广州市市售水产品食源性致病菌污染状况调查

目的了解广州市市售水产品食源性致病菌污染状况,为预防与控制食源性疾病发生提供依据。方法对2006—2013年广州市监测的1 602份水产品的食源性致病菌监测数据进行整理分析。结果 1 602份水产品食源性致病菌总体检出率为21.16%(339/1 602),副溶血性弧菌检出率高达19.54%(313/1 602),创伤弧菌检出率为8.63%(43/498),沙门菌检出率为1.08%(14/1 301),单增李斯特菌检出率为0.59%(6/1 021),霍乱弧菌检出率为0.14%(1/701)。结论广州市市售水产品存在常见的食源性致病菌污染,其中副溶血性弧菌依然是主要的致病菌,但是沙门菌、创伤弧菌、单增李斯特菌的污染也不可忽视。     

2013—2020年广州市市售生食动物性水产品食源性致病菌监测结果分析

目的 了解2013—2020年广州市市售生食动物性水产品中食源性致病菌污染状况及分布特点。 方法 2013—2020年共采集631份生食动物性水产样品, 进行沙门氏菌、单核细胞增生李斯特氏菌、副溶血性弧菌、创伤弧菌、霍乱弧菌和致泻性大肠埃希氏菌等食源性致病菌检测。结果 检出食源性致病菌阳性样品90份, 总检出率为14.26%。生食动物性淡水产品和生食动物性海产品食源性致病菌检出率差异有统计学意义, ?2=160.375, P<0.001。生食动物性淡水产品检出率较高, 达到了45.70%。6种食源性致病菌检测结果显示, 创伤弧菌检出率最高, 达到9.51%, 其次是副溶血性弧菌5.86%, 沙门氏菌1.90%。第3季度检出率最高, 为16.15%, 最低的是第1季度(11.36%)。餐饮单位所售生食动物性水产品食源性致病菌检出率最高(21.90%), 其次为超市(7.69%), 网店和农贸肉菜市场所售商品无检出。结论 广州市市售生食动物性水产品存在不同程度的食源性致病菌污染, 致病菌污染主要以创伤弧菌、副溶血性弧菌为主, 生食动物性淡水产品污染情况更严重, 相关政府部门应加强监管, 开展健康宣传教育, 预防食源性疾病的发生。     

病原性海洋弧菌致病机理及其快速检测方法研究进展

病原性海洋弧菌是引起我国特别是沿海地区细菌性食物中毒危害的首要食源性致病菌。本文重点综述了病原性海洋弧菌中能引发人类重要疾病的副溶血弧菌、霍乱弧菌和创伤弧菌的致病机理以及目前国内外关于其的各种检测方法、原理、应用及研究进展。     

2019年广州市售食品中食源性致病菌监测结果分析

目的 了解广州市售食品中食源性致病菌污染和分布情况,以及污染危险因素。方法 2019年共采集9类共1066份食品样品,对霍乱弧菌、副溶血性弧菌、创伤弧菌、溶藻弧菌、河弧菌、金黄色葡萄球菌、沙门氏菌、克罗诺杆菌、蜡样芽胞杆菌、单增李斯特氏菌、小肠结肠炎耶尔森菌等进行监测分析。结果127份样品食源性致病菌检出阳性,检出率为11.91％。食源性致病菌中克罗诺杆菌的检出率最高(24.69％),溶藻弧菌检出率为14.81%、创伤弧菌检出率为6.76%、副溶血性弧菌检出率为5.52%。不同食品类别中甲鱼和蛙的检出率最高,达到了43.21%,其次为冲调谷物制品（25.93%）、进口生畜肉（15.97%）、生食动物性水产品（15.83%）和水产肉糜（12.50%）。不同采样场所中采自网店的食品食源性致病菌检出率最高(29.17％),其次依次是餐饮单位（21.59%）、农贸肉菜市场（15.38%）、超市（14.36%）和学校(8.72％),最低的是零售店（3.88%）。预包装食品食源性致病菌检出率（21.33%）高于散装食品的检出率（10.37%）。结论 2019年广州市部分市售食品存在较高的食源性致病菌检出率,应对重点食品加强监管,降低食品中致病菌污染,预防食源性疾病的发生。     

