阴沟肠杆菌产超广谱β-内酰胺酶的基因型调查  

The resistance genes of extended-spectrum a-lactamases in Enteroba cter cloacae

作　　者：顾怡明[1] 张杰[1] 俞云松[2] 周志慧[2] 杜小玲[3] 

机构地区：[1]北京天坛医院,北京100050 [2]浙江大学医学院附属第一医院,杭州310003 [3]北京朝阳医院,北京100020

出　　处：《中国抗生素杂志》2004年第2期82-85,共4页Chinese Journal of Antibiotics

基　　金：国家自然科学基金(30270074)

摘　　要：目的了解北京朝阳医院阴沟肠杆菌中产ESBLs的流行情况,并对携带的ESBLs基因型进行调查。方法采用表型筛选法对58株对第三代头孢菌素或氨曲南敏感性降低的阴沟肠杆菌进行检测。对20株初筛阳性的细菌进行琼脂稀释法药敏试验、等电点测定,并对β-内酰胺酶编码基因进行克隆测序。结果表型筛选法对58株阴沟肠杆菌检测的结果显示产ESBLs菌株的检出率为34.48%(20/58)。药敏结果显示,单独产生ESBLs的菌株对头孢西丁、头孢吡肟、哌拉西林/三唑巴坦和头孢哌酮/舒巴坦的敏感率分别为100%、32.5%和87.5%。同时携带ESBLs和AmpC酶的菌株只对亚胺培南敏感。20株检测阳性的细菌中,14株ESBLs编码基因PCR结果阳性,分别为:SHV-2、SHV-2a、SHV-12、CTX-M-14和CTX-M-22型ESBLs。对另外6株进行粗酶等电点测定发现分别存在7.89、8.0、8.57等电点条带,并被克拉维酸抑制。结论产生超广谱β-内酰胺酶是造成阴沟肠杆菌对第三代头孢菌素耐药的另一重要原因。Objectives To elucidate the prevalence of extended-spectrum a-lact amases among Enterobacter cloacae and to investigate the genotypes of ESBLs prod ucers in Beijing Chaoyang Hospital.Methods Phenotype screening test was performe d to detect the 58 strains of Enterobacter cloacae resistant to the third-gener ation cephalosporins or aztreonam. Standard agar dilution method,isoelectric fo cusing,PCR amplification,gene clone and DNA sequencings were preformed in 20 cl inical isolates which were confirmed by phenotype screening test.Results Results of phenotype screening test showed 20 strains(34.48%) produced ESBLs enzymes.T he susceptible rates to cefoxitin,cefepime piperacillin/tazobactam and cefotaxim e/sulbactum was 100%,37.5%,50%and 87.5%,respectively.ESBLs puls AmpC beta-l actamase-producers were only susceptible to impenem.DNA sequencing of amplicons of 14 strains revealed ESBLs of SHV-2,SHV-2a,SHV-12,CTX-M-14 and CTX-M-2 2, respectively.The other six strains produced unidentified enzymes with pI 7.89 ,8.0,and 8.57 which were inhibited by clavulanic acid.Conclusion ESBLs are one o f the important drug-resistant mechanisms of Enterobacter cloacae.

关 键 词：阴沟肠杆菌 超广谱Β-内酰胺酶 基因型 序列分析 表型筛选法 抗生素 

分 类 号：R378.2[医药卫生—病原生物学] R978.1[医药卫生—基础医学]