对付新型大肠杆菌,难不难？

2011年4月以来，德国发生了新型“肠出血性大肠杆菌O104：H4”感染暴发疫情，波及部分欧洲其他国家及美国、加拿大等16个国家，累计病例数千例，死亡几十例。流行病学调查结果初步确认了本次疫情的传播媒介为芽苗菜，但疑问仍然不少。     

分子分型方法在肠出血性大肠杆菌检测中的应用

自1982年首次发现肠出血性大肠杆菌O157：H7在北美引起出血性肠炎以来,与肠出血性大肠杆菌O157：H7病原菌相关疾病的发生率逐年上升,尤以发达国家病例为多,这可能与其饮食习惯和监测报告系统完善有关。大多数O157：H7肠出血性大肠杆菌的感染是食用了被牛粪污染的食物和饮水引起的,临床症状主要表现为腹部痉挛性疼痛和出血性结肠炎。近些年已经报道过多起由肠出血性大肠杆菌O157：H7引起的暴发流行,因儿童和老年人患者有时会在腹泻后继发诸如溶血性尿毒综合征等严重的并发症而死亡率较高。O157：H7是肠出血性大肠杆菌的主要血清型别,     

2011年德国肠出血性大肠杆菌O104：H4疫情流行病学调查及启示

2011年5-7月德国发生一起肠出血性大肠杆菌(EHEC)O104(:)H4感染引起的暴发疫情,并波及欧盟其他13个国家及美国、加拿大等地,报告EHEC感染和溶血性尿毒综合征(HUS)病例4400余例[1].自发现疫情以来,德国联邦公共卫生机构罗伯特·科赫研究所(Robert Koch Institute,RKI)联合联邦及有关州卫生部门及医疗、研究机构开展了一系列流行病学调查,掌握了疫情特征,逐步查明病因,为采取控制措施提供了重要依据[1-3].     

肠出血性大肠杆菌感染的流行病学及临床医学资料概述

大肠杆菌在自然界广泛分布,其中,肠出血性大肠杆菌(EHEC)是引起出血性肠炎最常见的致病菌之一.2011年5月以来,德国由食用“毒蔬菜”引发的出血性肠炎暴发疫情波及了欧州许多国家,美国、加拿大也分别有确诊病例.为此,为了给防治出血性肠炎的暴发流行提供参考依据,从流行病学角度概述了肠出血性大肠杆菌感染的病原学、传染源、传...     

昆明市0_(157):H_7大肠杆菌检验结果分析

肠出血性大肠杆菌O157:H7感染是一种新发现的传染病,可引起出血性肠炎,严重者并发溶血性尿毒综合征和血栓性血小板减少性紫癜,病死率高,而且预后差。其感染流行已成为全球关注的公共卫生问题[1]。在美国、加拿大、英国、日本等发达国家都发生过O157:H7大肠杆菌的暴发流行。我国有不少地区相继发生病例,个别地区甚至出现暴发疫情[2]。为了解昆明市是否存在O157:H7大肠杆菌及流行情况,我们采集了3个养殖场、2个西式快餐店和市区9个农贸市场的155份样品,用O157免疫磁珠富集法[3]进行O157:H7大肠杆菌的检测。从中分离出19株O157:H7大肠杆菌,现将结果报告如下。     

德国肠出血性大肠杆菌O104:H4暴发疫情带来的思考

2011年4月以来,德国多个地方肠出血性大肠杆菌(EHEC)O104:H4感染和溶血性尿毒综合征(HUS)疫情暴发。本文概述本次疫情的概况以及德国政府采取的应对措施,并从机构协作、信息公开、流行病学发挥的作用、症状监测重要性四个方面讨论对我国口岸卫生检疫工作的启示。     

