Foodborne outbreak of gastroenteritis due to Norovirus and Vibrio parahaemolyticus

Vibrio parahaemolyticus and Norovirus have been recognized as the cause of sporadic cases or outbreaks of diarrhoeal illness in association with the ingestion of raw or improperly cooked seafood. This report describes a foodborne outbreak of gastroenteritis caused by both Norovirus and Vibrio parahaemolyticus following the consumption of raw seafood in a restaurant in Terrassa (Catalonia, Spain) in September 2005. Measures are needed to reduce contamination of raw seafood. Consumers can reduce the risk of foodborne illness by avoiding consumption of raw or undercooked food.     

杭州地区临床和环境分离副溶血弧菌菌株携带毒力基因的特征

目的　了解杭州地区临床和环境分离副溶血弧菌菌株的毒力基因特征。方法　对近年从食物中毒病人、临床散发病人和外环境 (小水产品 )中分离的 174株副溶血弧菌菌株 ,应用PCR技术进行耐热直接溶血素基因 (tdh)和耐热直接溶血素相关基因 (trh)的检测。结果　临床来源的副溶血弧菌 (94株来自食物中毒病人和 34株来自散发腹泻病人 )菌株的tdh携带率均大于 97% ,trh携带率为 0 % ;而所有 4 6株分离自环境 (小水产品 )的副溶血弧菌菌株未见有tdh携带 ,仅 1株trh阳性。 1株tdh阴性、trh阳性的副溶血菌株 ,其尿素酶试验为阳性 ,而在其他所有trh阴性的副溶血菌株中 ,不管其tdh是阳性或是阴性 ,尿素酶试验均为阴性。结论　引起杭州地区食物中毒及散发腹泻的副溶血弧菌主要为tdh阳性、trh阴性菌株 ,外环境中存在的trh阳性的副溶血弧菌也是一个潜在的病原     

Extraintestinal pathogenic Escherichia coli

Extraintestinal pathogenic Escherichia coli (ExPEC) possesses virulence traits that allow it to invade, colonize, and induce disease in bodily sites outside of the gastrointestinal tract. Human diseases caused by ExPEC include urinary tract infections, neonatal meningitis, sepsis, pneumonia, surgical site infections, as well as infections in other extraintestinal locations. ExPEC-induced diseases represent a large burden in terms of medical costs and productivity losses. In addition to human illnesses, ExPEC strains also cause extraintestinal infections in domestic animals and pets. A commonality of virulence factors has been demonstrated between human and animal ExPEC, suggesting that the organisms are zoonotic pathogens. ExPEC strains have been isolated from food products, in particular from raw meats and poultry, indicating that these organisms potentially represent a new class of foodborne pathogens. This review discusses various aspects of ExPEC, including its presence in food products, in animals used for food or as companion pets; the diseases ExPEC can cause; and the virulence factors and virulence mechanisms that cause disease.     

沈阳地区副溶血弧菌脉冲场凝胶电泳分析

目的运用脉冲场凝胶电泳技术(pulsed-field gel electrophoresis,PFGE)和PCR技术对辽宁沈阳市2010年7—8月份临床粪便标本分离的副溶血性弧菌进行毒力基因检测和分子分型分析。方法运用PCR技术检测24株副溶血弧菌的耐热溶血素基因(tdh)、耐热溶血素相关溶血素基因(trh)和不耐热溶血素基因(tl);用PFGE技术对其进行分子分型和聚类分析。结果 24株副溶血弧菌均含有tdh和tl基因,表明均为有毒株;PFGE结果显示,24株菌株可分为10种图谱型,其中17株O3:K6被分为4种型别(仅相差1～3条带),表明17株O3:K6在流行病学上密切相关,提示沈阳地区可能存在副溶血弧菌腹泻病的局部暴发或流行。结论沈阳地区流行的食源性副溶血弧菌存在基因型的多样性,但以遗传关系密切的O3:K6型为优势型别。     

The human health burden of foodborne infections caused by Campylobacter, Salmonella, and Vibrio parahaemolyticus in Miyagi Prefecture, Japan

