共查询到19条相似文献,搜索用时 125 毫秒
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整合子与细菌多重耐药性 总被引:2,自引:1,他引:2
细菌的多重耐药已成为临床治疗的难题,其耐药机制、耐药基因的传播与转移是近年来研究的热点。近来研究表明,细菌中存在一种能捕获和表达基因的遗传单位———整合子在细菌获得耐药机制中起了重要作用。整合子编码一个整合酶负责基因盒在重组位点attⅠ和attC上的插入及切除,同时整合子也提供一个启动子(Pant)负责基因盒耐药基因的表达。整合子携带着重组的基因盒插入到转座子或接合质粒中,在不同的细菌间运动而传播耐药性,同时一个整合子可以捕获多个基因盒,对细菌多重耐药的形成起重要作用。现就整合子的结构、类型、基因盒的种类与表达及其与细菌多重耐药性的有关研究进行综述。 相似文献
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《畜牧与兽医》2020,(11)
细菌耐药性是威胁人类健康的全球问题,对于耐药性传播机制的研究受到广泛关注。目前已知的可以介导细菌耐药性/耐药基因水平转移的机制包括转化、接合转移和转导等,其中质粒等可转移元件在细菌耐药性传播过程中发挥的作用已经得到共识,而对于噬菌体介导的耐药性转导作用及机制关注较少。噬菌体是一种感染细菌的病毒,其在生态环境中广泛存在,其对细菌基因组的多样性和细菌的进化发挥了重要作用。本文综述了噬菌体的类型、前噬菌体分布、噬菌体与耐药基因的共存现象、噬菌体介导的耐药基因转移证据及其分子机制、噬菌体对肠道菌群的影响等方面,指出有必要重新认识噬菌体对于细菌耐药性发展的重要性,并对噬菌体/耐药性的未来研究方向进行了展望。 相似文献
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一、细菌的耐药机理抗生素广泛用于临床后,细菌可在数月或数年间对其产生耐药性。细菌基因的突变是导致细菌产生耐药的根本原因,在一个感染周期中,处于对数生长期的细菌突变率约为1/107,如该突变可对抗生素耐药,将使细菌在敏感菌被杀灭后迅速繁殖成为优势菌。在抗生素的选择性压力下,突变率可成百倍增加,并极易发展为多重耐药。耐药性的迅速扩散通常由携带抗生素耐药性的质粒在不同种属的细菌间穿梭和复制所导致,高度耐药的细菌常同时涉及以下几种耐药机理。1.主动泵出机理药物在达到靶位发挥作用之前,必须通过G-菌的外膜和内膜、G 菌胞壁… 相似文献
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整合子-基因盒系统与细菌耐药性 总被引:1,自引:1,他引:0
整合子 基因盒系统在细菌中能捕获外来耐药基因,是细菌耐药性传播的机制之一。整合子携带着重组的基因盒插入到转座子或接合质粒中,在不同的细菌间运动而传播耐药性;同时一个整合子可以捕获多个基因盒,使细菌产生多重耐药性,细菌产生多重耐药性的能力取决于它们捕获新的抗生素耐药基因的能力。整合子是一种遗传因素,编码一个位点特异重组酶(IntI)负责基因盒在 attI位点的插入,同时整合子也提供一个启动子(Pant)负责基因盒耐药基因的表达。文章对整合子 基因盒的结构、种类、耐药基因盒的表达及耐药基因的获得和传播进行综述。 相似文献
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抗生素对畜禽养殖业的发展具有重大作用,但动物机体只能吸收少量抗生素,大部分随机体代谢排出体外。随着抗生素的大量应用,动物体内诱导出大量耐药菌和耐药基因,这些耐药菌和耐药基因随粪便排出机体进入环境。环境中的土著菌在抗生素的选择压力及耐药基因横向转移机制下获得耐药性,并向其他菌群扩散耐药基因。耐药基因在环境中的传播有可能对食品、水源和公共健康造成威胁。文章综述了抗生素的耐药性情况、耐药基因的检测方法、抗生素及耐药基因的去除方法等,以期为后续研究提供参考。 相似文献
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Resistance to antibiotics in the normal flora of animals. 总被引:14,自引:0,他引:14
The normal bacterial flora contains antibiotic resistance genes to various degrees, even in individuals with no history of exposure to commercially prepared antibiotics. Several factors seem to increase the number of antibiotic-resistant bacteria in feces. One important factor is the exposure of the intestinal flora to antibacterial drugs. Antibiotics used as feed additives seem to play an important role in the development of antibiotic resistance in normal flora bacteria. The use of avoparcin as a feed additive has demonstrated that an antibiotic considered "safe" is responsible for increased levels of antibiotic resistance in the normal flora enterococci of animals fed with avoparcin and possibly in humans consuming products from these animals. However, other factors like stress from temperature, crowding, and management also seem to contribute to the occurrence of antibiotic resistance in normal flora bacteria. The normal flora of animals has been studied with respect to the development of antibiotic resistance over four decades, but there are few studies with the intestinal flora as the main focus. The results of earlier studies are valuable when focused against the recent understanding of mobile genetics responsible for bacterial antibiotic resistance. New studies should be undertaken to assess whether the development of antibiotic resistance in the normal flora is directly linked to the dramatic increase in antibiotic resistance of bacterial pathogens. Bacteria of the normal flora, often disregarded scientifically, should be studied with the intention of using them as active protection against infectious diseases and thereby contributing to the overall reduction of use of antibioties in both animals and humans. 相似文献
