阴沟肠杆菌耐药性及氨基糖苷类抗生素耐药基因分析

Analysis of drug resistance and genotypes of aminoglycoside modifying enzymes in Enterobacter cloacae

目的调查临床分离的阴沟肠杆菌耐药性及氨基糖苷类抗菌药物耐药基因的携带状况。方法采用ATB药敏试验板微量肉汤法,对33株临床分离的阴沟肠杆菌进行抗菌药物敏感性试验,聚合酶链反应(PCR)法检测aac(3)-Ⅰ、aac(3)-Ⅱ、aac(3)-Ⅲ、aac(3)-Ⅳ、aac(6′)-Ⅰ、aac(6′)-Ⅱ、ant(3″)-Ⅰ、ant(2″)-Ⅰ、aph(3′)Ⅵ9种氨基糖苷类修饰酶基因。结果 33株阴沟肠杆菌株呈现多重耐药,亚胺培南和厄它培南均敏感,对头孢唑啉全部耐药,氨苄西林、氨苄西林/舒巴坦、头孢替坦耐药率均在90%以上。对阿米卡星、庆大霉素、妥布霉素3类氨基糖苷类抗生素的耐药率分别为33.3%、63.6%、81.8%。氨基糖苷类修饰酶基因的阳性率分别为aac(6′)-Ⅰ87.8%(29/33)、ant(3″)-Ⅰ63.6%(21/33)、aac(3-)II 54.5%(18/33)、ant(2″)-Ⅰ45.4%(15/33)及aph(3′)-Ⅵ24.2%(8/33)。aac(3)-Ⅰ、aac(3)-Ⅲ、aac(3-)IV、aac(6′-)II未检出。携带1种或1种以上基因的菌株有32株(97%)。结论临床分离的阴沟肠杆菌多重耐药严重,氨基糖苷类修饰酶基因携带率非常高。

Objective To investigate the drug resistance and genotypes of aminoglycoside modifying enzymes（AMES）in Enterobacter cloacae（E.cloacae） which isolated from clinical samples.Methods Microdilute tests using ATB drug susceptibility testing plate were performed to detect the antimicrobial susceptibility of 33 strains of E.cloacae.9 AMEs genes were detected by PCR.Results The 33 strains were multiple-drug-resistance.All strains were susceptible to imipenam and meropenem.The resistant rates to cefazolin was 100%.More than 90% of the isolates were resistant to ampicillin,ampicillin/sulbactam,and cefotetan.The resistant rates to amikacin,gentamicin and tobramycin were 33.3%,63.6% and 81.8%,respectively.The positive rates of AMEs genes of aac（6′）-Ⅰ,ant（3″）-Ⅰ,aac（3）-Ⅱ,ant（2″）-Ⅰand aph（3′）-Ⅵ were 87.8%,63.6%,54.5%,45.4% and 24.2%,respectively.But the AMEs genes of aac（3）-Ⅰ、aac（3）-Ⅲ、aac（3）-Ⅳ、aac（6′）-Ⅱ were not found.Conclusion There are multiple-drug resistance and high positive rate of AMEs genes in E.cloacae isolated from clinical samples.