大黄素对金黄色葡萄球菌生物膜抑制作用的体外研究

In vitro inhibitory effects of emodin on Staphylococcus aureus biofilm formation

目的研究大黄素对金黄色葡萄球菌生物膜早期形成及后期成熟的影响。方法以ATCC6538及编号为16-22的金黄色葡萄球菌为受试菌株,用琼脂稀释法测定大黄素的最低抑菌浓度(minimum inhibitory concentration,MIC);构建体外生物膜模型,用银染法观察载体表面的生物膜形态,结晶紫染色法和连续稀释法进行膜内活菌计数。结果大黄素对ATCC6538和16-22的MIC分别为32、16μg/ml。形态学观察发现≥4μg/ml的大黄素能有效减少金黄色葡萄球菌的黏附和破坏已成熟的生物膜。结晶紫染色法和连续稀释法的结果表明当大黄素的浓度达到8μg/ml后,75%的ATCC6538和70%的16-22金黄色葡萄球菌生物膜生成被抑制;56%的已成熟生物膜被破坏。结论大黄素在体外可以有效抑制金黄色葡萄球菌生物膜的形成并破坏成熟的生物膜。

Objective To investigate the effects of emodin on Staphylococcus aureus(S.aureus)biofilm formation and disruption.Methods ATCC6538 and S.aureus 16-22 were used in this study.The minimum inhibitory concentrations(MICs)of emodin against the two strains were detected by the standardized agar dilution method.After an in vitro biofilm model was established,silver staining method was used to observe the bacterial cell morphology;crystal violet staining and double dilution method were performed to measure the viable count of bacteria in biofilms.Results The MICs of emodin against ATCC6538 and 16-22 were 32μg/ml and 16μg/ml,respectively.The bacterial cell morphology showed that≥4μg/ml emodin effectively reduced the adherence of S.aureus to the plate and destroyed mature biofilms.The results of crystal violet staining and double dilution method showed that when the concentration of emodin reached to 8μg/ml,75%of ATCC6538 and 70%of 16-22 failed to form biofilms and 56%of the mature biofilms on the plate were broken.Conclusions Emodin could effectively inhibit the biofilm formation and destroy the mature biofilms of S.aureus in vitro.