中国首例产NDM-1阴沟肠杆菌感染病例研究
发布时间：2019-05-22 23:29
【摘要】：研究背景：随着碳青霉烯类抗生素在临床上广泛使用，耐碳青霉烯类抗生素的致病菌逐渐增加。致病菌产碳青霉烯酶是碳青霉烯类耐药的主要机制。碳青霉烯酶是指能够明显水解亚胺培南或美罗培南等碳青霉烯类抗生素的一类β-内酰胺酶，包括Ambler分子结构分类的A、B、D三类酶，其中B类为金属酶MBLs,其催化活性依赖Zn2+，能灭活青霉素类、头孢菌素类和碳青霉烯类抗生素，对氨曲南无水解活性,可被EDTA等金属螯合剂抑制。MBLs有IMP、VIM、SPM-1、GIM-1、SIM-1、AIM-1、DIM-1、TMB-1、KHM-1和NDM-1等基因型，主要分布于铜绿假单胞菌、不动杆菌属和肠杆菌科等临床常见病原菌中。耐药基因可通过质粒或整合子在不同细菌间水平扩散。首例产NDM-1的肺炎克雷伯菌（KP05-506）和大肠埃希菌（NF-NDM-1）于2008年报道后，这种耐药菌以惊人的速度向全球蔓延。欧洲、亚洲、南北美洲、拉丁美洲、澳大利亚相继报道了携带NDM-1基因的细菌。目前中国大陆已报道的产NDM-1的细菌有屎肠球菌、鲍曼不动杆菌、肺炎克雷伯菌、臭鼻克雷伯菌，而产NDM-1的阴沟肠杆菌仅在印度地区发现，，我国大陆地区未见报道。 目的：对重庆医科大学附属第一医院2007年1月至2012年2月临床分离的阴沟肠杆菌进行碳青霉烯类敏感性筛查，发现1株产NDM-1的阴沟肠杆菌。为进一步了解该菌株感染的特点，本研究重点分析了该菌株的临床特点、耐药性和耐药机制。 方法：常规分离菌株，采用纸片扩散法和琼脂稀释法进行不同抗菌药物敏感性试验，改良Hodge试验和Etest MBL确认纸条法表型筛查金属β-内酰胺酶，PCR扩增金属β-内酰胺酶基因型，接合试验分析质粒携带NDM-1基因的转移，PFGE鉴定产NDM-1金属酶的阴沟肠杆菌类型。Southern blotting进行blaNDM-1基因定位。 结果：临床分离299株阴沟肠杆菌发现14株对碳青霉烯类抗生素耐药，其中6株产碳青霉烯酶，PCR证实1株分离自一名67岁女性肺炎患者痰液中的E. cloacae413携带有blaNDM-1基因。E. cloacae413体外药敏试验仅对多粘菌素B和磷霉素敏感，该菌株PFGE分型属B型。其携带的blaNDM-1基因位于大小约20Kb的质粒上，该质粒上还同时携带有blaCTX-M-14，qnrA, qnrS, aac6'-Ib-cr，rmtA多种耐药基因，这些耐药基因可随质粒在不同的细菌间转移，使得接合子E.coli J53(PNDM-1)同E. cloacae413一样对β-内酰胺酶类、喹诺酮类和氨基糖苷类抗菌药物耐药。 结论：我院分离得到中国大陆地区首例产NDM-1的阴沟肠杆菌，该菌株对碳青霉烯类、喹诺酮类、氨基糖苷类抗菌药均耐药，且这种耐药性可随质粒在细菌间传递，加强该菌株的监控和合理使用抗菌药物具有重要意义。
[Abstract]:Background: with the wide use of carbapenem antibiotics in clinic, the pathogenic bacteria resistant to carbapenem antibiotics increase gradually. Carbapenase production by pathogenic bacteria is the main mechanism of carbapenem resistance. Carbapenemase refers to a class of 尾-lactamases that can obviously hydrolyze carbapenem antibiotics such as imipenem or meropenem, including Ambler molecular structure classification of A, B, D three kinds of enzymes, in which B is a metal enzyme MBLs,. Its catalytic activity is dependent on Zn2 and can inactivate penicillin, cephalosporins and carbapenem antibiotics. MBLs have no hydrolysis activity against aztreonam and can be inhibited by metal chelating agents such as EDTA. MBLs have IMP,VIM,SPM-1,GIM-1,SIM-1,AIM-1,. DIM-1,TMB-1,KHM-1 and NDM-1 were mainly distributed in Pseudomonas aeruginosa, Acinetobacter and Enterobacteriaceae. Drug resistance genes can be diffused at different levels among bacteria by plasmid or integron. Since the first cases of NDM-1-producing Klebsiella pneumoniae (KP05-506) and Escherichia coli (NF-NDM-1) were reported in 2008, the drug-resistant bacteria have spread to the world at an astonishing rate. Bacteria carrying NDM-1 gene have been reported in Europe, Asia, North and South America, Latin America and Australia. At present, Enterococcus faecium, Acinetobacter baumannii, Klebsiella pneumoniae and Klebsiella smelly have been reported to produce NDM-1 in mainland China, while Enterobacter cloacae producing NDM-1 has only been found in India, but it has not been reported in mainland China. Objective: to screen the carbapenene sensitivity of Enterobacter cloacae isolated from the first affiliated Hospital of Chongqing Medical University from January 2007 to February 2012, and to find a strain of NDM-1-producing Enterobacter cloacae. In order to further understand the infection characteristics of the strain, the clinical characteristics, drug resistance and drug resistance mechanism of the strain were analyzed. Methods: different antimicrobial sensitivity tests were carried out by disk diffusion method and Agar dilution method, and metal 尾-lactamases were screened by modified Hodge test and Etest MBL assay. The metal 尾-lactamase genotype was amplified by PCR, the transfer of NDM-1 gene carried by plasmid was analyzed by binding test, the type of Enterobacter cloacae producing NDM-1 metalloenzyme was identified by PFGE, and the blaNDM-1 gene was located by Southern blotting. Results: 299 strains of Enterobacter cloacae isolated from clinic showed that 14 strains were resistant to carbapenem antibiotics, of which 6 strains produced carbapenem enzyme. PCR confirmed that E. cloacae413, isolated from the sputum of a 67-year-old woman with pneumonia, carried blaNDM-1 gene. E. cloacae413 was only sensitive to polymyxin B and fosfomycin in vitro, and the PFGE typing of E. cloacae413 belonged to type B. The blaNDM-1 gene is located on a plasmid about the size of 20Kb, which also carries a variety of blaCTX-M-14,qnrA, qnrS, aac6'-Ib-cr,rmtA resistance genes, which can be transferred between different bacteria with the plasmid. E.coli J53 (PNDM-1), like E. cloacae413, was resistant to 尾-lactamases, quinolones and aminoglycosides. Conclusion: the first case of NDM-1-producing Enterobacter cloacae was isolated in our hospital. The strain was resistant to carbapenems, quinolones and aminoglycosides, and the drug resistance could be transmitted between bacteria with plasmid. It is of great significance to strengthen the monitoring of the strain and the rational use of antibiotics.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R516
