摘要
目的探讨我院肠杆菌科细菌对碳青霉烯类抗生素的耐药机制及其流行特点。方法收集杭州市富阳区第一人民医院2013年1月至2014年8月分离的对碳青霉烯类抗生素（厄他培南）敏感性下降的肠杆菌科细菌，采用K-B纸片法及E-test法进行药敏试验，改良Hodge试验、EDTA抑制试验及超广谱β-内酰胺酶（ESBLs）表型筛选试验进行耐药表型筛选；采用PCR法及测序技术检测耐药基因、KPC基因周围序列和肺炎克雷伯菌7个管家基因，多位点序列分型进行7个管家基因的序列分析；运用PFGE对鉴定为同一菌种的细菌进行同源性分析；采用S1-PFGE联合Southern杂交对已明确的碳青霉烯耐药基因进行基因定位。结果共收集到19株厄他培南敏感性下降的肠杆菌科细菌，所有菌株呈多重耐药现象，且同一菌株常携带有多种耐药基因，其中blaKPC-2、blaIMP-4、blaSHV-1、blaCTX-M-65、blaCTX-M-15、blaTEM-1、rmtB为最常见共同携带的耐药基因。PFGE结果提示14株肺炎克雷伯菌呈多克隆分布，MLST分型以ST11型为主。11株肺炎克雷伯菌和1株大肠埃希菌产KPC-2酶，blaKPC-2基因分别定位于4种大小不同的质粒上（大小分别约为95kb、140kb、200kb及240kb），所有菌株blaKPC-2。周围基因结构从上游至下游均为ISKpn8、blaKPC-2和ISKpn6-like元件；1株产酸克雷伯菌和1株肺炎克雷伯菌产IMP-4型碳青霉烯酶，blaIMP-4。基因定位于大小约为300kb的质粒上。结论KPC-2型及IMP-4型碳青霉烯酶是造成我院肠杆菌科细菌对碳青霉烯类抗生素耐药的主要原因；我院碳青霉烯类耐药肺炎克雷伯菌（CRKP）菌株呈多克隆散在播散的流行特点，未发现优势克隆。
Objective To investigate the mechanism of carbapenem-resistant in Enterobacteriaceae strains isolated from Fuyang First People＇s Hospital and to analyze their epidemiological features. Methods The Enterobacteriaceae strains with reduced ertapenem susceptibility were isolated from the Fuy- ang First People＇s Hospital during January 2013 to August 2014. K-B disk diffusion and E-test were per- formed to detect the antimicrobial susceptibilities of those strains. The modified Hodge test, ethylenediami- netetraacetic acid （EDTA） disk synergy test and extended-spectrum β-1actamases （ESBLs） confirmation test were used to screen out the carbapenem-resistant phenotypes. PCR analysis and gene sequencing were used to analyze drug resistance genes, genetic structures surrounding the blaxPc_2 gene and seven house-keeping genes of Klebsiella pneumonia （ K. pneumoniae） strains. The sequences of the seven house-keeping genes were analyzed with muhilocus sequence typing （MLST）. Pulsed field gel electrophoresis （PFGE） was per- formed for homology analysis within the same species. S1-PFGE in combination with Southern blot analysis was used to determine the location of carbapenem resistance genes. Results A total of 19 Enterobacteriace- ae isolates with reduced susceptibility to ertapenem were screened out. Each of them was resistant to muhiple antibiotics and harbored several resistance genes. Seven genes including the blaKPC-2、blaIMP-4、blaSHV-1、blaCTX-M-65、blaCTX-M-15、blaTEM-1 and rmtB genes were the prevalent drug resistance genes. Fourteen out of the nineteen strains were identified as K. pneumoniae strains, mainly belonged to the ST11 type according to the results of MLST. Among the nineteen strains, eleven K. pneumoniae isolates and one Escherichia coli isolate carried the blaKpca gene, located on plasmids varying in size （95 kb, 140 kb, 200 kb and 240 kb）. The ge- netic structures of all isolates were ISKpn8, blaKPC_2 and ISKpn6-like from upstream to downstream. The blalnp4 gene was dete
出处
《中华微生物学和免疫学杂志》
CAS
CSCD
北大核心
2015年第6期419-426,共8页
Chinese Journal of Microbiology and Immunology
基金
富阳市科学技术局社会科技发展项目（2011SF001）
