乳品微生物耐药性影响及防治途径研究进展

随着对乳品中耐药微生物影响人体健康关注度提高,如何控制微生物耐药产生和传播逐渐成为国际社会关注焦点。本文通过对当前乳制品生产现状、微生物耐药产生主要原因及其在世界范围内危害、传播现状概述,结合国内外研究进展及实际生产状况。就乳制品生产加工、乳牛养殖环节抗生素使用及其它不规范操作对乳品中耐药微生物、耐药基因产生和传播造成影响及其可能危害性,以及耐药微生物表型主要检测途径和牧场中主要存在问题国内外相关防治途径进行论述。旨在为牧场中抗生素使用和耐药微生物防治提供参考。     

食品中耐药细菌风险评估的研究进展

近年来抗生素的使用和滥用是普遍存在的问题,食品中耐药细菌和耐药基因引起的人类疾病威胁已成为全球性关注的热点。因此,全面开展从农场到餐桌耐药细菌的风险评估研究具有十分重要的意义。本文根据国际食品法典委员会拟定的微生物风险评估原则和指导方针,从危害识别、释放评估、暴露评估、剂量-反应关系评估、风险评估5 个步骤进行阐述。通过分析国内外抗生素耐药细菌风险评估案例,综述了食品中耐药细菌风险评估的研究进展及其预防控制措施,以期为未来耐药细菌风险评估提供理论依据。     

奶牛乳房炎主要致病菌耐药性研究进展

奶牛乳房炎是泌乳期奶牛最普遍和最重要的疾病之一,主要是由致病菌感染造成。而抗生素在奶牛乳房炎临床治疗过程中不合理的使用,导致了乳房炎源致病菌出现严重的抗生素耐药现象。本文主要从奶牛乳房炎的现状、主要致病菌的耐药情况、耐药性产生机制、耐药性检测方法及如何控制和监管致病菌耐药性等方面进行了概述,同时展望了奶牛乳房炎中微生物的重点研究方向,以期为奶牛乳房炎临床治疗提供参考。     

噬菌体控制主要食源性致病菌的研究进展

食源性细菌疾病是当今世界上最广泛的公共卫生问题之一。由抗生素滥用导致的耐药菌株出现,以及抗生素禁用,使得人们对食源性细菌疾病的控制更加困难。噬菌体是细菌的天敌,具有感染并裂解细菌的功能,与抗生素相比,噬菌体制剂具有特异性强、自我增殖快、抗菌能力强、研发时间短等优点,因此近年来有关噬菌体作为抗菌制剂的研究受到普遍关注。本文就噬菌体在食源性病原微生物控制方面的应用研究进展作一综述,以期为噬菌体及其制剂在保障动物性食品安全领域的深入研究提供一定的参考。     

蜂产品中四环素族残留量(杯碟法)检测结果计算机分析软件的编制

<正> 在防治蜜蜂细菌性或病毒性病害时,如果盲目使用抗生素,不按规定或加大剂量用药,或在采蜜期前的1个月以内或在采蜜期中使用抗生素,直接结果就是蜂产品中的抗生素残留超标。四环素族类等抗生素的潜在危害是使人们在治疗疾病时产生抗药性、肠道菌群失调,出现过敏症状以及其他毒副作用等,如“三致”作用——致癌、致畸、致突变。许多国家对蜂产品抗生素残留都有严格的规定和限制,蜂产品中的抗生素残留超标会严重影响我国蜂产品的出口。     

噬菌体在食品安全领域的研究进展

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,由抗生素滥用导致的耐药菌株出现,以及抗生素滥用,使得人们对食源性细菌疾病的控制更加困难。噬菌体是细菌的天敌,具有感染并裂解细菌的功能,噬菌体及其编码裂解酶的发现为食源性致病菌的检测及生物防治开辟了新的途径。因此近年来有关噬菌体作为抗菌制剂的研究受到普遍关注。就噬菌体在食品中病原微生物检测和控制方面的研究作以综述。     

