聚乙二醇小檗碱液对大肠埃希菌和金黄色葡萄球菌生长的抑制作用

Bacteriostatic effect of mixed solution of berberine and PEG on Escherichia coli and Staphylococcus aureus

目的明确聚乙二醇小檗碱液在琼脂培养基表面的抑菌特点,及其对大肠埃希菌和金黄色葡萄球菌的标准菌株、抗生素敏感菌株与多重耐药菌株生长的抑制作用,研究评价药物在皮肤黏膜表面的抑菌作用的合理实验方法。方法以大肠埃希菌和金黄色葡萄球菌(标准菌株、抗生素敏感菌株和多重耐药菌株)为研究对象,用常量肉汤稀释法测定聚乙二醇小檗碱液的最低抑菌浓度(Minimum Inhibitory Concentration,MIC);用平皿琼脂培养法和试管肉汤培养法测定不同浓度聚乙二醇小檗碱液的抑菌作用。结果在不同浓度的聚乙二醇小檗碱液的作用下,在琼脂培养基表面上或肉汤培养基中细菌的生长受到明显抑制,抑制作用与小檗碱浓度正相关,且对抗生素敏感菌株和多重耐药菌株的抑制作用差异无统计学意义;聚乙二醇小檗碱液在平皿琼脂表面和试管肉汤中对大肠埃希菌、金黄色葡萄球菌抑制100%菌株的浓度分别为1 500和375 mg/L、1 500和375 mg/L。聚乙二醇小檗碱液在琼脂培养基表面的抑菌作用明显低于在肉汤培养基中的抑制作用,在琼脂培养基表面的抑菌浓度是肉汤培养基中的抑菌浓度的4倍。并且金黄色葡萄球菌与大肠埃希菌之间差异无统计学意义。聚乙二醇小檗碱液必须达到肉汤培养基中4倍以上浓度时,才能获得抑制100%细菌在琼脂培养基表面生长的效果。结论高浓度的聚乙二醇小檗碱液可以抑制皮肤黏膜表面的细菌,包括抗生素耐药菌株的生长;皮肤黏膜表面应用聚乙二醇小檗碱液的适宜浓度为1 500 mg/L。琼脂培养基法适用于评价药物在皮肤黏膜表面的抑菌作用。

Objective To identify the antibacterial activity of mixed solution of berberine and polyethylene glycol （PEG） on the surface of agar and determine its bacteriostatic effect on reference strains, antibiotic-sensitive strains and multi-resistant strains of Esche- richia coli and Staphylococcus aureus, and discover reasonable experimental methods for evaluation of drug inhibitory effect on the surface of skin and mucous membrane. Methods The minimum inhibitory concentrations （MICs） were determined by macro-broth dilution method. Bacteriostatic effect was determined by both agar dilution method and broth dilution method. Results At different concentrations of the mixed berberine and PEG, the growth of the bacteria was obviously inhibited on the surface of agar and in broth. The bacteriostatic effect of berberine was dose-dependent. There was no significant difference in the inhibitory effect between antibiotic-sensitive strains and multi-resistant strains. The 100% inhibitory concentrations of mixed berberine and PEG against the two pathogens on the surface of agar or in broth were both 1 500 mg/L or 375 mg/L. The inhibition effect of mixed berberine and PEG solution on the surface of agar was obvious- ly lower than in broth, with the inhibitory concentration on the surface of agar being 4 times higher than that in broth, and there was no significant difference between the two pathogens. Conclusion Mixed solution of berberine and PEG at high concentration can significant- ly inhibit the growth of bacteria, including multi-resistant strains, on the surface of skin and mucous membrane. 1500 mg/L can be an ap- propriate concentration for application on the surface of skin and mucous membrane in clinical use. Agar dilution method is suitable for as- sessment of the inhibitory effect of antibacterial drugs on the surface of skin and mucous membrane.