大肠埃希菌和肺炎克雷伯菌质粒AmpC酶基因型及流行病学分析

THE ANALYSIS OF PLASMID-MEDIATED AMPC ENZYME GENOTYPE AND EPIDEMIOLOGY OF ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE

目的:研究大肠埃希菌和肺炎克雷伯菌中产质粒型AmpC酶株的比率、酶的基因型及其流行病学状况。方法:收集本院、福建省立医院两家医院2004年9月至2005年3月的67株耐头孢西丁不重复大肠埃希菌和肺炎克雷伯菌.用酶提取物三维试验检测高产AmpC酶;抽提高产AmpC酶株质粒,用聚合酶链式反应(PCR)及产物序列分析确定质粒AmpC酶和β内酰胺酶的基因型;质粒转化试验定位耐药基因;ERIC-PCR指纹图确定产酶株间的同源关系。结果:福州两家医院耐头孢西丁菌中产质粒型AmpC酶的发生率,大肠埃希菌分别为16.7%和10.5%,肺炎克雷伯菌则分别为8%和0。2株肺炎克雷伯菌产DHA-1型、4株大肠埃希菌产CMY-2型、1株大肠埃希菌产CMY-22型质粒Am- pC酶;5株产CMY型AmpC酶的大肠埃希菌还分别同时产CTX-M-14、CTX-M-27、TEM-144和TEM-1型β内酰胺酶。7株菌中,1株肺炎克雷伯菌和3株大肠埃希菌可将头孢西丁耐药性转移给受体菌。7株产酶菌ERIC-PCR指纹图显示,2株肺炎克雷伯菌来自相同克隆,其余菌株来自不同克隆。结论:福州地区发现产DHA-1型AmpC酶肺炎克雷伯菌和产CMY-2型及CMY-22型AmpC酶大肠埃希菌。CMY-22型AmpC酶和TEM-144型β内酰胺酶是国内外首次报道,GenBank登陆号为DQ256079和DQ256080。

Objective： To investigate the prevalence, genotype and epidemiolngy of plasmid - mediated AmpC enzyme of Escherichia coli and KlebsieUa pneumoniae. Method： A total of 67 clinical isolates of nonrepetitive cefoxitin - resistant Escherichia coli and Klebsiella pneumoniae collected by Fuzhou General Hospital and Fujian Provincial Hospital during a period of 2004.9 to 2005.3 were detected by three - dimensional extract test for AmpC enzyme, and PCR for AmpC enzyme and other β- lactamase gene amplification and DNA sequencing were carried out for genotype of β - lactamase . Plasmid transformation experiment was used to study the transfer of cefoxitin resistance. The homology of the isolates was determined by ER1C - PCR fingerprinting. Results： At two hospitals in Fuzhou, the prevalence of plasmid - mediated AmpC enzyme among celoxitin - resistant Escherichia coli and KlebsieUa pneumoniae were 16.5 % and 10.5 %, 8 % and 0 respectively. Two isolates of KlebsieUa pneumoniae produced DHA - 1 plasmid - mediated Amp（; enzyme, and four isolates of Escherichia coli and one strain of Escherichia coli produced CMY - 2 and CMY - 22 plasmid - mediated AmpC enzyme respectively. Furthermore, five strains of Escherichia coli with CMY AmpC enzyme were also found simultaneously to produce TEM - 144 , CTX - M - 27, CTX - M - 14 and TEM - 1 β- lactamase respectively. Three strains of Escherichia coil and one isolate of KlebsieUa pneumoniae can transfer cefoxitin resistance to acceptant bacillus. ERIC - PCR fingerprinting reveals two strains of KlebaieUa pneumoniae came from same done, but five strains of Escherichia coli came from different clones. Conclusion： The clinical isolates of KlebsieUa pneumoniae producing DHA - 1 plasmid - mediated AmpC enzyme and Escherichia coli producing CMY - 2, CMY - 22 plasmid - mediated AmpC enzyme were found in Fuzhou. CMY 22 AmpC enzyme and TEM - 144 13 - lactamase were the first reported in the world, GenBank accession number： DQ56079,DQ56080.