中國首例產NDM-1陰溝腸桿菌感染病例研究
發(fā)布時間：2019-05-22 23:29
【摘要】：研究背景：隨著碳青霉烯類抗生素在臨床上廣泛使用，耐碳青霉烯類抗生素的致病菌逐漸增加。致病菌產碳青霉烯酶是碳青霉烯類耐藥的主要機制。碳青霉烯酶是指能夠明顯水解亞胺培南或美羅培南等碳青霉烯類抗生素的一類β-內酰胺酶，包括Ambler分子結構分類的A、B、D三類酶，其中B類為金屬酶MBLs,其催化活性依賴Zn2+，能滅活青霉素類、頭孢菌素類和碳青霉烯類抗生素，對氨曲南無水解活性,可被EDTA等金屬螯合劑抑制。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，主要分布于銅綠假單胞菌、不動桿菌屬和腸桿菌科等臨床常見病原菌中。耐藥基因可通過質�；蛘献釉诓煌毦g水平擴散。首例產NDM-1的肺炎克雷伯菌（KP05-506）和大腸埃希菌（NF-NDM-1）于2008年報道后，這種耐藥菌以驚人的速度向全球蔓延。歐洲、亞洲、南北美洲、拉丁美洲、澳大利亞相繼報道了攜帶NDM-1基因的細菌。目前中國大陸已報道的產NDM-1的細菌有屎腸球菌、鮑曼不動桿菌、肺炎克雷伯菌、臭鼻克雷伯菌，而產NDM-1的陰溝腸桿菌僅在印度地區(qū)發(fā)現(xiàn)，，我國大陸地區(qū)未見報道。 目的：對重慶醫(yī)科大學附屬第一醫(yī)院2007年1月至2012年2月臨床分離的陰溝腸桿菌進行碳青霉烯類敏感性篩查，發(fā)現(xiàn)1株產NDM-1的陰溝腸桿菌。為進一步了解該菌株感染的特點，本研究重點分析了該菌株的臨床特點、耐藥性和耐藥機制。 方法：常規(guī)分離菌株，采用紙片擴散法和瓊脂稀釋法進行不同抗菌藥物敏感性試驗，改良Hodge試驗和Etest MBL確認紙條法表型篩查金屬β-內酰胺酶，PCR擴增金屬β-內酰胺酶基因型，接合試驗分析質粒攜帶NDM-1基因的轉移，PFGE鑒定產NDM-1金屬酶的陰溝腸桿菌類型。Southern blotting進行blaNDM-1基因定位。 結果：臨床分離299株陰溝腸桿菌發(fā)現(xiàn)14株對碳青霉烯類抗生素耐藥，其中6株產碳青霉烯酶，PCR證實1株分離自一名67歲女性肺炎患者痰液中的E. cloacae413攜帶有blaNDM-1基因。E. cloacae413體外藥敏試驗僅對多粘菌素B和磷霉素敏感，該菌株PFGE分型屬B型。其攜帶的blaNDM-1基因位于大小約20Kb的質粒上，該質粒上還同時攜帶有blaCTX-M-14，qnrA, qnrS, aac6'-Ib-cr，rmtA多種耐藥基因，這些耐藥基因可隨質粒在不同的細菌間轉移，使得接合子E.coli J53(PNDM-1)同E. cloacae413一樣對β-內酰胺酶類、喹諾酮類和氨基糖苷類抗菌藥物耐藥。 結論：我院分離得到中國大陸地區(qū)首例產NDM-1的陰溝腸桿菌，該菌株對碳青霉烯類、喹諾酮類、氨基糖苷類抗菌藥均耐藥，且這種耐藥性可隨質粒在細菌間傳遞，加強該菌株的監(jiān)控和合理使用抗菌藥物具有重要意義。
[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.
【學位授予單位】：重慶醫(yī)科大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：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.
【學位授予單位】：重慶醫(yī)科大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：R516
【參考文獻】
相關期刊論文 前4條
1 鄒明祥;鄔靖敏;李軍;豆清婭;周蓉蓉;黃Z
本文編號：2483373
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