肠道噬菌体与机体健康的研究进展及临床应用

肠道微生物被誉为人类"隐形的器官", 对维持机体健康有着重要作用, 涵盖细菌、病毒、真菌等成分, 其中噬菌体更是肠道病毒组的主要成员。随着近年来宏基因组的应用和细菌耐药性的增加, 肠道噬菌体对机体健康的影响以及噬菌体疗法的临床应用成为了国内外研究的重要方向。本文围绕国内外肠道噬菌体研究现状进行讨论, 探讨噬菌体对机体健康的影响并结合噬菌体疗法的临床应用做一综述。     

噬菌体在控制细菌感染中的临床应用

近年来，由于多重耐药菌感染引起新的威胁，而新型抗生素的研发进展缓慢且成本昂贵，使得噬菌体被重新考虑作为抗生素的替代疗法。本文旨在阐述噬菌体疗法在控制人类常见病原菌感染领域的研究进展以及开发噬菌体的新策略，并总结描述多种方法学理念，以促进对其进一步研究，早日使噬菌体作为治疗或预防药物应用于临床实践中。     

幽门螺杆菌感染患儿107例的微生态辅助治疗疗效观察

<正>大量研究已证实幽门螺杆菌(Hp)与慢性胃炎、消化性溃疡等密切相关。目前质子泵抑制剂联合两种抗生素的三联疗法治疗仍是抗Hp感染的主要方法,但近年来随着抗生素的广泛使用,幽门螺杆菌的耐药性逐年上升,使质子泵抑制剂三联疗法在幽门螺杆菌感染中的疗效逐年下降。因此近年提     

中国噬菌体的早期历史文献研究

本文对中国噬菌体早期发展进行了溯源，挖掘历史细节，找到了中国噬菌体研究及应用的目前已知的首个、首篇、首例等资料。中国噬菌体初识认知最早可追溯至1923年，并随着研究的深入而逐渐发展，1934年左右首次使用噬菌体疗法成功治愈了细菌性痢疾患者和五例伤寒病患者。结合笔者已发表的“20世纪50年代中国噬菌体研究的成就与不足”一文，共同绘制出我国噬菌体研究的发展渊源脉络图。本文主要目的是普及中国噬菌体早期研究历史知识，提高噬菌体的大众认知，填补公众对于中国噬菌体研究历史的认知空白，扩大中国噬菌体的影响力及知名度，为我国噬菌体领域基础研究的应用提供参考。     

抗病毒抗生素17997体外联合用药研究

目的：研究抗病毒抗生素17997与临床应用的抗病毒药物－阿昔洛韦、病毒唑及入干扰素α的联合用药抗单纯疱疹病毒I型的作用。方法：应用VERO细胞培养法及MTT染色法进行实验及观察结果,以Calcusyn软件计算,分析结果。结果：实验结果显示抗生素17997与阿昔洛韦、病毒唑及人干扰素α在ED50、ED70（或ED75）、ED90条件下均有协同抗单纯疱疹病毒I型的作用,表现在降低ED50值及联合指数＜1。仅抗生素17997与人干扰素α联合组,在ED90条件下,表现为相加或拮抗作用。结论：抗生素17997抗疱疹病毒活性强,在多次单纯疱疹病毒I型实验感染的兔多膜炎模型上显示抗病毒疗效。本研究结果为抗生素17997临床联合用药提供实验依据。     

噬菌体药物开发及质控研究进展

噬菌体治疗作为抗生素治疗细菌感染的替代方法之一,近年来受到越来越多科学家们的关注,该法主要用于针对由耐药菌及多重耐药菌(Multi-drug resistant,MDR)引起的公共卫生安全问题。如今,噬菌体在农业和兽医治疗方面及其在西方国家用于人类治疗方面越来越受到重视,过去几十年西方世界进行了许多临床试验和治疗探索,并且国外某些授权药店正在销售人用噬菌体药物。但噬菌体用于人类治疗时仍然存在一些问题,如噬菌体的高度特异性限制了其应用范围和噬菌体制剂管理法规不完善使得其不能进行规模化生产等。本文结合我国现行药典关于生物制品生产、制备及质量控制要求和欧洲药品管理局(The European Medicines Agency, EMA)近年来以噬菌体治疗药物批准途径的探索为参照,着重对噬菌体库构建与控制、噬菌体制备与质控和临床前测试等进行分析。     

