国外肠出血性大肠杆菌O157∶H7感染性疾病的主要监测系统

自1982年以来,肠出血性大肠杆菌(Enterohemorrhagic Escherichia Coli,EHEC)O157∶H7陆续在全世界六个洲的30多个国家报告了感染病例.由于它可引起出血性肠炎和病死率较高的溶血性尿毒综合症(hemolytic uremic syndrome,HUS)、血栓性血小板减少性紫癜(thrombotic thrombocytopenic porpura,TTP)等并发症,普通细菌培养技术对该菌的检出率较低,易造成漏诊、误诊和治疗的困难,做好监测工作尤为重要.本文就国外肠出血性大肠杆菌O157∶H7感染性疾病的主要监测系统及其工作概况进行综述.

肠出血大肠埃希菌O157:H7与食品安全

肠出血性大肠埃希菌(Enterohemorrhagic Escherichia coli,EHEC)主要包括O157:H7和O26:H11,其中O157:H7是出血性肠炎的主要致病菌,自1982年由美国首次报道了肠出血性大肠埃希菌(EHEC)O157:H7引起的出血性肠炎的爆发以来,EHEC的感染已经成为世界性问题[1].世界卫生组织已将O157:H7列为新的食源性疾病病原菌.尽管EHEC已被研究了近20年,但对由该菌引起的致命的溶血性尿毒综合症(HUS)和血小板减少性紫癜(TTP)仍没有有效的治疗方案.

从市售蔬菜和熟肉制品中检测出O157:H7大肠杆菌

肠出血性大肠杆菌(Entreohemorrhagic Escherichia Coli,EHEC)是Riley等于1982年首次报告的,[1]血清型为O157:H7.大肠杆菌O157:H7引起的食源性疾患死亡率较高.[2,4]近年来,大肠杆菌O157:H7在许多国家导致多起暴发流行,[2,4,8]以1996年日本食源性暴发流行为引人注目.我国迄今尚未有食源性O157:H7感染的报道.[4]近年来我国卫生防疫部门广泛开展了对大肠杆菌O157:H7的检测工作,我们于1998年从哈尔滨238份市售食品中检出2株大肠杆菌O157:H7.实验结果报告如下.

肠毒素性大肠杆菌疫苗的研制进展

细菌性腹泻是常见的肠道传染病,广泛流行于世界各地.据统计,全球年腹泻病人达30亿左右,我国年发病约8亿多人次,死亡率达0.02‰,其中常见的是由肠毒索性大肠杆菌(Enterotoxigenic escherichia coli,ETEC)引起的腹泻[1].由于是经口传播,所以常因食品或水源污染导致爆发性流行,特别是在自然灾害和战争时期更不易避免和控制,同时由于滥用抗菌药物而导致有耐药性细菌的大量增长,所以研制有效的疫苗加强免疫预防是迫切需要解决的公共卫生问题,但是目前还没有一种行之有效的ETEC疫苗[2-7].

山梨醇发酵产志贺毒素大肠埃希菌O157∶H-的特征与检测

山梨醇发酵产志贺毒素大肠埃希菌O157∶H-(sorbitol-fermenting Shiga toxin-producing Escherichia coli O157∶H-,简称SF STEC O157∶H-)已成为欧洲大陆感染性腹泻的主要原因[1,2].本文综述SF STEC O157∶H-菌株的致病性、感染流行病学、表型和分子特征以及适宜的微生物学诊断技术.

环介导等温扩增技术快速检测肠出血型大肠杆菌O157:H7

肠出血型大肠杆菌(enterohemorrhagic Escherichia coli,EHEC)主要包括O157:H7、O26:H11和O111等几种血清型,其中O157:H7是典型菌株,对人有很强的致病力.有研究表明O157:H7导致的感染占EHEC感染的50%～80%,它能引起出血性结肠炎、阑尾炎、食管狭窄和结肠穿孔等严重胃肠道并发症.

聚集性出血性大肠杆菌:2011年德国疫情大暴发之元凶

2011年5月,肠出血性大肠杆菌疫情在德国北部开始暴发,很快席卷整个德国和欧洲部分国家,并蔓延至美国和加拿大.到6月初为止,感染人数已超过2600例,其中1/3以上患者发展为溶血性尿毒综合症(haemolytic uraemic syndrome,HUS),26例死亡.该场疫情已经发展为有记录以来世界规模第3的大肠杆菌大流行[1].

EPEC野生型O119与H511对HEp-2细胞粘附力比较

肠致病性大肠杆菌(enteropathogenic Escherichia coli. EPEC)是引起婴幼儿腹泻的重要病原菌之一.粘附是EPEC感染宿主肠粘膜上皮细胞关键的第一步.因此准确测定EPEC对靶细胞的粘附能力,有助于判定其致病力.通过分析比较EPEC有菌毛株O119和无菌毛变异株H511对人喉癌上皮细胞HEp-2的粘附情况,以确定菌毛对EPEC粘附力的影响.