肠出血性大肠杆菌的临床、检测方法和流行病学特征

新发现的病原微生物和重新抬头的病原微生物是当前医学界面临的一个新的课题,对人类的健康构成了重大威胁,O157:H7大肠杆菌就是其中之一,属于肠出血性大肠杆菌(Entero-hemorrhagic E.coil:EHEC)。1996年5~8月份在日本发生了O157:H7血清型大肠杆菌的暴发流行,先后历时近3个月,波及3o多个都府县,9000多名儿童感染,近10名死亡。在日本这个号称是世界上最干净的国家里引起举国上下的震动。日本内阁曾召开紧急会议,成立了专门机构来处理疫情。这是世界上发生的最大一起O157:H7大肠杆菌引起的暴发流行。     

肠出血性大肠埃希菌O104:H4病原学及其防治研究进展

2011年5-7月在德国北部暴发一起肠出血性大肠埃希菌(enterohemorrhage,Escherichia coli,EHEC)O104:H4感染的疫情,该疫情从德国北部起始,很快就席卷整个德国并蔓延至欧洲、北美国家.EHEC O104:H4是新世纪以来出现的又一新发传染病,其致病性强,传播速度快,引起全世界的关注.迄今中国尚无此病的报道,但在全球化的今天,了解并充分防范已成共识.据此,该文就EHEC的病原学、快速检测法、所引起的主要疾病发病机制及临床症状、预防措施等方面的研究进展进行综述.     

肠出血性大肠杆菌与国境卫生检疫

德国近期的溶血性尿毒症(HUS)疫情引发关注,报告的有肠出血性大肠杆菌O104:H4感染的确诊或疑似病例2000余例,除德国外,奥地利、捷克、丹麦、法国、荷兰、挪威、西班牙、瑞典、瑞士、英国、美国等13个国家也报到了输入性肠出血性大肠杆菌感染病例或其严重并发症——溶血性尿毒综合征病例,全球数以百计的患者确诊感染,多名病例死亡。研究者发现,造成此次肠出血性大肠杆菌疫情的病菌"是常见的肠出血性大肠杆菌的一个非常远的远亲"。它大约80%的基因来自血清型为O104型的大肠杆菌,其余20%的基因来自另外一种大肠杆菌。这一新组合有利于病菌在肠细胞上附着,从而使其能在肠道内宿居更长时间,造成更大的破坏。此外,这种病菌还对抗生素具有很强的抗药性,研究人员已经发现该菌株携带氨基糖甙类、大环内酯类及磺胺类抗生素的耐药基因,对目前已知的绝大多数抗生素药物耐药,导致感染者几乎无药可医。肠出血性大肠杆菌感染疫情大规模蔓延的潜在危险给全球公共卫生事业和我国国境卫生检疫工作带来了巨大的威胁和挑战。如何正确的看待此次肠出血性大肠杆菌感染疫情带来的挑战,加强预警,防范于未然,进一步完善国境卫生检疫工作的手段,提高科技含量,满足《国际卫生条例(2005)》对卫生检疫核心能力建设提出的要求,力争做到对输入性病例包括肠出血性大肠杆菌在内的新发传染病早发现、早处置、早治疗、早隔离,保障国内人民身体健康,是值得每一个检疫工作者思考的问题。     

我国畜禽动物感染O157大肠杆菌情况分析

自1982年美国首次发现肠出血性大肠杆菌(EHEC)O157:H7致病性血清型后,该病成为全球稳速增长的食源性疾病的病原菌,成为新的凶险传染病之一.0157大肠杆菌(包括O157:H7与O157:H7?)能引起一系列人类病,如腹泻、出血性肠炎及危及生命的溶血性尿毒综合征.全球六大洲的许多国家相继发生多起由该菌引起的食物中毒,造成严重的公共卫生问题.我国自1987年首次发现该菌以来,许多地方已相继发现该菌株.1999年,在江苏、安徽交界的农村暴发了这一传染病.为此,特将近年来我国部分地区畜禽动物感染0157大肠杆菌情况报告如下.     

