Resistance mechanism and molecular epidemiology of Escherichia coli producing new delhi metal β-lactamase
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摘要: 目的 研究临床分离耐碳青霉烯类抗菌药物的大肠埃希菌中新德里金属β-内酰胺酶(New Delhi metallo-beta-lactamase,NDM)的分子分型、耐药机制及流行特点等,为医院感染的防控与治疗提供依据。 方法 收集浙江大学丽水医院2017年6月—2018年2月从各种临床标本中分离得到的产NDM的大肠埃希菌。结合临床药敏、EDTA协同及增效试验与PCR扩增检测blaNDM基因;通过肠杆菌基因间重复一致序列聚合酶链反应(ERIC-PCR)及多位点序列分型(MLST)分析菌株之间的同源性;采用药物敏感性试验、接合试验、聚合酶链式反应(PCR)和序列分析等技术研究大肠埃希菌NDM分子分型及耐药的分子机制。 结果 共筛选出9株产NDM的大肠埃希菌菌株,其中3株分离自新生儿科,2株分离自妇科,重症医学科、急诊、血液内科、肾内科各1株;经测定所有菌株的NDM亚型均为NDM-5型,质粒复制子类型均为IncX3型;5株细菌接合试验阳性,分别来自妇科、重症医学科、急诊和新生儿科,同时PCR结果表明接合菌的质粒复制子类型为IncX3型;所有菌株呈现多重耐药现象;MLST分型结果显示,这9株大肠埃希菌共有4个ST分型,分别为ST206、ST167、ST354和ST1642,与ERIC-PCR分型结果相一致。 结论 研究结果表明本地区存在携blaNDM-5基因的大肠埃希菌的流行,同时携带有多种耐药基因,并能够通过IncX3型质粒在大肠埃希菌中传播。因此,为了预防和控制医院感染的暴发,必须重视和加强对耐碳青霉烯类抗菌药物肠杆菌科细菌的监测。
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关键词:
- 大肠埃希菌 /
- 新德里金属β-内酰胺酶 /
- 耐药性 /
- 分子分型 /
- 流行病学
Abstract: Objective To study the molecular typing, drug resistance mechanism and epidemiological characteristics of New Delhi metal β-lactamase (NDM) in Escherichia coli isolated from clinical isolates for prevention and control of nosocomial infections, and provide the basis for treatment. Methods A total of 9 NDM-producing carbapenem-resistant E. coli strains were collected from various clinical samples from June 2017 to February 2018 in the hospital, combined with clinical susceptibility testing, EDTA synergy and synergistic experiments and polymerase chain reaction (PCR) were employed to amplify and detect the blaNDM and other drug resistance gene. Finding out their NDM subtypes through sequence analysis. Analysis of homology among strains by E. coli intergenic consensus polymerase chain reaction (ERIC-PCR) and multiple site typing (MLST). Drug sensitivity experiments, conjugation experiments, PCR amplification and sequence analysis were used to study molecular typing and drug resistance molecular mechanisms of metallo-β-lactamase in E. coli. Results A total of 9 strains of E. coli producing NDM were screened out and form different wards. The NDM subtypes of all the strains were NDM-5 type, and the plasmid replicon types were all IncX3 type. Five strains conjugation test were positive,they were from gynecology, intensive care, emergency and neonatal, and PCR results show that the plasmid replicon type of zygomycetes was also IncX3 type. All the strains showed multidrug resistance. The results of MLST classification showed that there were 4 ST genotypes in 9 NDM-producing E. coli strains, including ST206 type, ST167 type, ST354 type and ST1642 type, which were consistent with ERIC-PCR results. Conclusion The results showed that the presence of E. coli carrying the blaNDM-5 gene in the region presented a certain clonal and clustered fulminant, and it could spread through the IncX3 plasmid in E. coli. In order to prevent and control the outbreak of nosocomial infection, we must pay attention to and strengthen the monitoring of the carbapenem-resistant enterobacteriaceae.-
Key words:
- Escherichia coli /
- New Delhi metallo-β-lactamase /
- Drug resistance /
- Molecular typing /
- Epidemiology
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