徐州市2000年肠出血性大肠埃希菌O157∶H7感染性腹泻的调查

目的　了解徐州市丰县和铜山县肠出血性大肠埃希菌 (EHEC)O15 7∶H7引起的出血性结肠炎 (HC)在腹泻病患者中所占的比例 ,以及临床症状和肾功能变化的情况。方法　使用EHECO15 7胶体金快速检测试剂筛选粪便标本 ,阳性者使用免疫磁珠方法分离病原菌。对经过细菌学证实的EHECO15 7∶H7引起的HC患者 ,进行临床症状的观察和生化检验指标分析。结果　 2 0 0 0年 5月份 ,丰县由EHECO15 7∶H7引起的HC占腹泻病患者 0 .98% ,6月份铜山县的HC患者占腹泻病患者5 .89%。在出现腹泻病症状的同时 ,18.5 %患者的肾功能已经出现异常 ,表现为尿蛋白、血清肌苷或血尿素氮等指标的升高。在 2 7例HC患者中 ,有 14和 13例分别分离到不产生志贺毒素和产生志贺毒素的EHECO15 7∶H7菌株。根据分离菌株是否产生志贺毒素将患者分为两组进行比较 ,尿蛋白阳性患者的比例分别为 4 / 13和 1/ 14 ,血小板减少患者的比例分别为 6 / 13和 3/ 14。统计学分析有显著意义。提示分离到产生志贺毒素的EHECO15 7∶H7菌株的患者 ,发生肾功能异常的可能性较大。结论　此次调查证实了EHECO15 7∶H7感染所引起的HC在整个腹泻病患者中所占的比例随季节的变化而不同 ,感染产生志贺毒素EHECO15 7∶H7菌株的患者 ,发生肾功能异常的可能性要比不产生志贺     

我国部分产生志贺毒素肠出血性大肠埃希菌O157：H7脉冲电场凝胶电泳分型

目的 探讨我国部分地区产生志贺毒素的肠出血性大肠埃希菌（EHEC）O157：H7菌株的分布，流行以及分型情况。方法 用脉冲电场凝胶电泳（PFGE）方法进行分型，辅以药物敏感性试验对51株产生志贺毒素的EHECO157：H7菌株进行研究。结果 根据细菌染色体DNA的XbaI酶切图谱，可将从江苏省徐州市等地分离的51株产生志贺毒素的EHECO157：H7菌株分成8个PFGE型别（PFGE1-PFGE8），宁夏菌株为PFGE1型和2型，徐州菌株有6个PFGE型，1986-1988年的分离菌株属于PFGE7型，1999、2000年病人分离株的优势型别分别是PFGE5型与3型，1999年爆发性流行期间从患者分离的5株菌属于PFGE5型，从家畜家禽的粪便，食品，蔬菜等标本分离的19株菌，可以分为PFGE3-6等4个型别，其中，PFGE5型占优势（10株菌）。结论 爆发性流行的发生与携带病原菌的家畜家禽粪便污染的食品，蔬菜等有关，从我国部分地区分离的EHECO157：H7菌株的PFGE型别有地区性差异。     

中国部分地区大肠埃希菌O157的分子分型及变异研究

目的了解出血性大肠埃希菌（EHEC）O157的分子流行特征和遗传变异关系并完善EHECO157：H7感染性腹泻监测制度。方法采用聚合酶链反应分析毒力基因的分布情况；用脉冲场凝胶电泳技术对1988-2005年部分地区分离到的249株EHECO157：H7（其中产志贺毒素的245株，不产志贺毒素的4株）和51株O157非H7进行分子流行病学分析。结果stx2基因在我国的EHECO157：H7菌株中有着很高的分布率，部分菌株携带stx2基因变种。300株O157共分为161种带型，其中51株O157非H7菌株共有42种带型，4株O157：H7非产毒株分别为4种带型，245株EHECO157：H7共有115种带型。结论EHECO157间的基因变异较大；产stx2原毒素的菌株和5衄2毒素发生变异的菌株带型相差较大。部分菌株之间存在着一定的交叉，说明虽然这两大类菌株有其特有的流行克隆系，但是它们的克隆系之间亲缘关系较近。     