徐州市2007-2011年食品中食源性致病菌监测结果分析

目的 了解徐州市食品中食源性致病菌污染状况,为食源性疾病监测提供科学依据.方法 依据《全国食源性致病菌监测工作手册》对食源性致病菌进行监测.结果 2007-2011年间共监测630份食品,总检出率为15.08％:检出沙门菌、大肠杆菌O157:H7、单增李斯特菌、副溶血性弧菌、金黄色葡萄球菌;阪崎杆菌、志贺菌、创伤弧菌未检出.生肉类和水产品污染较严重,生肉以单增李斯特菌和沙门菌污染程度高,检出率为分别为18.28％和10.75％;水产品以副溶血性弧菌检出率最高,为23.08％.结论 徐州地区食品中存在食源性致病菌污染,卫生监督部门应加强食品安全管理.     

2016年北京市海产品中创伤弧菌的污染调查及两种检测方法比较

目的 对北京市市售海产品的创伤弧菌污染情况进行调查,并比较实时荧光聚合酶链式反应(RT-PCR)法与VITEK鉴定方法检测结果的一致性。方法 采用传统检验方法结合分子生物学方法对在北京市市场随机采集的105份海产品进行创伤弧菌检验,并比较了RT-PCR法和VITEK鉴定方法的准确性。结果 105份海产品中,有40份样品检出创伤弧菌,检出率为38.10%;其中,虾类产品检出率高达52.38%(11/21),其次为贝类产品(37.88%,25/66)和鱼类产品(22.22%,4/18)。经rpoB基因测序验证,RT-PCR和VITEK方法的准确率分别为100.00%(40/40)和67.50%(27/40)。结论 北京市海产品中存在创伤弧菌的污染,应对海产品中创伤弧菌引起食源性污染的潜在风险进行评估,预防食物中毒的发生。     

烟台海域海产品中食源性致病菌污染状况调查及膳食风险分析

目的了解烟台濒临的黄海和渤海海域海产品中食源性致病菌污染分布特征,掌握致病菌污染的"基线值",为市场监管、消费指导和风险预警提供数据支持。方法按照GB 4789规定的方法,进行6种食源性致病菌检测。借助快速微生物定量风险评估(s QMRA)方法,评价海产品中副溶血性弧菌的感染风险。结果 6类260种海产品中仅有副溶血性弧菌阳性检出,创伤弧菌、金黄色葡萄球菌、沙门菌、单增李斯特菌和大肠杆菌O157:H7均未检出。海产品中副溶血性弧菌总体污染率为19.62%(51/260),贝类、甲壳类污染水平较高,鱼类、海藻类偏低,污染率分别为26.42%(28/106)、20.00%(6/30)、10.00%(3/30)、10.00%(3/30);贝类中牡蛎是副溶血性弧菌高污染的海产品,污染率为31.03%(9/29)。普通人群摄食加热海产品后副溶血性弧菌致病风险概率值为2.97×10-7,年均患病率为6.03×10~(-6)次/人年,7~9月份为高发病时间段。结论烟台海域鲜活海产品主要存在副溶血性弧菌的污染,摄食人群具有潜在的感染风险,尤其温度较高的第三季度。     

海产品中副溶血弧菌检测方法研究进展

副溶血弧菌是主要的食源性致病菌之一,主要存在于鱼虾贝等海产品中。人们在食用被副溶血弧菌感染的海产品时,容易出现腹泻、呕吐、腹痛等急性肠胃炎症状。本文主要介绍了副溶血弧菌的分子生物学、免疫学等几种快速检测方法,并对未来的发展前景做了展望。     

创伤弧菌致病性及致病机制研究进展

创伤弧菌广泛存在于海水和牡蛎等海产品中,具有很强的细胞毒性和溶血性,被美国疾病预防控制中心(CDC)列为三大致病性弧菌之一。本文就创伤弧菌在食品中的污染状况,人类感染途径及临床表现,致病性、致病机制和检测方法等进行综述,以期为该菌感染的预防和治疗提供理论依据。     

