Bio-control of Some Food-Borne Pathogenic Bacteria by Bacteriophage

In recent years, researchers tended to bring new alternative to biological protective systems used in conservation of food and production of safe food. Use of bacteriophage against to pathogen bacteria in food was the most hopeful system in these methods about bio-control. Controls of bacteriophage for each pathogen species and subspecies and determination of phage-host originality are important because efficient bio-control was achieved. Researches concentrated on some food-borne pathogen bacteria such as E. coli O157：H7, Campylobacter, Salmonella and Listeria. In a consequence of these studies made as in vitro and in vivo, first commercial production of phage which will be used in foods was made in Netherlands. Also, it has been informed that use of phage is cost-efficient alternative as compared with other preservatives. This review, discussed application of bacteriophages as bio-control agents in food and advantages and disadvantages about uses of bacteriophages by taking into account antimicrobial characteristics of them.

Antimicrobial Activity of Wild Plant Seed Extracts against Human Bacterial and Plant Fungal Pathogens

Five wild plant species belonging to different families (Chenopodium album, Plantago major, Elytrigia elongata, Filipendula ulmaria and Nigella sativa) widely spread in Russian Federation and the former USSR were evaluated for their ability to inhibit growth of two important human food-borne pathogens (Escherichia coli O157:H7 and Listeria monocytogenes strain EGD-e) and eight plant pathogens (Alternaria alternata, Alternaria tenuissima, Bipolaris sorokiniana, Stagonospora nodorum, Fusarium solani, Fusarium oxysporum, Fusarium culmorum and Phytophtora infestans). To isolate biologically active compounds from seeds, a step-wise procedure including extraction with hexane, ethyl acetate, ethanol, and 10% acetic acid followed by reversed-phase HPLC was developed. Using disc-diffusion assay, the highest activity against E. coli O157:H7 was observed with extracts from F. ulmaria (hexane and ethyl acetate extracts and the unbound RP-HPLC fraction) and P. major (ethyl acetate extract and the unbound RP-HPLC fraction);E. elongate (the unbound RP-HPLC fraction) was less active. The extracts from P. major and E. elongate (the unbound RP-HPLC fractions) were equally highly active against L. monocytogenes, while those of F. ulmaria (the unbound RP-HPLC fraction) and N. sativa (hexane and ethyl acetate extracts) were less active against this pathogen. The dynamics of L. monocytogenes EGD-е and E. coli O157:H7 growth in the presence of two most potent extracts (RP-HPLC-unbound fractions of P. major and E. elongate and the hexane extract of F. ulmaria) was studied.

Quantum dot biosensor combined with antibody and aptamer for tracing food-borne pathogens

Due to the increasing number of food-borne diseases,more attention is being paid to food safety.Food-borne pathogens are the main cause of food-borne diseases,which seriously endanger human health,so it is necessary to detect and control them.Traditional detection methods cannot meet the requirements of rapid detection of food due to many shortcomings,such as being time-consuming,laborious or requiring expensive instrumentation.Quantum dots have become a promising nanotechnology in pathogens tracking and detection because of their excellent optical properties.New biosensor detection methods based on quantum dots are have been gradually developed due to their high sensitivity and high specificity.In this review,we summarize the different characteristics of quantum dots synthesized by carbon,heavy metals and composite materials firstly.Then,attention is paid to the principles,advantages and limitations of the quantum dots biosensor with antibodies and aptamers as recognition elements for recognition and capture of food-borne pathogens.Finally,the great potential of quantum dots in pathogen detection is summarized.

Fate of Nutrients, Trace Metals, Bacteria, and Pesticides in Nursery Recycled Water

Faced with rapid population growth and fresh water scarcity, reuse of reclaimed water is growing worldwide and becoming an integral part of water resource management. Our objective was to determine the fate of nutrients, trace metals, bacteria, and legacy organic compounds (organochlorine pesticides) in the recycled water from five commercial nursery ponds in Florida. The pH of recycled water at all sites was 8.1 - 9.3, except one site (6.5), while the electrical conductivity (EC) was 0.31 - 0.36 dS/m. Concentrations of trace metals in recycled water were low: Fe (0.125 - 0.367 mg/L), Al (0.126 - 0.169 mg/L), B (0.104 - 0.153 mg/L), Zn (0.123 - 0.211 mg/L), and Mn (<0.111 mg/L). Total phosphorus (P) and total nitrogen (N) in the recycled water were 0.35 - 1.00 mg/L and 1.56 - 2.30 mg/L, respectively. Among organochlorine pesticides, endrin aldehyde was the only pesticide detected in all nursery recycled water ponds, with concentrations from 0.04 to 0.10 μg/L at four sites and 1.62 μg/L at one site. Other detected pesticides in recycled water were methoxychlor, endosulfan sulfate, dichlorodiphenyldichloroethylene (DDE) and α-chlorodane, with concentrations < 0.20 μg/L. Total coliforms and Escherichia coli (E. coli) in recycled water were 20 - 50 colony forming units (CFU)/100 mL. We conclude that the concentrations of various inorganic and organic compounds in recycled water are very low and do not appear to be problematic for irrigation purposes in Florida’s nursery recycled water ponds.

