Posters and poster guidelines
Thank you for considering presenting your work as a poster at this conference.
Poster preparation and submission
- Poster size: Prepare your poster as you would normally do for printing.
- > Presenting digitally only: You can save your poster in sizes A1 or A0, landscape or portrait, as the page size is not important if presenting digitally only.
- > Presenting in-person: Print hardcopy posters in A1 portrait format only.
- > Larger posters and those in landscape format may not be displayed due to space constraints.
- Naming your poster files: Name your poster files as follows:<your surname>-Phg25-Poster.pdf. For example, for David Jones, name your file as Jones-Phg25-Poster.pdf.
> DO NOT name your poster files as, e.g., Abstract-Oxford, Oxford-talk, Oxford-poster, poster2025, Oxford-phage-poster. Such files will not be considered.
- Poster submission and deadlines: Poster submission and deadlines: All poster presenters, whether attending virtually or in-person, are required to submit a digital version of their poster for viewing by both virtual and in-person attendees. The posters will be made available via the conference documents page to all conference participants.
> Submit your final poster as a PDF (<5MB) and via the link below no later than the advertised dates.
> Late posters may not be included in the conference programme.
> DO NOT send your poster (or abstract) files by email.
> Please ensure you send us the very final version of your poster (as well as your poster abstract), as once published, it cannot be replaced.
Before uploading your poster, you must make sure that you follow ALL of the instructions above!
Poster presentation
- Presentation time: There is no specific time for presenting digital posters. The participants will be able to interact with virtual presenters via the Zoom chatbox during the conference. However, we strongly recommend that the presenters submit a flash-talk video (see below) of their poster to get maximum exposure during and after the conference.
- Flash-talk videos: We are pleased to offer poster presenters the opportunity to prepare a short video presentation about their poster and send it before the conference. The videos will be made available on the LPMHealthcare YouTube channel. Below is further information for sending your video presentation.
- Download the opening slide (PhgOx25 opening slide) and use it as the first slide of your presentation (see example: https://youtu.be/XatqenCd_IU?si=Yu1PooCD4JmSLAiz).
- Give your presentation (no longer than 5 minutes) using Zoom or another platform of your choice.
- Convert the video into a format compatible with YouTube (e.g., MP4).
- Send your video to PhageOxford@gmail.com using a file transfer program, such as MailBigFile or WeTransfer.
- Hardcopy posters: If attending in-person, you may bring along a printed copy of your poster (maximum A1 size) to be displayed during the conference.
- Please note that you are responsible for printing your poster and only print in A1 portrait format.
- You may be assigned a specific day for displaying your poster.
Upload Your Digital Poster
Before uploading your poster, you must make sure that you follow ALL of the instructions above!
Accepted posters
(Presenters in Bold)
Accepted poster abstracts will be displayed below. If your abstract has been accepted for presentation but it does not appear in the list below, please let us know as soon as possible by emailing PhageOxford@gmail.com.
Impact of bacterial density on ssDNA bacteriophage mutation rate
Amal Alkhafaji, Michael A Brockhurst, Claudia Igler, Rok Krašovec
Faculty of Biology, Medicine, and Health (FBMH), University of Manchester, Michael Smith Building, Dover Street, M13 9NT
DNA bacteriophages (phages) generally exhibit elevated mutation rates than their bacterial hosts, with single-stranded DNA (ssDNA) phages showing higher mutation rates compared to double-stranded DNA (dsDNA) phages. Control of phage mutation rates is poorly understood, but because most phages do not encode their own DNA polymerases or DNA repair proteins, is likely to be determined by the host’s replication and repair machinery. Our study examined how factors known to influence bacterial mutation rates also affect phage mutation rates. One key factor is density-associated mutation rate plasticity (DAMP), where bacterial mutation rate is increased at low population density due to elevated oxidative DNA damage. I used modified fluctuation assays to estimate mutation rates for ssDNA phage ϕX179 at different host densities ranging from 6×106 to 3.7×108 cells per ml. Mutants were quantified by plating supernatants on lawns of E. coli C gro87 which ϕX179 phage can only infect by a acquiring a specific point mutation. Our results show that the mutation rate of phage ϕX174 exhibits DAMP, such that its mutation rate is lower when the host cell density is higher. This finding shows that phage mutation rate is controlled by the host replication and repair machinery and tightly correlated with the host mutation rate. We are now studying how the ϕX179 mutation rate and mutational spectra varies between a wild-type and a mutator host phenotype. Understanding how the host’s control phage mutation rates will advance our understanding of phage evolution and is of relevance to the application of phages as antimicrobial therapeutics.
M-13 Bacteriophage Functionalized Graphene Oxide Biosensor for the Rapid Detection of Analytes in Clinical and Environmental Sample
Hamda Y Alshehhi1, Lina Tizani2, Selvakumar Palanisamy2, Habiba Alsafar2,3, Shadi W Hasan4,5, Ahmed F Yousef1,2,4
1Department of Biology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
2Center for Biotechnology (BTC), Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
3Department of Biomedical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
4Center for Membranes and Advanced Water Technology (CMAT), Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
5Department of Chemical Engineering, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
Rapid detection of infectious pathogens plays a critical role in public health, providing an early-warning system for identifying threats within clinical and environmental settings. Timely identification in such complex samples is essential for effective intervention and decision-making. Addressing this need, we previously developed a highly sensitive reduced graphene oxide (rGO)-based biosensor capable of detecting SARS-CoV-2 in clinical and environmental samples. In this study, we modified the biosensor to replace conventional antibodies with genetically engineered M13 bacteriophages, achieving a significant reduction in manufacturing costs and enabling in-house manufacturing to support greater manufacturing independence and quality control. The optimized biosensor maintained high sensitivity and specificity, with rapid detection in the millisecond range. Future work will focus on further engineering the biosensor to detect a broader range of pathogens and contaminants in wastewater and clinical samples, which will position the biosensor as a vital tool for public health surveillance and environmental monitoring, offering a scalable, reliable, and cost-effective solution for addressing global health challenges.
