苍山18种地衣体外抗菌活性及联合药敏研究

In Vitro Antibacterial Activity and Combined Drug Sensitivity of 18 Lichen Species from Cangshan

本研究旨在探究18种苍山地衣体外抗菌活性及其天然活性产物与抗生素联用对耐甲氧西林金黄色葡萄球菌(Methicillin-resistant Staphylococcus aureus,MRSA)的协同效应。采用打孔法测定18种地衣对6种食源性致病菌的体外抗菌活性,并以MRSA为示踪,采用棋盘法测定活性地衣与7种常用抗生素的联合作用,并进行体外杀菌曲线、防突变浓度及抗生素后效应的测定。结果显示18种地衣中有10种地衣具备体外抗MRSA活性,以白边岛衣的抗菌活性最强,达到了极度敏感(抑菌圈直径为22.0 mm)。其中,光肺衣、寸石蕊与哌拉西林具有协同抗菌作用,二者与哌拉西林联用可以显著降低MRSA的菌体浓度(P<0.05),增强细菌防突变的能力,延长了哌拉西林的后效应。本试验结果表明多种苍山地衣提取物对MRSA具有较好的抗菌活性,且寸石蕊、光肺衣与哌拉西林具有协同抗MRSA的作用,具有进一步开发为抗生素及抗生素佐剂的潜力。

This study aims to explore the in vitro antibacterial activity of 18 lichen species from Cangshan and the synergistic effect of their natural active products in combination with antibiotics against methicillin-resistant Staphylococcus aureus(MRSA).The in vitro antibacterial activity of 18 lichen species against 6 food-borne pathogens was determined using the agar well diffusion method,and the combined effect of active lichens and 7 common antibiotics was evaluated using the checkerboard method with MRSA as the tracer.Additionally,in vitro bactericidal curves,antimutagenic concentrations,and post-antibiotic effects were examined.The results demonstrated that 10 of the 18 lichen species exhibited in vitro anti-MRSA activity,with strongest antibacterial activity observed for Cetraria laevigata,showing extremely high sensitivity(the diameter of the inhibition zone was 22.0 mm).Furthermore,the combination of Lobaria kurokawae and Cladonia uncialis with piperacillin demonstrated a synergistic antibacterial effect,significantly reducing MRSA bacterial density(P<0.05),enhancing mutation prevention capability,and prolonging the post-antibiotic effect of piperacillin.These findings suggest that the extracts from various Cangshan lichen species exhibit promising antimicrobial activity against MRSA,and the combination of Lobaria kurokawae,Cladonia uncialis,and piperacillin shows a synergistic antibacterial effect, which have the potential for further development as antibiotics or antibiotic adjuvants.