Premi(R) Test国际标准检测产品:实现食品中抗生素残留的快速检测

近日有关"耐药宝宝"的报道,引起了人们对食品中抗生素残留问题的广泛关注.专家分析指出,新生儿的耐药性可能是因其母亲食用的肉蛋禽类食品中,残留有大量的抗生素所造成.据了解,使用抗生素能避免家禽家畜感染疾病,促进其生长.一些养殖户为了应对愈发严峻的传染性疾病风险,不得不在养殖过程中超量使用抗生素,这一做法很容易造成肉类产品抗生素残留超标;此外,有些不规范的兽药厂为了确保药效,在兽药中添加一些抗生素,却并未在药品说明书里明确标示,养殖户就会在不知情的情况下使用这些添加抗生素的兽药或饲料,同样也会导致食品中抗生素残留.     

浅谈食源性疾病的传播和耐药性

世界卫生组织认为,凡是通过摄食进入人体的各种致病因子引起的,通常具有感染性的或中毒性的一类疾病,都称之为食源性疾病。食源性疾病是目前世界上最广泛的卫生问题,包括食物中毒、肠道传染病、人兽共患传染病、寄生虫病等,其中以食源性致病菌最为突出。食源性疾病影响人的身体健康,轻则腹泻,重则导致人体中毒,甚至死亡。随着中国经济的发展,食品的消费水平持续增长,食品安全问题显得尤为重要。由于抗生素有促生长作用,导致畜牧业中滥用抗生素的情况非常严重。在日常生活中,由于管理体制等原因,抗生素滥用导致食源性致病菌对多种抗生素产生耐药性。食品中的多重耐药致病菌传播到人体中的情况日益严重,应从各方面入手杜绝耐药。     

益生菌对免疫细胞的影响及其在自身免疫性疾病中的应用

益生菌是一类摄入适当数量时会对宿主健康产生有益作用的活性微生物的总称,可以通过调节树突细胞(dendritic cell,DC)、单核细胞、调节性T细胞(regulatory cells,Treg)和Th17细胞介导的免疫反应,从而发挥其免疫调节能力。自身免疫性疾病(autoimmune diseases,AID)是机体免疫系统对自身组织细胞发生免疫应答,导致细胞破坏或组织损伤所引起的疾病。针对AID的治疗,目前尚无根治药物,传统的糖皮质激素和免疫抑制剂虽能够抑制病情,提高患者存活率,但长期使用会造成一系列不良后果。而大量研究发现益生菌能够有效缓解自身免疫性疾病。本文就益生菌对多种免疫细胞的影响及在自身免疫性疾病中的研究进展进行了综述。     

耐药基因在食品链中的传播及风险管控

抗生素的滥用导致多重耐药性频繁出现,给医疗环境带来新的挑战。不同生物个体或细胞内部DNA之间的遗传物质交流促进了遗传物质的交换和重组,耐药基因也因此发生进化从而适应新的耐药环境。人与动物以及一些生物物质的直接接触,可能引起耐药菌在宿主之间的快速传播。感染初期是风险高发期,并可通过密切接触进入各个家庭、社区。食物链中也可能通过接触或食用受污染的食品间接接触到耐抗生素细菌和耐药基因。耐药基因可以在食物链中的各个阶段传播,在人和动物体内仍保持一部分活性,并随代谢产物排入新的环境中传播。认识食物链中耐药基因的传播,以此进行风险管控,对排查感染等相关安全问题起到至关重要的作用。设立不同层次和领域的监测体系,对包括在抗菌药物的生产、流通、使用的各个阶段进行监测,将各领域所获得的信息互相配合,共同应对耐药基因的传播。     

Resistance responses of microorganisms in food environments.

