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目的：在世界范围内，Ｒ质粒在细菌间的传递，引起了多重耐药性菌株的增加，给临床上抗生素的使用造成了严重的困难。人们试图寻找有效的消除剂，把Ｒ质粒从宿主菌株中消除掉，使其重新恢复对抗生素的敏感性。中药黄连常用于治疗腹泻与细菌性痢疾。但对致婴幼儿腹泻的大肠杆菌的Ｒ质粒是否有消除作用？本课题以黄连为质粒消除剂，研究黄连对大肠杆菌Ｒ质粒的消除作用。方法：致婴儿腹泻的大肠杆菌为本室保存菌株，已知对四环素、链霉素、氨苄青霉素耐药，其耐药性均由质粒介导。黄连为多次蒸馏提取的水溶性粉剂，主要成分为小檗碱。由吉林省中医中药研究院药物研究室提供。首先将大肠杆菌接种ＬＢ培养基中，经活化后，分别加入含不同浓度黄连的培养基中，判定黄连的亚抑菌浓度。从亚抑菌浓度管中取５０ｕｌ菌液，分别划种于ＳＳ平板上，经培养后，挑取单个菌落，以影印培养法，依次转接于含ＴＣ（２０ｕｇ／ｍｌ），ＳＭ（４０ｕｇ／ｍｌ）或ＡＰ（２０ｕｇ／ｍｌ）的药物平板上，３７℃培养２４～４８ｈ。消除子的筛选和鉴定：选择在含抗素的选择平板上不生长，而在不含抗生素的普通平板上生长的菌落，即为Ｒ质粒消除子。再经快速质粒抽提，琼脂糖凝胶电泳，以检测质粒带的消失情况。结果：黄连（１．?
OBJECTIVE: Worldwide, the transmission of R plasmids between bacteria has caused an increase in multi-drug resistant strains, which has caused severe difficulties in the use of antibiotics in clinical practice. People are trying to find effective elimination agents to eliminate the R plasmid from the host strain and restore it to antibiotic susceptibility. Chinese medicine Coptis is often used to treat diarrhea and bacterial dysentery. But is there an elimination effect on the R plasmid of E. coli that causes diarrhea in infants and young children? In this study, Coptis chinensis was used as a plasmid elimination agent to study the elimination effect of Rhizoma Coptidis on R plasmid of E. coli. METHODS: Escherichia coli caused by infantile diarrhea was a preserving strain in the chamber and was known to be resistant to tetracycline, streptomycin, and ampicillin. The drug resistance was mediated by plasmids. Coptis chinensis is a water-soluble powder extracted by multiple distillations and its main component is berberine. Provided by the Jilin Provincial Institute of Traditional Chinese Medicine Research Institute of Medicine. First, Escherichia coli was inoculated into LB medium. After activation, each medium containing different concentrations of Coptis was added to determine the subinhibitory concentration of Coptis chinensis. 50 ul of bacterial solution was taken from the sub-inhibitory concentration tube and sowed on the SS plate. After the culture, a single colony was picked and transferred to the TC (20 μg/ml), SM (40 μg/ml). Ml) or AP (20ug/ml) on the drug plate, cultured at 37°C for 24-48h. Screening and Identification of Elimination Agents: The selection did not grow on the selection plate containing the antibiotic, but the colonies grown on the ordinary plate without the antibiotic were the R plasmid elimination agent. After rapid plasmid extraction and agarose gel electrophoresis, the disappearance of the plasmid band was detected. Result: Coptis (1.?