Towards Inhaled Phage Therapy in Western Europe

New lytic and new temperate Staphylococcus hyicus phages

A novel lytic phage with a broad host range was isolated from pig faeces and the complete genome was subsequently sequenced. The phage was found to lyse Staphylococcus hyicus, S. pseudintermedius, S. schleiferi and S. warneri, generating approximately 27 PFU per infected S. hyicus cell. The phage has an isometric head of 42 ± 2 nm in diameter and a noncontractile tail of 114 ± 9 nm long. The genome is 53,660 bp in size and consists of 79 predicted ORFs and one tRNAArg gene. The phage has been classified within the Caudoviricetes, specifically the Chaseviridae family. Its broad host range and absence of harmful genes make it suitable for use in phage therapy. In addition, a novel temperate phage was discovered that was spontaneously released from a S. hyicus isolate Pel11 from a pig with exudative epidermitis. This novel temperate phage differs from the known temperate phages in S. hyicus strains NCTC10350, MM2101 or 83/7-1B, representing a novel pathogenicity element in the S. hyicus genome.

The Medicinal Phage-Regulatory Roadmap for Phage Therapy under EU Pharmaceutical Legislation

Bacteriophage therapy is a promising approach to treating bacterial infections. Research and development of bacteriophage therapy is intensifying due to the increase in antibiotic resistance and the faltering development of new antibiotics. Bacteriophage therapy uses bacteriophages (phages), i.e., prokaryotic viruses, to specifically target and kill pathogenic bacteria. The legal handling of this type of therapy raises several questions. These include whether phage therapeutics belong to a specially regulated class of medicinal products, and which legal framework should be followed with regard to the various technical ways in which phage therapeutics can be manufactured and administered. The article shows to which class of medicinal products phage therapeutics from wild type phages and from genetically modified (designer) phages do or do not belong. Furthermore, the article explains which legal framework is relevant for the manufacture and administration of phage therapeutics, which are manufactured in advance in a uniform, patient-independent manner, and for tailor-made patient-specific phage therapeutics. For the systematically coherent, successful translation of phage therapy, the article considers pharmaceutical law and related legal areas, such as genetic engineering law. Finally, the article shows how the planned legislative revisions of Directive 2001/83/EC and Regulation (EC) No 726/2004 may affect the legal future of phage therapy.

The resurgence of phage-based therapy in the era of increasing antibiotic resistance: From research progress to challenges and prospects

Phage therapy was implemented almost a century ago but was subsequently abandoned when antibiotics emerged. However, the rapid emergence of drug-resistant, which has brought to the limelight situation reminiscent of the pre-antibiotic era, coupled with the unavailability of new drugs, has triggered the quest for an alternative therapeutic approach, and this has led to the rebirth of phage-derived therapy. Phages are viruses that infect and replicate in bacterial cells. Phage therapy, especially phage-derived proteins, is being given considerable attention among scientists as an antimicrobial agent. They are used alone or in combination with other biomaterials for improved biological activity. Over the years, much has been learned about the genetics and diversity of bacteriophages. Phage cocktails are currently being exploited for treating several infectious diseases as preliminary studies involving animal models and clinical trials show promising therapeutic efficacy. However, despite its numerous advantages, this approach has several challenges and unaddressed limitations. Addressing these issues requires lots of creativity and innovative ideas from interdisciplinary fields. However, with all available indications, phage therapy could hold the solution in this era of increasing antibiotic resistance. This review discussed the potential use of phages and phage-derived proteins in treating drug-resistant bacterial infections. Finally, we highlight the progress, challenges, and knowledge gaps and evaluate key questions requiring prompt attention for the full clinical application of phage therapy.

