阳离子卟啉衍生物的体外光动力抗菌活性研究

目的 研究阳离子卟啉衍生物介导的光动力抗菌化学疗法(CPD-PACT)对体外培养的绿脓杆菌的抑制作用,为研究其高效的抗菌作用特点提供依据.方法 采用二倍稀释法考察培养条件对CPD最小抑菌浓度(MIC)的影响,扩散法测定CPD的抑菌圈,活菌计数法测定CPD的体外抗菌后效应,并通过激光扫描共聚焦显微镜(CLSM)观察绿脓杆菌的活力和形态变化.结果 细菌接种量对MIC值存在一定的影响;培养基pH值的升高会使化合物的MIC值相应升高;血清蛋白体积分数的增加会使光反应的MIC值升高,而暗反应的MIC值降低.抑菌圈的大小主要取决于激光能量密度的强弱,而受光敏剂浓度的影响较小.CPD对绿脓杆菌有较强的抑制和杀灭作用,且存在明显的抗菌后效应,但光疗结束后存活的细菌会继续增殖.CLSM观察结果表明,CPD-PACT可破坏细菌外膜完整性,使细菌内容物泄露,活力减弱,最终导致细菌死亡.结论 CPD-PACT对绿脓杆菌具有高效的抗菌活性和明显的抗菌后效应,适合作为新一代抗菌候选药物进行深度开发.

In vitro photodynamic antibacterial activity of cationic porphyrin derivative

Objective To investigate susceptibility and antibacterial activity of cationic porphyfin derivative mediated photodynamic antimicrobial chemotherapy (CPD-PACT) against Pseudomonas aeruginosa,to provide experimental evidence for its high efficiency antibacterial activity.Methods The impacts of culture environments on minimum inhibitory concentration (MIC) were measured by double dilution method.The formation of inhibition zone was determined by diffusion plate method.The postantibiotic effect was analyzed by colony forming units.The viability and morphology of Pseudomonas aeruginosa were observed by confocal laser scanning microscopy (CLSM).Results The inoculum size of bacterial had a certain effect on the MIC.The MIC values increased as the pH of medium rose.When the calf serum content of culture medium increased,the MIC rose in light reaction and dropped in dark reaction.The diameter of inhibition zone mainly depended on the laser energy density,but not the concentration of photosensitizer.Though CPD possessed strong antimicrobial activity and persistent suppression on bacterial growth,the surviving Pseudomonas aeruginosa would soon continue to proliferate after PACT.The fluorescence images captured by CLSM showed that CPD-PACT could destroy the membrane integrity,leak the cytoplasmic component,decrease the bacterial activity and finally lead Pseudomonas aeruginosa to death.Conclusions CPD has strong inhibitory activity and obvious postantibiotic effect on Pseudomonas aeruginosa,which is suitable to be developed as an drug candidate for PACT.