细胞内抗嗜肺军团菌药物有效浓度测定

【目的】 探讨红霉素､环丙沙星､左氧氟沙星､莫西沙星4种抗菌药物对细胞内嗜肺军团菌的抗菌活性｡【方法】 分别采用E-test法和有限稀释法测定上述4种药物对嗜肺军团菌ATCC 33152的细胞外抗菌活性,再用噻唑蓝比色法(MTT法)测定上述药物对嗜肺军团菌ATCC 33152的细胞内抗菌活性｡【结果】 细胞外抗菌活性E-test法:红霉素0.047 μg/mL､环丙沙星0.38 μg/mL､左氧氟沙星0.125 μg/mL､莫西沙星0.125 μg/mL;有限稀释法:红霉素0.125 μg/mL､环丙沙星0.03 μg/mL､左氧氟沙星0.016 μg/mL､莫西沙星0.016 μg/mL｡4种药物的细胞内抗菌活性分别为:红霉素0.25 μg/mL､环丙沙星0.016 μg/mL､左氧氟沙星0.016 μg/mL､莫西沙星0.004 μg/mL｡【结论】 氟喹诺酮类药物在U937细胞模型中对嗜肺军团菌ATCC 33152具有很强的细胞内抗菌活性｡其中莫西沙星的细胞内抗菌活性最强｡MTT法是一种行之有效的用于检测药物对细胞内嗜肺军团菌抗菌活性的方法,可同时检测并对比各种药物样本的细胞内抗菌活性｡

Assay System for Antimicrobial Concentration of Drugs against Intracellular Legionella Pneumophila

[Objective]To explore the intracellular antimicrobial activities of erythromycin,ciprofloxacin,levofloxacin,moxifloxacin against Legionella pneumophila.[Methods]The minimum inhibition concentration(MIC)of each antibiotic was evaluated by E-test method and microdilution method respectively.The minimal extracellular concentration inhibiting intracellular multiplication(MIEC)of each antibiotic was evaluated by the MTT colorimetric assay system.[Results]The MIC concentration for each drug by E-test method were:erythromycin,0.047 μg/mL;ciprofloxacin,0.38 μg/mL;levofloxacin,0.125 μg/mL;moxifloxacin,0.125 μg/mL,the MIC concentrations for each drug by microdilution method were:erythromycin,0.125 μg/mL;ciprofloxacin,0.03 μg/mL;levofloxacin,0.016 μg/mL;moxifloxacin,0.016 μg/mL.The MIEC concentration for each drug were:erythromycin,0.25 μg/mL;ciprofloxacin,0.016 μg/mL;levofloxacin,0.016 μg/mL;moxifloxacin,0.004 μg/mL.[Conclusions]Fluoroquinolones have superior activity than erythromycin in U937 cells infected with L.pneumophila.Moxifloxacin is the most potent drug among the four tested antimicrobials.Our results indicated that the MTT assay system allows comparative and quantitative evaluations of the intracellular activities of antibiotics against L,pneumophila and efficient processing of a large number of samples.