噬菌体抗生素研究近况

目前美国 4家公司正试图发展噬菌体抗菌疗法 ,他们正在研制针对一些重要的病原菌 ,如耐万古霉素肠球菌 (VRE)、耐甲氧苯青霉素金黄色葡萄球菌 (MRSA)和食物传播的病原菌 (沙门菌 )的噬菌体 (或噬菌体混合物 )。　　Intralytix公司目前正在进行针对 VRE和 MRSA的项目 ,他们研究的目标是噬菌体混合物 ,这种方法能减少耐药。通过针对多个菌株和 /或应用杀菌机理不同的多种噬菌体 ,治疗不大可能产生耐药病原体。　　Biophage公司最终的研究目的也是人类健康应用 ,但近期研究是针对农业。公司处于后期市场前研究的两种制品是抗大肠杆菌和…     

噬菌体疗法

大量耐多种抗生素细菌的出现使抗生素化疗具有一定局限性,因此有必要重新考虑天然存在的噬菌体的应用。噬菌体治疗霍乱有效,对痢疾与伤寒疗     

幽门螺杆菌疫苗研究的现状及展望

<正>幽门螺杆菌(Helicobacter pylori,Hp)是全世界人群感染最广泛的致病菌,已确认Hp感染是慢性胃炎、消化性溃疡的主要原因,与胃癌及胃黏膜相关组织淋巴瘤的发病也密切相关。Hp感染的防治是临床亟待解决的问题。现今的抗Hp感染治疗方案是以铋剂或质子泵抑制剂联合应用抗生素的“三联”或“四联”疗法,但由于药物的不良反应及耐药菌株的迅速增加使其应用受限。近10年来的研究表明:Hp疫苗有可能成为控制这一全球性感染的更有效的方法。     

抗菌药物研究新方法

为了加快药物研发进程,解决日益严重的微生物耐药问题,众多新的技术方法被应用到抗菌药物研究领域:在发现药物靶点方面,比较基因组学研究方法和蛋白质组学研究方法得到广泛应用;在药物筛选方面,超微量抗生素,克服微生物耐药机制、抑制其毒力形成以及提高宿主免疫力等发挥辅助性作用的药物成为新的研究热点;同时抗菌药物的研究范围进一步扩大到噬菌体领域,能够直接杀伤病原微生物的噬菌体、噬菌体蛋白以及可以携带抗菌药物或致死性基因的噬菌体载体被成功用于治疗细菌性感染.本文综述了近年来在寻找新的药物靶点、探索新的筛选策略以及拓展新的研究领域方面所应用的一些新方法.     

Recent advances in bacteriophage-based therapeutics: Insight into the post-antibiotic era

Antibiotic resistance is one of the biggest threats to global health, as it can make the treatment of bacterial infections in humans difficult owing to their high incidence rate, mortality, and treatment costs. Bacteriophage, which constitutes a type of virus that can kill bacteria, is a promising alternative strategy against antibiotic-resistant bacterial infections. Although bacteriophage therapy was first used nearly a century ago, its development came to a standstill after introducing the antibiotics. Nowadays, with the rise in antibiotic resistance, bacteriophage therapy is in the spotlight again. As bacteriophage therapy is safe and has significant anti-bacterial activity, some specific types of bacteriophages (such as bacteriophage phiX174 and Pyo bacteriophage complex liquid) entered into phase III clinical trials. Herein, we review the key points of the antibiotic resistance crisis and illustrate the factors that support the renewal of bacteriophage applications. By summarizing recent state-of-the-art studies and clinical data on bacteriophage treatment, we introduced (i) the pharmacological mechanisms and advantages of antibacterial bacteriophages, (ii) bacteriophage preparations with clinical potential and bacteriophage-derived anti-bacterial treatment strategies, and (iii) bacteriophage therapeutics aimed at multiple infection types and infection-induced cancer treatments. Finally, we highlighted the challenges and critical perspectives of bacteriophage therapy for future clinical development.     

Bacteriophages: an appraisal of their role in the treatment of bacterial infections

Bacteriophages were first used successfully to treat bacterial infections a decade before penicillin was discovered. However, the excitement that greeted those initial successes was short-lived, as a lack of understanding of basic phage biology subsequently led to a catalogue of clinical failures. As a consequence, bacteriophage therapy was largely abandoned in the West in favour of the newly emerging antibiotics. Now, as the problem of antibiotic resistance becomes ever more acute, a number of scientists and clinicians are looking again at bacteriophages as a therapeutic option in the treatment of bacterial infections. The chances of success second time round would appear to be much better given our current extensive knowledge of bacteriophage biology following their important role in underpinning the advances in molecular biology. We also have available to us the experience of nearly 80 years of clinical usage in the countries of the former Soviet Union and Eastern Europe as well as a political climate that encourages sharing of that knowledge. This review outlines those features of bacteriophages that contribute to their utility in therapy and explores the potential for their re-introduction into Western medicine. An abundance of clinical evidence is available in the Soviet literature but much of this is technically flawed and a more realistic appraisal of the clinical value of phages can be obtained from animal studies conducted in the West. As interest in bacteriophages increases, a number of companies throughout the world have begun investing in phage technology and this has led to novel approaches to therapy, some of which will be discussed.     

