食源性致病菌耐药机制研究进展

食源性致病菌是危害食品安全与人体健康的关键因素,而细菌耐药性的不断出现与传播,更加剧了食源性致病菌的潜在风险,成为全球普遍关注的公共卫生焦点问题。本文中,笔者首先综述4种主要的细菌耐药机制:降低细胞膜通透性机制、外排泵机制、药物靶标位点突变机制以及酶解作用机制。在此基础之上,系统回顾了常见食源性致病菌耐药机制的研究进展,并对食源性致病菌耐药机制进一步的研究方向进行了展望,以期为食源性致病菌耐药机制的深入研究提供基础资料,为食源性致病菌耐药性风险的控制提供科学依据。     

常见食源性致病菌代谢组学研究进展

食源性致病菌是一类以食品为传播媒介,可引起食物中毒的致病性微生物,是目前食源性疾病的主要诱因。食源性致病菌代谢组学通过研究致病菌代谢小分子物质产生的规律性和特征性,寻找新的检测靶标和建立基于代谢组学方法的食源性致病菌鉴别技术。随着目前代谢组学研究技术逐渐成熟和微生物挥发性代谢产物数据库的建立,食源性致病菌挥发性代谢产物分析已被建议作为临床和食品中致病菌鉴别的替代方法。本文综述了目前常见食源性致病菌代谢组学主要研究技术及其在临床和食品检测中的研究进展,以期为进一步建立食源性致病菌代谢产物数据库和研发基于代谢组学方法的食源性致病菌检测技术提供参考。     

辽阳市2013年食品中致病菌污染状况分析

目的了解辽阳市食源性致病菌污染情况,为食品风险监测提供理论支持,降低食品安全事故发生几率。方法根据辽宁省卫生厅关于食品安全风险监测的相关文件和监测方案对可能存在食源性致病菌污染的食品采集260份样品进行检测并对检测出来的致病菌进行分析,总结辽阳市食源性致病菌污染的情况。结果对13种(类)食品进行采样,共检测样品260份,合格250份,合格率为96.15%。结论市售食品卫生质量存在一定安全隐患,微生物污染的食品占一定比例,食品卫生监督部门应加强速冻米面制品、桶装饮用水/桶装天然矿泉水/桶装矿物质水、婴幼儿辅助食品等的监督和管理。     

滨州市餐饮服务食品食源性致病菌污染状况

目的：了解滨州市餐饮服务食品中食源性致病菌污染状况,为食源性疾病的防控提供科学依据。方法：按照相关国标和标准检测方法对2014—2017年餐饮服务食品中主要食源性致病菌进行监测。共采集滨州市10大类食品共计328份,进行4种食源性致病菌的分离鉴定。结果：食源性致病菌检测中,328份样品中共检出致病菌45份,总检出率为13.72%。单核细胞增生李斯特氏菌合格率为100.00%,蜡样芽孢杆菌检出率较高。食源性致病菌高检出率样品集中在街头摊点及第三季度。结论：滨州市餐饮服务食品中食源性致病菌存在一定程度污染,应加强餐饮服务环节中食源性致病菌的防控措施,防止食源性疾病的发生。     

噬菌体在食品安全中的应用和潜在风险

近年来,经食品传播的感染性疾病时有发生,有的国家甚至有增多趋势。噬菌体在早期被用来治疗细菌性疾病,现在人们已经意识到噬菌体在食品工业上的应用前景也非常广阔。已经有人提出把它作为食品添加剂使用以杀灭食源性致病菌。而噬菌体本身的特性也确实说明,噬菌体是保障食品安全的理想工具。因为噬菌体不仅安全可靠,而且有严格的宿主特异性,在杀灭食源性致病菌的同时不会杀死生产中的发酵菌株。噬菌体可以用在食品生产中的各个环节以杀灭或抑制病原菌,比如原料采集、生产、储藏等环节。探讨噬菌体杀灭食源性致病菌的应用前景和潜在风险。     