Recent Progress in Phage Therapy to Modulate Multidrug-Resistant Acinetobacter baumannii, including in Human and Poultry

Acinetobacter baumannii is a multidrug-resistant and invasive pathogen associated with the etiopathology of both an increasing number of nosocomial infections and is of relevance to poultry production systems. Multidrug-resistant Acinetobacter baumannii has been reported in connection to severe challenges to clinical treatment, mostly due to an increased rate of resistance to carbapenems. Amid the possible strategies aiming to reduce the insurgence of antimicrobial resistance, phage therapy has gained particular importance for the treatment of bacterial infections. This review summarizes the different phage-therapy approaches currently in use for multiple-drug resistant Acinetobacter baumannii, including single phage therapy, phage cocktails, phage-antibiotic combination therapy, phage-derived enzymes active on Acinetobacter baumannii and some novel technologies based on phage interventions. Although phage therapy represents a potential treatment solution for multidrug-resistant Acinetobacter baumannii, further research is needed to unravel some unanswered questions, especially in regard to its in vivo applications, before possible routine clinical use.

Unmet needs in pneumonia research: a comprehensive approach by the CAPNETZ study group

Introduction

Despite improvements in medical science and public health, mortality of community-acquired pneumonia (CAP) has barely changed throughout the last 15 years. The current SARS-CoV-2 pandemic has once again highlighted the central importance of acute respiratory infections to human health. The “network of excellence on Community Acquired Pneumonia” (CAPNETZ) hosts the most comprehensive CAP database worldwide including more than 12,000 patients. CAPNETZ connects physicians, microbiologists, virologists, epidemiologists, and computer scientists throughout Europe. Our aim was to summarize the current situation in CAP research and identify the most pressing unmet needs in CAP research.

Methods

To identify areas of future CAP research, CAPNETZ followed a multiple-step procedure. First, research members of CAPNETZ were individually asked to identify unmet needs. Second, the top 100 experts in the field of CAP research were asked for their insights about the unmet needs in CAP (Delphi approach). Third, internal and external experts discussed unmet needs in CAP at a scientific retreat.

Results

Eleven topics for future CAP research were identified: detection of causative pathogens, next generation sequencing for antimicrobial treatment guidance, imaging diagnostics, biomarkers, risk stratification, antiviral and antibiotic treatment, adjunctive therapy, vaccines and prevention, systemic and local immune response, comorbidities, and long-term cardio-vascular complications.

Conclusion

Pneumonia is a complex disease where the interplay between pathogens, immune system and comorbidities not only impose an immediate risk of mortality but also affect the patients’ risk of developing comorbidities as well as mortality for up to a decade after pneumonia has resolved. Our review of unmet needs in CAP research has shown that there are still major shortcomings in our knowledge of CAP.

Bacteriophage and endolysin engineering for biocontrol of food pathogens/pathogens in the food: recent advances and future trends

Despite advances in modern technologies, various foodborne outbreaks have continuously threatened the food safety. The overuse of and abuse/misuse of antibiotics have escalated this threat due to the prevalence of multidrug-resistant (MDR) pathogens. Therefore, the development of new methodologies for controlling microbial contamination is extremely important to ensure the food safety. As an alternative to antibiotics, bacteriophages(phages) and derived endolysins have been proposed as novel, effective, and safe antimicrobial agents and applied for the prevention and/or eradication of bacterial contaminants even in foods and food processing facilities. In this review, we describe recent genetic and protein engineering tools for phages and endolysins. The major aim of engineering is to overcome limitations such as a narrow host range, low antimicrobial activity, and low stability of phages and endolysins. Phage engineering also aims to deter the emergence of phage resistance. In the case of endolysin engineering, enhanced antibacterial ability against Gram-negative and Gram-positive bacteria is another important goal. Here, we summarize the successful studies of phages and endolysins treatment in different types of food. Moreover, this review highlights the recent advances in engineering techniques for phages and endolysins, discusses existing challenges, and suggests technical opportunities for further development, especially in terms of antimicrobial agents in the food industry.