Food borne microorganisms display a broad spectrum of resistance responses to naturally occurring and intentionally added antimicrobial agents. Resistance may be conferred by innate structural features of the bacterial strain such as an impermeable outer membrane or a mechanism for antibiotic-inactivation. Bacteria previously susceptible to an antimicrobial compound can acquire resistance through mutation or through genetic transfer processes such as transformation, transduction, and conjugation. Resistance can also be conferred by biofilm formation on food processing surfaces as an adaptive response to protect colonies from cleaning and sanitation. Resistant pathogens are a global problem, facilitated by international trade of raw and processed foods. Cross resistance between clinical and nonclinical antimicrobials can exist and is of concern. The development of resistant foodborne pathogens has been attributed to increased antibiotic use in hospitals, outpatient facilities, and veterinary applications. Resistant microorganisms can also develop as a result of physical processes used in food preservation, such as acid treatments and irradiation processes. Strategies to effectively counter resistance development include: changing current practices of antibiotic usage, developing new antibiotics, applying hurdle preservation approaches, preventing bacterial adhesion, and utilizing competitive exclusion. This paper presents an overview of problems arising from the development of microbial resistance, and explores possible solutions for detecting and defeating the adaptive changes of microorganisms.     

Antibiotic-Resistant Bacteria: A Challenge for the Food Industry

Antibiotic-resistant bacteria were first described in the 1940s, but whereas new antibiotics were being discovered at a steady rate, the consequences of this phenomenon were slow to be appreciated. At present, the paucity of new antimicrobials coming into the market has led to the problem of antibiotic resistance fast escalating into a global health crisis. Although the selective pressure exerted by the use of antibiotics (particularly overuse or misuse) has been deemed the major factor in the emergence of bacterial resistance to these antimicrobials, concerns about the role of the food industry have been growing in recent years and have been raised at both national and international levels. The selective pressure exerted by the use of antibiotics (primary production) and biocides (e.g., disinfectants, food and feed preservatives, or decontaminants) is the main driving force behind the selection and spread of antimicrobial resistance throughout the food chain. Genetically modified (GM) crops with antibiotic resistance marker genes, microorganisms added intentionally to the food chain (probiotic or technological) with potentially transferable antimicrobial resistance genes, and food processing technologies used at sub-lethal doses (e.g., alternative non-thermal treatments) are also issues for concern. This paper presents the main trends in antibiotic resistance and antibiotic development in recent decades, as well as their economic and health consequences, current knowledge concerning the generation, dissemination, and mechanisms of antibacterial resistance, progress to date on the possible routes for emergence of resistance throughout the food chain and the role of foods as a vehicle for antibiotic-resistant bacteria. The main approaches to prevention and control of the development, selection, and spread of antibacterial resistance in the food industry are also addressed.     

Antibiotic resistance in food lactic acid bacteria--a review

Antibiotics are a major tool utilized by the health care industry to fight bacterial infections; however, bacteria are highly adaptable creatures and are capable of developing resistance to antibiotics. Consequently, decades of antibiotic use, or rather misuse, have resulted in bacterial resistance to many modern antibiotics. This antibiotic resistance can cause significant danger and suffering for many people with common bacterial infections, those once easily treated with antibiotics. For several decades studies on selection and dissemination of antibiotic resistance have focused mainly on clinically relevant species. However, recently many investigators have speculated that commensal bacteria including lactic acid bacteria (LAB) may act as reservoirs of antibiotic resistance genes similar to those found in human pathogens. The main threat associated with these bacteria is that they can transfer resistance genes to pathogenic bacteria. Genes conferring resistance to tetracycline, erythromycin and vancomycin have been detected and characterized in Lactococcus lactis, Enterococci and, recently, in Lactobacillus species isolated from fermented meat and milk products. A number of initiatives have been recently launched by various organizations across the globe to address the biosafety concerns of starter cultures and probiotic microorganisms. The studies can lead to better understanding of the role played by the dairy starter microorganisms in horizontal transfer of antibiotic resistance genes to intestinal microorganisms and food-associated pathogenic bacteria.     

Antibiotics: Has the magic gone?

