43株ICU医院感染者分离的铜绿假单胞菌耐药和产AmpC酶基因型分析

Analysis of drug resistance and AmpC-producing genotype of Pseudomonas aeruginosa isolated from 43 ICU nosocomial infected persons

目的了解本院近1年重症监护病房(ICU)医院感染者分离的铜绿假单胞菌产AmpC酶的基因型及耐药特征,为临床合理使用抗菌药物提供依据。方法采用全自动细菌分析仪和纸片扩散法进行细菌鉴定和抗菌药物敏感性试验;采用细菌基因组提取试剂盒提取细菌DNA;采用多重PCR和DNA测序检测分析AmpC酶基因型。结果43株铜绿假单胞菌经DNA提取物作PCR检测产AmpC酶,16株阳性,阳性率为37.21%;测序比对11株为DHA-1型,5株为CIT型。产酶菌株对常用抗菌药物的耐药性明显高于非产酶菌株,产酶菌株对碳青霉烯类、第四代头孢菌素、哌拉西林/他唑巴坦、阿米卡星显示较高敏感性,酶抑制剂中他唑巴坦抑菌活性明显强于舒巴坦。结论本院ICU患者分离的铜绿假单胞菌产AmpC酶菌株检出率较高,AmpC酶基因型以DHA-1型为主,另检出AmpC酶的基因型为CIT型,在本地区未见有报道;碳青霉烯类、头孢吡肟、阿米卡星及哌拉西林/他唑巴坦对产AmpC酶菌株有较好的抗菌活性。

Objective To understand the genotype and drug resistance of AmpC-producing Pseudomonas aeruginosa isolated from nosocomial infected persons in ICU in recent year,and to provide basis for rational use of antibiotics in clinic.Methods Bacterial identification and antimicrobial susceptibility test were carried out by automatic bacterial analyzer and disk diffusion method,bacterial DNA was extracted by bacterial genome extraction kit,and AmpC genotype was analyzed by multiplex polymerase chain reaction(PCR)and DNA sequencing.Results Forty-three strains of Pseudomonas aeruginosa produced AmpC enzyme by PCR with DNA extract,16 strains were positive,and the positive rate was 37.21%;11 strains were DHA-1 type and 5 strains CIT type by DNA purification and sequencing.The resistance of enzyme-producing strains to commonly used antibiotics was significantly higher than that of non-enzyme-producing strains.Enzyme-producing strains showed high susceptibility to carbapenems,fourth-generation cephalosporins,piperacillin/tazobactam and amikacin,and the antimicrobial activity of tazobactam in enzyme inhibitors was significantly stronger than that of sulbactam.Conclusion DHA-1 was the dominant genotype of AmpC-producing Pseudomonas aeruginosa isolated from nosocomial infections in ICU of our hospital,and CIT was the other genotype of AmpC-producing bacteria,which was not reported in this area.Carbapenems,cefepime,amikacin and piperacillin/tazobactam showed good antimicrobial activity against AmpC-producing strains.