河南省新发传染病EHEC O157:H7监测研究

[目的]了解河南省肠出血性大肠杆菌(EHEC)感染性腹泻的发病情况、宿主带菌状况、食品污染程度及志贺毒素(stx)基因型,为制订有效的防治对策提供依据。[方法]采集河南省监测点腹泻病人、家畜、家禽粪便,水和肉食品等标本分离EHEC菌株,应用分子生物学技术检测分析菌株rfbO157、rfbO111、hlyA、eaeA、stx2和stx1等毒力基因和突变基因。[结果](1)从腹泻病人、家畜、家禽、食品、水、蜣螂和苍蝇中均分离出EHEC菌株共275株,总分离率7.88%;其中O157︰H7菌株为232株(84.36%),携带stx2基因EHECO157︰H7菌株88株(37.93%);非O157︰H7菌株43株(15.64%)。(2)宿主动物中羊带菌率最高(6.96%),是河南省EHEC最主要宿主动物;多重PCR检测出8种不同毒力基因组合型,主要为rfbO157 、hlyA 、eaeA 、stx2 组合。stx2变种毒素GK探针检测出3种毒素变种杂交带型,其中stx2原毒素 stx2vha型占7.4%,stx2vha型的占72.2%,未知新杂交带型占20.4%。(3)EHECO157︰H7菌株可分为9个PFGE型,自羊、牛、鸡和蜣螂和腹泻病患者中分离的携带stx2vha菌株同属一个PFGE型。(4)144株不携带志贺毒素的O157菌株中发现O157︰H38、O157︰H42和O157︰Hund(未确定型)新菌株。[结论]河南省家禽、家畜中普遍携带EHECO157︰H7大肠杆菌,羊是最主要的宿主动物;EHECO157︰H7为我省优势菌型,其毒素基因型为stx2-eaeA-hlyA并以stx2vha亚型为主。EHEC在外环境中污染严重并可在人与人、动物与人之间传播,家畜、家禽携带stx2 EHECO157︰H7率的高低与EHEC人群感染发病呈相关关系。     

弗氏柠檬酸杆菌与EHEC O157∶H7的抗原交叉反应及生化鉴别的实验

肠出血性O157∶H7大肠艾希菌(EHECO157∶H7)于1982年报告并被确认为致病菌,感染该菌可引起人类出血性肠炎,溶血性尿毒综合症以及血小板减少性紫癜,并在国内外引起过爆发和流行,造成严重危害,已为世界瞩目,广泛关注。因此我市自1998年开始在食物及腹泻病患者中开展对该菌的监测工作,并于1998年～1999年在对鸡肉的监测中检测出2株EHECO157∶H7。但是我们在对腹泻病患者的粪便标本检测中,发现由于分离到的弗氏柠檬酸杆菌与EHECO157∶H7抗血清、O157单克隆抗体发生交叉凝集反应,极易引起混淆,因此要求我们利用系统生化鉴定以鉴别EHEC…     

浙江省检出首例带stx2 O157:H7病人的报告

目前大多数学者认为肠出血性大肠杆菌O157：H7之所以能对人类致病，其致病因子为志贺毒素，并认为该毒素为肠出血性大肠杆菌（EHEC）所特有。浙江省于1997年首次在杭州人和动物中检出肠出血性大肠杆菌O157：H7后，又相继在宁波等地从动物中检出，但是都不带志贺毒素1（stxl）和志贺毒素2（stx2）。本次检出的病人为浙江省首次发现带有stx2毒素的肠出血性大肠杆菌O157：H7菌株。现报告如下。     