肠道致病菌暴发事件中分子分型技术的应用

目的探讨建立快速敏感的肠道病原菌的诊断分型方法。方法2002年7月用脉冲场电泳胶（PFGE）与噬菌体分型实验方法对发生在日本静冈县的4起暴发事件中29株宋内志贺菌（Shigella.sonnei）分离株与1999年口本静冈县某区现场分离的12株肠出血性大肠埃希菌（enterohemorrhagic Escherichia coli,EHEC）O157：H7菌株进行分型。结果4起事件中Shigetta．sonnei的PFGE结果显示,同起事件的DNA条带几乎一致;2起EHEC O157：H7暴发事件中,同起事件的PFGE条纹几乎一致,而3株散发菌株的PFGE条纹各异;12株EHEC O157：H7噬菌体分型结果也显示了比较好的分型力。结论PFGE具有分型能力强、重复性好等特点,能直观地判断肠道致病菌的亲缘关系,及时查明暴发流行的传染源,从而有效控制疫情的蔓延。     

荧光定量PCR快速检测食品中肠出血性大肠杆菌O104

目的建立针对肠出血性大肠杆菌O104的荧光定量PCR快速检测方法。方法针对O104的wzx保守基因,设计特异性引物和探针,采用倍比梯度稀释法检测该体系的灵敏度,以另外34株肠道致病菌评价检测方法的特异性;建立了肠出血性大肠杆菌O104感染食品的检测模型以验证方法的适用性。结果建立了荧光定量PCR快速检测肠出血性大肠杆菌O104的方法。每次检测最低限为12.0copies,特异性为100%。结论该法缩短了检测时间,并有良好的灵敏性和特异性,在疾病防控及食品卫生行业中具有应用前景。     

Outbreak of Shiga toxin-producing Escherichia coli and haemolytic uraemic syndrome

Enterohaemorrhagic Escherichia coli (EHEC) is a group of pathogenic Shiga toxin-producing E. coli that can cause haemorrhagic colitis and haemolytic uraemic syndrome (HUS). The disease usually occurs sporadically, but sometimes also occurs in large outbreaks such as that which recently occurred in northern Germany. EHEC infection is a zoonosis and its reservoir is in ruminant farm animals (cattle, sheep and goats). EHEC infection should be considered in patients with bloody diarrhoea, but in the course of many severe EHEC infections a picture resembling HUS may also occur. Antibiotic treatment is contraindicated because it does not reduce the duration of the disease and may have negative complications. Patients with EHEC infection may spread the bacteria and their care includes contact isolation measures with their own toilet facilities. The E. coli type O104:H4 that occurred in Germany has a combination of specific virulence characteristics. This outbreak affected many people who developed HUS and neurological symptoms following bloody diarrhoea.     

肠出血性大肠埃希菌及其引起暴发的研究

大肠埃希菌属人肠道正常菌群.少数大肠埃希菌可使人致病,称致泻性大肠埃希菌.肠出血性大肠埃希菌( EHEC)是其中常见的一类,是重要的食源性疾病致病菌,常见血清型包括O157等.自1982年在美国引起首次暴发后,EHEC便在世界各国陆续引起暴发.此文针对EHEC的病原学特征、历年暴发及实验室鉴定等方面进行综述.     

The evolution of the Escherichia coli phylogeny

Escherichia coli is familiar to biologists as a classical model system, ubiquitous in molecular biology laboratories around the world. Outside of the laboratory, E. coli strains exist as an almost universal component of the lower-gut flora of humans and animals. Although usually a commensal, E. coli has an alter ego as a pathogen, and is associated with diarrhoeal disease and extra-intestinal infections. The study of E. coli diversity predates the availability of molecular data, with strains initially distinguished by serotyping and metabolic profiling, and genomic diversity illustrated by DNA hybridisation. The quantitative study of E. coli diversity began with the application of multi-locus enzyme electrophoresis (MLEE), and has progressed with the accumulation of nucleotide sequence data, from single genes through multi-locus sequence typing (MLST) to whole genome sequencing. Phylogenetic methods have shed light on the processes of genomic evolution in this extraordinarily diverse species, and revealed the origins of pathogenic E. coli strains, including members of the phylogenetically indistinguishable "genus"Shigella. In May and June 2011, an outbreak of haemorrhagic uraemic syndrome in Germany was linked to a strain of enterohaemorrhagic E. coli (EHEC) O104:H4. Application of high-throughput sequencing technologies allowed the genome and origins of the outbreak strain to be characterised in real time as the outbreak was in progress.     