Characteristics of a Bacteriophage, vB_Kox_ZX8, Isolated From Clinical Klebsiella oxytoca and Its Therapeutic Effect on Mice Bacteremia

Klebsiella oxytoca is an important nosocomial and community-acquired opportunistic pathogenic Klebsiella and has become the second most prevalent strain in the clinic after K. pneumoniae. However, there have been few reports of bacteriophages used for treating K. oxytoca. In this study, a novel bacteriophage, vB_Kox_ZX8, which specifically infects K. oxytoca AD3, was isolated for the first time from human fecal samples. The biological characteristics of vB_Kox_ZX8 showed an incubation period of 10 min, a burst size of 74 PFU/cell, and a stable pH range of 3-11. Genomic bioinformatics studies of vB_Kox_ZX8 showed that it belongs to the genus Przondovirus, subfamily Studiervirinae, family Autographiviridae. The genome of vB_Kox_ZX8 is 39,398 bp in length and contains 46 putative open reading frames encoding functional proteins, such as DNA degradation, packaging, structural, lysin-holin, and hypothetical proteins. We further investigated the efficacy of vB_Kox_ZX8 phage in the treatment of mice with bacteremia caused by K. oxytoca infection. The results showed that vB_Kox_ZX8 (5 × 10⁹ PFU/mouse) injected intraperitoneally alone was metabolized rapidly in BALB/c mice, and no significant side effects were observed in the control and treatment groups. Importantly, intraperitoneal injection with a single dose of phage vB_Kox_ZX8 (5 × 10⁷ PFU/mouse) for 1 h post-infection saved 100% of BALB/c mice from bacteremia induced by intraperitoneal challenge with a minimum lethal dose of K. oxytoca AD3. However, all negative control mice injected with PBS alone died. Owing to its good safety, narrow host infectivity, high lysis efficiency in vitro, and good in vivo therapeutic effect, phage vB_Kox_ZX8 has the potential to be an excellent antibacterial agent for clinical K. oxytoca-caused infections.

Bacteriophages for the Treatment of Graft Infections in Cardiovascular Medicine

Bacterial infections of vascular grafts represent a major burden in cardiovascular medicine, which is related to an increase in morbidity and mortality. Different factors that are associated with this medical field such as patient frailty, biofilm formation, or immunosuppression negatively influence antibiotic treatment, inhibiting therapy success. Thus, further treatment strategies are required. Bacteriophage antibacterial properties were discovered 100 years ago, but the focus on antibiotics in Western medicine since the mid-20th century slowed the further development of bacteriophage therapy. Therefore, the experience and knowledge gained until then in bacteriophage mechanisms of action, handling, clinical uses, and limitations were largely lost. However, the parallel emergence of antimicrobial resistance and individualized medicine has provoked a radical reassessment of this approach and cardiovascular surgery is one area in which phages may play an important role to cope with this new scenario. In this context, bacteriophages might be applicable for both prophylactic and therapeutic use, serving as a stand-alone therapy or in combination with antibiotics. From another perspective, standardization of phage application is also required. The ideal surgical bacteriophage application method should be less invasive, enabling highly localized concentrations, and limiting bacteriophage distribution to the infection site during a prolonged time lapse. This review describes the latest reports of phage therapy in cardiovascular surgery and discusses options for their use in implant and vascular graft infections.

Mycobacteriophages to Treat Tuberculosis: Dream or Delusion?

