畜禽源四环素类抗生素抗性基因的归趋及影响因素

兽用抗生素在畜禽养殖行业的不合理使用导致抗生素抗性基因(antibiotic resistance genes, ARGs)在农业环境中广泛传播,严重危胁人类健康及生态安全。畜禽源四环素类抗生素降解难、残留重等问题严重困扰着畜牧业的可持续发展。因此,文章综述了四环素类抗性基因(tetracycline resistance genes, TRGs)的类别、在畜禽粪便中的残留情况,在农业环境中的传播途径、传播方式,以及细菌自身系统、环境胁迫因子和可移动遗传元件等影响基因水平传播的因素,以期为有效防控畜禽源四环素类抗生素抗性基因在农业环境中的传播提供参考。     

兽用抗生素残留对环境中细菌耐药性影响的研究进展

兽用抗生素残留的生态毒理学效应已经受到人们的广泛关注,其中兽用抗生素残留对环境中细菌耐药性的影响也被逐步重视.论文介绍了兽用抗生素在环境中的残留现状以及环境中细菌的耐药性现状,耐药基因的产生及其在环境中的传播途径,综述了兽用抗生素残留对粪便、土壤和水体等环境介质中细菌耐药性的影响,并对今后该领域的研究进行了展望.     

动物微生态制剂及应用

微生态制剂是根据微生态学原理研制,用于调节动物机体微生态平衡的一种活菌制剂,可作为动物治疗药物或饲料添加剂使用。人们通过对化学药品残留和细菌抗药性的深入研究,发现化学药品,特别是抗生素作为治疗剂和饲料添加剂的广泛应用,对畜牧业生产和人类产生了较大的副作用：首先是抗生素在灭杀致病菌的同时,也灭杀了对机体有益的生理性细菌,破坏了肠道微生物的生态平衡,出现菌群失调现象,导致幼畜对病原微生物的易感性增加。另外,长期饲喂抗生素致使动物体内产生具有抗药性的细菌,这些细菌对人富有害。而使用微生态制剂则无此忧虑…     

微生态活菌制剂对雏鸡生长抗病作用的研究

抗生素作为饲料添加剂在预防和抵抗畜禽疾病,促进动物生长等方面起了很大作用,但它在杀死有害病菌的同时也杀死了肠道内的有益微生物,造成肠道内微生物菌群不平衡。另外,长期使用抗生素会使病菌产生抗药性,并残留于畜产品中对人体造成危害。近几年来,微生态制剂以其天然、无副作用、安全可靠、不产生抗性、不污染环境等优点而倍受世人的关注。我们选用乳酸杆菌、乳酸链球菌、双歧杆菌、芽孢杆菌等菌种制成微生态制剂饲喂雏鸡,观察雏鸡生长及抗病情况。1材料与方法雏鸡:郑州牧专孵化厂孵育的健康1日龄雏鸡。有益菌种:由本实验室分离并保存。…     

微生态制剂用于畜禽养殖业中的现状及展望

在现代化规模化畜禽养殖生产中,人们普遍在畜禽饲料中加入抗生素、化学合成药物以防治畜禽疾病,但这些物质的长期使用会引起病原微生物产生抗药性,同时在畜禽产品及环境中产生残留等,严重威胁着人类健康。因此,许多国家纷纷通过立法禁止用抗生素等物质作为饲料添加剂。微生态制剂是目前最有可能替代抗生素添加剂而成为应用最广、需求量最大的绿色饲料添加剂产品,许多试验表明它在提高饲料利用率、促进动物生长、改善生态环境和防治畜禽疾病等方面均有明显的效果。微生态制剂可解决长期困扰畜牧业发展的抗生素残留问题,提高生产率,减少畜牧业…     

动物微生态制剂在养牛业中的应用

众所周知,抗生素在畜牧业上的应用,大大的促进了畜牧业的发展,但随着抗生素的长期应用,其抗药性、药物残留、耐药性等弊端也日益明显.动物微生态制剂也称微生物饲料添加剂,由于其具有无污染无残留,维持动物肠道微生物平衡,提高动物免疫力的特点,近年来在养牛业中被广泛应用.     

