【摘要】 目的明确新的质粒介导的碳青霉烯酶IMI-3传播机制。方法采用E试验测定抗菌药物MIC,接合试验、酶切克隆筛选及鸟枪法测序对编码基因IMI-3传播机制进行研究。结果发现阳性克隆菌E.colipT103有5个开放读码框(ORF)。在编码基因IMI-3的两侧各有一相同的插入序列,氨基酸序列与IS903有71%的同源性。鸟枪法测序显示IMI-3与染色体介导的IMI-1有99%的同源性。结论IMI-3编码基因是由位于染色体上的IMI-1经点突变通过转座酶Tn903转移至可接合性质粒上。更多还原

【Abstract】 ObjectiveTo investigate the transmission mechanism of the novel plasmid-mediated carbapenemase IMI-3.MethodsThe minimum inhibitory concentrations(MICs) were determined by E test.The transmission mechanism of the novel plasmid-mediated carbapenemase IMI-3 was studied by conjugation experiment,restriction endonuclease digestion,cloning and screening,shot gun sequencing.ResultsThe inserted fragment from E.coli pT103 contained five open reading frames(ORFs).In each flanking side of the encoding gene IMI-3,there is an identical inserted sequence,which had 71% homology with IS903. Sequence analysis showed that IMI-3 has 99% homology with chromosome-mediated IMI-1 in terms of the deduced amino acid sequence.ConclusionsThis study confirms that IMI-3 is transferred from chromosome-mediated IMI-1 with point mutations to plasmid via Tn903.更多还原