒力恢复至野生株水平,表明omp A缺失能显著降低副溶血弧菌的毒力。[结论]omp A与副溶血弧菌的致病性相关,为潜在的毒力因子。

[Objectives]The outer membrane protein A(OmpA),a multifaceted protein,plays important roles in environmental adaptability and pathogenicity in many gram-negative bacteria.However,the function of OmpA in Vibrio parahaemolyticus is unclear.The aim of this study is to elucidate the role of ompA gene(VPA1186)in biological characteristics and virulence of V.parahaemolyticus.[Methods]With ompA gene deletion mutant and complementary strain constructed,we analyzed the differences of growth,biofilm,motility,adhesion and cytotoxicity to Caco-2 cells,serum resistance,and mice lethality rate,bacterial colonization between mutant strain and wild strain.[Results]Compared to the wild strain,the mutant strain had no differences on growth rate,biofilm formation,motility,serum resistance and adhesion to Caco-2 cells.However,ΔompA showed significantly weaker cytotoxicity to Caco-2 cells than wild type strain.In addition,the ompA mutant strain exhibited attenuated virulence in mice that it showed lighter clinical symptoms and higher survival rate than those of the wild type strain.Moreover,ΔompA showed significantly decreased colonization compared with the wild type strain in blood and liver,whereas the complementation strain restored the virulence to resemble that of wild-type strain.[Conclusions]The ompA gene was a potential virulence factor and associated with the pathogenesis of V.parahaemolyticus.