Comparative prevalence of pathogenic and spoilage microbes in chicken sausages from Egypt and Greece

This study investigated the spread of foodborne pathogens: Listeria monocytogenes, Es-cherichia coli O157:H7, Staphylococcus aureus and Salmonella in chicken sausage samples collected from retail markets in Greece and Egypt during 2006 and from Egypt through 2010. Other microbiological parameters;total viable count (TVC), lactic acid bacteria (LAB), pseudomonads (PS), staphylococci (STAPH), Brochothrix thermosphacta (BT), Enterobacteriaceae (EN), Escherichia coli (EC), yeasts and moulds (Y&M) were also counted. Egyptian chicken sausage samples were found to harbor L. mono- cytogenes, Staph. aureus and E. coli O157:H7;with frequencies equivalent to 24%, 60% and 26% of the total samples during 2006 and 37.87%, 64.44% and 41.11% of the total samples during 2010, respectively, while Greek samples were entirely free of theses pathogens. Enrichment techniques indicated the absence of Salmonella from both Greek and Egyptian samples. The obtained results may mobilize food producers and handlers in developing countries to take the due measures reducing food-borne pathogen risks and spoilage flora alongside the poultry chain.

Antimicrobial effects of carnosic acid,kaempferol and luteolin on biogenic amine production by spoilage and food-borne pathogenic bacteria

Antimicrobial effects of carnosic acid,kaempferol and luteolin on biogenic amine(BA)production by five spoilage(Photobacterium damselae,Proteus mirabilis,Enterobacter cloacea,Pseudomonas luteola and Serratia liquefaciens)and five food-borne pathogenic bacteria(Staphylococcus aureus ATCC29213,Enterococcus faecalis ATCC29212,Escherichia coli ATCC25922,Salmonella Paratyphi A NCTC13 and Yersinia enterocolitica NCTC 11175)were investigated.The formation of ammonia(AMN),trimethylamine(TMA)and BAs by all bacterial strains were observed using ornithine decarboxylase broth.BAs,AMN,and TMA were determined by using high performance liquid chromatography(HPLC)method.The results showed that significant differences were observed(P≤0.05)in formation among spoilage and also food-borne bacteria.The impact of phenolic compounds on AMN,TMA and BAs production was dependent on bacterial strains.When total amount of cadaverine(CAD),putrescine(PUT),histamine(HIS)and tyramine(TYR)was considered,the phenolic compounds presented antimicrobial activity against fish spoliage bacteria and food-borne pathogens following the order;kaempferol>carnosic acid>luteolin.These phenolics have potential to be used as food preservatives.

变性梯度凝胶电泳技术在食品微生物多样性研究中的应用前景

变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)可以克服传统微生物检测方法的弊端,不依赖于微生物的分离培养,是微生物分子多样性研究的热点技术之一。DGGE技术具有可靠性强、重复性好、易操作、可同时分析多个样品等优点,结合聚合酶链式反应(polymerase chain reaction,PCR),被广泛地应用在微生物群落组成及其遗传信息、多样性及不同种群动态比较分析等方面。本文介绍了DGGE技术的基本原理、操作过程、优缺点,并概述了其在食品微生物多样性分析中的应用,分析了该技术在水产品、酒类、发酵食品、肉制品等领域应用现状。通过分析目前在食品微生物多样性分析中的优点和不足,提出发展方向,最后对DGGE技术在食源性致病菌溯源应用前景进行评述,以期为我国食品安全食源性致病菌快速溯源技术的发展提供文献支持。

