3种蒙药复方对致病性Escherichia coli O1的抑菌机理及对小鼠的保护率

【目的】研究3种蒙药复方对致病性Escherichia coli O1的抑菌机理及对感染E.coli O1小鼠的保护率。【方法】分别采用酶标比浊法、微生物粘附法、试剂盒法和邻硝基苯β-D-半乳吡喃糖苷(ONPG)法测定3种蒙药复方对E.coli O1生长曲线、细胞表面疏水性、细胞壁及细胞膜渗透性的影响。同时,采用人工感染小鼠法测定其对小鼠的保护率。【结果】3种蒙药复方均能不同程度地抑制致病性E.coli O1,且对人工感染E.coli O1的小鼠有保护作用,其中蒙药复方Ⅲ的保护率与环丙沙星相当,均达到50%;7味单药组成的蒙药复方Ⅲ水煎剂作用于E.coli O1细胞时,首先改变其表面疏水性,其次随作用时间的延长破坏其细胞壁的完整性,进而破坏细胞膜并改变其通透性,最终导致细胞结构的破坏,从而起到抑制作用。【结论】蒙药复方Ⅲ的体内外抑菌效果最佳,其效果与抗生素环丙沙星相当。

Inhibition of pathogenic Escherichia coli O1 and protection of infected mice by three Mongolian medicinal compounds

[Objective] We studied the antibacterial effect of three Mongolian medicinal compounds against pathogenic Escherichia coli O1 and their protection of mice infected with E. coli O1. [Methods] The effects of Mongolian medicinal compounds on the growth curve, cell surface hydrophobicity, the cytoderm and cell membrane permeability of E. coli O1 were determined by turbidimetry, the microbial adhesion to solvents method, reagent kit and membrane permeability assay with ONPG as a substrate. In addition, the protection of mice was evaluated by E. coli O1 challenge. [Results] All three compound recipes inhibited the growth of pathogenic E. coli O1 and protected mice against E. coli O1. The highest protection rate (50%) was obtained for mice treated with Mongolian medicinal compound recipe III, as same rate as ciprofloxacin treated mice. When acting on the E. coli O1 cells, the decoction of Mongolian medicinal compound recipe III consisted of 7 herbs firstly changed the surface hydrophobicity of the cell and secondly destroyed the integrity of the cell wall over time, and then destroyed the cell membrane and changed the permeability, which eventually destroyed the cell structure. [Conclusion] Mongolian medicinal compound recipe III showed the best antibacterial effect against E. coli O1 both in vivo and in vitro and its protection rate in mice infected with E. coli O1 was comparable with the antibiotic ciprofloxacin.