Study on ceftazidime-induced endotoxin release in Escherichia coli and anti-endotoxin effect of Chinese medicine injections in vitro

Objective To study the factors that influence the endotoxin release induced by ceftazidime in different Escherichia coli concentrations,and to explore the anti-endotoxin effects of 3 kinds of Chinese medicine injections,namely Qingkailing injection,Shuanghuanglian injection and Xiyanping injection in vitro.Methods Two-fold dilution to determine the MIC of ceftazidime,and determine if the MIC could be altered by 3 kinds of injections when used in routine dosages;to study if ceftazidime(at 50×MIC) could affect the production of endotoxin while added to different concentrations of Escherichia coli which in logarithm phase;to determine the anti-endotoxin activity of the three injections when used concomitantly with ceftazidime. ResultsThe MIC of ceftazidime was 0.125 μg/ml,Qingkailing injection and Xiyanping injection had no effect on it,but Shuanghuanglian injection could lead it to increased;at high Escherichia coli concentrations(2.5×104～2.5×105 CFU/ml),ceftazidime induced a great deal of endotoxin release,but at low concentrations(2.5×10～2.5×103 CFU/ml),ceftazidime inhibited endotoxin release;the using sequence of Chinese medicine injections and ceftazidime could affect endotoxin release.When Qingkailing injection and Xiyanping injection used after giving ceftazidime,they showed anti-endotoxin effect,and Xiyanping injection was the better.Conclusion The endotoxin releasing activities of ceftazidime were not only related to the bacterial concentrations but also influenced by the sequence usage of Qinakailing or Xiyanpang injections.