论文部分内容阅读
【目的】研究废水中产超广谱β-内酰胺酶大肠杆菌中可移动质粒在耐药基因水平传播机制中的作用。【方法】对污水厂分离所得的50株产ESBLs大肠杆菌进行接合试验,并对所得的接合子采用纸片扩散法测定其对15种常见药物的耐药表型,针对质粒介导的产ESBLs菌株的耐药基因设计7对特异性引物对接合子进行PCR扩增。【结果】研究结果显示,80份水样分离得50株产ESBLs大肠杆菌,共接合成功35株细菌,接合成功率高达70%。接合子与供体菌相比,均发生耐药谱型的改变,且存在丢失一种或几种药物耐药性且产生另一种或几种药物耐药性的现象。PCR扩增结果显示,接合子与供体菌相比,耐药基因型有所减少或不变,bla_(TEM)、bla_(CTX-M)基因全部接合成功,bla_(SHV)基因仅1株未接合成功,耐氟喹诺酮类基因未发生转移。【结论】本研究表明,不同的耐药基因可能位于不同的可移动质粒上,可移动质粒在大肠杆菌耐药性水平传播的过程中起到了十分重要的作用。
【Objective】 The objective of this study was to investigate the role of transportable plasmids in extended-spectrum β-lactamase-producing Escherichia coli in drug-resistant gene transmission in wastewater. 【Method】 50 strains of ESBLs-producing Escherichia coli isolated from wastewater treatment plant were used for conjugation test. The obtained conjugates were tested for resistance phenotype to 15 common drugs by disk diffusion method. For plasmid-mediated ESBLs-producing ESBLs Strain drug-resistant gene design 7 pairs of specific primers for zygotic PCR amplification. 【Result】 The results showed that 50 strains of ESBLs-producing Escherichia coli isolated from 80 water samples were successfully combined with 35 strains of bacteria. The success rate of conjugation was as high as 70%. Compared with the donor conjugate, the change of the drug resistance pattern occurs, and there is a phenomenon that the drug resistance of one or several drugs is lost and another drug resistance is caused. The results of PCR amplification showed that the resistance genotypes of blaZ (TEM) and bla_ (CTX-M) genes were all successfully joined and the bla_ (SHV) gene was only 1 strain Did not join the success of fluoroquinolone resistance gene transfer did not occur. 【Conclusion】 This study shows that different resistance genes may be located on different movable plasmids. Removable plasmids play an important role in the spread of E. coli resistance.