原子力显微镜观察头孢美唑抗生素后效应期间大肠埃希菌形态学特征

目的: 通过应用原子力显微镜对头孢美唑体外抗生素后效应(PAE) 期间E. coliATCC25922 的形态学观察, 深入探讨其抗生素后效应形成机制。方法: 采用菌落计数法测定头孢美唑对E. coli 的PAE的同时, 应用原子力显微镜观察体外PAE 期间4MIC 、128 MIC 的头孢美唑不同时间点E. coli. ATCC25922 的形态学变化。结果: 菌落计数法测定4MIC 、128 MIC 头孢美唑的体外PAE 分别为-0. 03 h和3. 65 h 。原子力显微镜结果表明低浓度(4 MIC)时细菌呈丝状体, 高浓度(128 MIC) 时细菌呈球状体, 而且在菌落计数法所测定的PAE 之后仍有细菌形态学改变。结论: 不同浓度的头孢美唑PAE 期间E. coli 菌体形态呈现不同的变化, 从而显示了不同浓度的头孢美唑PAE 期间对E. coli 具有不同的作用靶位。

Observation of morphology in Escherichia coli with atom microscope during the cefmetazole-induced post-antibiotic effect period

AIM: To study the mechanism of postantibiotic effect (PEA) by observing the changes of morphology.METHODS: The morphological effects of Escherichia coli were studied with atomic force microscopy (AFM) during the cefmetazole-induced post-antibiotic effect.RESULTS: The cefmetazole-induced (4 ×MIC, 128 ×MIC) PAE as defined by viability counting were-0. 03 h and 3. 65 h in Escherichia coli There was noted formation of filamentous structures at low concentrations (4 ×MIC) and the formations of spheroplasts at higher concentrations (128 ×MIC) by atomic force microscopy (AFM), and this morphological form persisted past the classically defined PAE.CONCLUSION: The mechanism of PAE is different at different concentrations through the inhibition of different protective bacterial enzymes.