产毒性大肠杆菌肠毒素对豚鼠回肠上皮细胞的影响

产毒性大肠杆菌(enterotoxigenic Escherichia coli,ETEC)是引起人和家畜急性腹泻病的主要病原菌之一[1].ETEC的致病主要与肠毒素有关.它能产生两类肠毒素:不耐热肠毒素(heat-labile enterotoxin,LT)和耐热肠毒素(heat-stable enterotoxin,ST).为进一步探讨ETEC肠毒素的作用机制,本研究观察了LT和ST对豚鼠离体回肠上皮细胞的影响.

Objective: To achieve an optimized method for soluble expression of human carboxylesterase 1 (hCE-1) in escherichia coil and purification by Ni2+-NTA agarose affinity chromatography, to get improved protein yield and purity for further development of hepatocellular carcinoma (HCC) diagnosis ELISA kits. Methods: The best antigen epitopes of hCE1 were predicted by comparing secondary structure, flexible regions, hydrophilicity, antigenic index surface probability of residues. Afterwards, pET-42a (+) with a His-tag and a GST-tag was applied to form recombinant plasmid pET-42a (+)/hCE1, which facilitated purification when using Ni2+-NTA agarose affinity chromatography. Protein quality was measured by SDS-PAGE and BCA protein assay. Western-blot identification was also performed to ensure the correct expression of hCE1 protein. Results: The residues from 500 to 567 near C-terminal of hCE1 protein were considered the best epitopes which exhibited high hydrophilicity and high surface probability and relatively flexible secondary structure and low homology compared with hCE2 and hCE3. His-hCE1 500-567 fusion protein was achieved by IPTG-inducted expression with an expected mass of 42 kDa. After purification, the final product was specially identified, which reached over 95%purity and more than 10 mg/L of microbial culture. In Western blot, the purified fusion protein was recognized by anti-hCE1 monoclonal antibody, along with previous sequencing validation, which demonstrated the correct preparation of soluble hCE1 protein. Conclusion: This is an efficacious and affordable strategy to generate fusion hCE1 of high quality in E coli, which facilitates preparation of hCE1 monoclonal antibody and further HCC diagnosis research.

CpG寡核苷酸增强UPEC FimH疫苗黏膜免疫的实验研究

尿路致病性大肠杆菌(uropathogenic Escherichia coli,UPEC)是引起尿路感染(UTI)的主要病原菌.FimH蛋白是UPEC I型菌毛的黏附成分,介导UPEC侵入膀胱上皮细胞.本实验用FimH的真核表达质粒和蛋白免疫小鼠可产生较高浓度的IgG抗体.为提高尿路黏膜中保护性ISA的水平.以CpG质粒为佐剂,与FimH的真核表达质粒和原核表达蛋白进行不同组合免疫小鼠,观察不同组的小鼠产生的免疫反应.

肠出血性大肠杆菌O157:H7特异性脂多糖抗原的制备

肠出血性大肠杆菌(Enterohemorrhagic Escherichia coli,EHEC)O157:H7是产verd毒素的食源性肠道致病菌,可引起人类患血性腹泻、肾衰竭、尿毒综合征等症.本文应用热酚水法提取纯化了EHEC O157:H7脂多糖抗原及其O-特异性多糖(O-specific polysaccharide,O-SP)侧链.

肠致病性大肠埃希菌感染对靶细胞内钙信号变化的影响

肠致病性大肠埃希菌( Enteropatho-genic Escherichia coli, EPEC),经粪-口途径传播,是导致婴幼儿腹泻的主要病原体.

产志贺毒素肠聚集性大肠埃希菌感染的检验诊断与防治

2011年5月起,德国出现新型肠出血性大肠埃希菌(enterohhaemorrhagic Escherichia coli,EHEC)感染的疫情,来势凶猛,很快蔓延到英国、荷兰、法国、奥地利、挪威、西班牙、瑞士、丹麦、芬兰、捷克等几乎整个欧洲国家,美国也发现了确诊病例.截止6月底,已报告有3600余人发病,死亡52人[1].

