中药复方MHC-20的抗化脓性链球菌功效与作用机制探究OACSTPCD

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 31.25 μg/m L 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.