To estimate the human health burden of foodborne infections caused by Campylobacter, Salmonella, and Vibrio parahaemolyticus in Japan, an epidemiological study was conducted in Miyagi Prefecture. Laboratory-confirmed infections among patients with diarrhea caused by the three pathogens were ascertained from two clinical laboratories in the prefecture from April 2005 to March 2006. To estimate the number of ill persons who were not laboratory-confirmed, we estimated physician-consultation rates for patients with acute diarrhea by analyzing foodborne outbreak investigation data for each pathogen and the frequency at which stool specimens were submitted from a physician survey. Each factor was added to a Monte-Carlo simulation model as a probability distribution, and the number of laboratory-confirmed cases was extrapolated to estimate the total number of ill persons. The estimated incidence of foodborne infections per 100,000 per year in this region estimated by this model was 237 cases for Campylobacter, 32 cases for Salmonella, and 15 cases for V. parahaemolyticus. Simulated results indicate a significant difference between our estimated incidence and the reported cases of food poisoning in this region. An enhanced surveillance system is needed to complement the present passive surveillance on foodborne illnesses in Japan to identify food safety issues more precisely, and to monitor the effectiveness of risk management options.     

无公害畜禽肉和水产品中常见致病菌及其毒力因子

肠出血性大肠杆菌、单核细胞增生性李斯特菌、沙门菌和副溶血性弧菌是无公害畜禽肉和水产品中常见的4种食源性致病菌。这些致病菌的致病性与其毒力因子密切相关。肠出血性大肠杆菌的菌毛、pO157质粒、eaeA、志贺毒素和溶血素都是其重要的毒力因子；单核细胞增生性李斯特菌的重要毒素：李斯特菌溶血素O和内化素，也是其重要的毒力因子；沙门菌的毒力因子包括致病岛的众多基因和毒力质粒；副溶血性弧菌的毒力因子TDH、TRH。研究和了解这些毒力因子的特征，对于寻找食源性致病菌的快速特异的分子诊断方法具有重要意义。     

泰州市不同来源副溶血性弧菌分离株毒力基因型和耐药性的比较研究

目的　了解泰州市水产品及腹泻病人中副溶血性弧菌的检出情况,并对检出的所有阳性菌株进行毒力基因和耐药性的比较研究。方法　对采集的水产品和腹泻病人的粪便样本进行副溶血性弧菌的分离及鉴定,运用荧光PCR技术检测副溶血弧菌的tlh(不耐热溶血素)、tdh(耐热直接溶血素)、trh(相关耐热溶血素)这3种毒力基因,采用WHO推荐的纸片扩散法(K-B法)分别对所有阳性菌株进行药敏实验。结果　泰州市2014-2017年采集的水产品和腹泻病人样本中副溶血性弧菌的检出率分别为34.3%(37/108)、1.2%(18/1548),55株阳性菌株中tlh均为阳性,trh均为阴性,水产品分离株均未检出tdh,但腹泻病人分离株tdh的检出率为94.4%(17/18)。腹泻病人分离株对头孢唑啉、氨苄西林、四环素的耐药性高于水产品分离株,其中腹泻病人分离株和水产品分离株对氨苄西林的耐药率分别达到61.1%（11/18）、54.1%（20/37）。结论　本市水产品中副溶血性弧菌的污染情况较为严重,副溶血性弧菌是导致食源性腹泻的主要致病菌之一。腹泻病人分离株的tdh携带率较高而水产品分离株均未携带tdh;腹泻病人分离株对头孢唑啉、氨苄西林、四环素的耐药性高于水产品分离株,而且两种分离株对氨苄西林均有较高的耐药率。     

Crayfish: a newly recognized vehicle for vibrio infections.

We conducted a 1-year case-control study of sporadic vibrio infections to identify risk factors related to consumption of seafood products in two coastal areas of Louisiana and Texas. Twenty-six persons with sporadic vibrio infections and 77 matched controls were enrolled. Multivariate analysis revealed that crayfish (P < 0.025) and raw oysters (P < 0.009) were independently associated with illness. Species-specific analysis revealed an association between consumption of cooked crayfish and Vibrio parahemolyticus infection (OR 9.24, P < 0.05). No crayfish consumption was reported by persons with V. vulnificus infection. Although crayfish had been suspected as a vehicle for foodborne disease, this is the first time to our knowledge that consumption of cooked crayfish has been demonstrated to be associated with vibrio infection.     

