黄绵马酸BB对皮肤软组织感染致病菌的抗菌活性及机制研究

Antibacterial activity and mechanism of flavaspidic acid BB on pathogenic bacteria of skin and soft tissue infection

目的研究黄绵马酸BB对皮肤软组织感染致病菌的抗菌活性,并探讨其对金黄色葡萄球菌的抗菌机制。方法采用微量稀释法测定黄绵马酸BB对皮肤软组织感染相关致病菌的最低抑菌浓度(minimum inhibitory concentration,MIC)和最低杀菌浓度(minimumbactericidalconcentration,MBC);以对黄绵马酸BB敏感的耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)临床分离株和金黄色葡萄球菌标准株ATCC29213为受试菌,考察黄绵马酸BB对其生长活力和菌体形态结构的影响,采用酶标仪考察黄绵马酸BB对其细胞壁通透性的影响,采用荧光分光光度计考察黄绵马酸BB对细胞膜电位的影响,采用qRT-PCR法考察黄绵马酸BB对青霉素结合蛋白1(penicillin-binding protein1,PBP1)m RNA表达的影响。结果黄绵马酸BB对ATCC29213的MIC为10.0~20.0μg/mL,MBC为10.0~40.0μg/mL,且对MRSA临床分离株的MIC小于头孢唑啉;与对照组比较,黄绵马酸BB组ATCC29213和MRSA生长受到抑制,菌体细胞形态结构改变,细胞膜电位显著降低(P<0.05),1/2MIC黄绵马酸BB可显著下调PBP1 mRNA表达水平(P<0.01),2MIC黄绵马酸BB可显著上调PBP1 mRNA表达水平(P<0.01)。结论黄绵马酸BB对MRSA临床分离株表现出良好的抗菌活性,且其抗菌作用与破坏菌体细胞结构、降低细胞膜电位、影响PBP1 mRNA表达有关。

Objective To study the antibacterial activity of flavaspidic acid BB on pathogenic bacteria related to skin and soft tissue infections,and explore the antibacterial mechanism against Staphylococcus aureus.Methods The microdilution method was used to determine the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of flavaspidic acid BB against pathogenic bacteria related to skin and soft tissue infections;Clinical strain of methicillin-resistant Staphylococcus aureus(MRSA)and Staphylococcus aureus standard strain ATCC29213,which were sensitive to flavaspidic acid BB,were used as test bacteria to explore the influence of flavaspidic acid BB on growth vitality and the morphological structure of tested bacteria.Effect of flavaspidic acid BB on permeability of cell wall was detected by microplate reader;Effect of flavaspidic acid BB on cell membrane potential was detected by fluorescence spectrophotometer;Effect of flavaspidic acid BB on expression of penicillin-binding protein 1(PBP1)m RNA was detected by qRT-PCR.Results MIC of flavaspidic acid BB against ATCC29213 was 10.0—20.0μg/mL,MBC was 10.0—40.0μg/mL,MIC values of MRSA clinical strains were lower than cefazolin.Compared with control group,growth of ATCC29213 and MRSA in flavaspidic acid BB group were inhibited,morphological structure of bacterial cell was changed,and cell membrane potential was reduced(P<0.05),expression of PBP1 mRNA was down-regulated by 1/2 MIC flavaspidic acid BB and up-regulated by 2 MIC flavaspidic acid BB(P<0.01).Conclusion The flavaspidic acid BB exhibits good antibacterial activity against MRSA clinical strains,of which antibacterial effect is related to the destruction of bacterial cell structure,lowering the cell membrane potential and affecting the expression of PBP1 m RNA.