脆弱类杆菌亚胺培南抗性基因的分子克隆

Molecular Cloning of the Imipenem Resistant Gene in Bacteroides Fragilis

为从分子水平对类杆菌抗性基因和抗性转移进行深入研究，进而寻找出能有效阻断耐药基因传播的措施，并从分子水平上认识医院内感染耐药基因传播与表达的影响因素，作者对临床分离的脆弱类杆菌亚胺培南抗性株的染色体ＤＮＡ进行了分子克隆，获得了１．７ｋｂ的亚胺培南抗性基因片段，而且其重组质粒能在大肠杆菌ＤＨ５中稳定传代和表达。以随机引物法，用地高辛配基标记亚胺培南抗性基因制备探针，对临床分离的４０株类杆菌进行亚胺培南抗性基因检测，结果显示２株亚胺培南抗性株出现杂交信号，３８株亚胺培南敏感株无杂交信号。提示亚胺培南抗性基因探针可用于类杆菌耐药性的分子流行病学调查。

Imipenem, as a representative ofcabapenem, is one of the most effective β Lactam agents against Bacteroides, but recently there have been a few reports on the resistant strains of Bacteroides. To explore the mechanism of imipenem resistance (IMP r) at the molecular level, we extracted chromosome DNA of the resistant strains and acquired a 1.7kb fragment of resistant gene of imipenem. Recombinant plasmid was stably reserved in generation after generation in E. coli DH 5. Resistant gene of imipenem was labeled with Dig 11 dUTP by way of random prime, and 40 strains of clinically isolated Bacteroides were detected by the prepared DNA probe. Two IMP r strains showed hybridization signal, whereas 38 IMP s strains did not show such a signal. The result suggests that the Dig labeled IMP r gene probe can be used in molecular epidemiology for investigating IMP r strains.