微生态制剂在养鸡业中的作用

微生态制剂又称活菌剂、生菌剂,是以动物体内正常菌群为主体的有菌微生物经特殊工艺制成的活菌制剂。近年来,随着养鸡业的不断发展,人们常用抗生素来抑制或杀灭消化道内的有害微生物,以提高其生产性能。但是饲料中添加抗生素有副作用,如导致鸡体内菌群失调,产生抗药性以及药物残留对人类健康的影响等,日益引起世界的关注。微生态制剂是在微生态理论指导下,利用对宿主有益的、活的正常微生物或其促生长物质经特殊工艺制成的制剂,     

畜牧养殖业废弃物中抗生素及抗性基因研究进展

抗生素抗性基因(antibiotic resistance genes,ARGs)可以持久性存在于环境中,通过基因水平转移功能广泛传播于菌群之间,携带有抗性基因的细菌最终可能通过食物链进入人体,引发难以治愈的细菌性疾病,给人类健康带来严重威胁。该文主要针对畜禽养殖废弃物中抗生素及抗性基因污染这一问题,结合国内外最新研究对畜禽养殖中抗生素及抗性基因的污染现状、产生和传播机制以及消除技术等进行了综述,为我国畜牧业可持续发展提供理论参考。     

饲用微生态制剂的发展现状与应用性研究

随着动物微生态学的不断发展,以有益微生物菌群研制开发的饲用微生态制剂,作为一类新型无公害饲料资源已被广泛使用.研究发现,饲用微生物添加剂具有改善肠道微生态环境、提高畜禽生产性能、无抗药性、无毒、无不良反应、无药物残留及无污染等特点,已成为抗生素的有益替代品.就微生物添加剂的种类、作用机制、功能和微生物添加剂的生产及应用进行综述.     

微生态制剂在养禽生产中的应用

随着养禽业的不断发展,人们常用抗生素来抑制或杀灭消化道内的有害微生物,以提高其生产性能。但是,饲料中添加抗生素有副作用,如导致禽体内菌群失调,产生抗药性以及药物残留对人类健康的影响等,也日益引起人们的关注,许多国家已经越来越多地禁止用抗生素作为饲料添加剂。微生态     

Research Progress on Bacterial Resistance in Environment

Antibiotic resistance genes have become a recognized environmental pollutant, threatening the ecological safety and human health. The application of antibiotics in the clinical and animals breeding, making the environmental microorganisms living with the impact of the residue of antibiotics and elements of resistance genetic and leading to antibiotic resistant bacteria to gain a competitive advantage and destroyed the stability of ecosystem. In this paper, we expounded the concept of resistance gene transmission by the view of macro environment. Through analyzing the mechanism of resistance development,environmental pollution caused by drug resistance and the impact of environmental microorganism for drug resistance, we clarified the key role of the environment in the development of the characteristics of bacterial resistance and analysis environmental resistance.Such as the ecological diversity of flora, the types and the spread of resistant bacteria, the residues of antibiotics and the transmission of the resistance genes.     

多肽类抗生素的环境安全性评价研究进展

多肽类抗生素(AMPs)是目前国内应用较广泛的抗生素种类之一。该类化合物不易被生物体吸收,多数以原形形式随粪便和尿液排出体外,可能会对环境和人类健康造成严重危害。本文综述了环境中AMPs的暴露情况及检测方法,揭示了其在环境中的迁移转化、降解特性及生态效应,同时介绍了其耐药菌和抗性基因的产生和去除技术,分析了该类抗生素环境安全性研究的发展趋势,提出AMPs的环境行为和生态效应研究应从多药联合使用方面及发生机理等进一步深入,未来应开发出更有效地AMPs抗性基因去除技术。本文为全面评估AMPs的环境安全性及有效避免或降低该类抗生素耐药性及抗性基因(ARGs)的传播提供科学依据。     

Importance of integrons in the diffusion of resistance.