2016—2019年北京市海淀区副溶血性弧菌血清型、毒力基因及分子分型研究

目的　综合分析北京市海淀区副溶血性弧菌血清型分布、毒力基因携带情况和PFGE分型结果,并找出其相关性,从而掌握海淀区副溶血性弧菌的流行特征。方法　对2016—2019年北京市海淀区检出的63株副溶血性弧菌进行血清分型、毒力基因检测和PFGE分型试验。结果　海淀区副溶血性弧菌最优势流行株的血清型为O3:K6,毒力基因组合为tlh+tdh+,占比69.8%（44/63）;63株副溶血性弧菌经PFGE聚类分析得到37种带型,各带型之间相似度为84.8%～100.0%,其中,61株副溶血性弧菌聚集形成5个簇（带型相似度≥90%）;4年间共出现了8次一定时间内（发病日期间隔≤90 d）分离得到的菌株血清型、毒力基因和PFGE带型均一致的情况。结论　海淀区副溶血性弧菌的污染来源相对固定且单一。副溶血性弧菌血清分型和PFGE之间无特殊相关性;毒力基因相同的菌株,PFGE带型相似度更高。     

Wound infections caused by Vibrio vulnificus and other marine bacteria

Infections caused by Vibrio vulnificus were first reported in 1979 by Blake et al. of the US Centers for Disease Control. At that time described as a 'rare, unnamed halophilic lactose-fermenting Vibrio species', V. vulnificus has emerged as the most virulent foodborne pathogen in the United States with a hospitalization rate of 0.910 and a case-fatality rate of 0.390. It is in addition a significant cause of potentially life-threatening wound infections. Infections following ingestion of raw or undercooked seafood, commonly raw oysters, can lead to a primary septicaemia with a fatality rate of 50-60%. An unusual symptom, occurring in 69% of 274 cases reviewed by Oliver, is the development of secondary lesions, typically on the extremities, which are generally severe (often a necrotizing fasciitis) and require tissue debridement or amputation. These cases occur almost exclusively in males over the age of 50 years. Interestingly, this gender specificity has been found to be due to the female hormone oestrogen, which in some manner provides protection against the lethal V. vulnificus endotoxin. Further, most cases occur in persons with certain underlying diseases which are either immunocompromising or which lead to elevated serum iron levels (e.g. liver cirrhosis, chronic hepatitis, haemochromatosis). V. vulnificus infections resulting in primary septicaemia have been extensively studied, and the subject of several reviews. This review concentrates on the wound infections caused by this marine bacterial pathogen, including the more recently described biotypes 2 and 3, with brief discussions of those caused by other marine vibrios, and the increasingly reported wound/skin infections caused by Mycobacterium marinum, Erysipelothrix rhusiopathiae, and Aeromnonas hydrophila.     

Campylobacter jejuni--an emerging foodborne pathogen

Campylobacter jejuni is the most commonly reported bacterial cause of foodborne infection in the United States. Adding to the human and economic costs are chronic sequelae associated with C. jejuni infection--Guillian-Barré syndrome and reactive arthritis. In addition, an increasing proportion of human infections caused by C. jejuni are resistant to antimicrobial therapy. Mishandling of raw poultry and consumption of undercooked poultry are the major risk factors for human campylobacteriosis. Efforts to prevent human illness are needed throughout each link in the food chain.     

Lowbury Lecture. Listeriosis: epidemiology, virulence and the significance of contaminated foodstuffs.

Recent epidemiological evidence confirms that sporadic, as well as outbreak-associated, cases of listeriosis are primarily foodborne in origin. Implicated foodstuffs include meat products, dairy products, fruit, seafood and raw and processed vegetables. Large community-acquired outbreaks in North America and Europe have been complemented by smaller outbreaks involving hospitalized patients. Anecdotal reports and case clusters of nosocomial cases also support foodborne transmission. Cross-infection may be a major mode of transmission as demonstrated in a recent outbreak in Costa Rica. The sporadic nature of outbreaks of listeriosis are more consistent with changes in organism virulence rather than host susceptibility. The population of patients at risk for listeriosis (pregnant women and immunocompromised hosts) may not vary greatly. Establishment of infection is probably dose-dependent and gastric acidity may be protective. However, other organism-specific virulence factors, such as haemolysin production, may affect the post-intestinal phase of infection. Virulence factors other than haemolysins have not been characterized as yet. In summary, acquisition of Listeria monocytogenes infection from the environment by susceptible hosts may be widespread but invasive infection remains rare and the determinants of invasion require further elucidation.     

