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Extra-intestinal Escherichia coli express several virulence factors that increase their ability to colonize and survive in different localizations. The K1 capsular type is involved in several infections, including meningitis, urinary tract, and bloodstream infections. The aims of this work were to isolate, characterize, and assess the in vivo efficacy of phages targeting avian pathogenic E. coli (APEC) O18:K1, which shares many similarities with the human strains responsible for neonatal meningitis. Eleven phages were isolated against APEC O18:K1, and four of them presenting a narrow spectrum targeting E. coli K1 strains were further studied. The newly isolated phages vB_EcoS_K1-ULINTec2 were similar to the Siphoviridae family, and vB_EcoP_K1-ULINTec4, vB_EcoP_K1-ULINTec6, and vB_EcoP_K1-ULINTec7 to the Autographiviridae family. They are capsular type (K1) dependent and present several advantages characteristic of lytic phages, such as a short adsorption time and latent period. vB_EcoP_K1-ULINTec7 is able to target both K1 and K5 strains. This study shows that these phages replicate efficiently, both in vitro and in vivo in the Galleria mellonella model. Phage treatment increases the larvae survival rates, even though none of the phages were able to eliminate the bacterial load.

Objective: Diabetic foot ulcer (DFU) infections are a growing public health problem, with increasing prevalence, poor response to antibiotics and bacterial resistance to traditional antimicrobials leading to increased morbidity and mortality. Bacteriophages (phages), the viruses that target specific bacteria, are one option for addressing bacterial infections, especially where antibiotics fail. Of particular value is a class of virulent staphylococcal phages that hit almost all Staphylococcus aureus, including most methicillin-resistant Staphylococcus aureus (MRSA) strains. Here we report a continuous case series assessing the effectiveness of treating infected and poorly vascularised toe ulcers with exposed bone, after failure of recommended antibiotic therapy, using topically applied Staphylococcus aureus-specific phage. Method: This was a compassionate-use case series of nine patients with diabetes and poorly perfused toe ulcers containing culture-proven Staphylococcus aureus infected bone and soft tissue, who had responded poorly to recommended antibiotic therapy. Six representative cases are presented here. The only generally accepted other option in each case was toe amputation. Exposed portions of the infected phalanges were removed in three cases and left in place in two cases. One case presented as a micro-clot induced gangrene following vascular stenting. In this case, phage were used to prevent infection. The phage used was a commercially available fully sequenced preparation of staphylococcal phage Sb-1. Phage solution was applied topically to the ulcerations once weekly, following standard good wound care. The amount of phage solution applied varied from 0.1 to 0.5 cc depending on volume and area of the ulceration. Results: All infections responded to the phage applications and the ulcers healed in an average of seven weeks with infected bone debridement. One ulcer, where vascularity was extremely poor and bone was not removed to preserve hallux function, required 18 weeks of treatment. In the case of the toe with the micro-clot gangrene, the toe was salvaged and healed in seven weeks without complications. Conclusion: Topical application of a staph mono-phage preparation can be used successfully to treat infected toe ulcerations with bone involvement, despite very poor vascularity and failure of antibiotic treatment. The success within this small series provides the groundwork for controlled clinical trials of staph phage for diabetic foot infections. Declaration of interest: The authors have no conflict of interest.

Phage therapy is increasingly put forward as a "new" potential tool in the fight against antibiotic resistant infections. During the "Centennial Celebration of Bacteriophage Research" conference in Tbilisi, Georgia on 26-29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as policy makers, officials of the competent authorities for medicines, phage researchers and phage producers, and members of the pharmaceutical industry. This brief also points out potential avenues for future phage therapy research and development as it specifically addresses those overarching questions that currently call for attention whenever phages go into purification processes for application. ispartof: Viruses vol:10 issue:4 ispartof: location:Switzerland status: published

Intrinsic and acquired defenses against bacteriophages, including Restriction/Modification, CRISPR/Cas, and Toxin/Anti-toxin systems have been intensely studied, with profound scientific impacts. However, adaptive defenses against phage infection analogous to adaptive resistance to antimicrobials have yet to be described. To identify such mechanisms, we applied an RNAseq-based, comparative transcriptomics approach in differentPseudomonas aeruginosastrains after independent infection by a set of divergent virulent bacteriophages. A common host-mediated adaptive stress response to phages was identified that includes the Pseudomonas Quinolone Signal, through which infected cells inform their neighbors of infection, and what may be a resistance mechanism that functions by reducing infection vigor. With host transcriptional machinery left intact, we also observe phage-mediated differential expression caused by phage-specific stresses and molecular mechanisms. These responses suggest the presence of a conserved Bacterial Adaptive Phage Response mechanism as a novel type of host defense mechanism, and which may explain transient forms of phage persistence.

We here present detailed descriptions of successful treatment of a series of diabetic toe ulcers using the Eliava BioPreparations' commercial preparation of the very well-studied anti-staphylococcal bacteriophage Sb-1. This chapter outlines what we feel is an appropriate mechanism to speed movement toward full-scale clinical trials with bacteriophage use to treat wound infections and to help address the crisis in antibiotic resistance.

