表没食子儿茶素没食子酸酯及其纳米粒子制备及抗菌增敏作用研究

Study on the preparation and antibacterial sensitization of epigallocatechin gallate and its nanoparticles

  • 摘要: 目的:研究表没食子儿茶素没食子酸酯(EGCG)及其纳米粒子对6种临床常见多重耐药细菌(MDRO)的抗菌及药物增敏作用。方法:选取从临床标本中分离培养的6种MDRO,分别为耐甲氧西林金黄色葡萄球菌(MRSA)、耐甲氧西林表皮葡萄球菌(MRSE)、多重耐药鲍曼不动杆菌(MDR-Aba)、多重耐药铜绿假单胞菌(MDR-Pae)、产ESBL 大肠埃希菌(ESBL-Eco)及产ESBL 肺炎克雷伯菌(ESBL-Kpn),采用肉汤稀释法测定EGCG 及其纳米粒子的最低抑菌浓度(MIC),绘制细菌22 h生长曲线,采用活菌涂板法测定最低杀菌浓度(MBC),采用棋盘稀释法测定EGCG 及其纳米粒子分别联用7种抗菌药物(克林霉素、头孢西丁、青霉素、左氧氟沙星、氨曲南、头孢曲松、氨苄西林/舒巴坦)的联合效应及增敏效果。结果:EGCG 对6 种MDRO 的MIC 为350~500 μg/mL,MBC 为350~700 μg/mL;EGCG 纳米粒子对6 种多重耐药细菌的MIC 为62.5~125 μg/mL,MBC 为175~350 μg/mL,说明纳米粒子的MIC、MBC 较低,生长曲线也表明了纳米粒子较明显地延后了细菌的对数生长期。EGCG+抗菌药物的联合效应均为协同或相加作用,其中增敏效果最好的组合有EGCG恢复了MRSA对头孢西丁、MDR-Aba对左氧氟沙星的敏感性;EGCG 纳米粒子+抗菌药物的联合效应主要为相加作用,其中增敏效果最好的组合有EGCG 纳米粒子恢复了MRSA对头孢西丁、青霉素的敏感性。结论:EGCG及其纳米粒子对6种MDRO均有抑菌活性,单用EGCG纳米粒子的抑菌效果优于EGCG,EGCG及其纳米粒子分别联合7种抗菌药物可增加耐药细菌的敏感性。

     

    Abstract: Objective: To study the antibacterial and drug sensitizing effects of epigallocatechin gallate (EGCG)and its nanoparticles on 6 kinds of clinically common multi-drug-resistant organisms.Methods: Six multi-drugresistant organisms isolated from clinical samples were selected.The isolates were methicillin-resistant Staphylo-coccus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), multi-drug-resistant Acineto-bacter baumannii(MDR-Aba), multi-drug-resistant Pseudomonas aeruginosa(MDR-Pae), ESBL-producing Esch-erichia coli (ESBL-Eco) and ESBL-producing Klebsiella pneumoniae (ESBL-Kpn).Broth dilution method was used to determine the minimum inhibitory concentration (MIC) of EGCG and its nanoparticles, and the 22 h growth curve of bacteria was drawn.Live bacteria coating method was used to determine the minimum bactericidal concentration(MBC).The chessboard di-lution method was used to determine the combined effect and sensitization effect of EGCG and its nanoparticles in combination with 7 antibacterial drugs(clindamy-cin, cefoxitin, penicillin, levofloxacin, amtrexone, ceftriaxone, ampicillin/sulbactam).Results: The MIC of EGCG against 6 multi-drug-resistant organisms was 350 μg/mL-500 μg/mL, and the MBC was 350 μg/mL-700 μg/mL.The MIC of EGCG nanoparticles against 6 multi-drug-resistant organisms was 62.5 μg/mL-125 μg/mL, and the MBC was 175 μg/mL-350μg/mL.This indicated that the MIC and MBC of nanoparticles were lower, and the growth curve also indicated that nanoparticles significantly delay the logarithmic growth period of bacteria.The combined effects of EGCG and antibacterial drugs were synergistic or additive, and the combination with the best sensitization effect was that EGCG restored the sensitivity of MRSA to cefoxitin, and that EGCG restored the sensitivity of MDR-Aba to levofloxacin; the combined effects of EGCG nanoparticles and antibacterial drugs were mainly additive, and the combination with the best sensitization effect was that EGCG nanoparticles re-stored the sensitivity of MRSA to cefoxitin and penicillin.Conclusion: EGCG and its nanoparticles have antibac-terial activity against 6 kinds of multi-drug-resistant organisms.The antibacterial effect of EGCG nanoparticles alone is better than that of EGCG.The combination of EGCG and its nanoparticles with 7 antimicrobial drugs can increase the sensitivity of drug-resistant organisms.

     

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