铜绿假单胞菌超广谱β-内酰胺酶、质粒介导AmpC酶基因分布及流行特征分析

The distribution and prevalence characteristics of ESBLs and plasmid-mediated AmpC genes among Pseudomonas aeruginosa

目的研究临床分离铜绿假单胞菌超广谱β-内酰胺酶(ESBLs)和质粒介导AmpC酶的基因分布及流行特性,为细菌耐药性的监控提供依据。方法回顾性调查5年间临床分离的铜绿假单胞菌的分布和耐药情况。选取每年同一时间段的临床连续分离株共169株,用聚合酶链反应(PCR)检测TEM、SHV、VEB、PER、GES、TLA、IBC、CTX-M、OXA等β-内酰胺酶基因和AmpC酶基因。使用脉冲场凝胶电泳技术(PFGE)分析菌株间的同源性。结果铜绿假单胞菌主要分离自呼吸道(痰标本),占75.7%;对复方磺胺甲噁唑和头孢曲松耐药情况严重,耐药率分别为91.9%和91.7%;对其他主要抗菌药物的耐药率分别为头孢他啶46.7%、亚胺培南38.2%、左旋氧氟沙星30.2%、环丙沙星28.3%、阿米卡星5.0%。169株铜绿假单胞菌中产TEM、CTX-M、OXA和GES型β-内酰胺酶菌株84株(49.7%);质粒介导AmpC酶23株(13.6%)。PFGE结果显示铜绿假单胞菌仅3株具有同源性,呈散发流行。结论铜绿假单胞菌临床感染率高,呈多重耐药且散发流行趋势。

Objective To investigate the distribution and prevalence characteristics of extended-spectrum beta-lactamases（ESBLs） and plasmid-mediated AmpC genes among Pseudomonas aeruginosa,and provide the reference for monitoring the drug resistance.Methods Retrospective survey was performed to get the information of the distribution and resistance of Pseudomonas aeruginosa during 5 years.A total of 169 isolates were collected at the same period of each year.Polymerase chain reaction（PCR） was used to detect the genes of beta-lactamases including TEM,SHV,VEB,PER,GES,TLA,IBC,CTX-M and OXA and the AmpC genes,and the homology of the isolates was identified by the pulsed-field gel electrophoresis（PFGE）.Results Most isolates were from respiratory tract specimens（sputum） which accounted for 75.7%.A high resistance rate of compound sulfamethoxazole and ceftriaxone among Pseudomonas aeruginosa were identified,which was up to 91.9% and 91.7%.The resistance rates of ceftazidime,imipenem,levofloxacin,ciprofloxacin and amikacin were 46.7%,38.2%,30.2%,28.3% and 5.0%,respectively.Among the 169 isolates,the production genes of beta-lactamase TEM,CTX-M,OXA and GES and AmpC were 49.7%（84 isolates） and 13.6%（23 isolates）,respectively.PFGE showed that there were 3 isolates of Pseudomonas aeruginosa with homology and cross-transmission.Conclusions The prevalence of ESBLs and AmpC among Pseudomonas aeruginosa is high.They are mostly multi-resistant isolates,and that also exists the phenomenon of the cross-transmission.