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交叉耐药性(cross resistance)是指细菌耐药性进化过程中,对单一药物产生耐药性的同时,也会对结构或作用机理相似的药物产生耐药性的现象。附属敏感性(collateral sensitivity)则指细菌对某一药物敏感性下降时,反而对其他药物敏感性提高的现象。在抗菌药物的持续压力下,细菌会选择性地发生交叉耐药性或附属敏感性两种不同的进化路径。在后抗生素来临的时代背景下,科学家提出了一种新颖的治疗思路:借用细菌对药物的附属敏感性特征进行治疗方案的设计或优化。然而,细菌附属敏感性进化是极为复杂的过程,其发生概率不稳定且规律性不强。为更好地认知细菌附属敏感性的进化规律及应用前景,本文对影响细菌附属敏感性的关键因素及附属敏感性的产生规律进行综述,并以此提出目前研究的不足以及未来发展的可能方向。 相似文献
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建立人离体肠道模拟模型,研究微量环丙沙星对人源肠道大肠杆菌和粪肠球菌敏感性的影响,进而用聚合酶链反应法扩增耐药菌的gyrA基因的耐药决定区,并分析其耐药机制。结果显示,大肠杆菌连续培养后存活菌株对微量环丙沙星耐药,此耐药菌对其他抗菌药敏感;粪肠球菌绎连续培养,对环丙沙星和其他抗菌药物仍敏感;耐药大肠杆菌的gyrA基因发生突变,248位碱基由C变为T,259位由G变为T,相应地,该基因编码的蛋白质在83位的丝氨酸和87位的天冬氨酸分别改变为亮氨酸和酪氨酸。研究表明,微量环丙沙星对人肠道菌群具有不同的选择作用,能诱导大肠杆菌产生耐药性。这为动物源食品中环丙沙星残留的安全性评价提供了试验依据。 相似文献
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Cummings TS 《Preventive veterinary medicine》2006,73(2-3):209-212
There has been renewed concern in recent years about the use of antibiotics in food animal production and the potential risk it may pose to public health due to transfer of antibiotic resistance factors via the food supply. Although a legitimate concern, it bears reminding that this debate is not new. It has been ongoing for decades, yet there is still no documented case of human treatment failure due to antibiotic resistant bacteria acquired from USDA-inspected meat and poultry. This fact strongly suggests that the issue is not the imminent threat as has been portrayed by certain individuals or advocacy groups. The poultry industry as a whole has been using antibiotics responsibly for several decades, and there are strong beneficial arguments for their continued use. Responsible public policy demands a science-based approach be utilized in the decision making process before attempting to restrict or remove certain products due to overestimated risks. Part of this scientific review should include antibiotic use data, however this information has definite limitations and shortcomings which need to be understood before attempting to make any valid antibiotic resistance associations. 相似文献
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On a farm with therapeutic problems and unsatisfactory management conditions, the occurrence of antibiotic resistance and transferable antibiotic resistance has been studied in E. coli isolated from calves which were 5 and 30 days old. Strains with resistance to up to seven antibiotics as well as transferable resistance against up to five antibiotics were recorded. On an average, 4.2 strains with different patterns and 4.0 different strains with transferable resistance were isolated from each calf. The corresponding figures previously found for healthy control calves were 1.6 and 1.1 strains, respectively. Resistance and transferable resistance were most common against sulphonamide and penicillin. 相似文献
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Klein G 《Berliner und Münchener tier?rztliche Wochenschrift》1999,112(10-11):365-369