我国部分产生志贺毒素肠出血性大肠埃希菌O157∶H7脉冲电场凝胶电泳分型

目的　探讨我国部分地区产生志贺毒素的肠出血性大肠埃希菌 (EHEC)O15 7∶H7菌株的分布、流行以及分型情况。方法　用脉冲电场凝胶电泳 (PFGE)方法进行分型 ,辅以药物敏感性试验对 5 1株产生志贺毒素的EHECO15 7∶H7菌株进行研究。结果　根据细菌染色体DNA的XbaI酶切图谱 ,可将从江苏省徐州市等地分离的 5 1株产生志贺毒素的EHECO15 7∶H7菌株分成 8个PFGE型别 (PFGE1～PFGE8) ,宁夏菌株为PFGE1型和 2型 ,徐州菌株有 6个PFGE型。 1986～ 1988年的分离菌株属于PFGE7型 ,1999、2 0 0 0年病人分离株的优势型别分别是PFGE5型与 3型。 1999年爆发性流行期间从患者分离的 5株菌属于PFGE 5型 ,从家畜家禽的粪便、食品、蔬菜等标本分离的 19株菌 ,可以分为PFGE3～ 6等 4个型别 ,其中 ,PFGE5型占优势 (10株菌 )。结论　爆发性流行的发生与携带病原菌的家畜家禽粪便污染的食品、蔬菜等有关 ,从我国部分地区分离的EHECO15 7∶H7菌株的PFGE型别有地区性差异     

不同来源产志贺毒素大肠埃希菌分布特征

目的探讨不同标本中产志贺样毒素大肠埃希菌（STEC）的分布特征。方法采集动物粪便、肉类食品和排污口污泥样品，常规分离大肠埃希菌，血清学分型，PCR鉴定产志贺样毒素（stx1，stx2）菌株。结果293份标本中鉴定出8株STEC，1株为产志贺毒素O157：H7型，2株为不产志贺毒素O157：H7型，5株为产志贺毒素非O157：H7型。结论STEC存在于不同来源的标本中，菌株表型与毒力因子存在一定差异。     

安徽省1999～2003年O157：H7大肠杆菌实验监测及其意义

目的为了解我省肠出血性大肠杆菌O157：H7感染性腹泻的病人（宿主动物）带菌情况及其毒力基因携带情况,探索疾病发生的原因.方法对安徽省1999～2003年病人粪便进行O157：H7大肠杆菌的分离培养、动物宿主O157：H7大肠杆菌带菌状况调查及O157：H7大肠杆菌毒力基因的检测,并用免疫印迹法检测人群血清特异性O157：H7溶血素抗体.结果家禽家畜出血性大肠杆菌O157：H7带菌率为10.45%、2.50%、0.14%、0.72%和0.31%;从腹泻病人粪便中分离出O157：H7大肠杆菌、痢疾杆菌等,分离率分别为0.43%和4.75%;特异性O157：H7溶血素IgG抗体总阳性率为25.87%;志贺样毒素、溶血素毒力基因检测有53.2%的EHEC O157：H7菌株阳性.结论通过血清学、病原学、分子生物学实验监测,可以认为家禽家畜为O157：H7的动物宿主,分离的O157：H7大肠杆菌大部分携带毒力因子,染菌的家禽家畜是引起人群爆发流行的的重要传染源.     

动物宿主的EHECO157H7带菌调查

O157H7大肠杆菌是出血性大肠埃希菌(Enterohemorrhagic EColi EHEC)的一个重要血清型.该菌可导致腹泻、出血性结肠炎(HC)、溶血性尿毒综合症(HUS)[1].自1982年在美国首次报道了由O157H7大肠杆菌引起的出血性肠炎的暴发以来,EHEC的感染已成为世界性的问题. WHO已确认O157H7为食源性疾病的病原体[2].近年来我国防疫部门也开始致力于对O157H7的检测工作,有自腹泻病人、猪粪、鸡肉、牛肉、卤肉等检出本菌的报告,但EHECO157H7 在本地区动物宿主中的带菌调查尚未见报道,其流行病学资料尚属空白.为了解EHECO157H7在本地区禽畜粪便中的带菌状况,为预防O157H7等致泻性大肠杆菌引起爆发流行提供依据,我们于2000年6-10月,在石家庄市所管辖各县采集牛、猪、鸡粪便,苍蝇体表样品共计170份.对致泻性大肠杆菌EHECO157H7进行调查,现将结果报告如下:     