Escherichia coli O104 Associated with Human Diarrhea, South Africa, 2004-2011

To determine the origin of >4,000 suspected diarrheagenic Escherichia coli strains isolated during 2004-2011 in South Africa, we identified 7 isolates as serotype O104; 5 as enteroaggregative E. coli O104:H4, and 2 as enteropathogenic E. coli O104:non-H4. Pulsed-field gel electrophoresis showed that these isolates were unrelated to the 2011 E. coli O104:H4 outbreak strain from Germany.     

肠出血性大肠埃希菌O157:H7不同分型方法比较

目的探讨建立快速敏感的EHEC O157：H7诊断分型方法，有效地追踪溯源和控制传染源。方法分别用反向被动乳胶凝集试验(RPLA)、噬菌体分型、vt毒力基因PCR试验、脉冲场电泳胶(PFGE)4种实验方法对EHEC O157：m菌株进行分型。结果对同起事件菌株，4种方法均有较好的分型能力；PFGE对散发菌株有很强的分型能力，而RPLA与vt毒力基因PCR试验尚有不足，但其操作简便，实验要求相对不高，可以作为EHEC O157：H7致病毒素的初筛方法。结论几种分型技术联合使用比任一种技术单独使用能提供更为可靠的分型结果。     

An outbreak of Escherichia coli O157:H7 infection in southern Sweden associated with consumption of fermented sausage; aspects of sausage production that increase the risk of contamination

A large outbreak of enterohaemorrhagic Escherichia coli (EHEC) infections occurred in southern Sweden during autumn 2002. A matched case-control study was performed and indicated an association between consumption of fermented sausage and EHEC infection (odds ratio 5.4, P<0.002). Pulsed-field gel electrophoresis analysis identified a strain of E. coli O157:H7 in clinical faecal isolates, which was identical to a strain isolated from sausage samples obtained from households of infected individuals. A combination of microbiological and epidemiological results established a link between sausage consumption and the outbreak in 30 out of a total of 39 investigated cases. Contaminated beef was suspected to be the source of infection. Delayed start of fermentation, lack of heat-treatment and a short curing period in cold temperature were identified as the main factors enabling EHEC survival. EHEC can survive throughout the entire production process of fermented sausage if curing conditions are inadequate.     

Enteroaggregative E. coli O104 from an outbreak of HUS in Germany 2011, could it happen again?

Enterohaemorrhagic E. coli (EHEC) particularly O157:H7 (Sequence type 11 complex), is the best documented and most well-known of E. coli that cause diarrhoea. The importance of EHEC lies in the severity of disease. Outbreaks can infect thousands of people causing bloody diarrhoea and haemolytic uremic syndrome (HUS) that in turn can result in protracted illness or even death. The ability of EHEC to colonise the human gut is normally associated with the presence of genes from another group of diarrhoeagenic E. coli, the enteropathogenic E. coli (EPEC), via the locus of enterocyte effacement. However, the massive outbreak in Germany was caused by an EHEC which had acquired virulence genes from yet another group of diarrhoeagenic E. coli, the enteroaggregative E. coli (EAEC). In reality EAEC is probably the most common bacterial cause of diarrhoea but is not identified in most diagnostic laboratories. This outbreak emphasises the importance of being able to detect all diarrhoeagenic E. coli and not to focus on E. coli O157:H7 alone. Routine surveillance systems for EAEC, a once ignored global pathogen, would go a long way to reaching this goal. This review describes methods for identifying non-O157 EHEC and describes the key genetic features of EHEC and EAEC. Our aim is to provide information for laboratories and policy makers which enables them to make informed decisions about the best methods available for detecting newly emergent strains of diarrhoeagenic E. coli.