2018—2020年重庆市市售冷藏冷冻动物源食品致病微生物污染状况分析

目的 了解2018-2020年重庆市市售冷藏冷冻动物源食品中致病微生物的污染情况。方法 采集市售冷藏冷冻动物源食品,按照《国家食品污染物和有害因素风险监测工作手册》对产气荚膜梭菌、创伤弧菌、单核细胞增生李斯特氏菌、副溶血性弧菌、霍乱弧菌、弯曲菌、溶藻弧菌、沙门氏菌、小肠结肠炎耶尔森氏菌、致泻大肠埃希氏菌进行检测。结果 2018—2020年共采集检测720件样本,10类食源性致病菌项目均有检出,总体检出率为27.78%(200/720)。年检出率18.75%~32.50%。不同食源性致病菌中副溶血性弧菌检出最多,占总阳性样本的26.55%(60/226);不同种类的食品进行比较,螺类的食源性致病菌检出率最高, 为43.00%(86/200)。结论 重庆市市售冷藏冷冻动物源食品中存在不同程度的致病微生物污染,应加强对重点环节和重点食品的监管。     

Effects of electrolyzed oxidizing water treatment on reducing Vibrio parahaemolyticus and Vibrio vulnificus in raw oysters

Contamination of Vibrio parahaemolyticus and Vibrio vulnificus in oysters is a food safety concern. This study investigated effects of electrolyzed oxidizing (EO) water treatment on reducing V. parahaemolyticus and V. vulnificus in laboratory-contaminated oysters. EO water exhibited strong antibacterial activity against V. parahaemolyticus and V. vulnificus in pure cultures. Populations of V. parahaemolyticus (8.74 x 10(7) CFU/ml) and V. vulnificus (8.69 x 10(7) CFU/ml) decreased quickly in EO water containing 0.5% NaCl to nondetectable levels (> 6.6 log reductions) within 15 s. Freshly harvested Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus at levels of 10(4) and 10(6) most probable number (MPN)/g and treated with EO water (chlorine, 30 ppm; pH 2.82; oxidation-reduction potential, 1131 mV) containing 1% NaCl at room temperature. Reductions of V. parahaemolyticus and V. vulnificus in oysters were determined at 0 (before treatment), 2, 4, 6, and 8 h of treatment. Holding oysters inoculated with V. parahaemolyticus or V. vulnificus in the EO water containing 1% NaCl for 4 to 6 h resulted in significant (P < 0.05) reductions of V. parahaemolyticus and V. vulnificus by 1.13 and 1.05 log MPN/g, respectively. Extended exposure (> 12 h) of oysters in EO water containing high levels of chlorine (> 30 ppm) was found to be detrimental to oysters. EO water could be used as a postharvest treatment to reduce Vibrio contamination in oysters. However, treatment should be limited to 4 to 6 h to avoid death of oysters. Further studies are needed to determine effects of EO water treatment on sensory characteristics of oysters.     

Vibrio parahaemolyticus, Vibrio vulnificus and microorganisms of fecal origin in mussels (Mytilus galloprovincialis) sold in the Puglia region (Italy)

Mytilus galloprovincialis is one of the most commonly consumed of all bivalve molluscs. The consumption of raw bivalve molluscs has caused outbreaks of food poisoning due to Vibrio parahaemolyticus and Vibrio vulnificus. This paper reports the results of a survey on the presence of V. parahaemolyticus, V. vulnificus fecal coliform bacteria, Escherichia coli and Salmonella spp. in 600 M. galloprovincialis samples collected from retail outlets in the Puglia region. V. parahaemolyticus and V. vulnificus were found in 47 (7.83%) and 17 (2.83%) of the samples, respectively. One sample (0.16%) was contaminated with Salmonella spp. but no relationship was observed between vibrios and fecal coliforms and E. coli. There were no significant differences among vibrios present in bivalve molluscs during the 3-year survey.     