Food of animal origin has been considered as an important vector for the transfer of antibiotic resistances from animal to man. Such a transfer is possible by three ways: through antibiotic residues in food, through the transfer of resistant foodborne pathogens or through the ingestion of resistant parts of the original food microflora and resistance transfer to pathogenic microorganisms. A literature review and own investigations were performed in order to asses the potential impact of antibiotic resistance in food on the consumer health. In the first report Salmonella and Staph, aureus isolates were screened for their antibiotic resistance profiles. As a result it could be shown that residues in fresh meat or milk are quantitatively of minor interest. The resistance profile of Salmonella depended on the origin (pig or poultry), but only serovars could be identified which are generally not responsible for systemic infections. Staph. aureus isolates did not show any resistances relevant for human medicine. In these cases food can be considered as safe concerning its role as a vector for antibiotic resistances. However, a resistance monitoring seems to be necessary. 相似文献
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猪、禽安全生产中主要病原菌耐药性检测及控制技术研究进展 总被引:1,自引:0,他引:1
国内外研究及本课题组的调查表明,猪、禽养殖中主要病原菌的耐药性日趋严重,细菌产生耐药性的机理复杂多样.而药性的检测技术在常规药敏试验的基础上,国内外学者及本课题组已将质粒指纹图谱,PCR,SSCP,核酯探针等分子生物学技术用于耐药性检测.本文还综述和提出了加强兽药管理、制定用药规范、研究质粒消除技术、开发出针对性疫苗、益生素、噬菌体制剂等一系列耐药性的控制技术. 相似文献
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Lynn M. Pezzanite Dean A. Hendrickson Steven Dow Jason Stoneback Lyndah Chow Danielle Krause Laurie Goodrich 《Equine veterinary journal》2022,54(1):24-38
Antibiotics have been injected intra-articularly by equine veterinarians for decades, either prophylactically when other drugs are administered for osteoarthritis or therapeutically to treat septic arthritis. This route of administration has also more recently gained attention in human orthopaedic clinical practice, particularly as an alternative to systemic antibiotic administration to treat infections following prosthetic arthroplasty. While the rationale for injecting antibiotics intra-articularly has been largely focused on achieving high local drug concentrations, there has been relatively little focus on pharmacokinetic parameters of antibiotics administered by this route, or on the potential for local toxicity. The increasing incidence of antibiotic resistance in veterinary and human medicine prompts reconsideration of off-label antibiotic usage and evaluation of evidence-based dosing strategies. The purpose of this review was to summarise the current literature describing intra-articular antibiotic usage, including specific studies where pharmacokinetics, potential safety and toxicity have been evaluated. This review will advance practitioners’ understanding of the use of intra-articularly administered antibiotics, including the overall pros and cons of the approach. 相似文献
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通过给牦牛投喂硫酸头孢喹肟(CEF)、盐酸二氟沙星(DIF)和黄曲霉毒素B1(AFB1),并进行瘤胃微生物宏基因组测序,旨在揭示这3种外源性刺激因子对抗生素抗性基因(ARGs)种类、抗性类型、抗性机制等的影响,对于深入研究微生物抗性组特征和抗性机制具有重要价值。选取15头牦牛,随机分5组。Cef组和Dif组分别根据说明书推荐剂量按体重计算、灌服CEF 1 mg·kg^-1和DIF 1 mL·kg^-1;E1组和E2组分别按采食量投喂AFB120、60μg·kg^-1;C组为对照组。处理7 d后,采集瘤胃液,提取DNA,Illumina HiSeq测序,对reads counts进行标准化得到TPM值,并进行方差分析。结果显示,对照组共获得132种ARGs,分属30种抗性类型,其中,四环素类tetQ和tetW基因丰度较高;Cef组tetW基因丰度增加(P<0.05),Dif组tetQ丰度增加(P<0.05);Cef组四环素类和头孢菌素类抗性基因丰度增加(P<0.05),Dif组四环素类和氨基香豆素类抗性基因丰度增加(P<0.05),E1组氨基香豆素和青霉烯类抗性基因丰度增加(P<0.05),E2组青霉烯类、头孢菌素类等9类抗性基因丰度均增多(P<0.05);Dif组Erm基因23S核糖体RNA甲基转移酶丰度增加(P<0.05),E2组中ATP结合盒超家族等3种抗性机制相关基因的丰度增加(P<0.05);3种因子均显著增加四环素类ARGs宿主的种类。结论:瘤胃是蕴含丰富ARGs的储藏库,其中,四环素类抗生素抗性基因tetQ和tetW是主要的ARGs。不仅CEF和DIF使部分ARGs的种类、抗性类型以及耐药机制相关酶等的丰度升高,增加瘤胃微生物的耐药性,而且AFB1也具有类似作用,且高剂量AFB1对抗性类型的影响范围较抗生素大。这3种因子还导致携带四环素类ARGs宿主微生物的种类数量增加,从而强化横向转移机制,加快ARGs传播,增强微生物对四环素类的耐药性。 相似文献