PCR技术检测食源性致病菌的研究进展

食源性致病菌的检测技术是食源性疾病预防与控制的关键环节。PCR是近年来广泛应用于食源性致病菌快速检测的方法之一。在食源性致病菌中,用于PCR检测的靶基因包括各种毒力基因、酶基因及特异性鉴别基因。这些靶基因的发现推动了食源性致病菌PCR快速检测的发展。     

质谱法检测食源性致病菌技术研究进展

食源性致病菌存在广泛,能够引起人类的疾病甚至死亡,研究发现超过一半的食品安全问题来源于食源性致病菌的污染。如何快速有效地检测出食源性致病菌是预防和控制食品安全问题的关键环节。系统地介绍了检测食源性致病菌的方法,包括传统培养法、代谢学法、分子生物学法、免疫学方法等传统方法以及新兴的质谱法。质谱法有检测效率高、操作简便、灵敏度高等优点,着重对质谱法的原理、应用以及未来的发展趋势进行了阐述,以期为该技术的研究开发和推广应用提供参考。     

酶制剂清除食源性致病菌生物被膜的研究进展

食源性致病菌对人类健康与公众安全造成了极大的危害,形成生物被膜加剧了它们的致病与耐药风险。酶具有高度专一性,可靶向作用于生物被膜中的特殊物质,从而清除食源性致病菌的生物被膜,具有重要的科研价值和广泛的应用前景。因此,文中系统地综述了相关酶制剂清除食源性致病菌生物被膜的研究进展。根据酶制剂的不同作用靶点,着重介绍了群体感应抑制酶、环二鸟苷酸代谢酶、胞外基质水解酶等酶制剂的研究现状。文中还针对抗生物被膜酶制剂的未来研究方向进行了展望,旨在为食源性致病菌生物被膜的有效控制提供新的技术与策略。     

生物传感器在食源性致病菌检测中应用的研究进展

食源性致病菌作为引起食源性疾病的主要因素,受到人们的高度重视,发展简便、快速、高灵敏度和低成本的食源性致病菌检测方法对降低食源性疾病发病率具有重要意义。生物传感器技术是一种由多学科交叉渗透发展形成的全新微量分析技术,具有灵敏度高、分析速度快等特点,被广泛应用于食源性致病菌的检测。文中介绍了生物传感器的基本原理,综述了常见的生物传感器在食源性致病菌检测中的应用,并对其发展趋势进行了展望。     

食源性致病菌检测免疫传感器研究进展

食源性致病菌是造成食品安全事件的主要原因之一,因此其检测方法已成为人们研究的热点.食源性致病菌的检测方法主要有病原体培养法、免疫学方法、核酸检测和生物传感器等.其中,免疫传感器基于抗原抗体特异性结合,整合光学、电化学等多学科交叉技术,具有特异性强、检测速度快等特点.本文对比食源性致病菌传统检测方法,综述了近年来免疫传感...     

噬菌体及其裂解酶在食源性致病菌检测和控制中的应用

微生物致病菌引起的食源性疾病在全世界频频发生,对人类健康造成严重危害,尤其是致病菌耐药性的出现使常规治疗陷入困境。噬菌体及其编码的裂解酶的发现及应用,为食源性致病菌的检测及生物防治开辟了新的途径。综述噬菌体及其裂解酶在构建食源性致病菌的快速检测方法和生物防治方面的应用。     

Development of membrane filter holder (MFH) method for recovery of heat-injured Escherichia coli O157:H7 and Salmonella typhimurium

AIMS: A method of recovering sublethally heat-injured bacteria was developed with specific apparatus (membrane filter holder; MFH) which was originally used for Iso-Grid Hydrophobic membrane. filter holder. METHODS AND RESULTS: The procedure used a non-selective agar underlayed with a selective medium with a MFH. A non-selective agar was poured on upper part (compartment A) of MFH, and then injured foodborne pathogens were inoculated on the non-selective medium. After 3-h repair incubation period, selective agar was added to the bottom of the chamber (compartment B) of the MFH and further incubated. By diffusing through the non-selective top agar, selective agents from the underlay medium impart selectivity to the system. CONCLUSIONS: Using the MFH method, recovery of heat-injured foodborne pathogens (Escherichia coli O157:H7 and Salmonella typhimurium) were not different (P > 0.05) from recoveries with non-selective media (TSA). However, the recoveries of foodborne pathogens on MFH were significantly higher (P < 0.05) than those of direct plating on selective medium such as SMAC (MacConkey Sorbitol Agar) or XLD (Xylose Lysine Desoxycholate). SIGNIFICANCE AND IMPACT OF THE STUDY: In conclusion, the MFH method is a simple and convenient method for recovery of heat-injured foodborne pathogens.     

