临床分离大肠埃希菌产ESBLs的基因型及耐药性研究

发布时间：2018-06-29 08:04

  本文选题：大肠埃希菌 + 超广谱β-内酰胺酶　； 参考：《中国医科大学》2007年硕士论文

【摘要】： 目的 大肠埃希菌是临床上常见的致病菌，随着三代头孢菌素等广谱β-内酰胺类抗生素在临床上的广泛应用，产超广谱β-内酰胺酶(ESBLs)大肠埃希菌感染日益增多，这也是细菌对新一代β-内酰胺类抗生素耐药的主要原因。ESBLs由质粒介导，易在同种属甚至不同种属细菌间传递造成暴发流行。由于各个国家和地区使用的抗生素不同，流行的ESBLs基因型各不相同。ESBLs的传播性以及它们的多重耐药性给临床抗感染治疗造成了极大困难，，及时准确检出ESBLs对防止ESBLs流行、控制医院内感染和指导临床治疗有着非常重要的意义。为此，本研究以临床分离的大肠埃希菌为对象，采用NCCLS推荐的确证试验检测产ESBLs的菌株，计算ESBLs的分离率，分析其耐药性，并对ESBLs进行基因分型，为临床治疗、预防产ESBLs细菌引起的感染提供一定的参考。 方法 将2004年1月至2005年12月间的临床非重复菌株共120株，按照美国国家临床实验室标准化委员会(NCCLS)推荐的ESBLs表型确证试验法筛选产ESBLs大肠埃希菌。提取产ESBLs菌的质粒DNA，特异性引物扩增TEM型、SHV型、CTX-M-1组、CTX-M-9组基因，对所有阳性的PCR产物进行DNA测序。 结果 药敏结果显示本实验产ESBLs大肠埃希菌表现为多重耐药性，其中氨苄西林100％，第一、二代头孢菌素头孢唑啉、头孢呋新均在90％以上，第三代头孢菌素头孢曲松钠80％，头孢噻肟76.7％，其它四环素90％，左氧氟沙星86.6％，环丙沙星85％，复方新诺明83.3％，酶抑制复合制剂哌拉西林／他唑巴坦3.3％，头孢哌酮／舒巴坦16.7％，非产ESBLs大肠埃希菌组氨苄西林88％，四环素80％。产ESBLs菌株与非产ESBLs菌株未发现对亚胺培南耐药。 产ESBLs大肠埃希菌基因检测阳性45株，占75％。其中CTX-M-14占82.2％(37／45)、CTX-M-9占4.4％(2／45)、CTX-M-15占2.2％(1／45)、CTX-M-22占4.4％(2／45)、CTX-M-24占2.2％(1／45)、CTX-M-27占2.2％(1／45)。45株产ESBLs菌中，只有1株菌株检出两种基因型共同存在，占2.2％，为CTX-M-14和TEM-1。 讨论 本研究结果表明，产ESBLs的大肠埃希菌对多种抗生素耐药，但未发现对亚胺培南耐药菌株，建议对于重症感染的治疗应首选碳青霉烯类抗生素。 产ESBLs大肠埃希菌临床分离株中以产CTX-M型酶为最常见，其中主要为CTX-M-14。 合理使用抗生素，特别是三代头孢菌素，加强医院高危人群的耐药监测，实行目标治疗，有利于减少产ESBLs大肠埃希菌耐药菌株的产生及传播。 结论 产ESBLs大肠埃希菌对亚胺培南全部敏感，其他抗生素均有耐药。中国医科大学附属第一医院产ESBLs大肠埃希菌以CTX-M型酶最常见，主要为CTX-M-14。
[Abstract]:Purpose






Escherichia coli is a common pathogenic bacterium in clinic . With the wide application of the broad - spectrum 尾 - lactam antibiotics such as Cephalosporins in clinic , it is very important to produce extended - spectrum 尾 - lactam antibiotics .






method






A total of 120 clinical non - repetitive strains were screened from January 2004 to December 2005 . The strains of E . coli were isolated from the strains of Escherichia coli . The plasmid DNA was extracted from the producing strains , TEM type , SHV type , CTX - M - 1 group , CTX - M - 9 group , and DNA sequencing was performed on all positive PCR products .






Results






The results showed that the strains of Escherichia coli produced by this experiment showed multiple drug resistance , in which ampicillin was 100 % , the first , the second generation cephalosporin ceftizolin and ceftiofur were all over 90 % , the third generation Cephalosporins sodium 80 % , ceftiofur hydrochloride was 76.7 % , the other tetracyclines were 90 % , levofloxacin 86.6 % , ciprofloxacin 85 % , tetracyclines 80 % , and the non - producing strains were not found to be resistant to Imipenem .






CTX - M - 14 accounted for 82.2 % ( 37 / 45 ) , CTX - M - 9 was 4.4 % ( 2 / 45 ) , CTX - M - 15 was 2.2 % ( 1 / 45 ) , CTX - M - 27 was 2.2 % ( 1 / 45 ) , CTX - M - 27 accounted for 2.2 % ( 1 / 45 ) , CTX - M - 27 was 2.2 % ( 1 / 45 ) .






discuss






The results of this study showed that the strains of E . coli were resistant to various antibiotics , but did not find the resistant strains to Imipenem , suggesting that the treatment of severe infection should be the preferred choice of Carbapenem antibiotics .






CTX - M - type enzyme is the most common in the clinical isolates of Escherichia coli , which is CTX - M - 14 .






The rational use of antibiotics , especially the cephalosporin of the third generation , strengthens the drug resistance monitoring of the high - risk population in the hospital , carries out target treatment , and is beneficial to reduce the generation and spread of the drug - resistant strains of Escherichia coli .






Conclusion






In the first hospital , CTX - M - type enzyme is the most common type of CTX - M - type enzyme , and CTX - M - 14 is the most common .
【学位授予单位】：中国医科大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R378.2

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