摘要
目的研究多药耐药肺炎克雷伯菌GyrA突变及超广谱β-内酰胺酶(ESBLs)基因型。方法对2008年分离的46株肺炎克雷伯菌〔(30株分离自零售食品(凉拌菜),16株分离自医务人员鼻腔拭子)〕采用K-B法进行药敏试验,检测多药耐药菌是否产ESBLs,PCR法扩增多药耐药菌环丙沙星耐药相关基因gyrA,ESBLs基因bla-TEM、blaSHV和blaCTX-M,3类整合酶基因(intⅠ1,intⅠ2,intⅠ3)及第1类整合子可变序列;对PCR产物进行测序分析,脉冲场凝胶电泳(PFGE)对多药耐药菌进行分子分型。结果 9株菌为多药耐药菌,3株菌在GyrA的QRDR区83位Ser→Ile,1株菌在GyrA的QRDR区83位Ser→Thr,8株菌产ESBLs,6株菌携带SHV型ESBL,其中3株菌同时携带TEM型ESBL;2株菌携带OKP型ESBLs;未检测到CTX-M型ESBLs,1株菌intⅠ1基因阳性,携带有第1类整合子和耐药基因盒aacA7,PFGE将9株菌分为8个PFGE型,2株菌为同一个PFGE型。结论耐药基因的获得如gyrA基因突变和携带ESBLs基因是肺炎克雷伯菌产生多药耐药的主要机制。
OBJECTIVE To investigate the drug resistance,GyrA mutation and the genotypes of extended-spectrum beta-lactamases （ESBLs） in Klebsiella pneumoniae.METHODS A total of 46 strains of K.pneumoniae isolated from retailed food （cold dish,30 isolates） and nasal swabs of medical staff （16 isolates） were collected in 2008,the antimicrobial susceptibility test for all isolates was performed by KB method,and ESBLs production was tested for all multidrug-resistant isolates according to CLSI criteria.PCR was used to amplify ciprofloxacin resistance associated gene,gyrA,and ESBLs genes,blaTEM,blaSHV and blaCTX-M,integrase genes（intⅠ1,intⅠ2 and intⅠ3）,and variable sequence of class 1 integron.PCR products were sequenced and analyzed.Pulsed-field gel electrophoresis （PFGE） was performed for all multidrug-resistant isolates.RESULTS Nine out of forty-six isolates were multidrug-resistant from them three of had the Ser83→Ile change,and one had the Ser83→Thr change inside the quinolone resistance-determining region （QRDR） of GyrA.Eight out of nine isolates produced ESBLs including,six produced SHV-type ESBLs,and three carried TEM-type ESBLs,two out of six isolates carried OKP-type ESBLs.CTX-M-type ESBLs were not detected.One out of nine isolates carried the class 1 integron and the gene cassette,aacA7.Nine isolates were classified into eight patterns by PFGE,two of nine isolates belonged to the same PFGE pattern.CONCLUSION Acquisition of drug resistance genes,such as gyrA gene mutation and ESBLs gene,is the predominant mechanism for K.pneumoniae to cause multidrug resistance.
出处
《中华医院感染学杂志》
CAS
CSCD
北大核心
2010年第16期2365-2367,共3页
Chinese Journal of Nosocomiology
基金
国家自然科学基金(30700678)
天津市科技支撑计划重大项目(07SYSYSF05100)
