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Antimicrobial Resistance

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抗微生物耐药性(AMR)是微生物(包括细菌,真菌,病毒和寄生虫)抵抗抗菌药物(例如抗生素,抗真菌性,抗病毒药物,抗病毒药物,抗原药和暂量)的杀戮能力的能力。

尽管AMR融合了所有类微生物对抗菌治疗的抗性,但研究的主要重点一直在于细菌的抗生素耐药性。这是因为细菌感染负责大部分社区获得性和医院感染。与其他微生物相比,可用于研究耐药机制的分子工具更加完善,而且抗菌类别的数量更大,可提供更大的范围,可用于研究动作和耐药模式,这使得这一事实更加复杂。


Therefore, in the rest of this article, we are going to focus on antibiotic resistance in bacteria.

节快速链接

抗菌素抗性背后的科学
抗菌素抵抗发展和扩散的驱动因素
测试抗菌素耐药性
AMRprevention
抗菌素的替代品


抗菌素抗性背后的科学


抗生素分为两个大型类别,噬抑制性杀菌性,并通过多种行动进行工作,包括:

- 抑制细胞壁合成(β-内酰胺,万古霉素)
- 抑制蛋白质合成(氨基糖苷,四环素,氯霉素,大花环)
- 细胞膜的改变(多碳素)
- Inhibition of nucleic acid synthesis (quinolones, metronidazole, rifampicin)
- 干扰代谢(磺酰胺,甲氧苄啶)

In order to be resistant, a bacterium must be able to work around or prevent the action of antibiotics. This they achieved by a number of routes, including:

防止抗生素以足够高的浓度达到靶标
- 外排泵从细胞中抽出抗生素

- 降低膜渗透性可防止抗生素进入
- Enzymes destroy the antibiotic, e.g. β-lactamase against penicillin
- 酶修饰抗生素,添加抑制其活性的化学基团

修改或绕过抗生素作用的靶标
- 生产可以使用的替代蛋白,而不是由抗生素靶向的蛋白
- 改变抗生素的靶标,以免它与之相互作用

To achieve the resistance mechanisms described, the bacterium requires the correct tools (proteins) for the job, and that requires the正确的基因


AMRmay arise naturally as a result ofgenetic mutations或复制过程中发生的“错误”。细菌还能够通过称为称为其他细菌的遗传物质水平基因转移


基因的水平转移可以通过三种机制发生,转型,transductionconjugation。当细菌从周围环境中占据自由DNA时,就会发生转化。该DNA可能是质粒的形式。在转导中,细菌受到称为噬菌体的病毒攻击,可以将自己整合到细菌基因组中。当他们从宿主基因组中移动自身繁殖时,他们也可以与宿主DNA一起进行。因此,当它们整合到新的宿主基因组中时,它们会在细菌之间渡轮细菌基因,其中一些可能赋予抗生素耐药性。结合是细菌的“性”版本。性pili是在细菌细胞之间形成的,它们通过它们交换遗传物质。


在正常条件下,赋予对抗生素耐药性的突变或添加遗传物质可能没有任何益处,在某些情况下,由于再现额外的遗传物质的额外能量负担,获得抗药性基因的生物可能会降低。因此,他们可能会从人口中丢失,甚至被选为反对。但是,在存在抗生素的情况下,图片发生了变化。那些具有抗药性的人具有选择性的优势,能够持续和复制,传递对下一代的抵抗,而易感竞争者则被杀死。这积极的选择drives the spread of antibiotic resistance through a population in the face of antibiotic exposure.


Altering bacterial mode of growth can also confer resistance to antibiotic treatment. Slowed growth rates, sometimes called持续细胞, mean that antibiotics that rely on interrupting cell replication are less effective. Bacterial生物膜还提供防止抗生素作用的保护。生物膜是一个结构化的细菌群落,其中有一个自制的水合聚合物基质,并带有养分获取和废物处理的通道。该结构提供了物理保护,因为抗生素可能难以到达发达的细菌生物膜的心脏。细胞复制通常在生物膜的生长模式下放慢速度,该模式也可以保护不受细胞周期依赖性作用。


