ICU常见病原菌及鲍曼不动杆菌质粒上耐药基因的研究

Study on common pathogenic bacteria in ICU and plasmid mediated drug-resistant gene of Acinetobacter baumannii

目的分析南昌大学一附院ICU常见菌的种类、分布、耐药性及鲍曼不动杆菌(AB)质粒上的耐药基因。方法用Microscan-autoscan-φ型自动微生物分析仪鉴定到种并测定其对常用抗菌药物的最低抑菌浓度(MIC50),按美国临床实验室标准委员会(NCCLS)2003年版标准判断结果,利用WHONET 5.2软件进行统计和分析,并用聚合酶链式反应(PCR)分析AB质粒上的耐药基因。结果ICU分离菌中革兰阴性菌占75.3%,常见的菌种有铜绿假单胞菌(16.27%)、金葡菌(15.66%)、AB(15.06%)和肺炎克雷伯菌(14.66%),非发酵菌的分离率明显上升,占分离菌总数的42.77%,87.35%的标本来自痰液。革兰阴性菌耐药率高,AB对包括IPM在内的13种常用抗生素均高度耐药且其质粒上携带可接合传递并稳定传代的三种耐药基因。结论细菌的多重耐药日趋严重,开展细菌耐药性监测,对指导临床合理使用抗生素,降低医院感染率和病死率有重要意义。质粒上带一种或多种可接合传递并稳定传代的blaTEM-1(EU022370)、blaPER-1(EU022369)和blaOXA-23(EU022368)基因是ICU AB多重耐药的分子学机制之一。

Obejective To investigate the species, distribution and drug resistance of isolates obtained from ICU of the first affiliated hospital of Nanchang University, and study the drug resistant gene of Acineto- bacter baurnannii （AB）. Methods The minimal inhibitory concentrations （MICs） and bacteria were identified by Microscan-autoscan-φ automatic microbe analytic instrument and the results were anzlyzed according to NCCLS （2003） by WHONET 5.2 software. Drug-resistant gene on plasmid of AB was performed by PCR. Results Gram-negative strains accounted for 75.3% in ICU infections. The main pathogen included P. aerugi- inosa （16.27%）, Staph. aureus （15.66%）, AB （15.06%） and K. pneumoniae （14.46%）. The isolate rate of nonfermenting pathogen was increasing, accounted [or 42.77% of total isolates, 87.35 % isolates were obtained from the sputum. Drug resistant rates of Gram-negative bacteria were very high. AB isolates were resistant to all the 13 commonly used antibiotics including imipenem （IPM） and its plasmid harbored three kinds of geno-types could be transferred and hereditary stable. Conclusion The serious of bacterial multi - drug resistance is increasing, it is urgent to carry out surveillance of bacterial resistance for use antibiotics rationally in order to decrease the morbidity and fatality rates. Plasmid harboring one or more blaTEM-1, blaPER-1 and blaOXA-23 genes which can be transferred and hereditary stable is one of the molecular mechanism of MDR AB in ICU infections.