大肠埃希菌临床分离株质粒介导16S rRNA甲基化酶基因的检测及转移机制研究

近年来,发现一类质粒介导的16S rRNA甲基化酶,该酶能够保护细菌的30S核糖体的16s rRNA不与氨基糖苷类药物结合,造成其对包括阿贝卡星在内的所有的氨基糖苷类药物耐药,并且为高水平耐药~[1-4].目前,在革兰阴性杆菌中已发现ArmA、RmtA、RmtB、RmtC、RmtD和NpmA 6种16SrRNA甲基化酶,且该酶通常和ESBL基因共处一个质粒上,通过质粒在不同的菌株之间播散~[2-3,5-6].我们在前期的研究中发现肺炎克雷伯菌临床分离株中存在rmtB和armA两种16S rRNA甲基化酶基因~[7],16S rRNA甲基化酶基因也可能存在于大肠埃希菌临床分离株中.在本研究中,我们对从温州医学院附属第一医院2006年1月至2008年7月临床标本中分离的680株大肠埃希菌进行了16S rRNA甲基化酶基因筛查,并对其转移机制进行了研究.

住院患者肠道大肠埃希菌质粒介导喹诺酮类耐药基因研究

大肠埃希菌是肠道内主要定植菌,是耐药基因的重要储存库~([1]),其耐药水平直接关系到临床感染株的耐药水平,另外,肠道正常定植的大肠埃希菌还可将所携带的耐药基因传递给致病性大肠埃希菌、沙门菌及志贺菌等不同菌属~[2].

从尿液中分离出aac(6')-Ib基因新亚型的大肠埃希菌

迄今为止,已发现的细菌对氨基糖苷类抗菌药物产生的耐药机制主要有5种,其中由获得性耐药基因介导的耐药机制有2种,即产生氨基糖苷类修饰酶(AMEs)和产16S rRNA甲基化酶.

致腹泻性大肠埃希菌感染的快速检验诊断

致腹泻性大肠埃希菌(下称大肠杆菌,EC)种类很多,在发达国家或发展中国家均为腹泻的重要病原.在国内,其微生物学诊断技术长期滞后,常规应用的细菌培养和鉴定手段难以鉴别多种致腹泻性大肠埃希菌,故国内大多数腹泻患者的病原尚不能明确,尤其是儿童腹泻的病原.

肠出血性大肠杆菌O157:H7感染

大肠杆菌O157:H7是肠出血性大肠杆菌(enterohaemorrhagic escherichia coli,EHEC)的一种主要血清型,可引起消化道传播的人畜共患病,临床表现为无症状感染、轻度腹泻、出血性结肠炎(hemorrhagic colitis,HC),溶血性尿毒综合症(hemolytic uremics syndrome,HUS),血栓性血小板减少性紫癜(thrombotic thromobocyto penicporpura,TTP).自1982年美国发生首起O157引起的小型暴发后,世界20多个国家有散发或流行的报道,已引起广泛关注.

AIM To select a test method for specifical, sensitive and rapid identification of LT+ E. coli.METHODS Stool samples inoculated into LB solution were cultured for 4 hours at 35℃. 10 μ boiled culturesolution was taken to template. Two oligonucleotide primers were used in a polymerase chain reaction (PCR)procedure to amplify a highly conserved DNA sequence of the A subunit of the heat-labile enterotoxin.Detection of the 110 bp amplified product can be done by agarose gel electrophoresis. Thirty strains ofknown bacteria (LT+ E. coli (EC-129), ST+ E. coli (EC-130)and LT+ ST+ E. coli (EC-142), Salmonellatyphimurium , Salmonella typhi , Salmonella paratyphi A, Salmonella group C, Shigella sonnei , Enterobacteraerogenes, Alcaligenes sp, Providencia rettgeri, Proteus mirabilis, Morganella morganii, Pseudomouasaeruginosa, Aeromonas hydrophila, Klebsiella pneumoniae, Citrobacter diversus, Enterobacter cloacae, 12strains of E. coli isolated from bile samples ) and 108 diarrhea samples were detected. A total of 108 diarrheasamples were compared with LT probe hybridization, modified Eleck (M-Eleck) and ELISA simultaneously.RESULTS By PCR, of the 30 strains of bacteria, only LT+ E. coli and LT+ ST+ E. coli were positive; in40 of the 108 diarrhea samples, 20 were positive and in the other 68 samples from infants, only five werefound to be positive. Of the 25 positive samples by PCR, 23 were also found to be positive in the other 3tests; 1 was found to be positive by M-Eleck and ELISA. Of the 83 negative samples by PCR, the samenegative results were found by M-EIeck and ELISA, but 2 were found to be positive by LT probehybridization. The overall coincidence rate was about 95%. Analysis of correlation showed a significantdifference between PCR and other three tests (P<0.01) and analysis of difference showed no significantdifference (P>0.05) between them. In the detection of LT+ E. coli by means of PCR, the minimumnumber of target bacteria required was 50 CFU. The whole test was finished in 7 hours.CONCLUSION Detection of LT+ E. coli by PCR showed that the method is specific, sensitive and rapid.