产CTX型超广谱β-内酰胺酶的大肠埃希菌基因分析及耐药特征  

Resistance and genotyping of producing CTX-type extended-spectrumβ-lactamase Escherichia coli isolates

作　　者：潘玫[1] 李稳[1] 王靖男[1] 张苗[1] 刘泉[1] 陈山[2] 

机构地区：[1]山东中医药大学附属医院检验科,济南250011 [2]山东大学附属省立医院检验科,济南250021

出　　处：《山东大学学报（医学版）》2013年第11期61-65,共5页Journal of Shandong University:Health Sciences

基　　金：国家自然科学基金(81000869);济南"泉城学者"建设工程招标课题(Q2-06)

摘　　要：目的探讨产超广谱β-内酰胺酶(ESBLs)大肠埃希菌blaCTX-M基因分型及相应耐药特征。方法采用双纸片法检测ESBLs,PCR检测blaCTX-M及blaCTX-M-1、-2、-8、-9、25组基因,肉汤稀释法检测抗菌药物MIC值。结果 83株大肠埃希菌中,45株ESBLs表型确证实验阳性,PCR扩增结果显示44株blaCTX-M扩增阳性,其中12株单独检测出blaCTX-M-1组,29株单独检测出blaCTX-M-9组,3株同时具有blaCTX-M-1组和blaCTX-M-9组,未检测出blaCTX-M-2、-8、-25组。所有菌株对亚胺培南皆敏感,对头孢唑林、头孢噻肟、头孢曲松皆耐药。CTX-M-1组菌株对头孢他啶、头孢吡肟的耐药率皆为91.6%(11/12),氨曲南耐药率为100%,左旋氧氟沙星、庆大霉素耐药率分别为100%和83.3%(10/12)。CTX-M-9组菌株对头孢他啶、头孢吡肟耐药率分别为44.8%(13/29)、41.4%(12/29),氨曲南耐药率为55.2%(16/29),左旋氧氟沙星耐药率为89.7%(26/29)、庆大霉素耐药率为58.6%(17/29)。CTX-M-1、-9两组菌株对头孢他啶、头孢吡肟、氨曲南耐药率差异有统计学意义(P<0.05)。结论产ESBLs大肠埃希菌基因型以blaCTX-M为主,blaCTX-M-9组在blaCTX-M基因中占优势。CTX-M-9组菌株对头孢他啶、头孢吡肟、氨曲南敏感性高于CTX-M-1组。Objective To detect the genotypes and resistance of producing CTX-M type extended-spectrum β-lactamase E.coli isolates. Methods ESBLs was confirmed with phenotypic confirmatory test; blaCTX-M, blaCTX-M-1, -2, -8, -9, -25 genotypes were detected with polymerase chain reaction （PCR）; MIC was determined with broth dilution method. Results Of the 83 Escherichia coli isolates, 45 were ESBLs-producing strains, and 44 produced CTX-M-type ESBLs. Of these 44 isolates, 12 produced blaCTX-M-1, 29 produced blaCTX-M-9 and 3 produced both blaCTX-M-1 and blaCTX-M-9. The blaCTX-M-2, blaCTX-M-8 and blaCTX-M -25 genotypes were not detected. No imipenem-resistant strains were found. All 44 strains showed resistance to cefazolin, cefotaxime, and ceftriaxone. The drug resistance rates of CTX-M-1 strain to ceftazidime, cefepime, aztreonam, levofloxacin and gentamicin were 91.6%, 91.6%, 100%, 100% and 83.3%. The drug resistance rates of CTX-M-9 strain to ceftazidime, cefepime, aztreonam, levofloxacin and gentamicin were 44.8%, 41.4%, 55.2%, 89.7% and 58.6%. There was significant difference between the two rates concerning ceftazidime, cefepime, and aztreonam （P〈0.05）. Conclusion The blaCTX-M is the major genotype producing ESBLs, in which blaCTX-M-9 is dominant. CTX-M-9 strains are more sensitive to ceftazidime, cefepime and aztreonam than CTX-M-1 strains.

关 键 词：大肠埃希菌 CTX-M型超广谱Β-内酰胺酶 基因型 耐药特征 

分 类 号：R378.21[医药卫生—病原生物学]