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.