红霉素、左氧氟沙星对铜绿假单胞菌生物被膜作用的体外研究

EFFECTS OF ERYTHROMYCIN AND LEVOFLOXACIN ON PSEUDOMONAS AERUGIN-OSA BIOFILM IN VITRO

目的:建立铜绿假单胞菌生物被膜(BF)的体外模型,研究红霉素(EM)对细菌BF的影响及对左氧氟沙星(LFX)的增效作用。方法:采用生理盐水—吸痰管系统进行BF的培养,建立铜绿假单胞菌BF体外模型,银染法快速鉴定,扫描电子显微镜观察BF的变化。将头孢他啶(CAZ)、LFX单独或分别与EM联合作用于早期BF和成熟BF,连续稀释法进行各组几个作用时间的存活菌菌落计数,用试管二倍稀释法测定药物的最低抑菌浓度(MIC)。结果:小剂量的EM即可以抑制铜绿假单胞菌对吸痰管载体的黏附和抑制BF的形成(P<0.01)。无论是对早期BF或成熟BF,LFX对BF内细菌的杀菌活性均强于CAZ(P<0.01),LFX与EM联合应用后效果优于LFX单独应用(P<0.01)。结论:相对于CAZ,LFX对BF有较强的通透性,对BF内细菌有较强的清除作用。EM可以减少细菌的黏附,抑制铜绿假单胞菌BF的形成,增加抗菌药物对BF的渗透性,从而增强抗菌药物对铜绿假单胞菌的杀菌作用。LFX和EM联合应用效果更佳,是治疗细菌生物被膜相关感染的良好选择。

Objective：To investigate the destructive effect of erythromycin （EM） on biofilm of pseudomonas aeruginosa （PA） in vitro. Methods： Pseudomonas aeruginosa were cultivated in physiological saline solution-aspirate sputum pipe system to establish bacterial biofilm model in vitro, which was identified by silver staining and observed under scanning electronic microscope （SEM）. After the biofilm was treated by EM ,ceftazidime （CAZ） and LFX respectively,and by the combination of EM with CAZ or LFX, the number of viable bacteria were measured by serial dilution. Minimal inhibitory concentrations （MIC） were determined by tube broth dilution method. Result： 16 μg/ml EM significantly inhibited the adherence of pseudomonas aeruginosa and the formation of biofilm compared with the control（ P 〈 0.01）. Whether for earlier period BF or for mature BF, LFX significantly reduced the number of viable PA compared with CAZ alone（ P 〈 0.01）. Combined with EM, the effect was better than LFX alone（ P 〈 0. 01）. The results of silver nitrate staining were consistent with SEM and the number of viable bacteria. Conclusion：The results suggest that LFX has more potent of permeability into biofilm and has stronger eradication on boifilm bacteria than CAZ. Inhibiting the adherence of pseudomonas aeruginosa, blocking the formation of biofilm and reinforcing the permeability into biofilm, EM enhances the antibacterial activity of antibiotics against PA. When LFX was combined with EM, there were synergetic actericidal effect against PA.