住院新生儿大肠埃希菌分离株毒力因子研究  

Virulence gene detection of Escherichia coli strains isolated from hospitalized neonates

作　　者：沈艳华[1] 王亚娟[1] 姚开虎[2] 高薇[2] 丁翊君[1] 吴丹[1] 董方[3] 

机构地区：[1]首都医科大学附属北京儿童医院新生儿中心,北京100045 [2]首都医科大学附属北京儿童医院微生物免疫室,北京100045 [3]首都医科大学附属北京儿童医院检验科细菌室,北京100045

出　　处：《中国循证儿科杂志》2015年第1期62-66,共5页Chinese Journal of Evidence Based Pediatrics

摘　　要：目的了解住院新生儿大肠埃希菌毒力因子的携带情况。方法收集2009年9月至2012年5月临床诊断为新生儿肺炎、败血症的连续病例,选择其中抗生素使用之前痰液、血液、脑脊液或脐分泌物培养为大肠埃希菌的病例。根据发病日龄不同,将菌株分为早发型及晚发型。根据标本来源不同,将菌株分为侵袭性感染和非侵袭性感染。选取11种最常见的毒力基因,应用PCR方法对大肠埃希菌菌株进行检测。采用Chromas软件进行读序,测序结果采用Chromas软件直接进行BLAST Search比对。结果 110株大肠埃希菌分离自102例住院新生儿,源于痰液79株(71.8%),血液18株(16.4%),脑脊液6株(5.4%),脐分泌物7株(6.4%);源于足月儿102株,早产儿8株。早发型27株,晚发型83株;侵袭性感染24株,非侵袭性感染86株。1Einv基因阳性91.8%,CNF1基因阳性21.8%,CNF2基因阳性12.7%,Eagg基因0.9%;共有7种毒力基因携带模式:单纯携带Einv基因66株,单纯携带CNF1基因1株,携带Einv-CNF1基因20株,携带Einv-CNF2基因11株,携带Einv-CNF1-CNF2基因3株,携带Einv-Eagg基因1株。8株(7.3%)11种毒力基因检测均阴性。2携带CNF1或CNF2菌株的37例患儿中22例合并呼吸衰竭,15例需予NCPAP呼吸支持,10例合并多脏器受损,3例肺出血。38对菌株分别来自同一患儿不同时期或不同部位,其中7对菌株经PFGE分型分别属于同一基因型。3对分别来源于同一患儿不同时期的痰液标本菌株,PFGE分型一致,但毒力基因携带模式不相同。结论本研究检测到4种大肠埃希菌毒力基因,以Einv基因携带率最高;共发现7种毒力基因携带模式,以单纯携带Einv基因最多见。CNF1及CNF2基因可能与肺部感染的严重性相关。Objective To detect some virulence genes of the Escherichia coli( E. coli) isolated from hospitalized neonates.M ethods Subjects were recruited based on consecutive cases who were diagnosed as pneumonia and septicemia from neonates hospitalized in the Neonatal Center of Beijing Children' s Hospital from September 2009 to May 2012. Before using antibiotics sputum,blood,cerebrospinal fluid,or navel secretion cultivation were selected for cases of E. coli. According to the onset age,strains were divided into early-onset or late onset. According to different sources of specimens,strains were divided into invasive infection and non invasive infection. Polymerase chain reaction( PCR) method was used to detect the 11 most common virulence genes of Escherichia coli,including heat-labile( LT1),heat-stable( ST1 and ST2) toxins,verotoxin types1,2,2e( VT1,VT2 and VT2 e,respectively), cytotoxic necrotizing factors( CNF1 and CNF2), attaching and effacing mechanisms( eae A),enteroaggregative mechanisms( Eagg),and enteroinvasive mechanisms( Einv). Chromas software was used to read sequence,the sequencing results directly performed for BLAST searching by using Chromas software. Results A total of 110 Escherichia coli strains were isolated from extraintestinal sites in 102 neonates. From respiratory secretions( sputum) 79 strains( 71. 8%) were isolated,and blood 18 strains( 16. 4%),cerebrospinal fluid 6 strains( 5. 4%),umbilical discharge 7 strains( 6. 4%). Among the involved neonates,102 were from full-term infants,8 strains from preterm neonates. There were 27 early-onset strains,83 late onset strains. 24 strains of invasive infection,86 strains of non invasive infection. Sixty-seven cases were diagnosed as pneumonia and 35 cases as neonatal septicemia. 1 One hundred and one strains( 91. 8%) were positive for Einv gene,24 strains( 21. 8%)were positive for CNF1 gene,14 strains( 12. 7%) were positive for CNF2 gene,1 strain( 0. 9%) was positive for Eagg gene. 2Among 110 strains,there were 7 different toxin gene profiles. Only carry

关 键 词：大肠埃希菌 新生儿 毒力基因 

分 类 号：R722.1[医药卫生—儿科]