Phage Therapy Research Articles

Antibacterial efficacy of mycobacteriophages against virulent Mycobacterium tuberculosis

Tuberculosis (TB) remains a major global health concern, with drug-resistant strains posing a significant challenge to effective treatment. Bacteriophage (phage) therapy has emerged as a potential alternative to combat antibiotic resistance. In this study, we investigated the efficacy of widely used mycobacteriophages (D29, TM4, DS6A) against Mycobacterium tuberculosis (M. tuberculosis) under pathophysiological conditions associated with TB, such as low pH and hypoxia. We found that even at low multiplicity of infection (MOI), mycobacteriophages effectively infected M. tuberculosis, got rapidly amplified, and lysed M. tuberculosis, demonstrating their potential as therapeutic agents. Furthermore, we observed a novel phage tolerance mechanism with bacteria forming aggregates after several days of phage treatment. These aggregates were enriched with biofilm components and metabolically active bacteria. However, no phage tolerance was observed upon treatment with the three-phage mixture, highlighting the dynamic interplay between phages and bacteria and emphasizing the importance of phage cocktails. We also observed that phages were effective in lysing bacteria even under low pH and low oxygen concentrations as well as antibiotic-resistant bacteria. Our results provide key insights into phage infection of slow-growing bacteria and suggest that mycobacteriophages can effectively eliminate M. tuberculosis in complex pathophysiological environments like hypoxia and acidic pH. These results can aid in developing targeted phage-based therapies to combat antibiotic-resistant mycobacterial infections.

Bacteriophage therapy reduces Staphylococcus aureus in a porcine and human ex vivo burn wound infection model.

Burn wounds are a major burden, with high mortality rates due to infections. Staphylococcus aureus is a major causative agent of burn wound infections, which can be difficult to treat because of antibiotic resistance and biofilm formation. An alternative to antibiotics is the use of bacteriophages, viruses that infect and kill bacteria. We investigated the efficacy of bacteriophage therapy for burn wound infections, in both a porcine and a newly developed human ex vivo skin model. In both models, the efficacy of a reference antibiotic treatment (fusidic acid) and bacteriophage treatment was determined for a single treatment, successive treatment, and prophylaxis. Both models showed a reduction in bacterial load after a single bacteriophage treatment. Increasing the frequency of bacteriophage treatments increased bacteriophage efficacy in the human ex vivo skin model, but not in the porcine model. In both models, prophylaxis with bacteriophages increased treatment efficacy. In all cases, bacteriophage treatment outperformed fusidic acid treatment. Both models allowed investigation of bacteriophage-bacteria dynamics in burn wounds. Overall, bacteriophage treatment outperformed antibiotic control underlining the potential of bacteriophage therapy for the treatment of burn wound infections, especially when used prophylactically.

Optimization of bacteriophage therapy for difficult-to-treat musculoskeletal infections: a bench-to-bedside perspective.

Given the increasing threat of antimicrobial resistance, scientists are urgently seeking adjunct antimicrobial strategies, such as phage therapy (PT). However, despite promising results for the treatment of musculoskeletal infections in our center, crucial knowledge gaps remain. Therefore, a prospective observational study (PHAGEFORCE) and a multidisciplinary approach was set up to achieve and optimize standardized treatment guidelines. At our center, PT is strictly controlled and monitored by a multidisciplinary taskforce. Each phage treatment follows the same pathway to ensure standardization and data quality. Within the PHAGEFORCE framework, we established a testing platform to gain insight in the safety and efficacy of PT, biodistribution, phage kinetics and the molecular interaction between phages and bacteria. The draining fluid is collected to determine the phage titer and bacterial load. In addition, all bacterial isolates are fully characterized by genome sequencing to monitor the emergence of phage resistance. We hereby present a standardized bench-to-bedside protocol to gain more insight in the kinetics and dynamics of PT for musculoskeletal infections.

Prospects for the application of cell therapy in combustiology

Currently, one of the urgent problems in the field of surgery and traumatology is burn injury. A significant part of the victims has deep and extensive burns, the treatment of which is the most difficult problem of modern combustiology. In this aspect, one of the main problems faced by surgeons in combustiology is the lack of donor material and an increased risk of complications of burn wounds. In this regard, the most promising direction in kombustiology is the application of cell engineering methods, including the use of fibroblasts and stem cells. Fibroblasts have a number of advantages, such as efficiency, safety and accessibility. Stem cells are also a common method of cell therapy, they have great potential in regenerative processes. Mesenchymal stem cells (MSCs), which have a pronounced regenerative and immunosuppressive effect, are also used in kombustiology. In the treatment of infected burn wounds, phage therapy, which provides lysis of infectious pathogens, showed a positive result. In addition to fighting pathogens, bacteriophages, like MSCs, have an immunosuppressive effect, thereby reducing the risk of transplant rejection.

