无迁徙生长碳青霉烯耐药奇异变形杆菌耐药机制及分子分型研究  

Mechanisms and molecular typing of carbapenem-resistant Proteus mirabilis strains deficient in swarming motility

作　　者：孙龙[1,2] 李曦[3] 华孝挺[1] 史可人[1] 王燕飞[1] 陈然峰[2] 俞云松[1] 

机构地区：[1]浙江大学医学院附属邵逸夫医院感染科,杭州310016 [2]武警浙江总队杭州医院检验科,杭州310051 [3]浙江省人民医院检验中心,杭州310014

出　　处：《中华微生物学和免疫学杂志》2016年第10期734-739,共6页Chinese Journal of Microbiology and Immunology

摘　　要：目的：探讨无迁徙生长碳青霉烯耐药奇异变形杆菌耐药机制及分子流行病学特点。方法收集2013年1月至2014年12月武警浙江总队杭州医院临床分离的无迁徙奇异变形杆菌,通过半固体培养及鞭毛染色试验观察菌株动力及鞭毛；采用脉冲场凝胶电泳（ PFGE）分析菌株之间同源性；利用表型确证试验以及PCR扩增测序明确耐药基因型；运用S1-PFGE联合Southern印迹杂交及质粒电转化试验对碳青霉烯耐药基因进行定位,并分析耐药基因周围环境。结果共收集无迁徙生长奇异变形杆菌42株,对亚胺培南与美罗培南耐药率分别为57.1%和52.4%；其中碳青霉烯耐药的无迁徙生长奇异变形杆菌24株,PFGE结果提示分为3个克隆型且均携带blaKPC-2基因,菌株动力及鞭毛染色均为阴性；Southern印迹杂交表明blaKPC-2基因分别定位在约为26、55、139 kb不同大小质粒上；部分菌株在携带blaKPC-2基因的质粒上同时携带blaTEM-1、blaCTX-M-65、rmtB等多种耐药基因；携带blaKPC-2基因菌株周围结构显示,其上游含有插入元件ISKpn8,下游则由插入元件ISKpn6-like构成。结论无迁徙生长奇异变形杆菌具有较高碳青霉烯类抗生素的耐药率,产KPC-2型碳青霉烯酶是导致无迁徙奇异变形杆菌对碳青霉烯类抗生素耐药的主要原因。碳青霉烯耐药无迁徙生长奇异变形杆菌在我院呈克隆播散趋势,应引起临床高度重视。Objective To investigate the mechanism and epidemiological characteristics of carbap-enem-resistant Proteus mirabilis （ PM） strains deficient in swarming motility. Methods PM strains were isolated from Hangzhou General Hospital of CAPF （ Chinese People′s Armed Police Forces） during January 2013 to December 2014. Bacterial motility and flagella of the PM strains were observed through semi-solid agar culture and flagella staining. Pulsed-field gel electrophoresis （ PFGE） was performed for homology anal-ysis. Antimicrobial susceptibility test and phenotypic confirmatory test were also carried out. PCR analysis and DNA sequencing were performed to confirm the genotype of resistant genes. Plasmid electroporation and S1-PFGE in combination with Southern blot hybridization were used to determine the location of the carbap-enem-resistant genes. Genetic structure of the blaKPC-2 gene was obtained by PCR mapping. Results A total of 42 PM isolates deficient in swarming motility were screened out and the resistance rates to imipenem and meropenem were 57. 1% and 52. 4%, respectively. PCR analysis and DNA sequencing confirmed that 24 carbapenem-resistant PM isolates deficient in swarming motility carried blaKPC-2 gene and belonged to three clones as indicated by the results of PFGE. Southern blot hybridization indicated that the blaKPC-2 gene was located on plasmids varying in size （26 kb, 55 kb and 139 kb）. In addition, some of the strains harbored several resistant genes, such as blaTEM-1 , blaCTX-M-65 and rmtB. The genetic structures of strains carrying blaKPC-2 gene were ISKpn8, blaKPC-2 and ISKpn6-like from upstream to downstream. Conclusion Compared with the PM strains with swarming motility, the carbapenem-resistance rate was significantly higher in these PM strains deficient in swarming motility. Carbapenemases KPC-2 played an important role in the carbapen-em-resistant PM strains deficient in swarming motility. There was a cloning spread trend for carbapenem-re-sistant PM strains in our hospital. Cl

关 键 词：奇异变形杆菌 群集运动 碳青霉烯酶 鞭毛 院内感染 

分 类 号：R446.5[医药卫生—诊断学]