目的研究比阿培南等抗生素诱导鲍曼不动杆菌释放内毒素（LPS）的作用机制。方法比阿培南、美罗培南、左氧氟沙星、头孢他啶4种药物以不同浓度作用于鲍曼不动杆菌，采用鲎试剂动态浊度法检测不同时间点的LPS含量；检测各药物在0.5×MIC时的细菌数量，并观察作用7 h后细菌的形态学改变。结果与对照组比较，各给药组释放的LPS均明显减少，且各高浓度给药组的LPS释放在作用后期趋于平缓。各给药组的细菌数量均明显低于对照组。细菌形态学研究显示，头孢他啶和左氧氟沙星组的细菌形态呈丝状，比阿培南和美罗培南组呈球形，且比阿培南组可观察到破碎菌体。结论 LPS释放水平与药物种类、药物浓度、作用时间等因素有关；比阿培南、美罗培南、左氧氟沙星、头孢他啶诱导鲍曼不动杆菌细菌释放LPS的作用机制不同。%Objective To study mechanisms of lipopolysaccharide (LPS) release from Acinetobacter baumannii (A. baumannii) induced by biapenem (BIPM), meropenem (MEM) and levofloxacin (LVFX). Methods A. baumannii was ex-posed to different concentrations of BIPM, MEM, LVFX, and ceftazidime (CAZ) at different time points. The LPS release was measured by tachypleus amebocyte lysate (TAL) test. Quantities of bacteria exposing to 0.5 MIC antibiotics were measured. The morphology of bacteria treated with different antibiotics for 7-hour was evaluated by light microscope. Results The LPS releases of A. baumannii treated with four kinds of antibiotics were significantly less than those of control group. In the later period, LPS releases of A. baumannii exposed to the high concentration of antibiotics tended to smooth. The cell quanti-ties of bacteria were significantly lower in treatment group than that of control group. The cells of A. baumannii treated with CAZ and LVFX showed long filamentous shape. The bacteria exposed to MEM and BIPM showed obviously globular. At the same time, some bacterial cells were induced to lysis rapidly by BIPM. Conclusion The level of LPS release is influenced by kinds of antibiotics, concentration and incubation period. All kinds of antibiotics could induce morphological changes of A. baumannii, which may be related to the different mechanisms that bacteria induce the different levels of LPS release.
展开▼