[Abstract]:Background: with the wide use of carbapenem antibiotics in clinic, the pathogenic bacteria resistant to carbapenem antibiotics increase gradually. Carbapenase production by pathogenic bacteria is the main mechanism of carbapenem resistance. Carbapenemase refers to a class of 尾-lactamases that can obviously hydrolyze carbapenem antibiotics such as imipenem or meropenem, including Ambler molecular structure classification of A, B, D three kinds of enzymes, in which B is a metal enzyme MBLs,. Its catalytic activity is dependent on Zn2 and can inactivate penicillin, cephalosporins and carbapenem antibiotics. MBLs have no hydrolysis activity against aztreonam and can be inhibited by metal chelating agents such as EDTA. MBLs have IMP,VIM,SPM-1,GIM-1,SIM-1,AIM-1,. DIM-1,TMB-1,KHM-1 and NDM-1 were mainly distributed in Pseudomonas aeruginosa, Acinetobacter and Enterobacteriaceae. Drug resistance genes can be diffused at different levels among bacteria by plasmid or integron. Since the first cases of NDM-1-producing Klebsiella pneumoniae (KP05-506) and Escherichia coli (NF-NDM-1) were reported in 2008, the drug-resistant bacteria have spread to the world at an astonishing rate. Bacteria carrying NDM-1 gene have been reported in Europe, Asia, North and South America, Latin America and Australia. At present, Enterococcus faecium, Acinetobacter baumannii, Klebsiella pneumoniae and Klebsiella smelly have been reported to produce NDM-1 in mainland China, while Enterobacter cloacae producing NDM-1 has only been found in India, but it has not been reported in mainland China. Objective: to screen the carbapenene sensitivity of Enterobacter cloacae isolated from the first affiliated Hospital of Chongqing Medical University from January 2007 to February 2012, and to find a strain of NDM-1-producing Enterobacter cloacae. In order to further understand the infection characteristics of the strain, the clinical characteristics, drug resistance and drug resistance mechanism of the strain were analyzed. Methods: different antimicrobial sensitivity tests were carried out by disk diffusion method and Agar dilution method, and metal 尾-lactamases were screened by modified Hodge test and Etest MBL assay. The metal 尾-lactamase genotype was amplified by PCR, the transfer of NDM-1 gene carried by plasmid was analyzed by binding test, the type of Enterobacter cloacae producing NDM-1 metalloenzyme was identified by PFGE, and the blaNDM-1 gene was located by Southern blotting. Results: 299 strains of Enterobacter cloacae isolated from clinic showed that 14 strains were resistant to carbapenem antibiotics, of which 6 strains produced carbapenem enzyme. PCR confirmed that E. cloacae413, isolated from the sputum of a 67-year-old woman with pneumonia, carried blaNDM-1 gene. E. cloacae413 was only sensitive to polymyxin B and fosfomycin in vitro, and the PFGE typing of E. cloacae413 belonged to type B. The blaNDM-1 gene is located on a plasmid about the size of 20Kb, which also carries a variety of blaCTX-M-14,qnrA, qnrS, aac6'-Ib-cr,rmtA resistance genes, which can be transferred between different bacteria with the plasmid. E.coli J53 (PNDM-1), like E. cloacae413, was resistant to 尾-lactamases, quinolones and aminoglycosides. Conclusion: the first case of NDM-1-producing Enterobacter cloacae was isolated in our hospital. The strain was resistant to carbapenems, quinolones and aminoglycosides, and the drug resistance could be transmitted between bacteria with plasmid. It is of great significance to strengthen the monitoring of the strain and the rational use of antibiotics.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R516
【参考文献】
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1 邹明祥;邬靖敏;李军;豆清娅;周蓉蓉;黄Z
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