The emergence of antibiotic resistant bacteria has diminished the efficacy of several antibiotics that were used to treat infectious diseases in humans and animals. In recent years, the problem of antibiotic resistance has become more apparent as increasing numbers of bacteria have acquired resistance to multiple antibiotics. Antibiotics inhibit bacterial growth through a variety of mechanisms including inhibition of cell wall or protein synthesis, interference with DNA (or RNA) replication, and disruption of metabolic pathways or cell membrane. Bacteria develop resistance through genetic mutations or by acquiring resistant genes involved in the production of antibiotic degrading enzymes, overproduction of target molecules, efflux pumps to drain out antibiotics, and/or altered cell wall permeability to survive adverse physiological conditions. Published literature suggests that sub‐therapeutic feeding of food animals for growth promotion along with casual use of antibiotics in household products such as soaps and creams is contributing to increased antimicrobial resistance in the environment. If steps are not taken to minimize selective pressure on bacteria, the effectiveness of antibiotics (hailed as ‘magic bullets’) may be marginalized. Important steps in the judicious use of antibiotics on the farm are: (1) education of farmers on the pitfalls of using antibiotics sub‐therapeutically in the production of food animals; (2) development of animal production practices that reduce dependence on antibiotics; and (3) development of manure disposal practices that minimize the spread of residual antibiotics and antibiotic resistant bacteria into the environment. In addition, educating the general public on the use and misuse of antibiotics in daily life is also important if there is to be any significant impact on reducing the environmental spread of antibiotic resistance. Copyright © 2006 Society of Chemical Industry     

Colonization resistance of the digestive tract--mechanism and clinical consequences

Potentially pathogenic bacteria and yeasts meet a number of resistance factors. These colonization resistance (CR) determining factors control the growth density of potentially pathogenic microorganisms in the various parts of the alimentary canal. The CR of the digestive tract is to be seen partially of host origin but to a greater extent due to direct and indirect activity of the (anaerobic) indigenous microflora. This implies that the CR mechanism is vulnerable to antibiotics which affect the indigenous flora during treatment. A decreased CR enhances colonization by microorganisms that are resistant to the antibiotic(s) used for therapy. Increased population densities of potentially pathogenic bacteria ("overgrowth") may correlate with invasion of the mucosal tissues often followed by translocation to remote lymphatic organs. Overgrowth also may correlate with development or acquisition of resistance to the antibiotic applied. By screening in experimental animals antibiotics have been selected which do not affect the CR. Such antimicrobial drugs have successfully been used to selectively eliminate potentially pathogenic bacteria and yeast in neutropenic patients.     

The antibiotic resistance characteristics of non-typhoidal Salmonella enterica isolated from food-producing animals, retail meat and humans in South East Asia

Antimicrobial resistance is a global problem. It is most prevalent in developing countries where infectious diseases remain common, the use of antibiotics in humans and animals is widespread, and the replacement of older antibiotics with new generation antibiotics is not easy due to the high cost. Information on antibiotic resistance phenotypes and genotypes of Salmonella spp. in food animals and humans in different countries and geographic regions is necessary to combat the spread of resistance. This will improve the understanding of antibiotic resistance epidemiology, tracing of new emerging pathogens, assisting in disease treatment, and enhancing prudent use of antibiotics. However, the extent of antibiotic resistance in food-borne pathogens and humans in many developing countries remains unknown. The goal of this review is to discuss the current state of antibiotic resistance of non-typhoid Salmonella spp. in food-producing animals, retail meat and humans from South East Asia. It is focused on resistance characteristics of traditional and "critically important" antibiotics in this region, and the emergence of multidrug resistant strains and genetic elements that contribute to the development of multidrug resistance, including integrons and the Salmonella Genomic Island (SGI).     

蜂蜜中抗生素残留的检测方法研究进展

蜂蜜中富含多种营养物质,在食品加工业中,蜂蜜不仅可以作为生产饮料、糖果等食品的甜味剂,还可以用于腌制果品、蔬菜。但在养蜂过程中,对于预防和治疗蜜蜂感染性疾病存在抗生素使用不当的问题。由于大多数抗生素难以被蜜蜂自身代谢,导致抗生素残留于蜂蜜中。消费者长期食用含有抗生素的蜂蜜会危害健康,因此检测蜂蜜中抗生素的残留有助于评估产品对人体健康的潜在风险。本文概述了蜂蜜中抗生素的残留现状,总结了蜂蜜中抗生素残留的检测技术,色谱法具有检测快速、灵敏等优点,但存在设备昂贵、检测成本较高等问题,传感器法和免疫分析法检测成本较低且操作简便,其中电化学传感器检测响应快速、灵敏度较高,具有良好的发展前景。最后对蜂蜜中抗生素残留检测技术的发展进行展望,以期为蜂蜜中抗生素残留的检测方法研究及应用提供理论参考。     