副溶血弧菌分子致病机制研究进展

副溶血弧菌易引起食物中毒,研究表明副溶血弧菌的致病性是多种毒力因子共同作用的结果。本文从分子水平对副溶血弧菌的溶血毒素、尿素酶、蛋白酶、侵袭力和黏附力等毒力因子进行综述,为进一步研究该菌的分子致病机理提供参考。     

南京市主要细菌性病原体食源性疾病负担研究

目的 研究南京市主要细菌性病原体致食源性疾病负担,提出食源性疾病监测策略。方法 根据南京市11个区17家食源性疾病哨点医院主动监测和食源性疾病负担调查结果,结合各主要细菌性病原体的食源性比例等各项乘数,获得人群中各主要细菌性病原体的发病率及疾病负担。结果 2015年全市共采集1 208份食源性疑似病例生物标本,检出非伤寒沙门氏菌31株、副溶血性弧菌20株、致泻大肠埃希氏菌15株,检出率分别为2.57%、1.66%、2.56%;全市疾病负担调查3 600人,急性胃肠炎的月患病率为3.9%,年发病率为0.55次/人年;推算出南京市非伤寒沙门氏菌食源性感染发病率为1 292/10万,0~4岁年龄组发病率最高(3 481/10万);副溶血性弧菌食源性感染发病率为619/10万,15~24岁年龄组发病率最高(2 076/10万),致泻性大肠埃希氏菌的食源性感染发病率为1 653/10万,5~14岁年龄组发病率最高(5 263/10万)。结论 南京市非伤寒沙门氏菌、副溶血性弧菌、致泻性大肠埃希氏菌感染负担较重,儿童非伤寒沙门氏菌和致泻性大肠埃希氏菌、青壮年副溶血性弧菌的感染负担尤为突出,针对不同人群加强相应病原体的监测,同时应进一步完善相关监测及研究,为制定相应的风险控制措施提供科学依据。     

深圳市龙岗区2008年4类生肉食品中副溶血性弧菌检出情况

目的了解深圳市龙岗区生肉中副溶血性弧菌的污染状况,提高人们对副溶血性弧菌的重视程度,为食源性疾病的监测提供科学的依据。方法依据国家标准方法,并采用显色培养基,对样品进行副溶血性弧菌的分离、生化及血清学鉴定。结果检测4类样品共79份,共检出目标菌24株,总检出率为30.38%,其中淡水鱼检出17株,检出率41.94%;海产品4株,检出率21.53%;生禽肉5株,检出率29.41%;生畜肉2株,检出率16.67%。结论该区动物类生肉副溶血性弧菌污染较严重。建议政府加大对动物宰杀行业及食品销售渠道的严格管理,尽量减少食源性致病菌的交叉污染,减少食源性疾病的发生。     

多位点序列分型技术在深圳副溶血弧菌同源性分析中的应用研究

目的 了解副溶血弧菌临床分离株的毒力基因、血清型及基因分型特征,探讨多位点序列分型(MLST)分型技术对其同源性分析的应用价值。方法 收集深圳地区2007-2014年食物中毒及医院散发病例来源的68株副溶血弧菌菌株,对其进行血清型、毒力基因分析。选择副溶血弧菌MLST数据库提供的7个管家基因,PCR扩增测序后采用BioEdit、eBURST等软件,对本次研究的68株副溶血弧菌进行MLST同源性分析。结果 68株副溶血弧菌共得到7种不同的血清型,优势血清型为O3∶K6(47/68),其余血清型分别为O4∶K8、O5∶K68、O4∶K13等。副溶血弧菌临床分离株94%为tdh+trh-。MIST分型将68株副溶血弧菌分为5个序列型(ST型),ST3为优势序列型(55/68),其余4种ST型中的ST189与ST345构成一个同源复合体CC345,且ST189为ST345的单位点变异型。结论 深圳地区副溶血弧菌所致的腹泻病暴发疫情,其流行菌株ST型别多样化,疾病控制中需警惕非主流ST型别引起暴发可能。     