Sorbitol-fermenting, β-glucuronidase-positive, Shiga toxin-negative Escherichia coli O157:H7 in free-ranging red deer in South-Central Spain

We investigated the prevalence of Escherichia coli O157:H7 in free-ranging red deer in south-central Spain, to assess their potential as reservoir hosts of sorbitol-fermenting (SF) E. coli O157:H7 strains, which are emerging causes of hemolytic uremic syndrome in Europe. Fecal samples from 264 hunter-harvested Iberian red deer (Cervus elaphus) were collected in 25 different game estates and examined for E. coli O157:H7 by culture and PCR. E. coli O157:H7 was detected and isolated in 4 of the 25 game estates sampled (16%) and the isolates obtained (four in total) were further phenogenotypically characterized. One of them was biochemically typical of E. coli O157:H7, that is, neither fermented sorbitol nor exhibited β-glucuronidase (GUD) activity, and carried genes encoding Shiga toxins (Stx) 1 and 2, the intimin subtype γ1, the enterohemorrhagic E. coli (EHEC)-hemolysin, and the ter gene cluster. The rest of the isolates (three of four) fermented sorbitol, exhibited GUD activity after 18-24?h incubation, and carried genes encoding the intimin subtype γ1 and the EHEC-hemolysin, although no Stx-encoding genes were detected. All these atypical isolates carried the sfp gene cluster, lacked the ter gene cluster, and were unable to grow on cefixime tellurite sorbitol MacConkey agar, which are typical features of SF E. coli O157:H7 strains isolated from patients. In total, SF, GUD-positive, Stx-negative E. coli O157:H7 strains were isolated in 3 of the 25 game estates sampled (12%), with an overall sample-level prevalence of 1.1% (3/264). Our findings indicate that free-ranging red deer may be one of the possible reservoir hosts of Stx-negative derivatives of SF E. coli O157:H7.     

衢州市2000-2009年肠出血性大肠埃希菌O157∶H7监测

目的了解浙江省衢州市肠出血性大肠埃希菌O157∶H7人的感染、食品污染以及动物和媒介昆虫带菌情况。方法在流行季节采集腹泻患者、动物粪便以及各类食品、苍蝇等样本,MEC肉汤增菌后,用特异性免疫磁珠集菌,以科玛嘉显色平板分离,纯化的菌株进行生化鉴定、血清分型及毒力基因检测。结果 2000-2009年,共检测样本12 292份,检出EHEC O157∶H7 19株,总检出率为0.15%。其中4种宿主动物粪便样本中检出18株,检出率分别为羊2.14%、牛1.29%、猪0.45%、鸭0.19%;食品中从生猪肉中检出1株,检出率0.17%;腹泻患者和苍蝇样本中均未检出。经毒力基因检测,其中16株stx2+hly+eaeA阳性,1株hly+eaeA阳性,其余2株不带毒力基因,带毒率89.47%。结论浙江省衢州市部分动物中产毒的EHEC O157∶H7带菌率较高,表明该地区存在暴发或流行的潜在危险,应加强综合监测。     

Importance of culture confirmation of shiga toxin-producing Escherichia coli infection as illustrated by outbreaks of gastroenteritis--New York and North Carolina, 2005