Rates of antimicrobial resistance are increasing globally while the pipeline of new antibiotics is drying up, putting patients with disease caused by drug-resistant bacteria at increased risk of complications and death. The growing costs for diagnosis and management of drug resistance threaten tuberculosis control where the disease is endemic and resources limited. Bacteriophages are viruses that attack bacteria. Phage preparations served as anti-infective agents long before antibiotics were discovered. Though small in size, phages are the most abundant and diverse biological entity on earth. Phages have co-evolved with their hosts and possess all the tools needed to infect and kill bacteria, independent of drug resistance. Modern biotechnology has improved our understanding of the biology of phages and their possible uses. Phage preparations are available to treat meat, fruit, vegetables, and dairy products against parasites or to prevent contamination with human pathogens, such as Listeria monocytogenes, Escherichia coli, or Staphylococcus aureus. Such phage-treated products are considered fit for human consumption. A number of recent case reports describe in great detail the successful treatment of highly drug-resistant infections with individualized phage preparations. Formal clinical trials with standardized products are slowly emerging. With its highly conserved genome and relative paucity of natural phage defence mechanisms Mycobacterium tuberculosis appears to be a suitable target for phage treatment. A phage cocktail with diverse and strictly lytic phages that kill all lineages of M. tuberculosis, and can be propagated on Mycobacterium smegmatis, has been assembled and is available for the evaluation of optimal dosage and suitable routes of administration for tuberculosis in humans. Phage treatment can be expected to be safe and active on extracellular organisms, but phage penetration to intracellular and granulomatous environments as well as synergistic effects with antibiotics are important questions to address during further evaluation.

Phage Therapy for Multi-Drug Resistant Respiratory Tract Infections

The emergence of multi-drug resistant (MDR) bacteria is recognised today as one of the greatest challenges to public health. As traditional antimicrobials are becoming ineffective and research into new antibiotics is diminishing, a number of alternative treatments for MDR bacteria have been receiving greater attention. Bacteriophage therapies are being revisited and present a promising opportunity to reduce the burden of bacterial infection in this post-antibiotic era. This review focuses on the current evidence supporting bacteriophage therapy against prevalent or emerging multi-drug resistant bacterial pathogens in respiratory medicine and the challenges ahead in preclinical data generation. Starting with efforts to improve delivery of bacteriophages to the lung surface, the current developments in animal models for relevant efficacy data on respiratory infections are discussed before finishing with a summary of findings from the select human trials performed to date.

Phage therapy as a revolutionary medicine against Gram-positive bacterial infections

BACKGROUND

Antibiotic resistance among pathogenic bacteria has created a global emergency, prompting the hunt for an alternative cure. Bacteriophages were discovered over a century ago and have proven to be a successful replacement during antibiotic treatment failure. This review discusses on the scientific investigation of phage therapy for Gram-positive pathogens and general outlook of phage therapy clinical trials and commercialization.

MAIN BODY OF THE ABSTRACT

This review aimed to highlight the phage therapy in Gram-positive bacteria and the need for phage therapy in the future. Phage therapy to treat Gram-positive bacterial infections is in use for a very long time. However, limited review on the phage efficacy in Gram-positive bacteria exists. The natural efficiency and potency of bacteriophages against bacterial strains have been advantageous amidst the other non-antibiotic agents. The use of phages to treat oral biofilm, skin infection, and recurrent infections caused by Gram-positive bacteria has emerged as a predominant research area in recent years. In addition, the upsurge in research in the area of phage therapy for spore-forming Gram-positive bacteria has added a wealth of information to phage therapy.

SHORT CONCLUSION

We conclude that the need of phage as an alternative treatment is obvious in future. However, phage therapy can be used as reserve treatment. This review focuses on the potential use of phage therapy in treating Gram-positive bacterial infections, as well as their therapeutic aspects. Furthermore, we discussed the difficulties in commercializing phage drugs and their problems as a breakthrough medicine.

Bacteriophages as drivers of bacterial virulence and their potential for biotechnological exploitation