The Evolution of Phage Therapy: A Comprehensive Review of Current Applications and Future Innovations.

Phage therapy, using bacteriophages to target and destroy bacteria, has evolved significantly from its early 20th-century inception to its modern resurgence as a promising alternative to antibiotics. This review explores the historical development of phage therapy, detailing its initial successes, subsequent decline with the rise of antibiotics, and recent revival in response to increasing antibiotic resistance. We examine the fundamental mechanisms of phage therapy, including the specificity of phages for bacterial targets and their ability to combat resistant strains. Current applications are discussed, highlighting the use of phage therapy in treating chronic infections, personalizing treatment strategies, and its role in veterinary and food safety contexts. Innovations in phage therapy, driven by advancements in genetic engineering and synthetic biology, are also reviewed, showcasing the development of engineered phages, phage libraries, and novel delivery systems. Despite its potential, phage therapy faces challenges such as regulatory hurdles, safety concerns, and issues related to bacterial resistance to phages. The review underscores the need for ongoing research and clinical trials to address these challenges and to integrate phage therapy into modern treatment paradigms. By offering a detailed overview of the evolution, current status, and future directions of phage therapy, this review aims to highlight its potential as a crucial component in the fight against antibiotic-resistant infections and to inform future research efforts.

Addressing the rising threat of antibiotic resistance by optimizing phage therapy to combat antibiotic resistant bacteria

Antibiotics have long been a cornerstone in the fight against virulent microbial infections, significantly improving public health outcomes. However, their widespread and persistent use has led to a serious threat: antimicrobial resistance (AMR). This growing issue thus raises a consequential threat to public health and the environment. Consequently, necessitating the search for an efficacious substitute is the need of the hour. The resurgence of interest in phage therapy, one of the old remedies, is due to its preciseness in targeting the bacterial cells and causing lysis of the bacterial cell without causing harm to human or animal cells. Researchers worldwide are exploring the viability and efficiency of phage therapy as a means to address the challenge raised by the growing antibiotic resistance. This review paper discusses the current progress on bacteriophages as a promising alternative to antibiotics in response to the growing issue of antibiotic resistance. It covers various aspects, including the history and structure of bacteriophages, methods of preparation, their current status in research and therapy, and their potential future applications

Phage Therapy's Neglected Potential Is Finally Being Realized

Phage Therapy's Neglected Potential Is Finally Being Realized

Viral adaptations to alternative hosts in the honey bee pathogen Paenibacillus larvae.

Bacteriophages (phages) that are intended to be used to treat bacterial infections are often improved using genetic engineering or experimental evolution. A protocol called "Appelmans" utilizes evolution in microtiter plates to promote the evolution of phages that can infect nonpermissive hosts. We tested a modification of the Appelmans protocol using the honey bee pathogen, Paenibacillus larvae. Three phages evolved together on four P. larvae strains following the standard Appelmans protocol and a modified version to ensure high phage diversity throughout ten rounds of passaging. The host range of 360 plaques were characterized and six new phage lysis patterns were identified. These new phage lysis patterns included plaque formation on previously nonpermissive, phage-resistant isolates that were used to identify phage types. The modified protocol did not drastically change the rate or number of new phage types observed but did prevent the phage population from being dominated by one phage that tended to rapidly raise in frequency. These findings showed how a minor modification of the Appelmans protocol influenced the development of phages for phage therapy. The method also provided improved phages for the treatment of bacterial infections in honey bees.

Variable fitness effects of bacteriophage resistance mutations in Escherichia coli: implications for phage therapy.

This study isolated more than 50 phage-resistant mutants from both in vitro and in vivo conditions, exposing an extra-intestinal pathogenic Escherichia coli strain to a single virulent phage. The characterization of these clones revealed several key findings: (1) mutations occurring during phage treatment affect the same pathways as those identified in vitro; (2) the resistance mechanisms are associated with the modification of two cell-wall components, with one involving receptor deletion (phage-specific mechanism) and the other, less frequent, involving receptor masking (phage-nonspecific mechanism); (3) an in vivo virulence assay demonstrated that the absence of the receptor abolishes virulence while masking the receptor preserves it; and (4) clones with a resistance mechanism nonspecific to a particular phage can remain susceptible to other phages. This supports the idea of incorporating diverse phages into therapeutic cocktails designed to collectively target both wild-type and phage-resistant strains, including those with resistance mechanisms nonspecific to a phage.

