碳青霉烯非敏感大肠埃希菌耐药机制初步研究及分子流行病学调查

发布时间：2018-05-26 17:27

本文选题：碳青霉烯非敏感 + 大肠埃希菌　；参考：《重庆医科大学》2015年硕士论文

【摘要】：目的：了解我院2012年碳青霉烯非敏感大肠埃希菌(Carbapenem non-susceptible Escherichia coli, CNS E. coli)的耐药情况,对碳青霉烯.非敏感大肠埃希菌的耐药机制作初步研究,并进行分子流行病学调查。方法：收集我院2012年1月至2012年12月分离的碳青霉烯非敏感大肠埃希菌分离株,通过检验科LIS系统(Laboratory Information System, LIS)查询菌株信息,微量肉汤稀释法检测其对各类抗生素的MIC值；通过PCR (Polymerase chain reaction)技术检测菌株中的碳青霉烯酶基因blaSME、blaKPC、blaIMP、blaVIM、blaNDM-1、blaOXA-48, ESBLs基因blaCTX-M、blaTEM、blaSHV,氟喹诺酮类耐药决定因子(Fluoroquinolones resistance determinants, QRDs)基因qnrA、qnrB、 qnrC、qnrD、qnrS、aac(6')-Ib-cr,氨基糖苷类耐药决定因子(Aminoglycosides resistance determinants, ARDs)基因armA、rmtB、 aac(6')-Ib,整合子基因Intl1,以及外膜蛋白(Outer membrane proteins, OMPs)基因ompC、ompF,并将检出的耐药相关基因进行测序；脉冲场凝胶电泳(Pulse field gel electrophoresis, PFGE)进行分子流行病学的调查。结果：1.2012年1月至2012年12月,我院共检出大肠埃希菌1585株,其中非重复的碳青霉烯非敏感大肠埃希菌30株,占1.89%。CNSE.coli主要分离自尿液标本(13株,43.3%),病区来源主要为外科病房和重症监护室,依次为肝胆外科(6株,20.0%)、泌尿外科(5株,16.7%)、重症监护室(5株,16.7%)和胃肠外科(3株,10.0%)；病人大多数为老年人,年龄"g65周岁的为14人(46.7%),男性多于女性。2.药敏试验结果显示：CNS E.colif菌株中有30株(100.0%)对厄他培南(Ertapenem,ETP)表现为非敏感,11株(36.7%)对亚胺培南(Imipenem,IPM)非敏感,1株(3.3%)对美罗培南(Meropenem,MEM)非敏感。100.0%(30/30)的CNS E.coli对至少一种头孢菌素类抗生素耐药。氟喹诺酮类抗生素和氨基糖苷类抗生素的耐药率分别为96.7%(29/30)和63.3%(19/30)。3.耐药相关基因检测结果显示：有2株(6.7%)CNS E.coli携带碳青霉烯酶基因,且均为blaKPC_2；29株(96.7%)检出的ESBLs基因：blaCTX-M(26/30,86.7%)、blaTEM(12/30,40.0%);20株(66.7%)检出QRDs基因:qnrA(5/30,16.7%)、qnrB(7/30,23.3％)、aac(6'),-Ib-cr(13/30,43.3%)；11株(36.7%)检出ARDs基因：,armA(1/30,3.3%). rmtB(2/30,6.7%)、aac(6')-Ib(11/30,36.7%),8株(26.7%)存在OMPs基因缺失：1株(3.3%)仅存在ompC基因缺失,5株(16.7%)仅存在ompF基因缺失,2株(6.7%)存在ompC、ompF基因同时缺失；整合子基因Intll的检出率为40.0%(12/30)。4.在2株碳青霉烯酶基因阳性的菌株中,ESBLs基因、QRDs基因、ARDs基因和Intll基因的联合表达率分别为100.0%、50.0%、50.0%和50.0%,膜孔蛋白基因缺失率为0.0%；29株ESBLs基因阳性的菌株中,QRDs基因、ARDs基因和Intll基因的联合表达率分别为65.5%、37.9%和37.9%,膜孔蛋白基因缺失率为24.1%。我们首次报道了联合表达blaKPC-2、blaCTX-M-14,'、blaCTX-M-55'、blaTEM、aac(6')-Ib-cr、qnrB、aac(6')-Ib和rmtB的多重耐药大肠埃希菌分离株(已发表于Infection, Genetics and Evolution 杂志)。5. PFGE结果显示：30株CNS Ecoli分属于27个型别,提示我院CNS Ecoli菌株呈现克隆多样性,且这些菌株的流行并不是由克隆传播导致的。结论：1. CNS E.coli菌株主要分离自尿液标本,病区分布以外科病房和重症监护室为主；我院CNS E.coli菌株主要对厄他培南非敏感,亚胺培南非敏感次之,美罗培南非敏感最少,且大部分菌株表现为多重耐药。2.碳青霉烯酶基因并不是导致我院大肠埃希菌对碳青霉烯类抗生素非敏感的主要原因,ESBLs基因联合膜孔蛋白缺失可能是我院CNSE.coli产生的主要机制；多种耐药基因的联合表达可能会导致多重耐药。3.我院的CNS E.coli菌株呈现克隆多样性,其流行并不是由克隆传播导致的。
[Abstract]:Objective: to understand the drug resistance of Carbapenem non-susceptible Escherichia coli (CNS E. coli) in our hospital in 2012, and to make a preliminary study on the drug resistant machine of carbapenems and non sensitive Escherichia coli and to investigate the molecular epidemiology. Methods: the isolation of our hospital from January 2012 to December 2012 was collected. Non sensitive Escherichia coli isolates of carbapenems were querying by LIS system (Laboratory Information System, LIS), and microdilution method was used to detect the MIC values of various antibiotics. PCR (Polymerase chain reaction) technique was used to detect carbapenem genes in the strains. DM-1, blaOXA-48, ESBLs gene blaCTX-M, blaTEM, blaSHV, and fluoroquinolone resistance determinants (Fluoroquinolones resistance determinants, QRDs) gene qnrA. Intl1, and the Outer membrane proteins (OMPs) gene ompC, ompF, and the detection of resistance related genes were sequenced, and the molecular epidemiology investigation was carried out by pulse field gel electrophoresis (Pulse field gel electrophoresis, PFGE). Results: from January to December 2012 1.2012, 1585 strains of Escherichia coli were detected in our hospital. 