Bacteria-infecting viruses (phages) and their hosts maintain an ancient and complex relationship. Bacterial predation by lytic phages drives an ongoing phage-host arms race, whereas temperate phages initiate mutualistic relationships with their hosts upon lysogenization as prophages. In human pathogens, these prophages impact bacterial virulence in distinct ways: by secretion of phage-encoded toxins, modulation of the bacterial envelope, mediation of bacterial infectivity and the control of bacterial cell regulation. This review builds the argument that virulence-influencing prophages hold extensive, unexplored potential for biotechnology. More specifically, it highlights the development potential of novel therapies against infectious diseases, to address the current antibiotic resistance crisis. First, designer bacteriophages may serve to deliver genes encoding cargo proteins which repress bacterial virulence. Secondly, one may develop small molecules mimicking phage-derived proteins targeting central regulators of bacterial virulence. Thirdly, bacteria equipped with phage-derived synthetic circuits which modulate key virulence factors could serve as vaccine candidates to prevent bacterial infections. The development and exploitation of such antibacterial strategies will depend on the discovery of other prophage-derived, virulence control mechanisms and, more generally, on the dissection of the mutualistic relationship between temperate phages and bacteria, as well as on continuing developments in the synthetic biology field.

Treatment of chronic left ventricular assist device infection with local application of bacteriophages

Left ventricular assist device-associated infections represent a major complication during long-term support. Driveline exit site infections harbour the risk of ascending into the pump, causing deep-seated infections. We report on the successful treatment of a chronic recurrent left ventricular assist device pump-associated infection by the local application of bacteriophages as adjunct to standard surgical and antimicrobial treatment.

Microbiome and Infection: A Case for "Selective Depletion"

In most instances where a pathogen has initiated an infection, the primary goal of the treating physician or pharmacist is to eliminate the pathogen. In the absence of knowledge of the precise identity of the problem-causing microbe, a broad-spectrum antimicrobial gives the best chance of success. This approach has saved many lives and is an invaluable tool in fighting infections. However, perhaps our current appreciation of the importance of the microbiome in human health should give us pause. We can regard the microbiome as a virtual organ within the human body, and we would surely hesitate to advance any therapeutic approach that would cause substantial damage to one of our organs. This is one consequence of many broad-spectrum antimicrobial therapies. There may be instances where a more precise approach would be useful. I have termed this "selective depletion"; a concept where pathogen numbers are curtailed by a narrow-spectrum inhibitor but the microbiome is protected and can play a role in restoring health and suppressing the outgrowth of the pathogen in the infected patient. It may well be that the best reservoir of microbiome-friendly antimicrobial agents is the microbiome itself, and I provide examples of where the microbiome has been mined for novel precision antimicrobials.

Phages and their lysins: Toolkits in the battle against foodborne pathogens in the postantibiotic era

Worldwide, foods waste caused by putrefactive organisms and diseases caused by foodborne pathogens persist as public health problems even with a plethora of modern antimicrobials. Our over reliance on antimicrobials use in agriculture, medicine, and other fields will lead to a postantibiotic era where bacterial genotypic resistance, phenotypic adaptation, and other bacterial evolutionary strategies cause antimicrobial resistance (AMR). This AMR is evidenced by the emergence of multiple drug-resistant (MDR) bacteria and pan-resistant (PDR) bacteria, which produces cross-contamination in multiple fields and poses a more serious threat to food safety. A "red queen premise" surmises that the coevolution of phages and bacteria results in an evolutionary arms race that compels phages to adapt and survive bacterial antiphage strategies. Phages and their lysins are therefore useful toolkits in the design of novel antimicrobials in food protection and foodborne pathogens control, and the modality of using phages as a targeted vector against foodborne pathogens is gaining momentum based on many encouraging research outcomes. In this review, we discuss the rationale of using phages and their lysins as weapons against spoilage organisms and foodborne pathogens, and outline the targeted conquest or dodge mechanism of phages and the development of novel phage prospects. We also highlight the implementation of phages and their lysins to control foodborne pathogens in a farm-table-hospital domain in the postantibiotic era.

Phage-Encoded Endolysins

Due to the global emergence of antibiotic resistance, there has been an increase in research surrounding endolysins as an alternative therapeutic. Endolysins are phage-encoded enzymes, utilized by mature phage virions to hydrolyze the cell wall from within. There is significant evidence that proves the ability of endolysins to degrade the peptidoglycan externally without the assistance of phage. Thus, their incorporation in therapeutic strategies has opened new options for therapeutic application against bacterial infections in the human and veterinary sectors, as well as within the agricultural and biotechnology sectors. While endolysins show promising results within the laboratory, it is important to document their resistance, safety, and immunogenicity for in-vivo application. This review aims to provide new insights into the synergy between endolysins and antibiotics, as well as the formulation of endolysins. Thus, it provides crucial information for clinical trials involving endolysins.