基于CRISPR/Cas系统的纸基分析在快速检测食源性致病菌中的应用

由食源性致病菌引起的食品安全事件严重影响人类健康,开发针对食源性致病菌的快速检测技术十分必要。成簇间隔短回文重复序列（clustered regularly interspaced short palindromic repeats,CRISPR）及相关蛋白（CRISPR-associated protein,Cas）是原核生物的适应性免疫系统,具有特异性识别并切割核酸序列的功能。纸基分析方法作为一种简便性好、成本低廉的分析检测工具,在快速检测领域展现出良好的前景。因此,将CRISPR/Cas系统的高效识别能力和纸基分析方法的简便性相结合可实现对食源性致病菌的快速灵敏检测。本文简要介绍了CRISPR/Cas系统用于核酸检测的概况,对第二类单Cas效应蛋白系统的特点及原理进行概述,重点综述基于CRISPR/Cas系统的试纸分析、侧向流动分析和纸基微流控装置在检测食源性致病菌方面的应用,并讨论了CRISPR/Cas系统结合纸基分析建立检测方法的优势、当前的挑战及未来的发展前景。     

人工模拟胃肠道模型在食源性致病菌耐受及致病机理中的应用

人工模拟胃肠道模型是研究食源性致病菌耐受及致病机理的一种重要工具,其本质是在实验室模拟的条件下,重现人体消化过程中的化学、物理及生物作用,以研究食源性致病菌的耐受性、致病机理、肠道菌群互作及疫苗开发,对食源性致病菌的控制和治疗具有十分重要的意义。文中综述了人工模拟胃肠道模型在食源性致病菌研究中的应用,将现有胃肠道模型系统地划分为体外静态模型、体外动态模型、普通动物模型及人源化动物模型,并详细介绍了各类模型的概念及特性。在此基础之上,进一步分析了现有模型的不足,并对未来人工模拟胃肠道模型的研究方向进行了展望,以期为食源性致病菌耐受及致病机理的研究奠定扎实的研究基础。     

Detection of Foodborne Bacterial Pathogens from Individual Filth Flies

There is unanimous consensus that insects are important vectors of foodborne pathogens. However, linking insects as vectors of the pathogen causing a particular foodborne illness outbreak has been challenging. This is because insects are not being aseptically collected as part of an environmental sampling program during foodborne outbreak investigations and because there is not a standardized method to detect foodborne bacteria from individual insects. To take a step towards solving this problem, we adapted a protocol from a commercially available PCR-based system that detects foodborne pathogens from food and environmental samples, to detect foodborne pathogens from individual flies.Using this standardized protocol, we surveyed 100 wild-caught flies for the presence of Cronobacter spp., Salmonella enterica, and Listeria monocytogenes and demonstrated that it was possible to detect and further isolate these pathogens from the body surface and the alimentary canal of a single fly. Twenty-two percent of the alimentary canals and 8% of the body surfaces from collected wild flies were positive for at least one of the three foodborne pathogens. The prevalence of Cronobacter spp. on either body part of the flies was statistically higher (19%) than the prevalence of S. enterica (7%) and L.monocytogenes (4%). No false positives were observed when detecting S. enterica and L. monocytogenes using this PCR-based system because pure bacterial cultures were obtained from all PCR-positive results. However, pure Cronobacter colonies were not obtained from about 50% of PCR-positive samples, suggesting that the PCR-based detection system for this pathogen cross-reacts with other Enterobacteriaceae present among the highly complex microbiota carried by wild flies. The standardized protocol presented here will allow laboratories to detect bacterial foodborne pathogens from aseptically collected insects, thereby giving public health officials another line of evidence to find out how the food was contaminated when performing foodborne outbreak investigations.     