副溶血性弧菌及其引起的食物中毒检验研究进展

在沿海地区 ,副溶血性弧菌是引起食物中毒的重要病原菌。近年来 ,由副溶血性弧菌与其它细菌混合感染引起食物中毒屡见报道 ,主要是生食或加热不彻底的熟食。 1995年以前检出频率最高的副溶血性弧菌血清型为O4 :K8,1996年以后由产生耐热的直接溶血毒素 (TDH)的O3:K6取而代之。用于副溶血性弧菌的快速检验法有噬菌体裂解法、PCR法、PFGE法。采用免疫磁株法可有效地收集、浓缩神奈川现象阳性的副溶血性弧菌 ,可显著提高环境样品及食品中病原性副溶血性弧菌的检出率     

Effects of "host factor" bile on adaptability and virulence of Vibrios, foodborne potential pathogenic agents

In order to improve the knowledge of host/pathogenic agent interaction and to obtain a more careful estimation of risk related to ingestion of food contaminated by Vibrio spp., the effects of bile extracts have been studied. The growth of one V. fluvialis, two V. alginolyticus, and three V. parahaemolyticus strains, isolated from mollusks and crustaceans, has been determined to evaluate their adaptability to intestinal environment. Moreover, the expression of virulence factors responsible for the colonization, as bacterial "swarming mobility", biofilm production, adherence on epithelial cells and hydrophobicity, has been evaluated. Using a bile concentration of 1.5%, all examined strains showed a constant inhibitory effect, quite moderate in the first growth phases. Bile increased the "swarming mobility" and biofilm production; also the adherence was favored, but only after adaptation and during the early logarithmic phase. The decreased hydrophobicity could explain the reduction of adherence during the stationary phase. Studying the phenotypic expression of virulence factors in "minor vibrios" in the presence of bile, it was possible to extend the knowledge about their pathogenetic mechanisms owing to the ingestion of contaminated food. That permits a more careful estimation of risk related to the contamination, considering the high frequency of isolation of these species in some seafood.     

广东省食源性副溶血弧菌表型特征与分型比较研究

目的 了解广东省食源性副溶血弧菌的表型特征,并对其分型进行综合比较.方法 对分离自广东省水产品和食物中毒的74株副溶血弧菌分离株进行生化鉴定、药敏试验、耐热直接溶血素(tdh)和耐热直接溶血素相关溶血素(trh)毒力基因的PCR检测.并对副溶血弧菌进行血清分型、核糖体基因分型(Ribotyping)和脉冲场凝胶电泳(PFGE)分型,应用BioNumerics软件对不同来源、时间和地点的分离株进行比对,分析菌株之间的相关性.结果 副溶血弧菌除对氯霉素100.00％敏感外,对其余13种抗生素均有不同程度的耐药.tdh阳性率为24.32％、trh阳性率为4.05％.74株副溶血弧菌分为26种血清型,O5:K17和O2:K28型为水产品分离株的优势血清型,O3:K6型为食物中毒分离株的优势血清型.74株副溶血弧菌分为62个核糖体型、67个PFGE型,表现出较大的遗传多样性.结论 广东省大部分食物中毒副溶血弧菌分离株携带tdh毒力基因.3种分型方法中,PFGE的分辨率最高,Ribotyping居中,血清分型最低,3种方法相结合可提高分辨率.     

不同来源副溶血性弧菌血清群和毒力基因及其耐药性

目的了解副溶血性弧菌水产品分离株和食物中毒患者分离株的血清群、毒力基因及其耐药性,为预防控制溶血性弧菌引起的食物中毒提供依据。方法对副溶血性弧菌分离株利用血清凝聚试验进行分群,应用聚合酶链式反应(PCR)方法检测耐热直接溶血素(TDH)和耐热直接溶血素相关毒素(TRH)毒力基因,采用纸片扩散法进行药敏试验。结果 35株水产品分离株分布于O4、O3、O2、O11、O5、O1共6个血清群,无优势菌群,TDH与TRH毒力基因均阴性。22株食品中毒分离株分布于O3、O4、O1共3个血清群,以O3群为主,占81.8%,TDH阳性率77.3%,TRH阳性率13.6%。药敏试验结果显示副溶血性弧菌对青霉素类、头孢类、磺胺类抗生素部分耐药或完全耐药,对其他类抗生素敏感。结论副溶血性弧菌水产品分离株与食物中毒分离株的血清群、毒力基因存在较大的差异,所分离菌株对多种常用药物敏感性高。