Mycobacteriophages as Potential Therapeutic Agents against Drug-Resistant Tuberculosis

The current emergence of multi-, extensively-, extremely-, and total-drug resistant strains of Mycobacterium tuberculosis poses a major health, social, and economic threat, and stresses the need to develop new therapeutic strategies. The notion of phage therapy against bacteria has been around for more than a century and, although its implementation was abandoned after the introduction of drugs, it is now making a comeback and gaining renewed interest in Western medicine as an alternative to treat drug-resistant pathogens. Mycobacteriophages are genetically diverse viruses that specifically infect mycobacterial hosts, including members of the M. tuberculosis complex. This review describes general features of mycobacteriophages and their mechanisms of killing M. tuberculosis, as well as their advantages and limitations as therapeutic and prophylactic agents against drug-resistant M. tuberculosis strains. This review also discusses the role of human lung micro-environments in shaping the availability of mycobacteriophage receptors on the M. tuberculosis cell envelope surface, the risk of potential development of bacterial resistance to mycobacteriophages, and the interactions with the mammalian host immune system. Finally, it summarizes the knowledge gaps and defines key questions to be addressed regarding the clinical application of phage therapy for the treatment of drug-resistant tuberculosis.

Pharmacokinetics and Time-Kill Study of Inhaled Antipseudomonal Bacteriophage Therapy in Mice

Inhaled bacteriophage (phage) therapy is a potential alternative to conventional antibiotic therapy to combat multidrug-resistant (MDR) Pseudomonas aeruginosa infections. However, pharmacokinetics (PK) and pharmacodynamics (PD) of phages are fundamentally different from antibiotics and the lack of understanding potentially limits optimal dosing. The aim of this study was to investigate the in vivo PK and PD profiles of antipseudomonal phage PEV31 delivered by pulmonary route in immune-suppressed mice. BALB/c mice were administered phage PEV31 at doses of 107 and 109 PFU by the intratracheal route. Mice (n = 4) were sacrificed at 0, 1, 2, 4, 8, and 24 h posttreatment and various tissues (lungs, kidney, spleen, and liver), bronchoalveolar lavage fluid, and blood were collected for phage quantification. In a separate study combining phage with bacteria, mice (n = 4) were treated with PEV31 (109 PFU) or phosphate-buffered saline (PBS) at 2 h postinoculation with MDR P. aeruginosa Infective PEV31 and bacteria were enumerated from the lungs. In the phage-only study, the PEV31 titer gradually decreased in the lungs over 24 h, with a half-life of approximately 8 h for both doses. In the presence of bacteria, in contrast, the PEV31 titer increased by almost 2-log10 in the lungs at 16 h. Furthermore, bacterial growth was suppressed in the PEV31-treated group, while the PBS-treated group showed exponential growth. Of the 10 colonies tested, four phage-resistant isolates were observed from the lung homogenates sampled at 24 h after phage treatment. These colonies had a different antibiogram to the parent bacteria. This study provides evidence that pulmonary delivery of phage PEV31 in mice can reduce the MDR bacterial burden.