Escherichia coli O157:H7 and other strains of E. coli that produce Shiga toxin are collectively known as Shiga toxin-producing E. coli (STEC). The current outbreak of STEC O157 infections associated with eating fresh spinach illustrates the importance of obtaining isolates to identify the source of the infections. Laboratory methods that do not require bacterial culture of stool specimens to identify STEC are being used increasingly by clinical diagnostic laboratories, sometimes without subsequent confirmation of a strain by isolating it in culture. This report describes findings from outbreaks of gastroenteritis in 2005 in New York and North Carolina in which clinical diagnostic laboratories initially used only non-culture methods to detect Shiga toxin (Stx). The findings highlight the importance of confirmation of Stx-positive stool specimens by bacterial culture for timely and reliable identification of STEC infections, including E. coli O157 and non-O157 STEC, to enable implementation of appropriate public health actions. An important part of that identification is determining the serotype of all STEC isolates and the subtype of STEC O157 strains so that outbreaks can be detected and traced back to sources.     

江苏省淮北地区肠出血性大肠埃希菌O157:H7感染性腹泻并发急性肾衰的研究

目的 了解1999～2000年江苏省淮北部分地区发生肠出血性大肠埃希菌O157:H7感染性腹泻并发急性肾衰病例的病因与流行特点。方法 运用流行病学、微生物学、分子生物学等方法,对传染源、传播途径、流行因素进行调查和分析。结果 1999年共在9个县(区)报告肠出血性大肠埃希菌O157:H7感染性腹泻并发急性肾衰病例95例,死亡83例,病死率87.37％。6月中、下旬为发病高峰,男女之比为1:1.44,年龄以50岁以上为主,占88.42％。2000年发生38例,死亡34例,病死率89.47％。引起爆发的主要危险因素有不饮自来水、吃剩饭菜、厨房卫生差、生食瓜果和饭前便后不洗手。从2例重症患者及3例腹泻患者粪便标本分离到O157:H7;宿主动物O157:H7携带率为9.62％(170/1767),菌株毒力基因阳性率达99.41％(169/170)。从患者粪便标本分离的菌株与家禽家畜分离的菌株属同一克隆群。结论 这是中国首次发现由O157:H7引起的爆发疫情,其发生与宿主动物带菌率高且菌株毒力基因阳性率高有密切关系,引起疫情的具体传播途径复杂多样,主要的感染危险因素与个人卫生、家庭卫生不良有关。     

Comparison of Escherichia coli Isolates from humans, food, and farm and companion animals for presence of Shiga toxin-producing E. coli virulence markers

The objective of this study was to characterize Escherichia coli isolates from dairy cows/feedlots, calves, mastitis, pigs, dogs, parrot, iguana, human disease, and food products for prevalence of Shiga toxin-producing E. coli (STEC) virulence markers. The rationale of the study was that, isolates of the same serotypes that were obtained from different sources and possessed the same marker profiles, could be cross-species transmissible. Multiplex polymerase chain reaction (PCR) was used to detect presence of genes encoding Shiga toxin 1 and 2 (stx1 and stx2), H7 flagella (flicC), enterohemolysin (hly) and intimin (eaeA) in E. coli isolates (n = 400). Shiga toxin-producing isolates were tested for production of Shiga toxins (Stx1 and Stx2 and enterohemolysin. Of the E. coli O157:H7/H- strains, 150 of 164 (mostly human, cattle, and food) isolates were stx+. Sixty-five percent of O157 STEC produced both Stx1 and Stx2; 32% and 0.7% produced Stx2 or Stx1, respectively. Ninety-eight percent of O157 STEC had sequences for genes encoding intimin and enterohemolysin. Five of 20 E. coli O111, 4 of 14 O128 and 4 of 10 O26 were stx+ . Five of 6 stx+ O26 and O111 produced Stx1, however, stx+ O128 were Stx-negative. Acid resistance (93.3%) and tellurite resistance (87.3%) were common attributes of O157 STEC, whereas, non-O157 stx+ strains exhibited 38.5% and 30.8% of the respective resistances. stx-positive isolates were mostly associated with humans and cattle, whereas, all isolates from mastitis (n = 105), and pigs, dogs, parrot and iguanas (n = 48) were stx-negative. Multiplex PCR was an effective tool for characterizing STEC pathogenic profiles and distinguished STEC O157:H7 from other STEC. Isolates from cattle and human disease shared similar toxigenic profiles, whereas isolates from other disease sources had few characteristics in common with the former isolates. These data suggest interspecies transmissibility of certain serotypes, in particular, STEC O157:H7, between humans and cattle.     

