中药复方MHC-20的抗化脓性链球菌功效与作用机制探究

Efficacies and mechanisms of a formula of Chinese medicinal plants(MHC-20)against Streptococcus pyogenes

以化脓性链球菌(Streptococcus pyogenes)为研究对象,探究了MHC-20的抑菌性能及作用机制。通过微量肉汤稀释法以及常量稀释法测得MHC-20对化脓性链球菌的MIC值为31.25μg/mL或0.31%,并且对金黄色葡萄球菌以及白色念珠菌等均有较强杀伤作用。瞬时杀菌活性结果表明:MHC-20在5 min时可以完全杀死化脓性链球菌。定量生物膜与疏水性测定结果表明:MHC-20能够极显著降低化脓性链球菌细胞表面疏水性(P<0.0001)以及极显著抑制生物膜的形成(P<0.01)。细胞膜通透性测定结果表明:MHC-20作用下菌液相对电导率、碱性磷酸酶均上升、蛋白严重泄露,并且呈浓度依赖性。扫描电子显微镜结果表明:MHC-20对菌体形态有很强的破坏作用。最后,构建了小鼠化脓性链球菌皮肤感染模型,结果表明:复方MHC-20可以促进创口恢复,极显著抑制创口的细菌(P<0.01),5%MHC-20与20%MHC-20均极显著降低小鼠血清以及创口炎症因子IL-6表达(P<0.001),20%MHC-20极显著降低白细胞的表达(P<0.01),综上所述,MHC-20有望成为广谱抗菌剂以及抗化脓性链球菌皮肤感染的有效药物。

The antimicrobial properties and mechanisms of a formula of Chinese medicinal plants(MHC-20)against Streptococcus pyogenes were studied.The MIC of MHC-20 against S.pyogenes was 31.25μg/mL or 0.31%as measured by broth micro-or macro-dilution.MHC-20 was also found to have strong killing effects on Staphylococcus aureus,Escherichia coli and Candida albicans.The results of instantaneous bactericidal activity showed that MHC-20 was able to kill S.pyogenes completely in 5 min.It could also significantly reduce the cell surface hydrophobicity and inhibit the formation of biofilm.Cell membrane permeability test showed that MHC-20 could induce the increase of relative conductivity and alkaline phosphatase,as well as the protein leakage,in a concentration-dependent manner.The results of scanning electron microscopy further confirmed that MHC-20 had a strong destructive effect on cell morphology.Finally,a mouse model of cutaneous infection with S.pyogenes was established.It was shown that MHC-20 could promote wound healing and significantly inhibit the loading concentration of S.pyogenes(P<0.01);5%MHC-20 and 20%MHC-20 significantly decreased the expression of IL-6 in serum and tissue of the mice(P<0.001).20%MHC-20 significantly decreased the expression of leukocytes(P<0.01).In conclusion,MHC-20 had the potential to be developed into a broad-spectrum antibiotic and an effective drug for cutaneous infection with S.pyogenes.