呼吸内科常见菌及鲍曼不动杆菌质粒上耐药基因的研究

Study on bacteria in respiratory unit and plasmid mediated drug-resistant gene of Acinetobacter baumannii

目的分析155株呼吸内科分离菌的种类、分布、耐药性及鲍曼不动杆菌(Acinetobacter baumannii,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化研究所(CLSI/NCCLS)2003年版标准判断结果,利用WHONET5.2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。结果呼吸内科分离菌中革兰阴性菌占85.81%,常见的菌种是肺炎克雷伯菌(17.29%),AB(15.79%),洛菲不动杆菌(13.53%),铜绿假单胞菌(11.28%),大肠埃希菌(9.77%)和短黄杆菌(9.02%),非发酵菌的分离率明显上升,占分离菌总数的45.81%,91.61%的标本来自痰液。革兰阴性菌菌耐药率高,有一株AB对除亚胺培南以外的14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3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。质粒上带一或多种可接合传递并稳定传代的blaTEM-1、blaPER-1和blaOXA-23基因是呼吸内科AB多重耐药的分子学机制之一。

Obejective To analyse the species, distribution and drug resistance of 155 isolates obtained from respiratory unit. To study the drug resistant gene of Acinetobacter baumannii（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 CLSI/NCCLS （2003） by WHONET 5.2 software. The analysis of drug-resistant gene on plasmid of AB by PCR. Results Gram-negative bacilli strains accounted for 85.81% in respiratory infection unit. The main pathogen included K. pneumoniae（ 17.29% ） ,AB（ 15.79% ） ,A. lwoffi（ 13.53% ）, P. aerugiinosa（ 11. 28% ）, E. coil（9.77% ） and E. brevis（9.02% ）. The isolate rate of nonfermenting pathogen were increasing, accounted for 45.81% of total isolates,91.61% isolates were isolated from the sputum. Drug resistant rates of Gram-negative bacilli were very high. There was a AB isolates which resistant to 14 usually used antibiotics except imipenem and it＇s plasmid harbored three kinds of drug resistant genes that can be transferred and passed stably. Conclusion The serious of bacterial multi-drug resistance is increasing, it is urgent to carry out surveillance of bacterial resistance for use antibiotics reasonably in order to decrease the morbidity rate and fatality rate. Plasmid harboring one or more blaTEM-1, blaPER-1 and blaOXA-23 genes which can be transferred and passed stably is one of the molecular mechanism of multi-drug resistant AB in respiratory infection unit.