Horizontal transfer of resistance genes is a successful mechanism for the transmission and dissemination of multiple drug resistance among bacterial pathogens. The impact of horizontally transmitted genetic determinants in the evolution of resistance is particularly evident when resistance genes are physically associated in clusters and transferred en bloc to the recipient cell. Recent advances in the molecular characterisation of antibiotic resistance mechanisms have highlighted the existence of genetic structures. called integrons, involved in the acquisition of resistance genes. These DNA elements have frequently been reported in multi-drug resistant strains isolated from animals and humans, and are located either on the bacterial chromosome or on broad-host-range plasmids. The role of integrons in the development of multiple resistance relies on their unique capacity to cluster and express drug resistance genes. Moreover, the spread of resistance genes among different replicons and their exchange between plasmid and bacterial chromosome are facilitated by the integration of integrons into transposable elements. The association of a highly efficient gene capture and expression system, together with the capacity for vertical and horizontal transmission of resistance genes represents a powerful weapon used by bacteria to combat the assault of antibiotics.     

兔支气管败血波氏杆菌的分离鉴定及耐药基因检测

本试验旨在了解近年来浙江省兔支气管败血波氏杆菌的感染情况及耐药状况,指导合理用药,检测细菌的耐药基因,探究其耐药机理.根据细菌形态、培养特性、生化试验,结合PCR法对分离菌株进行鉴定;K-B纸片扩散法检测细菌对18种常用抗生素的耐药率;设计耐药基因特异性引物,PCR法扩增耐药基因,并进行测序分析.结果显示,分离鉴定出2012-2014年22株兔支气管败血波氏杆菌;药敏结果显示,分离菌对青霉素G、头孢拉定、链霉素、林可霉素、克林霉素、甲氧嘧啶耐药严重,对多黏菌素B、左氟沙星、强力霉素、四环素等药物敏感,耐β-内酰胺类药物的细菌中检测到耐药基因bla_TEM.结果表明,兔支气管败血波氏杆菌是引起兔呼吸道疾病的主要病原菌,分离菌多重耐药,耐药率较高,检测到的耐药基因与耐药表型相符.     

中草药对细菌耐药质粒的消除作用研究

动物养殖中常见病原菌对抗菌药物的耐药性呈逐年上升的趋势,引起了广大科研工作者的极大关注。病原菌耐药性的产生主要与质粒有关,质粒能够将耐药基因传递给环境中的其他细菌,进而引起多重耐药菌株的出现。本文就细菌耐药现状、细菌耐药性与质粒关系、中草药对细菌耐药质粒的消除效果、中草药消除耐药质粒的机理、存在的问题、中草药对耐药质粒消除的展望这些方面进行简单综述。     

兽药环境风险评估研究进展

随着畜禽集约化养殖数量增加,兽药被广泛用于治疗疾病或作为促生长剂添加到动物饲料中,中国2010-2017年兽用抗菌药的销售量从31 500 t增长到56 800 t。兽药的不合理使用、畜禽养殖过程中废弃物处理不当以及药物经过动物机体代谢后以原形药或代谢物随粪尿排出体外是兽药造成环境污染的主要原因。兽药进入环境后发生迁移转化造成了严重危害,包括抗生素耐药菌或耐药基因的产生、兽药在动植物源性食品和饮用水中的暴露间接影响人类健康、对非靶标动物的生态毒性等。作者就兽药在环境中的暴露、转归及对生态环境的主要影响进行了论述,并对药物的环境风险评估的重要性进行了阐述,针对降低兽药环境风险的措施提出了建议,以引起人们对兽药环境风险评估的关注和重视。     

Increase of bacterial resistance in human medicine by resistance genes of bacteria from meat supplying animals

