三黄汤与环丙沙星对大肠杆菌体外抑菌作用的比较

目的]比较三黄汤与环丙沙星对耐药性大肠杆菌体外抑菌作用的差异,探讨二者联合使用的临床意义。方法]试管稀释法测定三黄汤和环丙沙星的MIC,采用分批培养法绘制在亚MIC浓度下二者抑菌曲线和组合用药时抑菌曲线。结果]三黄汤、环丙沙星的MIC值分别为450 mg/ml和15.63μg/ml;在亚MIC浓度下三黄汤对大肠杆菌的抑菌曲线一直保持平稳状态;而环丙沙星抑菌曲线在起始3～4 h内呈下降趋势,随后保持较平稳状态。通过转接20次培养后,发现三黄汤的MIC没有明显改变,而环丙沙星MIC增至90.7μg/ml,显著增高;组合药物培养时,FIC指数<0.5,表现为协同作用;通过不同梯度组合培养测出最佳组合浓度为三黄汤112.5 mg/ml、环丙沙星9.38μg/ml,在最佳组合药物的培养下,大肠杆菌的抑菌曲线起初表现环丙沙星的抑菌作用,但随后保持稳定;组合药物中转接20次的大肠杆菌对环丙沙星的药敏性有所提高,其MIC值降至11.4μg/ml。

Inhibitory Effect Comparison of Sanhuang and Ciprofloxacin against E.coli in vitro

Objective] To comparative Sanhuang with Ciprofloxacin reinstating E.coli in vitro antibacterial and explore the clinical significance of combination.Method] Use tube dilution method to determine the minimum inhibitory concentration（MIC） of Sanhuang and Ciprofloxacin and drawn the bacteriostatic curves when in the conditions of Sub-MIC concentration.Result] The MIC of Sanhuang and Ciprofloxacin are 450 mg/ml and 15.63 μg/ml.When expose to Sub-MIC of Sanhuang,bacteriostatic curves kept flat in the entire times,but decreased quickly in the first 3-4 h and then increased to the beginning in the Ciprofloxacin liquid.After 20 times serial passage in Sub-MIC Ciprofloxacin,To combination drug culture fractional inhibitory concentration（FIC） index 0.5 for synergy,the MIC of Ciprofloxacin to E.coli rose from 15.63 μg/ml to 90.7 μg/ml,while it did not increase in Sanhuang.By serial dilutions,the best rate were Sanhuang 112.5 mg/ml and Ciprofloxacin 9.38 μg/ml;bacteriostatic curves growth decreased quickly in the first 3-4 h like Ciprofloxacin but soon increased to the beginning,it was found that the MIC of Ciprofloxacin in combination drug dropped to 11.4 μg/ml.