加替沙星和环丙沙星体外抗生素后效应期间大肠埃希菌形态学观察及膜电位和膜通透性变化

目的:通过对加替沙星和环丙沙星体外抗生素后效应(PAE)期间E.coliATCC25922的形态学观察以及膜电位、膜通透性变化的研究,以期为探讨PAE形成机制提供实验依据。方法:在不同时间点吸取加替沙星和环丙沙星抗PAE期间的大肠埃希菌培养液,用荧光探针碘化丙啶和DiBAC4(3)进行染色,应用荧光显微镜观察E.coliATCC25922的形态学变化,并采用流式细胞仪分析其膜电位、膜通透性变化。结果:荧光显微镜结果表明:菌落计数法所测定的PAE之后仍有丝状体存在,但流式细胞仪结果表明加替沙星和环丙沙星PAE期间E.coliATCC25922膜电位及膜通透性与空白对照组比较无显著性差异。结论:加替沙星和环丙沙星PAE期间E.coli菌体显著延长,呈丝状体,而其膜电位及膜通透性比较则无显著性变化,提示丝状体形成与细胞膜变化不直接相关。

Investigation of morphological characteristics, membrance potential and membance patency in Escherichia coli following ciprofloxacin exposure

AIM: To study the changes of bacterial ultrastructure, membrance potential and membrance patency of Escherichia coli during the postantibiotic effect after exposure to gatifloxacin and ciprofloxacin in order to investigate the mechanisms of PAE. METHODS: During the Postantibiotic effect after exposure to gatifloxacin and ciprofloxacin, the aliquots were taken from the bacterial culture at regular intervals. Then the fluorescence microscope was used to observe changes in bacterial ultrastructure and at the same time we studied the changes of membrance potential and membrance patency in Escherichia coli during the postantibiotic effect by flow cytometry in conjunction with fluorescent probes. RESULTS: The PAE phase characterized by filament formation after exposure to gatifloxacin by fluorescence microscopy,yet no significant changes in membrance potential and membrance patency of Escherichia coli were observed. CONCLUSION: Gatifloxacin and ciprofloxacin can induce filamentation, and this change is indifferent with membrance potential and membrance patency of Escherichia coli.