Do leafy green vegetables and their ready-to-eat [RTE] salads carry a risk of foodborne pathogens?

Over the past 10 years, there is an increasing demand for leafy green vegetables and their ready-to-eat (RTE) salads since people changed their eating habits because of healthier lifestyle interest. Nevertheless fresh leafy green vegetables and their RTE salads are recognized as a source of food poisoning outbreaks in many parts of the world. However, this increased proportion of outbreaks cannot be completely explained by increased consumption and enhanced surveillance of them. Both in Europe and in the USA, recent foodborne illness outbreaks have revealed links between some pathogens and some leafy green vegetables such as mostly lettuces and spinaches and their RTE salads since fresh leafy green vegetables carry the potential risk of microbiological contamination due to the usage of untreated irrigation water, inappropriate organic fertilizers, wildlife or other sources that can occur anywhere from the farm to the fork such as failure during harvesting, handling, processing and packaging. Among a wide range of pathogens causing foodborne illnesses, Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes are the most common pathogens that contaminate leafy green vegetables. Children, the elderly, pregnant women and immunocompromised people are the most at risk for developing complications from foodborne illness as a result of eating contaminated leafy greens or their RTE salads. These outbreaks are mostly restaurant associated or they sometimes spread across several countries by international trade routes. This review summarizes current observations concerning the contaminated leafy green vegetables and their RTE salads as important vehicles for the transmission of some foodborne pathogens to humans.     

Foodborne Transmission of Bovine Spongiform Encephalopathy to Non-Human Primates Results in Preclinical Rapid-Onset Obesity

Obesity has become one of the largest public health challenges worldwide. Recently, certain bacterial and viral pathogens have been implicated in the pathogenesis of obesity. In the present study, we retrospectively analyzed clinical data, plasma samples and post-mortem tissue specimens derived from a risk assessment study in bovine spongiform encephalopathy (BSE)-infected female cynomolgus monkeys (Macaca fascicularis). The original study design aimed to determine minimal infectious doses after oral or intracerebral (i.c.) infection of macaques to assess the risk for humans. High-dose exposures resulted in 100% attack rates and a median incubation time of 4.7 years as described previously. Retrospective analyses of clinical data from high-dosed macaques revealed that foodborne BSE transmission caused rapid weight gain within 1.5 years post infection (β = 0.915; P<0.0001) which was not seen in age- and sex-matched control animals or i.c. infected animals. The rapid-onset obesity was not associated with impaired pancreatic islet function or glucose metabolism. In the early preclinical phase of oral transmission associated with body weight gain, prion accumulation was confined to the gastrointestinal tract. Intriguingly, immunohistochemical findings suggest that foodborne BSE transmission has a pathophysiological impact on gut endocrine cells which may explain rapid weight gain. To our knowledge, this is the first experimental model which clearly demonstrates that foodborne pathogens can induce obesity.     

Wildtool,a flexible,first-line risk assessment system for wildlife-borne pathogens

We describe the prototype of an electronic tool for risk assessment with dynamic ranking of wildlife-borne pathogens in function of their need for surveillance. Data about pathogens, their hosts and occurrences are obtained from literature and are classified as qualitative scores under six main criteria with their sub-criteria, corresponding to the elements of a standard risk assessment. Pathogen-specific data are reviewed by experts. The information is processed per pathogen through an algorithm and through summing up of the values obtained by converting four-tiered qualitative sub-criteria scores to weighted five-tiered numerical values. For a consistent comparison between pathogens, the “unknown” sub-criteria scores are assigned a median value of 3, allowing preservation of the sub-criteria concerned and their weights for the risk assessment, but minimizing the effect of this score on the outcome. Irregular data availability is further accommodated by a different data processing for comprehensiveness and refinement requirements, which is realised by a respective first- and second-level ranking of pathogens, the latter using additional quantitative and qualitative data for the release assessment. Continuous data updates are necessary to reflect the current situation in the field. Output flexibility is implemented by the possibility to run queries based on the choice of a region, a specific target group susceptible to the pathogens and a set of weights for the sub-criteria.