产金属酶嗜麦芽窄食单胞菌13株的耐药谱和基因型分析

Analysis of species homology and resistant spectrum of Stenotrophomonas maltophilia producing metallo β-lactamase

目的 :研究产金属 β内酰胺酶 (MBL)的嗜麦芽窄食单胞菌感染的菌株同源性和耐药谱。 方法 :MBLE试验检测临床分离对亚胺培南耐药嗜麦芽窄食单胞菌的产MBL菌株 ;E试验检测MBL阳性株对 1 1种抗菌药物的药敏结果 ;用肠杆菌科基因间重复一致序列为引物的聚合酶链反应 (ERIC PCR)方法确定菌株之间的同源性。结果 :MBLE试验检测到MBL阳性株1 3株 ,为我院 1 998— 2 0 0 2年医院感染株 ,1 2株来源于下呼吸道感染 ,1株为尿路感染。 1 3株MBL阳性株对亚胺培南、庆大霉素、阿米卡星、头孢噻肟和头孢曲松均耐药 ,对哌拉西林 三唑巴坦、替卡西林 克拉维酸、头孢哌酮 舒巴坦、头孢他啶、头孢吡肟和环丙沙星等 6种抗菌药物呈现 8种耐药模式 ;ERIC PCR结果显示 ,1 3株MBL阳性株呈现 1 0种基因型 ,4株MBL阳性株为同一基因型 ,其余 9株为独立的基因型。综合分析 ,菌株来源、药敏谱和基因型与之间无显著相关性。结论 :我院产MBL嗜麦芽窄食单胞菌感染以下呼吸道为主 ,其发生呈散发性 ,抗生素的选择性压力可能是造成耐药谱和基因型多态性的主要原因。

Objective: To study the homology among different isolates and resistant pattern of MBL positive Stenotrophomonas maltophilia strains. Methods:Using MBL E test strip to screen MBL positive strains from imipenem resistant Stenotrophomonas maltophilia strains, and antibiotic susceptibility were tested by E test, the homology among different strains was tested by enterobacterial repetitive intergenic consensus PCR(ERIC PCR) system. Results:13 strains of Stenotrophomonas maltophilia producing MBL were isolated from patients with nosocomial infections. Antibiotic susceptibility data showed that all 13 strains were resistant to imipenem, cefotaxime, amikacin and gentamicin, and there were eight drug resistant profiles including six antimicrobial agents. Results of ERIC PCR showed that there were ten PCR patterns, and there was no significant relationship among strains from different sources, antibiotic resistant profiles and genotypes of metallo β lactamase producing strains. Conclusions:The MBL producing strains in S.maltophilia exist sporadically, and it could be the result of antibiotic selective pressure.