当微生物对多种药物具有抗性(称为)时,就会出现严重的问题multidrug resistance。这可能是因为单个电阻机制赋予对多种药物的耐药性,或者如果获得了多种抗性基因,单一或组合。


AMRis present inevery country in the world。Approximately 700,000 deaths per year globally are attributed to AMR, but this figure is predicted to rise to到2050年1000万,引起重大的全球关注。因此,减少AMR的发生并防止其扩散对于保护人和动物至关重要。


抗菌素抵抗发展和扩散的驱动因素


虽然AMR可能自然发生,但有很多可以帮助促进AMR发生和传播的因素

不适当处理受污染的水和废物pharmaceutical manufacturing植物可以看到水排入被抗生素污染的环境中。尽管水本身可能不会伤害您,但它会暴露于环境中的细菌抗生素,促进耐药性通过细菌种群的发展和传播。如果这些抗性菌株与动物接触,可能会感染动物,例如通过消费,其他食品的污染或游泳。



下水道is another key source of motivation for bacteria to develop antibiotic resistance. When humans or animals are given antibiotics, not all of them will be processed by the body, and the remainder will be排出粪便。这些“剩下的”抗生素暴露于我们的下水道系统中的微生物的混合锅,或者在动物的环境和同居者的情况下,暴露于抗生素中,施加了压力以获得耐药性。虽然下水道治疗消除了许多不需要的污染物,但目前不包括抗生素。因此,“处理过的下水道”,被排出,回收,用于灌溉或肥料,可能含有抗生素。找到有效且可持续的拆除方法已成为一个积极的研究领域。


许多food-producing animalsare prophylactically treated with antibiotics to try and keep them healthy. However, this means that the naturally occurring bacteria in their gut, which can include species such asStaphylococcus aureus, are exposed to antibiotics. This promotes the survival and spread of resistant strains which may then contaminate the environment they live in, personnel that handle them and the food produced from them. If contaminated feces enter the water or are used as fertilizer, crops too can become contaminated.


诸如卫生和拥挤不良之类的因素只是人类,动物和环境之间抗菌抗性的条件,因此采用有效的预防措施是关键。


测试抗菌素耐药性


There are a variety of testing strategies that can be performed, bothphenotypic and molecular, that enable scientists to determine which antibiotics a given strain of bacteria is sensitive to and which it is not.


灵敏度
testing, in which a lawn of the bacterial strain of interest is cultured on agar plates onto which antibiotic-infused discs are placed has been a popular phenotypic screening technique for many years and remains the gold standard. The larger the area of clearance around a disc, the more sensitive the strain is to that particular antibiotic.微流体设备designed to look at the minimum inhibitory concentration of antibiotics needed to kill a strain have been used to the same end. However, the downside of methods requiring culture is the length of time it can take to isolate, culture and then test the sensitivity of a strain, often taking 48 hours of more to draw a conclusion. When treating aggressive infections this can be too long.


主要进步在过去的十年中whole genome sequencing(WGS) take its place in the study and fight against AMR. WGS enables known and unknown AMR-related genes to be identified and their propagation through a population monitored. Multiple mutations or genes may confer the same resistance which is not typically differentiated by phenotypic methods. WGS provides a much more detailed picture of resistance progression and spread and has enabled the chains of resistant infection spread to be mapped precisely, which is helpful in monitoring studies.


放大测试
, such asPCRRT-QPCR和LAMP分析可以为检测抗性基因提供快速而特定的解决方案。但是,他们只能通过测定方法识别已知的靶标和进一步的突变,使其无效。


杂交分析
, such as arrays, fluorescent原位hybridization (FISH) and line probe assays (LPAs), rely on the hybridization of probes to target DNA sequences which can then be detected using techniques such as fluorescence. As with amplification-based tests, they require prior knowledge of target mutations and will not identify any novel AMR-conveying targets.


Immunoassays
, 包括lateral flow tests酶联免疫吸附测定(ELISAs), can be useful for AMR detection too. The binding of antibodies either to the target gene or gene product can be then be used to detect their presence, usually via conjugation to a visible indicator.