30 non - repetitive carbapenem non sensitive Escherichia coli, which accounted for 1.89%.CNSE.coli mainly from urine specimens (13 strains, 43.3%), were mainly from the surgical ward and intensive care unit, followed by Department of hepatobiliary surgery (6, 20%), Department of Urology (5, 16.7%), severe guardianship (5, 16.7%) and gastrointestinal surgery (3, 10%); the majority of the patients were The elderly, 14 years old G65 (46.7%), and male more than women.2. susceptibility test, 30 strains of CNS E.colif (100%) were non sensitive to eopenem (Ertapenem, ETP), 11 (36.7%) insensitive to imipenem (Imipenem, IPM), 1 (3.3%) against Mei Lopez Nan (Meropenem, MEM) non sensitive.100.0% (30/30) E.coli was resistant to at least one cephalosporin antibiotic. The resistance rates of fluoroquinolones and aminoglycoside antibiotics were 96.7% (29/30) and 63.3% (19/30).3. resistance related genes, respectively: 2 (6.7%) CNS E.coli carried carbapenenase gene, and all were blaKPC_2; 29 (96.7%) found ESBLs gene: BlaCTX-M (26/30,86.7%), blaTEM (12/30,40.0%); 20 strains (66.7%) detected the QRDs gene: qnrA (5/30,16.7%), qnrB (7/30,23.3%), AAC (6'), -Ib-cr (36.7%), 8 strains (26.7%), 1 (3.3%) had only gene deletion, 5 There were only ompF gene deletion (16.7%), 2 (6.7%) ompC and ompF gene deletion, and the detection rate of integron Intll was 40% (12/30).4. in 2 strains of carbapenems gene positive, and the joint expression rates of ESBLs, QRDs, ARDs and Intll genes were 100%, 50%, 50% and 50%, respectively, and the membrane pore protein gene, respectively. The loss rate was 0%, and the joint expression rates of QRDs, ARDs and Intll genes were 65.5%, 37.9% and 37.9% in 29 ESBLs positive strains, and the loss rate of the membrane pore protein gene was 24.1%.. We first reported the joint expression of blaKPC-2, blaCTX-M-14, blaCTX-M-55', blaTEM, AAC (6') -Ib-cr. The Escherichia coli isolates (published in Infection, Genetics and Evolution magazine).5. PFGE results showed that 30 strains of CNS Ecoli belong to 27 types, suggesting that our hospital CNS Ecoli strains present clonal diversity, and the prevalence of these strains is not caused by cloned transmission. Conclusion: 1. CNS E.coli strains are mainly isolated from urine specimens, The area of the disease area was mainly in the surgical ward and the intensive care unit. The CNS E.coli strain in our hospital was not sensitive to eopenem, imipenem was not sensitive, and meropenem was the least sensitive, and the multidrug-resistant.2. carbapenem gene was not caused by Escherichia coli insensitive to carbapenems in our hospital. The main reason for this is that the loss of ESBLs gene combined with membrane pore protein may be the main mechanism of CNSE.coli in our hospital; the joint expression of multiple resistance genes may lead to multiple drug resistance.3. in our hospital, the CNS E.coli strain is cloned diversity, and its prevalence is not caused by the spread of cloning.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R446.5

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