Susceptibility of the heat-, acid-, and bile-adapted Vibrio vulnificus to lethal low-salinity stress

As a marine pathogenic bacterium that inhabits seawater or seafood, Vibrio vulnificus encounters low salinity and other stresses in the natural environment and during food processing. This investigation explores the cross-protective response of sublethal heat-, acid-, or bile-adapted V. vulnificus YJ03 against lethal low-salinity stress. Experimental results reveal that the acid (pH 4.4)- and heat (41 degrees C)-adapted V. vulnificus were not cross-protected against the lethal low-salinity challenge (0.04% NaCl). The bile (0.05%)-adapted exponential- and stationary-phase cells were cross-protected against low salinity, whereas low-salinity (0.12% NaCl)-adapted stationary cells were sensitized against 12% bile stress. Results of this study provide further insight into the interaction between low salinity and other common stresses in V. vulnificus.     

Detection and Enumeration of Vibrio vulnificus by Direct Colony Immunoblot

ABSTRACT:  A direct colony immunoblot method (DCI) for the enumeration of Vibrio vulnificus was developed. Bacterial colonies were transferred from agar plates to membranes, which were then dried and blocked with bovine serum albumin. Subsequently, the membranes were treated with anti- V. vulnificus H antibodies, washed and incubated with peroxidase-conjugated goat anti-rabbit IgG. After a final wash, the membranes were exposed to a substrate mixture containing H₂O₂ which resulted in the development of a purple color by V. vulnificus colonies. The DCI detected all clinical and environmental V. vulnificus strains tested and did not cross-react with other Vibrio species including V. cholerae , V. parahaemolyticus , or V. fluvialis . The DCI was then compared to the DNA hybridization procedure (DNAH) using V. vulnificus agar plates inoculated with mixed cultures of V. vulnificus and V. parahaemolyticus and V. vulnificus -seeded oyster homogenates. Both DCI and DNAH detected 1 to 2 log colony forming units (CFU)/mL V. vulnificus mixed with 4 log CFU/mL V. parahaemolyticus . Both methods were comparable and demonstrated no significant statistical differences when enumerating V. vulnificus in mixed cultures or in oyster homogenates seeded with levels of V. vulnificus from 2 to 6 log CFU/mL. The DCI demonstrated clearer color development and was less time consuming than the DNAH.     

Use of diacetyl to reduce the load of Vibrio vulnificus in the Eastern oyster,Crassostrea virginica

Vibrio vulnificus is a highly virulent human pathogen that occurs naturally among the microflora of oysters. This organism has two portals of entry into humans, one of which is ingestion. Oysters containing V. vulnificus consumed in a raw or undercooked state often serve as a vehicle for the transmission of this organism. Previous studies conducted in our laboratory have examined various generally recognized as safe compounds and have determined that diacetyl, a component of butter, is among the most effective of these compounds in reducing loads of V. vulnificus in oysters. The purpose of this study was to further examine the role of diacetyl, along with that of depuration, in reducing loads of V. vulnificus. Shellstock oysters were treated with various concentrations of diacetyl, and we found that many of the oysters ceased pumping when diacetyl was added. The data obtained in this study indicated that treatment with diacetyl is ineffective; however, any reduction in V. vulnificus numbers may be masked when groups of oysters, some of which may not have taken up diacetyl, are sampled. We then investigated the efficacy of diacetyl in lowering levels of V. vulnificus in shucked oysters. Diacetyl was found to significantly reduce the load of V. vulnificus in shucked oysters containing natural populations. Overall, it appears that treatment with diacetyl is ineffective for shellstock oysters, although it has potential for use in reducing loads of V. vulnificus in shucked oysters.     

Impact of acid on survival of Vibrio vulnificus and Vibrio vulnificus phage

Three strains of Vibrio vulnificus and V. vulnificus phages were tested for acid sensitivity at 21 degrees C. V. vulnificus strain 304 was more resistant to pH 4.0 than strains CVD-1 and A-9, whereas acid sensitivities of V. vulnificus strains at pH 3.0 and 2.0 were similar. V. vulnificus phage strain 110A-7 was more resistant to pH 4.0 than strain 153A-7, whereas acid sensitivities of phage strains at pH 3.5 and 3.0 were similar. Numbers of V. vulnificus and its phage were close to the limit of detection after 100 s at pH 2.0 and after 24 min at pH 3.0. Acid D-values at 21 degrees C decreased as pH decreased for both V. vulnificus and phages. D-values of phage strains at pH 3.5 were 10-fold greater than those of host strain at pH 4.0. D-values of phage strains were slightly greater than those of host strain at pH 3.0. These results suggest that V. vulnificus and its phage were very sensitive to pH of less than 3.0, although V. vulnificus phages were more resistant to acid than their host.     