Viral plasticity facilitates host diversity in challenging environments

The antagonistic coevolution of microbes and viruses influences fundamentally the diversity of microbial communities. Information on how environmental variables interact with emergent defense-counterdefense strategies and community composition is, however, still scarce. Following biological intuition, diversity should increase with improved growth conditions, which offset evolutionary costs; however, laboratory and regional data suggest that microbial diversity decreases in nutrient-rich conditions. Moreover, global oceanic data show that microbial and viral diversity decline for high latitudes, although the underlying mechanisms are unknown. This article addresses these gaps by introducing an eco-evolutionary model for bacteria-virus antagonistic coevolution. The theory presented here harmonizes the observations above and identifies negative density dependence and viral plasticity (dependence of virus performance on host physiological state) as key drivers: environmental conditions selecting for slow host growth also limit viral performance, facilitating the survival of a diverse host community; host diversity, in turn, enables viral portfolio effects and bet-hedging strategies that sustain viral diversity. From marine microbes to phage therapy against antibiotic-resistant bacteria or cancer cells, the ubiquity of antagonistic coevolution highlights the need to consider eco-evolutionary interactions across a gradient of growth conditions.

Bacteriophage therapy: an alternative to antibiotics in the age of multi-drug resistance

Phage therapy involves the use of specific viruses that can infect and lyse pathogenic bacteria. Since, antibiotic resistance is widely increasing among bacteria phages offer a promising field as natural, self-replicating and self-limiting antibiotics. Clinical trials are conducted to use phages against multi-drug resistant bacterial infections. The most powerful and cost-effective application of phage therapy is in the treatment of diseases such as cholera and dysentery. While phage therapy has been around for over 100 years, the treatment still is not a main part of medicine. Phage therapy has largely existed on the fringes of medicine, particularly in Western countries like the USA, where it is occasionally approved for compassionate use, on emergency basis when no other approved therapies are available. This review was undertaken to discuss, review and highlight the importance and future research of phage therapy.

The evolution of knowledge for treating Gram-negative bacterial infections.

Infections caused by nonprimarily pathogenic Gram-negative bacilli (GNB) have been increasingly reported from the second half of the 20th century to the present. This phenomenon has expanded during the antibiotic era and in the presence of immunodeficiency.Before the discovery of sulphonamides and penicillin G, infections caused by GNB were rare compared to Gram-positive infections. The advent of anticancer therapy, the expansion of surgical procedures, the use of corticosteroids, and the implantation of prosthetic materials, along with better control of Gram-positive infections, have promoted the current increase in GNB infections.GNB have similar antimicrobial targets to Gram-positive bacteria. However, only antibiotics that can penetrate the double membrane of GNB and remain in them for a sufficient duration have antibacterial activity against them. Sulphonamides and early penicillins had limited activity against GNB. Ampicillin and subsequent beta-lactams expanded their spectrum to treat GNB. Aminoglycosides may re-surge with less toxic drugs, as highly resistant to beta-lactams GNB rise. Polymyxins, tetracyclines, and fluoroquinolones are also used for GNB. Combinations with other agents may be needed in specific cases, such as in the central nervous system and prostate, where beta-lactams may have difficulty reaching the infection site.Alternatives to current treatments must be sought in the discovery of new drug families and therapies such as phage therapy combined with antibiotics. Narrower-spectrum immunosuppressive therapies and antibiotics, antimicrobials that minimally intervene with the human microbiota, and instant diagnostic methods are necessary to imagine a future where currently dominant bacteria in infectious pathology lose their preeminence.

Optimized Dosing and Delivery of Bacteriophage Therapy for Wound Infections.

Lytic bacteriophages, viruses that lyse (kill) bacteria, hold great promise for treating infections, including wound infections caused by antimicrobial-resistant Pseudomonas aeruginosa. However, the optimal dosing and delivery strategies for phage therapy remain unclear. In a mouse wound infection model, we investigated the impact of dose, frequency, and administration route on the efficacy of phage therapy. We find that topical but not intravenous delivery is effective in this model. High-doses of phage reduces bacterial burden more effectively than low-doses, and repeated dosing achieves the highest eradication rates. Building on these insights, we developed "HydroPhage", a hyaluronan-based hydrogel system that uses dynamic covalent crosslinking to deliver high-titre phages over one week. HydroPhage eradicates infections five times more effectively than intravenous injection. We conclude that hydrogel-based sustained phage delivery enhances the efficacy of phage therapy and offers a practical, well-tolerated option for topical application.