老年住院病人下呼吸道感染病原菌分布与耐药性分析

[目的]了解老年住院病人下呼吸道感染病原菌的分布和药物敏感性的特点。[方法]对2003年1月～2005年12月间﹥60岁以上老年住院病人下呼吸道感染进行回顾性调查。[结果]3年间﹥60岁以上老年住院呼吸道感染病人共分离到371株病原菌,G+菌占51.2%(190/371),G-菌占44.7(166/371),其中G+菌以金黄色葡萄球菌、肺炎链球菌和肠球菌为常见;G-菌以大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌和铜绿假单胞菌为常见;同时还检出白色念珠菌33株、热带念珠菌5株;药敏结果显示G+菌对万古霉素、克林霉素较为敏感,G-菌对亚胺培南、阿米卡星普遍较为敏感。[结论]老年住院病人下呼吸道感染的病原菌广、且耐药性严重,应加强耐药性监测,并要掌握病原菌及耐药性的新动态,对合理使用抗生素十分重要。

下呼吸道感染的病原菌分布与耐药性分析

目的:分析临床下呼吸道感染病原菌构成及耐药情况,以指导临床医师合理应用抗菌药物。方法:分析2008年1月一2012年12月解放军总医院第一附属医院从痰(19 365份)、支气管灌洗液(4 203份)以及支气管肺泡灌洗液(302份)标本分离细菌的鉴定及药敏试验结果。结果:共分离出非重复病原菌10 635株,其中革兰阴性杆菌5 244株(49.3%),革兰阳性球菌2 495株(23.5%),真菌2 896株(27.2%)。未发现葡萄球菌属对万古霉素、替考拉宁和利奈唑胺的耐药菌株,发现3株大肠埃希菌和32株肺炎克雷伯菌对碳青霉烯类耐药菌株(CRE),多重耐药铜绿假单胞菌(MDRPA)和鲍曼不动杆菌(MDRAB)分别占14.2%和46.3%。真菌以白色念珠菌为主,对抗真菌药较敏感。结论:下呼吸道感染分离的病原菌中鲍曼不动杆菌、铜绿假单胞菌和金黄色葡萄球菌是主要病原菌,同时耐碳青霉烯类的肠杆菌科细菌(CRE)以及耐万古霉素的肠球菌属(VRE)也是临床抗感染治疗的难点。

某三甲妇幼保健院血源性病原体职业暴露特点与随访研究

目的研究血源性病原体职业暴露发生特点、应急处置、随访情况及防控费用,为医院职业暴露防控政策的制定提供依据。方法采用回顾性调查方法,收集及分析某三甲妇幼保健院2016年1月1日—2020年12月31日上报的血源性病原体职业暴露事件,对未完成全程检验追踪的暴露者进行电话回访。结果共收集149例次职业暴露,保洁员发生密度最高(0.036例次/人年),其次为护士(0.031例次/人年),高于医生(0.018例次/人年)和医技人员(0.005例次/人年)(P<0.001);初级及以下职称医务人员发生密度高于中、高级职称者(P<0.001)。手术室(25.50%)是最高发地点,锐器伤是最主要的暴露方式(85.23%),关联操作以发生于处理锐器时最多(34.90%),暴露病原体中以乙型肝炎病毒最多(20.81%),10~12点是一天中职业暴露发生的高峰时刻(28.86%),暴露部位以手部(82.55%)最多,暴露发生于非利手(46.98%)较利手(35.57%)多见,食指是手部最常见的受伤部位(42.28%)。发生原因居前三位者依次为自己操作不慎(48.99%)、意外或紧急情况(20.80%)、他人锐器处理不当(15.44%)。6.04%的暴露者存在局部应急处置不规范,20.13%的案例存在迟报,职业暴露后全程追踪落实率为41.89%。未落实全程追踪居前三位原因依次为:遗忘、未足够重视和错误认知。职业暴露后防控总费用20926.10元,平均每例140.44元,暴露源不明者平均费用最高(273.70元/例)。结论应针对血源性病原体职业暴露的高发人群、地点、环节、时间和部位等特点,以及存在的迟报率高、全程追踪落实率低等问题,进一步采取有效措施,减少职业暴露的发生,降低暴露后感染风险,保障医院工作人员职业安全。

病原体溯源技术研究进展及在寄生虫上的应用

病原体是导致人和动植物感染疾病的根源,带来一系列的安全隐患。病原体溯源研究对于基因型鉴定、分类地位准确化、流行病学调查及疾病的防控具有重大意义。近年来,分子生物学技术已被广泛用于病原溯源研究。作者主要对病原体溯源技术的最新研究进展及其在寄生虫上的应用作一综述。

Recent developments of lactic acid bacteria and their metabolites on foodborne pathogens and spoilage bacteria:Facts and gaps

