EGCG、ECG对异质性耐万古霉素萄球菌抗药性的逆转作用研究

Reverse effect of EGCG, ECG on antibiotic resistance of heterogeneous vancomycin-resistant Staphylococcus

目的研究表没食子儿茶素没食子酸酯（EGCG）和表儿茶素没食子酸酯（ECG）对异质性耐万古霉素葡萄球菌（h-VRS）耐药性的体外逆转作用，并初步探讨其逆转机制。方法用微量肉汤稀释法测定EGCG、ECG对h—VRS的MIC值；以菌落计数法观察万古霉素在不同浓度EGCG、ECG协同作用下对h—VRS的生长抑制作用；用青霉素结合蛋白（PBP2a）胶乳凝集试验检测EGCG、ECG对待检菌PBP2a生成的抑制效力。结果EGCG、ECG对h-VRS原代菌株的MIC为128～512μg／mL，子代菌株的MIC为256～512μg／mL；在64～1024μg／mL的EGCG、ECG干预下，待测菌株在万古霉素作用下的生长受到明显抑制，生长菌落数降低程度随药物浓度的增加而升高；EOCG、ECG作用后h—VRS原代菌株PBP2a的凝集浓度为128～256μg／mL，子代菌株PBP2a的凝集浓度为32～128μg／mL。结论EGCG、ECG,ECG能够逆转h-VRS对万古霉素的耐药性，通过抑制h-VRS产生PBP2a是其发挥逆转作用的机制之一，是否还存在其它机制有待进一步的研究。

Objective To study the reverse effect of Epigallocatechin gallate （EGCG） and Epicatechin gallate（ECG） on antibiotic resistance of heterogeneous vancomycin resistant Staphylococcus（h-VRS） in vitro and its mechanism. Methods The minimal inhibitory concentration （MIC） against the h-VRS was detected by broth micro-dilution method. Colony count was used to observe the inhibitory growth effect of vancomycin with EGCG, ECG against the h-VRS. The inhibitory effect of EGCG, ECG on the penicillin binding protein 2a （PBP2a） was detected by PBP2a latex agglutination assay kit. Results The MIC of EGCG, ECG against the h-VRS primary and progeny strain were128 to 512μg/mL and 256 to 512μg/mL, respectively. Bacterial growth was inhibited obviously with EGCG, ECG in the range of 64 to 1024μg/mL, and the degree of decrease of colony number increased with the addition of drug. The aggregation concentration of PBP2a in h-VRS primary and progeny strain with EGCG or ECG was found to be 128 to 256μg/mL and 32 to 128μg/mL repectively. Conclusion EGCG and ECG have activities reverse resistance to vancomycin and inhibiting PBP2a expression in the h-VRS is the one of the mechanisms, whether there are other mechanisms to be further studied.