Phage therapy: delivering on the promise

Bacteriophages are viruses that infect and, in many cases, destroy their bacterial targets. Within a few years of their initial discovery they were being investigated as therapeutic agents for infectious disease, an approach known as phage therapy. However, the nature of these exquisitely specific agents was not understood and much early use was both uninformed and unsuccessful. As a result they were replaced by chemical antibiotics once these became available. Although work on phage therapy continued (and continues) in Eastern Europe, this was not conducted to a standard allowing it to support clinical uses in areas regulated by the European Medicines Agency or the US FDA. To develop phage therapy for these areas requires work carried out in accordance with the requirements of these agencies, and, driven by the current crisis of antibiotic resistance, such clinical trials are now under way. The first Phase I clinical trial of safety was reported in 2005, and the results of the first Phase II clinical trial of efficacy of a bacteriophage therapeutic was published in 2009. While the delivery of these relatively large and complex agents to the site of disease can be more challenging than for conventional, small-molecule antibiotics, bacteriophages are then able to multiply locally even from an extremely low (picogram range) initial dose. This multiplication where and only where they are needed underlies the potential for bacteriophage therapeutics to become a much needed and powerful weapon against bacterial disease.     

A first step toward liposome-mediated intracellular bacteriophage therapy

Objectives: The emergence of antibiotic-resistant bacteria presents a severe challenge to medicine and public health. While bacteriophage therapy is a promising alternative to traditional antibiotics, the general inability of bacteriophages to penetrate eukaryotic cells limits their use against resistant bacteria, causing intracellular diseases like tuberculosis. Bacterial vectors show some promise in carrying therapeutic bacteriophages into cells, but also bring a number of risks like an overload of bacterial antigens or the acquisition of virulence genes from the pathogen.

Methods: As a first step in the development of a non-bacterial vector for bacteriophage delivery into pathogen-infected cells, we attempted to encapsulate bacteriophages into liposomes.

Results: Here we report effective encapsulation of the model bacteriophage λeyfp and the mycobacteriophage TM4 into giant liposomes. Furthermore, we show that liposome-associated bacteriophages are taken up into eukaryotic cells more efficiently than free bacteriophages.

Conclusion: These are important milestones in the development of an intracellular bacteriophage therapy that might be useful in the fight against multi-drug-resistant intracellular pathogens like Mycobacterium tuberculosis.     

Toward modern inhalational bacteriophage therapy: nebulization of bacteriophages of Burkholderia cepacia complex

Antibiotic-resistant bacterial infections have renewed interest in finding substitute methods of treatment. The purpose of the present in vitro study was to investigate the possibility of respiratory delivery of a Burkholderia cepacia complex (BCC) bacteriophage by nebulized aerosol administration. Bacteriophages in isotonic saline were aerosolized with Pari LC star and eFlow nebulizers, at titers with mean value (standard deviation) of 2.15 x 10(8) (1.63 x 10(8)) plaque-forming unit (PFU)/mL in 2.5-mL nebulizer fills. The breathing pattern of an adult was simulated using a pulmonary waveform generator. During breath simulation, the size distributions of the nebulized aerosol were measured using phase doppler anemometry (PDA). Efficiency of nebulizer delivery was subsequently determined by collection of aerosol on low resistance filters and measurement of bacteriophage titers. These filter titers were used as input data to a mathematical lung deposition model to predict regional deposition of bacteriophages in the lung and initial bacteriophage titers in the liquid surface layer of each conducting airway generation. The results suggest that BCC bacteriophages can be nebulized successfully within a reasonable delivery time and predicted titers in the lung indicate that this method may hold potential for treatment of bacterial lung infections common among cystic fibrosis patients.     

