大肠埃希菌中质粒AmpC酶的流行分布

Distribution of plasmid-mediated AmpC beta-lactamase in Escherichia coli

目的了解河南地区大肠埃希菌中质粒AmpC酶的流行分布及其基因特征。方法对380株大肠埃希菌进行AmpC酶表型筛选,对筛选阳性株进行多重聚合酶链反应(PCR)及型特异PCR、克隆、测序;等电聚焦电泳检测细菌β-内酰胺酶等电点;接合实验验证质粒传递性;肠杆菌科基因组内重复一致序列(ERIC-2)PCR检测同源性。结果380株大肠埃希菌中2.1%(8株)的细菌产AmpC酶,经测序证实均为DHA-1型质粒AmpC酶基因,ERIC-2 PCR结果显示质粒AmpC酶主要以非克隆传播为主。结论河南地区发现DHA-1型质粒AmpC酶以非克隆传播为主。

Objective To investigate the genotype and distribution of plasmid-mediated AmpC β-1actamases in Escherichia colt in Henan. Methods 380 Escherichia colt were detected by standard disc diffusion method which was used as screen test for AmpC β-lactamase. Multiplex polymerase chain reaction （PCR） , type-specific PCR, clone, sequencing, isoelectric focusing analysis, conjugation and enterobacterial repetitive intergenic consensus-2 （ERIC-2） PCR were performed on positive strains to determine the genotype, the isoelectric point, the transitivity of plasmid and the homology of AmpC β-1actamases. Results 8 of 380 Escherichia colt strains （2. 1% ） were AmpC β-1actamasespositive strains. All of them were blaDnA which were confirmed by sequencing. The results of ERIC-2 PCR analysis indicated that the prevalences of plasmid-mediated AmpC β-1actamase were not due to epidemic strains. Conclusions The clinical isolate of Escherichia colt producing DHA-1 type plasmid-mediated AmpC β-1actamase was found in Henan. The prevalence were not due to epidemic strains.