药物在体外消除肠道杆菌携带的耐药质粒pRsT98的研究

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式菌携带的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。

Study on the Elimination Antibiotic Resistant Plasmid pRST98 in Different Enteric Bacilli in Vitro

Objective To explore the possibility of eliminating the pR ST98 in different enteric bacilli using Chinese traditional medicine and Oflocaxin in vitro.Methods pR ST98 original presented in S.typhi was transferred to E.coli and S.typhimurium by conjugation-transfermation test.Subinhibitory concentration of the drugs was used to crue the plasmid in these three bacteria.Then the trea ted bacteria were tested by drug sensibility obtained by methods of Kirby-Bauer disc agar diffusion,MIC and plasmid electrophoresis.Results The drugs couldn't eliminate the pR ST98 in vitro.But the kinds of resistant markers coded by the plasmid were reduced and the level of drug resistance (MIC) had declined remarkably in some bacteria strain.Conclusion The used drugs can reduce the drug resistant level of the pR ST98 hosted bacteria.But the same plasmid treated by the same drugs in different bacteria has different resistant changes.The various expression of pR ST98 in different strains demonstrates the diversity and complexity of the resistant plasmid.