Bacteriophage Therapeutics: A Primer for Clinicians on Phage-Antibiotic Combinations

Multidrug-resistant organisms have caused a marked depletion of effective antimicrobials, and the narrow pipeline of antibiotics has demanded the need to find novel therapeutic alternatives including nonantibiotic agents. Bacteriophages (phages) are viruses that use the bacterial machinery to infect, replicate, and kill bacterial cells. Although a marked decline in their use was driven by the discovery of antibiotics, the era of antibiotic resistance has led to a resurgence of phage therapy into clinical practice. The term phage-antibiotic synergy (PAS) was coined just over a decade ago and described that sublethal concentrations of antibiotics could stimulate phage production by bacterial cells. Recent literature has described PAS and other encouraging interactions with various phage and antibiotic combinations against a variety of bacterial strains. The primary objective of this review is to discuss the positive interactions between phage and antibiotic combinations, with an emphasis on PAS, reductions in bacterial growth or minimum inhibitory concentrations, enhanced biofilm eradication, and alterations in the emergence of bacterial resistance. A peer-reviewed literature search was conducted (1890–2019) using the PubMed, Medline, and Google Scholar databases. Although more investigation is certainly needed, the combination of bacteriophages with antibiotics is a promising strategy to target organisms with limited or no therapeutic options. This approach may also foster the ability to lower the antibiotic dose and may reduce the potential for antibiotic resistance emergence during therapy.     

A freeze-dried formulation of bacteriophage encapsulated in biodegradable microspheres

With the emergence of widespread antibiotic resistance, there has been renewed interest in the use of bacteriophages. While their potency, safety and specificity have underpinned their clinical potential, to date, little work has been focussed on their formulation with respect to controlled release and/or passive targeting. Here, we show that bacteriophages selective for Staphylococcus aureus or Pseudomonas aeruginosa can be encapsulated into biodegradable polyester microspheres via a modified w/o/w double emulsion-solvent extraction protocol with only a partial loss of lytic activity. Loss of lytic activity could be attributed to the exposure of the bacteriophages to the water-dichloromethane interface, with the lyophilization process itself having little effect. The microspheres were engineered to have an appropriate size and density to facilitate inhalation via a dry-powder inhaler and fluorescently labeled bacteriophages were distributed entirely within the internal porous matrix. The release profile showed a burst release phase (55-63% release within 30 min), followed by a sustained release till around 6 h, as appropriate for pulmonary delivery. Despite the poor shelf-life of the formulation, the work is proof-of-concept for the formulation and controlled delivery of bacteriophages, as suitable for the treatment of bacterial lung infections.     

乳酸细菌噬菌体的检测及在发酵生产中的控制研究

噬菌体感染是乳制品发酵过程中乳酸细菌活性降低的常见原因,不仅影响乳制品质量,严重时会出现乳制品倒罐现象.此文介绍了乳制品发酵过程中感染乳酸细菌的常见噬菌体种类、来源和特征,讨论了目前常用检测此类噬菌体的方法,归纳了大规模乳制品发酵过程中控制噬菌体感染的途径和方法.     

抗生素诱导的细胞感受态与肺炎链球菌的耐药性

针对环境中的压力,细菌会采取不同的响应以维持自身的稳定。某些抗生素能够诱导肺炎链球菌转变为感受态细胞,提高细胞转化率,从而产生更适宜生存的耐药突变株。本文根据近年来有关感受态的研究,重点阐述肺炎链球菌中抗生素诱导的感受态与耐药性之间的关系。     

Lyophilized inserts for nasal administration harboring bacteriophage selective for Staphylococcus aureus: in vitro evaluation

Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) poses an infection risk and eradication during hospitalization is recommended. Bacteriophage therapy may be effective in this scenario but suitable nasal formulations have yet to be developed. Here we show that lyophilization of bacteriophages in 1 ml of a viscous solution of 1-2% (w/v) hydroxypropyl methylcellulose (HPMC) with/without the addition of 1% (w/v) mannitol, contained in Eppendorf tubes, yields nasal inserts composed of a highly porous leaflet-like matrix. Fluorescently labeled bacteriophage were observed to be homogenously distributed throughout the wafers of the dried matrix. The bacteriophage titer fell 10-fold following lyophilization to 10⁸ pfu per insert, then falling a further 100- to 1000-fold over 6 to 12 months storage at 4 °C. This compares well with a total dose of 6 × 10⁵ pfu in 0.2 ml liquid applied into the ear during a recent clinical trial in humans. The residual water content of the lyophilized inserts was reduced upon the addition of mannitol to HPMC, but this did not have any correlation to the lytic activity. Mannitol underwent a transition from its amorphous to crystalline state during exposure of the inserts to increasing relative humidities (as would be experienced in the nose), although this transition was suppressed by higher HPMC concentrations and the presence of buffer containing gelatin and bacteriophages. Our results therefore suggest that lyophilized inserts harboring bacteriophage selective for S. aureus may be a novel means for the eradication of MRSA resident in the nose.