Characterization of Novel Lytic Bacteriophages of Achromobacter marplantensis Isolated from a Pneumonia Patient

Achromobacter spp. are becoming increasingly associated with lung infections in patients suffering from cystic fibrosis (CF). A. marplatensis, which is closely related to A. xylosoxidans, has been isolated from the lungs of CF patients and other human infections. This article describes the isolation, morphology and characterization of two lytic bacteriophages specific for an A. marplatensis strain isolated from a pneumonia patient. This host strain was the causal agent of hospital acquired pneumonia–the first clinical report of such an occurrence. Full genome sequencing revealed bacteriophage genomes ranging in size from 45901 to 46,328 bp. Transmission electron microscopy revealed that the two bacteriophages AMA1 and AMA2 belonged to the Siphoviridae family. Host range analysis showed that their host range did not extend to A. xylosoxidans. The possibility exists for future testing of such bacteriophages in the control of Achromobacter infections such as those seen in CF and other infections of the lungs. The incidence of antibiotic resistance in this genus highlights the importance of seeking adjuncts and alternatives in CF and other lung infections.

Respiratory Bacterial Microbiota in Cattle: From Development to Modulation to Enhance Respiratory Health

The respiratory tract of cattle is colonized by complex bacterial ecosystems also known as bacterial microbiotas. These microbiotas evolve over time and are shaped by numerous factors, including maternal vaginal microbiota, environment, age, diet, parenteral antimicrobials, and stressful events. The resulting microbiota can be diverse and enriched with known beneficial bacteria that can provide colonization resistance against bacterial pathogens or, on the contrary, with opportunistic pathogens that can predispose cattle to respiratory disease. The respiratory microbiota can be modulated by nonantimicrobial approaches to promote health, creating new potential strategies for prevention and treatment of bovine respiratory disease.

Therapeutic bacteriophages as a rescue treatment for drug-resistant infections - an in vivo studies overview

Bacteriophages, highly prevalent in all environments, have found their use in medicine as an alternative or complement to antibiotics. The therapeutic use of bacteriophages was particularly popular in the 1920s and 1930s, until the discovery and introduction of antibiotics. Due to the dynamic growth of antibiotic resistance among bacterial strains, numerous international institutions (such as the FDA) have declared the search for novel treatment modalities to be of the highest priority. To date, bacteriophage therapy has not been registered for general use in Western countries. The regulation of biological medicinal products (within medicinal product regulation) does not contain a specific documentation frame for bacteriophages (only for vaccines, blood derived products, etc.) which, as active substances, need to meet specific requirements. Recently, the FDA allowed bacteriophage therapy to be used in the United States, via the Emergency Investigational New Drug scheme; clinical trials to compare the safety and efficacy of bacteriophage therapy are also permitted. To date, several therapeutic products of this type have made it to phase I or II; some clinical programmes have also been completed. This article cites numerous animal model studies and registered clinical trials, showing the safety and effectiveness of bacteriophage therapy, including infections caused by bacterial strains resistant to antibiotic treatment.

Phage-Antibiotic Combination Treatments: Antagonistic Impacts of Antibiotics on the Pharmacodynamics of Phage Therapy?

Bacteria can evolve resistance to antibiotics. Even without changing genetically, bacteria also can display tolerance to antibiotic treatments. Many antibiotics are also broadly acting, as can result in excessive modifications of body microbiomes. Particularly for antibiotics of last resort or in treating extremely ill patients, antibiotics furthermore can display excessive toxicities. Antibiotics nevertheless remain the standard of care for bacterial infections, and rightly so given their long track records of both antibacterial efficacy and infrequency of severe side effects. Antibiotics do not successfully cure all treated bacterial infections, however, thereby providing a utility to alternative antibacterial approaches. One such approach is the use of bacteriophages, the viruses of bacteria. This nearly 100-year-old bactericidal, anti-infection technology can be effective against antibiotic-resistant or -tolerant bacteria, including bacterial biofilms and persister cells. Ideally phages could be used in combination with standard antibiotics while retaining their anti-bacterial pharmacodynamic activity, this despite antibiotics interfering with aspects of bacterial metabolism that are also required for full phage infection activity. Here I examine the literature of pre-clinical phage-antibiotic combination treatments, with emphasis on antibiotic-susceptible bacterial targets. I review evidence of antibiotic interference with phage infection activity along with its converse: phage antibacterial functioning despite antibiotic presence.