Antibiotic resistance in non-enterococcal lactic acid bacteria and bifidobacteria

Over the last 50 years, human life expectancy and quality of life have increased dramatically due to improvements in nutrition and the use of antibiotics in the fight against infectious diseases. However, the heyday of antibiotic treatment is on the wane due to the appearance and spread of resistance among harmful microorganisms. At present, there is great concern that commensal bacterial populations from food and the gastrointestinal tract (GIT) of humans and animals, such as lactic acid bacteria (LAB) and bifidobacteria, could act as a reservoir for antibiotic resistance genes. Resistances could ultimately be transferred to human pathogenic and opportunistic bacteria hampering the treatment of infections. LAB species have traditionally been used as starter cultures in the production of fermented feed and foodstuffs. Further, LAB and bifidobacteria are normal inhabitants of the GIT where they are known to exert health-promoting effects, and selected strains are currently been used as probiotics. Antibiotic resistance genes carried by LAB and bifidobacteria can be transferred to human pathogenic bacteria either during food manufacture or during passage through the GIT. The aim of this review is to address well-stated and recent knowledge on antibiotic resistance in typical LAB and bifidobacteria species. Therefore, the commonest antibiotic resistance profiles, the distinction between intrinsic and atypical resistances, and some of the genetic determinants already discovered will all be discussed.     

Dairy farmers' perspectives on antibiotic use: A qualitative study

An important step in limiting the development of antibiotic resistance is reducing use of antibiotics in animal husbandry. Much research in this area has focused on individual farmer behavior, aiming to better align actual use with medical recommendations. However, farmers' practices and reasoning around their antibiotic use do not reflect solely that farmer as an individual. Rather, practices and worldviews are guided by context (e.g., veterinary advice, peer pressure, regulation, and interactions with farm animals). Studies that jointly embrace farmer agency and the wider structures for this agency, however, remain scarce. This paper draws on theories of behavior as socially constructed, and in particular on the concept of the “good farmer,” to interpret findings from a study of 7 Swedish dairy farms. The results show that all farmers have close daily contact with their animals, have strong emotional ties, and place emphasis on the importance of being able to judge animal health status by eye. Half of the farms use an automatic milking system, and for these farmers automation means better monitoring of animal health without losing contact with the cows. The local veterinarian is considered a positive and important authority whose advice is valued. Despite comparatively strict antibiotic use regulations in Sweden, the farmers do not report lack of access to antibiotics when needed. However, they report feeling disadvantaged in international trade and poorly treated by the Swedish government, which allows imports of cheaper meat and dairy products produced under less strict regulations. The farmers are well informed about how to prevent and treat common diseases. In cases where they do not follow recommendations, we found that economic and labor constraints are the reason rather than lack of knowledge. We concluded that structural limitations faced by farmers, rather than lack of information, impose constraints to further limiting antibiotic use in Sweden. Overall stricter and more uniform global regulations on antibiotic use in animal farming could be an effective measure for reducing antibiotic use.     

噬菌体裂解酶在食品安全领域的研究进展

食源性疾病引发的食品安全问题对人类健康造成严重危害, 其中微生物致病菌是引起食源性疾病的最主要因素,近年来国内外由微生物致病菌引起的食源性疾病事件频频发生,受到世界各国的高度关注。食品工业防治食源性致病微生物的传统方法中,化学防腐剂存在副作用、天然防腐剂较弱的抗微生物活性以及大规模抗生素使用带来的耐药性等一系列问题,使寻求新的抗菌药物或制剂迫在眉睫。噬菌体裂解酶是双链DNA噬菌体复制后期表达, 能够裂解细菌细胞壁释放子代噬菌体的一种蛋白水解酶。随着近些年针对噬菌体及其产物展开的研究不断深入,噬菌体裂解酶凭借高度特异性、不影响正常菌群等特性, 从治疗人类耐药感染到控制多个领域的细菌污染, 成为了包括微生物食品安全在内多种应用中有效的抗微生物制剂。