Recovery and detection of Vibrio vulnificus during cold storage

Different cultural techniques and molecular methods for the detection of Vibrio vulnificus during cold storage in a model broth system were compared. Two strains of V. vulnificus were grown to stationary phase and inoculated (10(6) CFU/mL) into tryptic soy broth with 2% sodium chloride (TSBN2) or artificial seawater (ASW), both pre-chilled to 5 degrees C. These were stored for 10 days, with sub-sampling conducted at time 0 and every 2 days thereafter. Each subsample was plated, by both pour and spread plate techniques, onto tryptic soy agar 2% sodium chloride (TSAN2) with or without catalase (400 or 600 U) or sodium pyruvate (80 or 160 mg) supplementation. Nucleic acids were extracted from subsamples and subjected to PCR and RT-PCR with hemolysin as the target. Higher recoveries of V. vulnificus were obtained with spread plating compared to pour plating (P<0.05). The addition of sodium pyruvate (80 mg) or catalase (400 U) significantly increased cell recovery (P<0.05). PCR amplification signals were stronger than RT-PCR signals at each timepoint, and results were generally consistent between TSAN2 and ASW for each strain. These results will aid in the design of optimum methods to recover and/or detect V. vulnificus cells subjected to sublethal stress that might be encountered in food processing and storage.     

Characterization of the low-salinity stress in Vibrio vulnificus

Vibrio vulnificus is a marine pathogenic bacterium commonly found in seawater or seafood. This organism encounters low-salinity stress in its natural environment and during food processing. This study was designed to investigate the response of V. vulnificus YJ03 to lethal low salinity (0.04% NaCl) and its adaptation to sublethal salinity (0.12% NaCl with 20 amino acids added). A short period in the nonculturable state was induced by lethal low-salinity stress followed by cell death after 30 min of stress. Addition of 1 mM glycine betaine or 0.5 mM sucrose reduced the damage. Low-salinity adaptation was achieved in the exponential-phase cells but not in the stationary-phase cells. Significant protection against lethal low-salinity stress was attained when the cells were adapted for as little as 1.5 min. The adapted cells were significantly protected against lethal low salinity and 2.4% sodium sorbate but sensitized to the challenge of heat (52 degrees C) and acid (pH 3.2). Nonlethal low-salinity treatment of seafood should be avoided to prevent stress adaptation of V. vulnificus.     

Vibrio vulnificus load reduction in oysters after combined exposure to Vibrio vulnificus--specific bacteriophage and to an oyster extract component

Oysters infected with Vibrio vulnificus can present a serious health risk to diabetic, immunocompromised, and iron-deficient individuals. Numerous studies have been conducted with the goal of eliminating this organism from raw oysters. We utilized two natural oyster-associated components: pooled Vibrio vulnificus-specific bacteriophage and an extract of the eastern oyster (Crassostrea virginica) that contains an antimicrobial component we named anti-Vibrio vulnificus factor, which is bactericidal for V. vulnificus. Although each component alone can reduce V. vulnificus numbers independently, the simultaneous use of both components in an in vitro system successfully more effectively reduced V. vulnificus bacterial loads.     

基于vvhA基因检测创伤弧菌实时荧光PCR方法的建立

为建立创伤弧菌(VV)的快速检测方法,根据vvhA基因序列设计合成引物和探针,建立实时荧光PCR方法。结果显示:所建立的方法能特异扩增出VV标准阳性菌株,而对其它14种菌株没有扩增;该方法的灵敏度为15CFU/mL;稳定性和重复性试验结果表明,同一样品重复检测4次Ct值(循环阈值)的变异系数均小于2%;利用该检测方法对采集的156份样品进行检测,共计检出2份VV阳性样品,与行标法(SN/T 1870—2007)检测结果一致。该检测方法灵敏度高、特异性强,具有良好的实用性。