Lactic acid bacteria(LAB)are common microorganisms found in various ecosystems including in plants,fermented foods,and the human body.Exploring the biodiversity of lactic acid microflora and characterization of LAB is a new approach to form a variety of starter communities to create innovative nutritional food matrices.There has been growing interest in LAB isolated from non-dairy environments as these bacteria exhibit significant metabolic diversity and have unique taste-forming activities.Disease may be prevented,or treated by LAB but the treatment of disease conditions with LAB is highly dependent on the host's microbiome and diet and varies in both effectiveness and side effects from individual to individual.Future perspectives on the study of LAB may be related to the expansion of our knowledge in the fields of genetics and genetic engineering.The application of genetic science may help to improve existing strains and develop new strains with characteristics designed for specific purposes.Therefore,the preservative effects of LAB and their metabolites,as well as their interaction on the growth of food borne pathogens and food spoilage microorganisms were elucidated.In addition,the competitive models for microbial growth between LAB and other microorganisms as well as the role of LAB in the elimination of toxic compounds in food products were discussed.Moreover,the review provided an overview of the risks and benefits of using LAB in the food industry.

规模化蛋鸡场病原菌溯源与生物安全防控研究

细菌病严重威胁蛋鸡健康,以抗生素为主导的细菌病传统防控方式会导致病原菌耐药性严重、鸡蛋药物残留,影响蛋品安全。要保证蛋鸡产蛋期不用抗菌药物而又能生产出"无菌、无抗"的鸡蛋,是国内外技术难题。本团队以规模化蛋鸡场全封闭鸡舍为研究对象,基于PFGE、MLST、全基因组测序等技术,探明了蛋鸡病原菌的种类及基因组特征;对病原菌的耐药性研究表明,蛋鸡病原菌多重耐药严重,依靠药物防控的方式亟待转变;对规模化蛋鸡场细菌溯源研究结果表明,鸡舍生物媒介(鼠、苍蝇等)和非生物媒介(空气、饮水、饲料、鸡粪等)是蛋鸡病原菌的重要传染来源和传播途径;对规模化蛋鸡场生物安全量化评价结果表明,外部和内部生物安全权重高达92.2%。根据溯源和生物安全权重分析结果,提出了在规模化全封闭蛋鸡舍将蛋鸡细菌病从药物防控转变为生物安全防控的新策略;创新了规模化蛋鸡场细菌病防控的系统技术,实现蛋鸡规模养殖整个产蛋期不用抗生素,为生产"无菌、无抗"安全鸡蛋提供技术支撑。

奶牛隐性乳房炎诊断技术研究新进展

奶牛隐性乳房炎是由病原微生物等引起的一种炎症性疾病,严重制约着奶牛养殖业的健康发展,一度成为奶牛养殖业健康发展的瓶颈问题。奶牛乳房炎会导致奶牛产奶量下降、生产性能降低,并且在治疗过程中会产生高额医药费,还会带来食品安全隐患。为了科学、有效地防控奶牛隐性乳房炎,早期快速诊断该病意义重大。文章采用文献综述法,全面、系统地搜集了近年来奶牛隐性乳房炎诊断的先进方法,拟从病原检测法、乳汁检测法、微量元素检测法、酶学检测法、蛋白检测法以及分子生物学检测法等方法展开论述,以期为早期诊断奶牛隐性乳房炎提供技术支持。

Grape Phenolic Extract Potentially Useful in the Control of Antibiotic Resistant Strains of <i>Campylobacter</i>

In this work, a grape phenolic extract obtained by methanol extraction has been demonstrated to be effective in inhibiting the growth of different strains and species of Campylobacter, one of the most important bacterial foodborne pathogens causing gastroenteritis worldwide. Noteworthily, it was particularly effective against several strains presenting multiple antibiotic resistances. In all cases, the minimum inhibitory concentration (MIC) was lower than 300 mg GAE/L, being of 60 mg GAE/L for one of the most resistant strains (C. coli LP2), while the others were between 120 mg GAE/L and 180 mg GAE/L. The analytical study of the main phenolic compounds in the grape extract revealed that it was mainly constituted by catechins (85.7%) and phenolic acids (13.7%). However, experiments developed using pure standards demonstrate that phenolic acids (such as gallic, p-hidroxibenzoic, vanillic, and homovanillic acids) were the most active, provoking a Campylobacter growth decrease between 6.7 and 7.6 log, while epicatechin was the only catechin with activity as pure compound (1 log of growth decrease).

