多重耐药阴沟肠杆菌流行状况及耐药机制的研究  

Drug-resistant Mechanisms and Prevalence of Enterobacter cloacae Resistant to Multi-antibiotics

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]首都医科大学附属北京天坛医院,北京100050 [2]浙江大学医学院附属第一医院,浙江杭州310003 [3]首都医科大学附属北京朝阳医院,北京100020

出　　处：《中华医院感染学杂志》2004年第12期1321-1324,共4页Chinese Journal of Nosocomiology

基　　金：国家自然科学基金项目(编号:30270074)

摘　　要：目的了解多重耐药阴沟肠杆菌的流行状况及耐药机制。方法58株临床分离的对第三代头孢菌素耐药的阴沟肠杆菌进行琼脂稀释法药敏试验、表型筛选法和聚合酶链反应克隆测序。结果58株阴沟肠杆菌表型筛选结果显示,高产AmpC酶株、单产ESBLs株和同时产AmpC酶和ESBLs株的检出率分别为65.52%、13.79%和20.69%;58株阴沟肠杆菌对多种抗菌药物耐药,高产AmpC酶菌株、单产ESBLs菌株和同时产AmpC酶和ESBLs菌株对头孢哌酮/舒巴坦的敏感率分别为55.3%、87.5%和16.7%;对哌拉西林/他唑巴坦的敏感率分别为28.9%、50%和8.3%;对头孢吡肟的敏感率分别为97.4%、37.5%和16.7%;对亚胺培南的敏感率均为100%;58株临床分离株ESBLs编码基因的测序结果显示,分别为SHV2、SHV2a、SHV12、CTXM14和CTXM3型ESBLs;58株临床分离株的ampD基因PCR扩增显示49株阳性,占84.48%,对其中8株进行克隆测序,均存在可疑的羧基端突变位点。结论产生AmpC酶和ESBLs是阴沟肠杆菌对头孢菌素耐药的主要机制。OBJECTIVE To investigate the main drug resistant mechanisms of Enterobacter cloacae and to make clear the prevalence of E. cloacae resistant to multi antibiotics. METHODS Standard agar dilution method, phenotype screening test, PCR amplification, gene clone and DNA sequencings were performed in the 58 strains of E. cloacae resistant to the third generation cephalosporins. RESULTS From the 58 strains of E. cloacae, AmpC beta lactamase producers were 65.52%; ESBLs producers were 13.79%, ESBLs plus AmpC beta lactamase producers were 20.69%, respectively. Fifty eight clinical isolates of E. cloacae were multi drug resistant. The susceptible ratio to cefotaxime+sulbactam was 55.3% for AmpC beta lactamase producers, 87.5% for ESBLs producers and 16.7% for ESBLs plus AmpC beta lactamase producers, respectively. The susceptible ratio to piperacillin+tazobactam was 28.9% for AmpC beta lactamase producers, 50% for ESBLs producers and 8.3% for ESBLs plus AmpC beta lactamase producers, respectively. The susceptible ratio to cefepime was 97.4% for AmpC beta lactamase producers, 37.5% for ESBLs producers and 16.7% for ESBLs plus AmpC beta lactamase producers, respectively. All of strains were susceptible to imipenem. DNA sequences of the strains revealed ESBLs of SHV 2, SHV 2a, SHV 12, CTX M 14 and CTX M 3, respectively. Forty nine of 58 strains harbored ampD gene. The ampD gene sequencing results of 8 strains highly producing AmpC beta lactamase showed that there were amino acid substitutions or deletion in the carboxy terminal of ampD. CONCLUSIONS The main drug resistant mechanisms of E. cloacae are producing ESBLs and the derepressed AmpC beta lactamase.

关 键 词：阴沟肠杆菌 AMPC酶 超广谱Β-内酰胺酶 耐药性 基因分析 

分 类 号：R378.99[医药卫生—病原生物学]