用1.29×107 CFUs肺炎杆菌滴鼻,引起小鼠呼吸道感染,未治疗组的动物大部分死亡.本文比较了左氧氟沙星、氧氟沙星和洛美沙星对小鼠呼吸道感染的治疗作用.结果发现感染20h后,40mg/kg的左氧氟沙星可使小鼠肺研磨液中的细菌数由每毫升109.29减少到105.84,其ED50分别为氧氟沙星和洛美沙星的2.25和2.42倍,说明左氧氟沙星的疗效明显优于氧氟沙星和洛美沙星.%Experimental respiratory tract infection was induced in mice by intranasal instillation of 1.29×107 CFUs Klebsiella pneumonia. Bacterial challenge directly resulted in deposition of 105.24 CFUs of the organisms in the lungs. The number of organisms in the lungs increased rapidly, and by 18h, a well-developed pneumonia was apparent. Most of the untreated mice died within two days after infection. The therapeutic effectiveness of levofloxacin, ofloxacin and lomefloxacin was compared with this established pneumonia model. For each compound, the CFUs decreased with the increase of dosage. The effectiveness of levofloxacin, however, was superior to those of the others. Administration of 40 mg of levofloxacin per kg can decrease the CFUs in the lungs from 109.29 to 105.84 at 20h after infection, and saved all infected animals. ED50 of levofloxacin was 2.25 and 2.42 times that of ofloxacin and lomefloxacin respectively.
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