屠宰场非洲猪瘟防控措施

防止非洲猪瘟疫情发生,做好非洲猪瘟防控工作,不仅要做好日常生猪调运检疫监管工作,更重要的环节是屠宰场生猪调运,屠宰场非洲猪瘟防控工作尤其显得重要,是重中之重。

鼩鼱科动物携带汉坦病毒科病毒的研究进展

鉴于近年来全球性动物传染源的疫情不断发生,病原溯源研究成为人类关注的焦点之一。鼩鼱科动物具有十分广泛的地理分布范围,且与人类生活存在密切联系,其携带病毒应该得到更多的关注。本文就鼩鼱科动物种类及其分布、鼩鼱科动物携带汉坦病毒研究及其在汉坦病毒传播与进化中作用等进行综述,以期为小型野生动物携带病原调查及溯源研究提供一定借鉴。

一起肠炎沙门菌引起的食物中毒检测及菌株同源性分析

目的检测食物中毒样品中致病菌,分析其同源性,为追踪污染源、明确病因诊断提供帮助,为控制和减少食物中毒提供依据。方法荧光定量PCR快速筛检致病菌,参照GB 4789.4—2010《食品安全国家标准食品卫生微生物检验沙门氏菌检验》分离致病菌,全自动细菌鉴定仪鉴定致病菌,脉冲场凝胶电泳(PFGE)分析同源性。结果从21份病人和从业人员粪便样品中检出8株肠炎沙门菌,9份食品样品中检出2份肠炎沙门菌,检出率分别为25.00%和6.25%;食堂用水及井水检测均未检出肠炎沙门菌等致病菌。荧光定量PCR法阳性率结果与GB 4789.4—2010方法一致。PFGE分型显示10株肠炎沙门菌的DNA条带图谱完全一致,相似性100%,聚类分析为同一型,表明菌株来自同一克隆系。结论采用荧光定量PCR筛检能提示食物中毒样品中病原菌是否存在的信息,通过GB 4789.4—2010方法仔细寻找到目标菌,两法联合使用能快速、准确地检测出引起食物中毒的致病菌。运用PFGE对致病菌进行溯源,分析其亲缘关系,能追踪到菌株来源,有利于防止食物中毒的发生。

两起肠炎沙门菌所致食物中毒的病原学研究及溯源分析

目的探讨两起同地区连续发生的肠炎沙门菌食物中毒分离株之间的分子流行病学关系。方法参照GB 4789.4—2010《食品安全国家标准食品微生物学检验沙门氏菌检验》方法进行病原分离培养,对检出菌株进行表型鉴定;用VITEK-ⅡCompact全自动微生物分析系统检测菌株抗生素敏感性;采用脉冲场凝胶电泳(PFGE)技术对检出菌株进行分子分型和流行病学特征分析。结果共检出23株肠炎沙门菌,其中从25份患者肛拭样本中检出17株,8份从业人员肛拭样本中检出2株,8份留样食物中检出3株,厨具涂抹样本中检出1株。23株肠炎沙门菌血清抗原式均相同(9∶g,m∶-);生物学性状和药敏试验结果基本一致;PFGE图谱带型完全一致(相似度为100%),且与当地散发病例PFGE图谱带型相似。结论综合流行病学调查、病原学检测和分子分型结果,证实这两起食物中毒是由同一来源的肠炎沙门菌污染所引起。

2015年-2017年山西省阳泉市食源性多病原监测与溯源分析

目的提高阳泉市食源性多病原实验室监测和溯源能力。方法采集2015年-2017年阳泉市食源性疾病监测点病例样本,进行沙门菌、志贺菌、副溶血性弧菌、5种致泻性大肠埃希菌病原分离和诺如病毒核酸检测,省级实验室复核菌(毒)株的血清、毒力和耐药表型,结合流行病学和实验室诊断开展疑似聚集性病例的分子溯源。结果3年监测标本752份,总阳性率为16.1%,病原谱型依次为诺如病毒38例(Ⅱ型为优势)、致泻性大肠埃希菌34株(不典型EPEC为优势)、副溶血性弧菌20株(tdh阳性)、沙门菌17株(存在暴发菌型)和志贺菌1株(宋内志贺菌)。分子分型确认导致餐饮场所食源性事件的汤卜逊沙门菌为国内新的分子克隆型、1例有乌龟接触史婴幼儿便血病例来自波摩那沙门菌的致病性克隆。结论阳泉市食源性多病原监测、基于流行病学的分子溯源和精准识别行为生态学传染病能力显著加强。