Isolation and characterization of two novel phages, ?Rspv1 and ?Rspv2, with a potential for biocontrol of Ralstonia solanacearum.

Bacteriophages offer an effective biocontrol strategy, presenting an environmentally friendly alternative to combat the issues of antibiotic and copper-based bactericide resistance in bacterial phytopathogens. In this study, two phages targeting Ralstonia solanacearun (designated as ?Rspv1 and ?Rspv2) were identified as potential biocontrol agents against solanaceous wilt, a highly destructive disease causing significant economic losses globally. Both phages demonstrated resistance to chloroform, while ?Rspv1 exhibited a broader host range compared to ?Rspv2 across five isolates of R. solanaceraum. The replication cycle for ?Rspv2 was determined to be 90 min. for a single growth cycle, with a burst size of 85 PFU per cell. Morphologically, ?Rspv1 featured icosahedral heads with long tails, characteristic of the Myoviridae family, whereas ?Rspv2 displayed a filamentous particle shape typical of Inoviridae viruses. Additionally, a Random Amplified Polymorphic DNA (RAPD) analysis using four random primers revealed a diverse nature of the two phages, suggesting their potential utility in disease management strategies. This research unveils two novel virulent phages, and their characterization highlights promising for phage therapy with future investigations aim to field level evaluation against R. solanacearum.

Bacteriophage Therapy on an In Vitro Wound Model and Synergistic Effects in Combination with Beta-Lactam Antibiotics.

One of the primary opportunistic pathogens that can cause a wide range of diseases is Pseudomonas aeruginosa. This microorganism can become resistant to practically every antibacterial currently in use, including beta-lactam antibiotics. Its ability to proliferate as biofilm has been linked to, among other things, the failure of antimicrobial therapies. Due to a variety of virulence factors and host immune system modifications, P. aeruginosa is one of the most significant and common bacteria that colonize wounds and burns. A novel therapeutic option for treating these multidrug-resistant (MDR) bacterial infections is the combination of antibiotics and bacteriophages. This approach has been linked to improved biofilm penetration, a decreased selection of antibiotic and bacteriophage resistance, and an enhanced antibacterial impact. Combining the F1Pa bacteriophage and beta-lactam antibiotics reduced the viability of the mature biofilm of MDR P. aeruginosa strains and suppressed bacterial growth in vitro. F1Pa critically reduced the amount of biofilm that MDR P. aeruginosa clinical strains formed in the in vitro wound model. These findings highlight the bacteriophage F1Pa's therapeutic potential as a prophylactic topical treatment against MDR pseudomonal infections in wounds and burns.

A Novel Dhillonvirus Phage against Escherichia coli Bearing a Unique Gene of Intergeneric Origin.

Antibiotics resistance is expanding amongst pathogenic bacteria. Phage therapy is a revived concept for targeting bacteria with multiple antibiotics resistances. In the present study, we isolated and characterized a novel phage from hospital treatment plant input, using Escherichia coli (E. coli) as host bacterium. Phage lytic activity was detected by using soft agar assay. Whole-genome sequencing of the phage was performed by using Next-Generation Sequencing (NGS). Host range was determined using other species of bacteria and representative genogroups of E. coli. Whole-genome sequencing of the phage revealed that Escherichia phage Ioannina is a novel phage within the Dhillonvirus genus, but significantly diverged from other Dhillonviruses. Its genome is a 45,270 bp linear double-stranded DNA molecule that encodes 61 coding sequences (CDSs). The coding sequence of CDS28, a putative tail fiber protein, presented higher similarity to representatives of other phage families, signifying a possible recombination event. Escherichia phage Ioannina lytic activity was broad amongst the E. coli genogroups of clinical and environmental origin with multiple resistances. This phage may present in the future an important therapeutic tool against bacterial strains with multiple antibiotic resistances.

Phage against the Machine: The SIE-ence of Superinfection Exclusion.

