嗜麦芽寡养单胞菌Ⅰ类整合酶基因检测及定位表达研究

Genetic testing and positioning expression study of typeⅠintegrase in Stenotrophomonas maltophilia

目的检测临床分离多药耐药嗜麦芽寡养单胞菌的整合酶基因分型与定位表达,研究嗜麦芽寡养单胞菌整合酶介导多药耐药机制,为开发新药物奠定基础。方法筛选2010-2012年下呼吸道医院感染患者中通过VITEK-IMS系统分离的73株多药耐药嗜麦芽寡养单胞菌为试验菌株;应用RT-PCR、DNA菌落与印迹杂交、质粒接合试验对多药耐药嗜麦芽寡养单胞菌,进行Ⅰ类整合酶基因检测、同源性分析及定位表达检测。结果Ⅰ类整合酶基因检出31株,检出率42.4%,Ⅱ类整合酶基因检出8株,检出率10.9%,5株同时带有Ⅰ+Ⅱ类整合酶基因,检出率为6.8%;Ⅰ类整合酶阳性菌株质粒接合试验阴性,染色体DNA印迹杂交试验阳性。结论Ⅰ类整合酶基因是嗜麦芽寡养单胞菌多药耐药的主要因素,推测Ⅰ类整合酶基因可位于染色体上。

OBJECTIVE To detect the integrase genotyping and positioning expression of Stenotrophomonas malto‐philia isolated clinically and to explore its multidrug resistance mechanism so as to lay a foundation for drug development .METHODS Totally 73 strains of multidrug resistant S . maltophilia detached by VITEK‐IMS system from patients with lower respiratory tract infection during the period of 2010-2012 were chosen as experimental strains ;RT‐PCR ,hybridization of DNA bacterial colony and blot and plasmid conjugation experiment were used to make a genetic testing ,homology analysis and positioning expression testing of type Ⅰ integrase in the multi‐drug resistant S .maltophilia .RESULTS A total of 31 strains of type Ⅰ integrase gene were detected and the detection rate was 42 .4% .And totally 8 strains of type Ⅱ integrase gene were detected with the constituent ratio of 10 .9% .There were 5 strains carrying both type Ⅰ and type Ⅱ integrase gene and the detection rate was 6 .8% . The experiment result of positive strains of type Ⅰ integrase plasmid conjugation was negative while the blot cross experiment of chromosomal DNA proved to be positive .CONCLUSION TypeⅠ integrase gene is the main factor causing multidrug resistance of S .maltophilia .We speculate that type Ⅰ integrase enzyme gene may be located on chromosome ,not plasmid .