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目的 观察不同浓度的环丙沙星对培养的铜绿假单孢菌释放DNA的影响。方法 选择体外对铜绿假单孢菌 1244株(ATCC27317)敏感的环丙沙星为实验所用的抗生素, 检测其最小最小抑菌浓度(MIC)和最小杀菌浓度(MBC);将不同稀释度 ( 32 ~0. 03mg/L)的环丙沙星与该菌株菌液在 37℃培养,分别取其培养 4h和 24h的上清液经DNA电泳法检测其细菌DNA释放的情况。结果 无论有无环丙沙星,DNA电泳法均未见到培养 4h的样本存在细菌释放的游离DNA。体外培养 24h,铜绿假单孢菌可自发释放一定量的游离DNA分子,呈两个明显的区带, 其分子量分别大于2000bp和小于 100bp;远低于MIC的环丙沙星可诱导铜绿假单孢菌释放更多的游离DNA, 分布在 3个明显的区带,其中两个区带大于 2000bp,另 1个区带小于 100bp;大于或等于MIC的环丙沙星对铜绿假单孢菌无诱导DNA释放的作用。结论 自然生长情况下铜绿假单孢菌就可自发释放一定量的游离DNA分子;低于MIC的环丙沙星存在使这一现象更加明显,而且铜绿假单孢菌释放游离DNA分子的多少和分子量大小均有明显的差别。
Objective To observe the effect of different concentrations of ciprofloxacin on DNA release from cultured Pseudomonas aeruginosa. Methods Ciprofloxacin sensitive to Pseudomonas aeruginosa 1244 (ATCC27317) was selected as the antibiotic used in this study. The minimum and minimum bactericidal concentration (MIC) and minimum bactericidal concentration (MBC) ~ 0.03mg / L) of ciprofloxacin and the strain of bacteria culture at 37 ℃, respectively, and cultured for 4h and 24h supernatant was detected by DNA electrophoresis bacterial DNA release. Results No DNA was found in the samples incubated with bacteria for 4h with or without ciprofloxacin and DNA electrophoresis. In vitro cultured Pseudomonas aeruginosa spontaneous release of a certain amount of free DNA molecules, showed two distinct bands, the molecular weight were greater than 2000bp and less than 100bp; much lower than the MIC of ciprofloxacin can be induced pseudolobus single Spore release more free DNA, distributed in three obvious bands, of which two bands greater than 2000bp, another band less than 100bp; greater than or equal to MIC of ciprofloxacin Pseudomonas aeruginosa no Induction of DNA release. Conclusions Pseudomonas aeruginosa can spontaneously release a certain amount of free DNA molecules under natural growth conditions; the presence of ciprofloxacin below MIC makes this phenomenon more pronounced, and Pseudomonas aeruginosa releases more free DNA molecules and Significant differences in the size of the molecular weight.