Species in the genusPseudomonas thrive in diverse ecological niches and are infected with equally diverse bacteriophages. In this Review, De Smet et al. discuss the interactions between Pseudomonasspp. and their phages and also address the biotechnological applications that may be derived from phage–bacteria interactions. Species in the genus Pseudomonas thrive in a diverse set of ecological niches and include crucial pathogens, such as the human pathogen Pseudomonas aeruginosa and the plant pathogen Pseudomonas syringae. The bacteriophages that infect Pseudomonas spp. mirror the widespread and diverse nature of their hosts. Therefore, Pseudomonas spp. and their phages are an ideal system to study the molecular mechanisms that govern virus–host interactions. Furthermore, phages are principal catalysts of host evolution and diversity, which directly affects the ecological roles of environmental and pathogenic Pseudomonas spp. Understanding these interactions not only provides novel insights into phage biology but also advances the development of phage therapy, phage-derived antimicrobial strategies and innovative biotechnological tools that may be derived from phage–bacteria interactions.

Immediately after infection, virulent bacteriophages hijack the molecular machinery of their bacterial host to create an optimal climate for phage propagation. For the vast majority of known phages, it is completely unknown which bacterial functions are inhibited or coopted. Early expressed phage genome regions are rarely identified, and often filled with small genes with no homology in databases (so-called ORFans). In this work, we first analysed the temporal transcription pattern of the N4-like Pseudomonas-infecting phages and selected 26 unknown, early phage ORFans. By expressing their encoded proteins individually in the host bacterium Pseudomonas aeruginosa, we identified and further characterized six antibacterial early phage proteins using time-lapse microscopy, radioactive labelling and pull-down experiments. Yeast two-hybrid analysis gaveclues to their possible role in phage infection. Specifically, we show that the inhibitory proteins may interact with transcriptional regulator PA0120, the replicative DNA helicase DnaB, the riboflavin metabolism key enzyme RibB, the ATPase PA0657and the spermidine acetyltransferase PA4114. The dependency of phage infection on spermidine was shown in a final experiment. In the future, knowledge of how phages shut down their hosts as well ass novel phage-host interaction partners could be very valuable in the identification of novel antibacterial targets.

As interest in the therapeutic and biotechnological potentials of bacteriophages has grown, so has value in understanding their basic biology. However, detailed knowledge of infection cycles has been limited to a small number of model bacteriophages, mostly infecting Escherichia coli. We present here the first analysis coupling data obtained from global next-generation approaches, RNA-Sequencing and metabolomics, to characterize interactions between the virulent bacteriophage PAK_P3 and its host Pseudomonas aeruginosa. We detected a dramatic global depletion of bacterial transcripts coupled with their replacement by viral RNAs over the course of infection, eventually leading to drastic changes in pyrimidine metabolism. This process relies on host machinery hijacking as suggested by the strong up-regulation of one bacterial operon involved in RNA processing. Moreover, we found that RNA-based regulation plays a central role in PAK_P3 lifecycle as antisense transcripts are produced mainly during the early stage of infection and viral small non coding RNAs are massively expressed at the end of infection. This work highlights the prominent role of RNA metabolism in the infection strategy of a bacteriophage belonging to a new characterized sub-family of viruses with promising therapeutic potential., Author Summary The increase of the proportion of multidrug resistant bacterial strains is alarming and alternative ways to treat infections are necessary such as the use of the natural enemies of bacteria, also known as phage therapy. However, explorations of the molecular mechanisms underlying the viral cycle of bacteriophages have been so far restricted to a small number of viruses infecting model bacteria such as Escherichia coli. By combining next-generation transcriptomics and metabolomics approaches, we have now demonstrated that the virulent bacteriophage PAK_P3, infecting the opportunistic pathogen Pseudomonas aeruginosa, directly interferes with specific host metabolic pathways to complete its infection cycle. In particular, it triggers a dramatic degradation of host RNAs and stimulates bacterial pyrimidine metabolism to promote a nucleotide turnover. Overall, we found that upon PAK_P3 infection, host metabolism is redirected to generate the required building blocks for efficient viral replication. We also showed that PAK_P3 gene expression relies on RNA-based regulation strategies using small non coding RNAs and antisense RNAs. Our findings highlight the molecular strategies employed by this virulent phage, which is a representative of a new subfamily of viruses shown to display promising therapeutic values.

Phages as bactericidal agents have been employed for 90 years as a means of treating bacterial infections in humans as well as other species, a process known as phage therapy. In this review we explore both the early historical and more modern use of phages to treat human infections. We discuss in particular the little-reviewed French early work, along with the Polish, US, Georgian and Russian historical experiences. We also cover other, more modern examples of phage therapy of humans as differentiated in terms of disease. In addition, we provide discussions of phage safety, other aspects of phage therapy pharmacology, and the idea of phage use as probiotics.

The worldwide antibiotic crisis has led to a renewed interest in phage therapy. Since time immemorial phages control bacterial populations on Earth. Potent lytic phages against bacterial pathogens can be isolated from the environment or selected from a collection in a matter of days. In addition, phages have the capacity to rapidly overcome bacterial resistances, which will inevitably emerge. To maximally exploit these advantage phages have over conventional drugs such as antibiotics, it is important that sustainable phage products are not submitted to the conventional long medicinal product development and licensing pathway. There is a need for an adapted framework, including realistic production and quality and safety requirements, that allowsa timely supplying of phage therapy products for 'personalized therapy' or for public health or medical emergencies. This paper enumerates all phage therapy product related quality and safety risks known to the authors, as well as the tests that can be performed to minimize these risks, only to the extent needed to protect the patients and to allow and advance responsible phage therapy and research., SCOPUS: re.j, info:eu-repo/semantics/published