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目的 探讨用中西药在体外消除肠道杆菌携带的耐药质粒 pRST98的可能性。方法 将原存在于伤寒杆菌中的耐药质粒 pRST98经接合转移分别导入大肠杆菌和鼠伤寒杆菌 ,选用双黄连和氧氟沙星对上述 3种细菌进行亚抑菌浓度的消除试验 ,并对实验前后的受试菌分别进行K -B纸片扩散法和最小抑菌浓度法 (MIC)药敏试验及质粒电泳检测。结果 两种药物在体外未能将受试菌携带的 pRST98消除 ;但该质粒编码的耐药标志减少 ;部分菌株对原有药物的耐药程度明显下降。结论 双黄连和氧氟沙星能降低pRST98宿主菌的耐药性 ,但药物作用后同一质粒在不同宿主菌中耐药性变化的差异 ,显示该质粒表达的多样性和复杂性。
Objective To explore the possibility of using traditional Chinese and western medicine to eliminate the resistant plasmid pRST98 carried by enterobacter in vitro. Methods The resistant plasmid pRST98 existing in Salmonella typhi was introduced into Escherichia coli and Salmonella typhimurium by conjugation and transfer respectively. Shuanghuanglian and ofloxacin were used to eliminate the sub-bacteriostatic concentration of the above three bacteria. Before and after the test bacteria were K-B disk diffusion method and the minimum inhibitory concentration method (MIC) susceptibility testing and plasmid electrophoresis. Results The two drugs failed to eliminate the pRST98 carried by the tested bacteria in vitro; however, the resistance markers of the plasmid were reduced. The resistance of some strains to the original drug was obviously decreased. Conclusion Shuanghuanglian and ofloxacin can reduce the drug resistance of pRST98 host bacteria, but the difference of the drug resistance of the same plasmid in different host bacteria after drug action shows the diversity and complexity of expression of the plasmid.