Human infections with non-O157 Shiga toxin-producing Escherichia coli, Switzerland, 2000-2009

We characterized 97 non-O157 Shiga toxin (stx)-producing Escherichia coli strains isolated from human patients during 2000-2009 from the national reference laboratory in Switzerland. These strains belonged to 40 O:H serotypes; 4 serotypes (O26:H11/H-, O103:H2, O121:H19, and O145:H28/H-) accounted for 46.4% of the strains. Nonbloody diarrhea was reported by 23.2% of the patients, bloody diarrhea by 56.8%. Hemolytic uremic syndrome developed in 40.0% of patients; serotype O26:H11/H- was most often associated with this syndrome. Forty-five (46.4%) strains carried stx2 genes only, 36 strains (37.1%) carried stx1, and 16 (16.5%) strains carried stx1 and stx2. Genes encoding enterohemolysin and intimin were detected in 75.3% and 70.1% of the strains, respectively. Resistance to ≥1 antimicrobial agent was present in 25 isolates. High genetic diversity within strains indicates that non-O157 stx-producing E. coli infections in Switzerland most often occurred as single cases.     

Hamburger-associated Escherichia coli O157:H7 infection in Las Vegas: a hidden epidemic.

OBJECTIVES: This study sought to determine whether a multistate fast food hamburger-associated outbreak of Escherichia coli O157:H7 infection involved Las Vegas residents as well and, if so, why public health officials had not detected it. METHODS: A matched case-control study was conducted among persons with bloody diarrhea and their healthy meal companions. Hamburger production, distribution, and cooking methods were reviewed. Unused hamburger patties were cultured, and E. coli O157:H7 isolates were characterized. Local laboratory stool culture practices were reviewed. RESULTS: Fifty-eight cases of bloody diarrhea were identified. Illness was associated with eating regular hamburgers (matched odds ratio [OR] = 9.0, 95% confidence interval [CI] = 1.02,433.4), but 25% of ill persons reported eating only jumbo hamburgers. Regular and jumbo hamburger patties yielded E. coli O157:H7 indistinguishable from the lone clinical isolate. No local laboratory cultured routinely for E. coli O157:H7 until after the outbreak. CONCLUSIONS: A large outbreak of E. coli O157:H7 infections escaped timely notice in Las Vegas because local laboratories did not culture for this pathogen. Health officials should encourage laboratories to screen at least all bloody stools on sorbitol-MacConkey medium.     

河南省睢县一起腹泻后并发急性肾功能衰竭爆发的调查

目的 调查大肠埃希菌O157：H7感染性腹泻的分布特征，临床特点及家畜、家禽的带菌状况和外环境污染程度，方法 用现患调查方法，描述大肠埃希菌O157：H7感染性腹泻的发病情况，分析引起流行的原因，用O157特异性筛查方法进行病原体分离培养，应用分子生物学，微生物学，细胞学技术进行病人，家畜、家禽的病原学分离，培养，毒素因子测定。结果 睢县是河南省首先发现的疫区，从3月17日至7月6日共发生病人35例，合并急性肾功能衰竭32例，死亡28例，病死率87.50%，60岁以上发病占91%；从家畜，家禽分离出107株O157：H7菌株，从腹泻病人中分离出48株；微生物学，分子生物学及细胞学技术鉴定67株具有毒素基因；显示有5个毒素因子组合型。结论 大肠埃希菌O157：H7感染性腹泻并发急性肾功能衰竭是病人死亡的主要原因，家畜、家禽的高速 菌率可通过污染水，食物传染给人，亦可通过蝇和日常生活接触感染，睢县疫情是一起大肠埃希菌O157：H7感染引起的溶血性尿毒综合征的爆发。