Two different groups of bacteria carrying genes encoding for resistance to antibiotics may be transmitted from animals to humans via food products: a.) obligate infectious agents (enteric pathogens, e.g. Salmonella enterica spp., Campylobacter spp., EHEC) and b) facultative pathogenic species (e.g. E. coli, enterococci). Thus far, it is unknown whether genes encoding for resistance to antibiotics from these bacteria may be transferred to bacteria in normal flora of the host. The transfers of genes encoding for resistance to vancomycin from animal sources to the mucosa of humans has been suggested. Thus, there is a threat that these plasmid-encoded resistance genes may also be transferred to other gram-positive organisms present in the human flora. Vancomycin is the antibiotic in reserve for treatment of infections caused by oxacillin (methicillin) resistant strains of S. aureus and by strains of pneumococcus resistant to penicillin.     

河北省犊牛腹泻大肠杆菌致病性及耐药性分析

为确定河北省犊牛腹泻大肠杆菌的致病性与耐药性,本研究对2018年1月至2019年6月期间从河北省石家庄、保定、承德、唐山、廊坊的部分肉牛场腹泻犊牛样品中分离到的50株大肠杆菌进行了致病性试验、药物敏感性试验、毒力基因和耐药基因检测。结果显示:50株分离菌均对小鼠具有致病性,致病菌占比100%(50/50)。毒力基因fyuA、irp2、eaeA、ler检出率分别为68.0%、66.0%、34.0%、34.0%。50株分离菌均对15种抗生素中的2种及以上表现为耐药,对10种及以上抗生素耐药的菌株占比达34%(17/50);分离菌对土霉素、磺胺对甲氧嘧啶、磺胺间甲氧嘧啶、替米考星4种药物表现为高度耐药,耐药率分别为90%、90%、94%、100%。除四环素类tetD基因检出率为0外,其它耐药基因均有检出,其中四环素类tetC、氨基糖苷类aadA1、喹诺酮类gyrA、gyrB基因检测率高达100%。试验的50株大肠杆菌均具有较强的毒力和多重耐药性。本研究为河北省大肠杆菌所致犊牛腹泻病的防治提供了实验依据。     

Human health aspects of antibiotic use in food animals: a review

Antibiotic use not only selects for resistance in pathogenic bacteria, but also in the commensal flora of exposed individuals. Veterinary surgeons regularly prescribe antibiotics for food animals to treat bacterial infections just as doctors do for human patients. In addition, however, animal feeds contain added antibiotics not for therapy but for economic reasons: to enhance the growth rate of these animals. Several of the antibiotics used as growth promoters are analogues of and fully cross resistant with important antibiotics used in human medicine. As a result of this high exposure to antibiotics, the prevalence of resistant bacteria in the faecal flora of these animals is high. These resistant bacteria can be directly and indirectly, via foods of animal origin, transferred to humans and either colonize the human intestinal tract or exchange their resistance genes with commensal bacteria of humans. As the intestinal flora functions as a reservoir of resistance genes for pathogenic bacteria and because many bacterial species of the intestinal flora are potential pathogens, the efficacy of antibiotic therapy in human medicine may be jeopardized.     

Resistance to various antibiotics of Salmonella and Escherichia coli isolated from registrable farm feeds

Resistance to 20 antibiotics of 128 Salmonella and 97 Escherichia coli isolates from various registrable farm feeds was determined. A high frequency of comparatively low levels of resistance was found in both the Salmonella and E. coli isolates. This, together with an elevated frequency of multiple resistance, indicates that problems related to an effective transfer in bacterial populations of resistance to certain antibiotics are a distinct possibility. The addition of antibiotics, such as penicillin and tetracyclines, to animal feeds can create conditions for rapid selection amongst bacteria resistant to antibiotics. The numbers of resistant bacteria in the animal environment may be increased and may lead to the development of veterinary and human health problems from the possible transfer of antimicrobial resistance from animal pathogens to human pathogens or spreading in the human population of animal pathogens resistant to antibiotics. There is a need for caution in the use of antibiotics, particularly in animal feeds. Extended survey of, and epidemiological research on, farm feeds, manufacturing mills and animal production units are emphasized.