Prophages can alter their bacterial hosts to prevent other phages from infecting the same cell, a mechanism known as superinfection exclusion (SIE). Such alterations are facilitated by phage interactions with critical bacterial components involved in motility, adhesion, biofilm production, conjugation, antimicrobial resistance, and immune evasion. Therefore, the impact of SIE extends beyond the immediate defense against superinfection, influencing the overall fitness and virulence of the bacteria. Evaluating the interactions between phages and their bacterial targets is critical for leading phage therapy candidates like Pseudomonas aeruginosa, a Gram-negative bacterium responsible for persistent and antibiotic-resistant opportunistic infections. However, comprehensive literature on the mechanisms underlying SIE remains scarce. Here, we provide a compilation of well-characterized and potential mechanisms employed by Pseudomonas phages to establish SIE. We hypothesize that the fitness costs imposed by SIE affect bacterial virulence, highlighting the potential role of this mechanism in the management of bacterial infections.

Harnessing Bacteriophages to Combat Antibiotic-Resistant Infections in Africa: A Comprehensive Review.

The conventional treatment of bacterial infections with antibiotics is becoming increasingly ineffective due to the emergence of multidrug-resistant (MDR) pathogens. This literature review explores the potential of bacteriophages as an alternative or adjunctive therapy to antibiotics in combating MDR infections in Africa. This analysis focuses on current research regarding the integration of phage therapy into African healthcare, highlighting its challenges and opportunities. This review begins with the AMR crisis and the need for new treatments, then covers the history, mechanisms, benefits, and limitations of phage therapy. Key African studies are summarized, identifying major obstacles such as regulatory issues, infrastructure, and research standardization. Research efforts in West Africa that have made notable progress in bacteriophage research are highlighted. This review concludes with recommendations for policymakers, researchers, and healthcare professionals to enhance the development and use of phage therapy in Africa, aiming to reduce antibiotic resistance and improve patient outcomes. By addressing the identified challenges and leveraging the unique advantages of phages, there is potential to significantly mitigate the impact of antibiotic resistance and improve patient outcomes in Africa.

Infection Prevention and Control Strategies According to the Type of Multidrug-Resistant Bacteria and Candida auris in Intensive Care Units: A Pragmatic Resume including Pathogens R0 and a Cost-Effectiveness Analysis.

Multidrug-resistant organism (MDRO) outbreaks have been steadily increasing in intensive care units (ICUs). Still, healthcare institutions and workers (HCWs) have not reached unanimity on how and when to implement infection prevention and control (IPC) strategies. We aimed to provide a pragmatic physician practice-oriented resume of strategies towards different MDRO outbreaks in ICUs. We performed a narrative review on IPC in ICUs, investigating patient-to-staff ratios; education, isolation, decolonization, screening, and hygiene practices; outbreak reporting; cost-effectiveness; reproduction numbers (R0); and future perspectives. The most effective IPC strategy remains unknown. Most studies focus on a specific pathogen or disease, making the clinician lose sight of the big picture. IPC strategies have proven their cost-effectiveness regardless of typology, country, and pathogen. A standardized, universal, pragmatic protocol for HCW education should be elaborated. Likewise, the elaboration of a rapid outbreak recognition tool (i.e., an easy-to-use mathematical model) would improve early diagnosis and prevent spreading. Further studies are needed to express views in favor or against MDRO decolonization. New promising strategies are emerging and need to be tested in the field. The lack of IPC strategy application has made and still makes ICUs major MDRO reservoirs in the community. In a not-too-distant future, genetic engineering and phage therapies could represent a plot twist in MDRO IPC strategies.

Resolution of Chronic Bacterial Prostatitis with Bacteriophage-antibiotic Therapy

Chronic bacterial prostatitis is a commonly diagnosed genitourinary infection that presents significant challenges both in diagnosis and treatment. In an upcoming era of antibiotic resistance, and limited therapeutic options it becomes imperative to revise current guidelines and to provide more effective treatment strategies. At the Eliava Phage Therapy Center (Tbilisi, Georgia) we utilize bacteriophage therapy as an alternative approach against chronic bacterial infections. Bacteriophages, viruses that target and lyse specific bacterial cells, can be used as a stand-alone treatment or in conjunction with antibiotics. We present a case report of a patient with prostatitis caused by Escherichia coli infection, who prior to addressing our clinic, has been receiving antibiotic therapy without any positive effect. Our approach of combined use of antibiotics and phages was successful not only in complete clinical improvement but also in total bacterial eradication. This outcome shows the potential of bacteriophage therapy as a valuable adjunct to conventional antibacterials in the management of prostatitis.