Sokolova G B, Kunichan A D, Litovchenko K V, Tsybanev A A
Research Institute of Phtisiopulmonology, I. M. Sechenov Moscow Medical Academy, Moscow.
Antibiot Khimioter. 2002;47(12):15-9.
Levofloxacin in vitro demonstrated bactericidal effect against susceptible and multi-drug resistant Mycobacterium tuberculosis: range of MICs was 0.25-0.5 mcg/mL, MBC-0.5-1.0 mcg/mL. Postantibiotic effect after 24-hour exposition to bactericidal concentrations was 35-39 days. Levofloxacin possesed low toxicity when tested in mice lungs tissue culture--maximum safety concentration was 50 mcg/mL. Bactericidal effect of levofloxacin started three days after exposition and was maximal by 7 days of incubation: by this time mycobacterial microcolonies destruction started with detritus formation. It is emphasized that lung cells kept their viability completely. Combination of levofloxacin with isoniazide or pirazinamide resulted in strong synergistic effect obvious after 5 days of incubation, mycobacterial colonies destruction was registered by 7th day. Combination of levofloxacin with rifampicin resulted in antagonistic effect obvious by 7th day of the contact: the resulting effect was statistically significant and was manifested as microcolonies number and size enlargement when compared to data for single levofloxacin.
最低抑菌浓度（MIC）范围为0.25 - 0.5微克/毫升，最低杀菌浓度（MBC）为0.5 - 1.0微克/毫升。在杀菌浓度下暴露24小时后的抗生素后效应为35 - 39天。在小鼠肺组织培养中测试时，左氧氟沙星毒性较低——最大安全浓度为50微克/毫升。左氧氟沙星的杀菌作用在暴露三天后开始，培养7天时达到最大：此时分枝杆菌微菌落开始破坏并形成碎屑。需要强调的是，肺细胞的活力完全得以保持。左氧氟沙星与异烟肼或吡嗪酰胺联合使用，在培养5天后产生明显的强协同效应，到第7天可观察到分枝杆菌菌落被破坏。左氧氟沙星与利福平联合使用，在接触第7天时产生明显的拮抗效应：与单用左氧氟沙星的数据相比，所产生的效应具有统计学意义，表现为微菌落数量增加和尺寸增大。