有一个真正的努力,朝着快速的护理测试进行,横向流和一些测定法microfluidic devices借用自己,使临床医生能够克服一些当前的抗菌管理挑战,并适当规定。


资金机会are vital in facilitating research to improve the diagnostics available, promoting the development of affordable, accurate, fast and easy-to-use tests for bacterial infections.


无论使用哪种技术细菌隔离和鉴定, and which methods of resistance testing are employed, it is important that bacteria are适当培养安全处理。好的无菌技术is essential to protect yourself and your sample.


AMRprevention


采取步骤以防止AMR的进一步发展和传播至关重要。简单的卫生预防措施,例如洗手,适当处理食品并使用清洁水可以帮助减少抗药性感染的可能性。但是,它们并不能避免首先在驱动AMR发展的微生物上施加的抗生素暴露所带来的压力。


限制细菌暴露于抗生素很重要,并且有许多措施可以提供帮助。


抗生素管理
- 衡量和改善临床医生处方并使用患者使用的抗生素的努力是减少AMR的核心。这包括使用狭窄而不是宽光谱抗生素来更具体地靶向感染,仅在必要时才使用,并且仅在必要时才使用。责任并不全都落在医务人员和兽医身上,公众还可以发挥自己的作用,以确保他们(或他们的动物)仅在建议的时间以规定的剂量服用开处方的抗生素,并完成课程。


减少预防性使用
抗生素,尤其是在食品动物行业中,是防止人体自己的细菌和与含抗生素的粪便接触的抗生素的关键。


测量procalcitonin, the precursor to the hormone calcitonin, via immunoassay has been shown to be a good indicator of bacterial infection where levels become elevated. These indicators援助治疗决策对于临床医生,因此是抗生素管理。如果怀疑感染或败血症的进展是一种风险,抗生素管理可以促进适当的使用,并旨在减少抗生素疗法的天数。快速多重PCR还将用于区分细菌和病毒感染以引导抗生素处方。


Whilst we may still not have an answer to antibiotics entering the environment from domestic effluent, stricter monitoring and enforcement of the废水由制药公司排放可以帮助防止抗生素进入环境和供水系统。


AMR监视programs are vital in keeping diagnostics up-to-date as new AMR targets emerge and identifying patterns from which remedial plans can be actioned.人工智能is also playing its part, helping to monitor microbes in real time and predict AMR and antibiotic susceptibility.


Scientists are working on ways to从受污染的土壤中清除抗生素使用能够将抗生素分解为生物药物的工程细菌菌株。从废水中删除仍在证明具有挑战性,但研究人员是tackling the issue


抗菌素的替代品


With the frequency with which bacterial strains are exhibiting resistance growing, even to antibiotics of last resort, scientists are looking for新药备择方案to antimicrobial treatment.


The discovery of “新的抗生素” however is not trivial, compounded by财务和法规障碍, leading scientists to look elsewhere for solutions.


噬菌体疗法
被探讨为一种在1928年发现青霉素之前治疗细菌感染的方法,此后几乎被废弃了。由于缺乏获得西方抗生素的机会,苏联国家继续在该地区进行研究。现在,随着我们努力用抗生素对抗感染,兴趣再次达到噬菌体疗法。尽管噬菌体能够感染和破坏细菌,但它们是物种,甚至是特定于菌株。另外,某些细菌预先存在免疫力的潜力意味着靶向噬菌体治疗并不是一个微不足道的过程,并且必须针对个体感染量身定制,从而使其成本高昂且冗长。


CRISPR-CAS9
has garnered much attention in the field of gene therapy, however it may also have a role in antimicrobial therapy. Currently more work is required.


抗菌肽
到目前为止,成功的成功有限,但是合成肽和合成膜活性剂可能会提供未来的探索途径。


Antibody therapy
是一种昂贵但高度特定的替代方案,但已部分实施。


一氧化氮
是一种天然抗菌素,在我们对病原体的免疫反应中起着至关重要的作用。因此,科学家正在探索如何将其纳入治疗方案。


指某东西的用途抗生素抗性破坏者(ARB)也正在探索,其中涉及与抗生素失败的非抗生素药物共同管理。


In the meantime, we all have our part to play in the prevention of AMR development and spread.

Meet the Author
Karen Steward博士
Karen Steward博士
高级科学作家
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