北京地区6家医院重症监护病房嗜麦芽窄食单胞菌耐药性及基因同源性分析

Drug resistance and their genetic homology of Stenotrophomonas maltophilia at department of intensive care unit of 6 hospitals in Beijing

目的对北京地区6家医院重症监护病房（ICU）2005年1月～2006年2月临床分离的嗜麦芽窄食单胞菌进行耐药性分析及分子同源性检测，了解其耐药趋势与传播流行情况。方法应用微量稀释法测定82株嗜麦芽窄食单胞菌对12种抗菌药物最低抑菌浓度；通过脉冲场凝胶电泳（PFGE）进行基因分型，明确是否为同一菌株的克隆。结果嗜麦芽窄食单胞菌对常用抗生素耐药，敏感性超过50％的抗菌药物依次为多西环素、加替沙星、头孢哌酮／舒巴坦、左氧氟沙星、复方磺胺甲基异嗯唑、头孢他啶、替卡西林／克拉维酸。82株嗜麦芽窄食单胞菌经PFGE指纹图谱分析显示7～18条大小不等的DNA片断，同源性在85％以上的有4对发生在同一医院ICU病房，其中解放军第一附属医院有3株菌属于同一克隆，来自不同医院的2对嗜麦芽窄食单胞菌分别为80．6％、79．6％同源，其余菌株则显示了较低的同源性或无同源性。结论北京地区6家医院IC-U病房嗜麦芽窄食单胞菌由72种不同克隆构成，表现为基因多态性。该菌对常用抗生素呈多重耐药。解放军总医院第一附属医院存在院内感染的嗜麦芽窄食单胞菌的优势克隆。PFGE是耐药性及分子流行病学分析的有效手段。

Objective To investigate the antibiotic resistance and their genetic homology of Stenotrophomonas maltophilia isolated from January 2005 to February 2006 at intensive care unit（ICU） of 6 hospitals in Bejing area. Methods The minimal inhibitory concentration（MIC） of 12 antibiotics against 82 Strenotrophomonas maltophilia was determined by broth dilution method. PFGE was used to analyze the homology of 82 Stenotrophomonas maltophilia. Results The drug sensitivity tests in vitro showed these strains were resistance to commonly-used antibiotics. Antibiotics with sensitive rate over 50% included doxycycline, gatifloxacin, cefoperazone-sulbactam, levofloxacin, compound sulfamethoxazole, ceftazidime and ticarcillin-clavulanate. 7-18 DNA bands of different size were present in the gel and different homology was shown among the 82 strains. Four couples with homology over 85% were isolated from the same ICU. Three strain were same clones in PLA General Hospitals first hospital. 2 couples from the different wards had homology of 80.6% and 79.6% ,respictively. Others strains had either poor or no homology. Conclusions No clonal outbreak is certified at ICU of 6 hospitals in Beijing area. There are only vertical dissemination of single clone in 6 ICU wards. PFGE is an effective approach for drug resistance test and epidemic analysis.