Cure of a difficult-to-treat Pseudomonas aeruginosa canine chronic otitis externa (OE) with the PYO bacteriophage cocktail followed by antibiotics
Raphaël Baudin1, Verena Ducret2, Line Gentsch3*, Karl Perron2,4,5* and Grégory Resch1*
*These authors contributed equally to this work.
1Center for Research and innovation in Clinical Pharmaceutical Sciences (CRISP), Lausanne University Hospital (CHUV), Lausanne, Switzerland
2Microbiology Unit, Department of Plant Sciences, University of Geneva, 30 Quai Ernest-Ansermet, Geneva, 1211, Switzerland
3Veterinary practice Amivet Sàrl, Neuchâtel, Switzerland
4Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, 1 Rue Michel Servet, Geneva, 1211, Switzerland
5Section of Pharmaceutical Sciences, University of Geneva, 1 Rue Michel Servet, Geneva, 1211, Switzerland
A Labrador presented with severe chronic otitis externa. The ear canal was thickened and covered with foul-smelling purulent secretions, the walls showing extensive erythema with ulcerations. Pseudomonas aeruginosa was identified and standard of care (SoC, gentamycin + polymyxin) treatment had failed. Phage therapy, which uses specific bacterial viruses called bacteriophages, was proposed. PYO bacteriophage cocktail (Eliava biopreparation, Georgia) was applied locally into the ear canal after soft cleaning over three consecutive days (0.5mL per day). P. aeruginosa and phage loads were monitored from ear swabs. Antibiotic and phage susceptibility was assessed on recovered clones. Resistance mechanisms were investigated through comparative genomics. Before onset of treatment, P. aeruginosa isolates were fully susceptible to PYO in vitro. After a 2-log10 P. aeruginosa load reduction by D2 post-treatment, levels returned to baseline. Interestingly, rapid and significant clinical improvement was observed, with reduced secretions and pain. We found that already at D1, the pathogen population changed with the emergence of phage-resistant clones, without modification of antibiograms. These clones harboured large genomic deletions or mutations impacting genes involved in O-antigen and type IV pilus biosynthesis known as phage receptors. Still, phages persisted in the ear canal for three weeks, with evidence of phage-susceptible P. aeruginosa at D65. Finally, instillations of SoC at D65 and D90 cleared the infection after >2 years of ineffectiveness. Phage therapy alone significantly improved clinical symptoms and modified the P. aeruginosa ear community towards mixed-resistance profiles. Although antibiograms remained similar, we believe that this pathogen community switch could explain the observed successful therapeutic outcome. Decrease in virulence or capacity to form biofilm of the selected phage-resistant clones might be involved and are currently investigated.
Anoxic conditions alter the phage receptor landscape and shape phage susceptibility in Staphylococcus aureus
Félicie M Chaumont1, David Alsteens2, Annika Gillis1
1Laboratory of Food and Environmental Microbiology, Earth and Life Institute, UCLouvain, Louvain-la-Neuve, Belgium
2Laboratory of NanoBiophysics, Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
The use of phages as antimicrobials to treat bacterial infections in human and veterinary medicine requires a reliable and effective phage infection across a spectrum of environments where oxygen is frequently present at a low concentration. However, there is a noticeable gap in our understanding of how the oxygen availability affects the ability of phages to infect their hosts, making the clinical outcome of phage therapy unpredictable. This project aims to investigate the impact of oxygen deprivation on the molecular mechanisms underlying Staphylococcus aureus-phage interactions. To this end, the behaviour of the well-characterised myovirus phage K against S. aureus was analysed under anoxic conditions through various experiments, including time-kill dynamics, adsorption efficiency, and one-step growth curve assays. In addition, the phage receptor landscape of S. aureus under anaerobic growth conditions was investigated by analysing the expression of genes encoding for proteins involved in phage receptor synthesis, along with a WGA-binding assay. These analyses revealed that phage K partially loses its ability to infect S. aureus in the absence of oxygen, with a notable reduction in adsorption efficiency. Moreover, both the gene expression and surface availability of phage receptors were found to be downregulated under anoxic conditions compared to normoxic conditions. Given the growing interest in developing phage therapies, there is a need to deepen our understanding of phage-pathogen dynamics in microenvironments that mimic those of the human body. Such knowledge could provide the basis for new approaches to combat multi-drug resistant bacterial infections.
How Cellular Resources Limit T7 Bacteriophages Growth
Liqi Chen, Aidan T Brown
School of Physics and Astronomy, King’s Buildings, EH9 3FD, University of Edinburgh, Edinburgh, UK
Efficient resource allocation is crucial for cellular growth and survival, particularly under constrained conditions. A well-established “growth law” shows a linear correlation between bacterial growth rates and the cellular concentration of ribosomes, the machines that make proteins. Ribosomes can be inactivated by the ribosome-targeted antibiotic chloramphenicol, leaving only a fraction capable of translating proteins, referred to as active ribosomes. Our study extends a growth principle to bacteriophages T7, showing that T7 replication rates are directly proportional to the number of active ribosomes per cell under ribosome-limited conditions. Under the specific conditions, this findings suggest that ribosome availability can be a key limiting factor for bacteriophages growth.
Beware of host immune responses towards bacteriophages potentially impacting phage therapy
Thomas Démoulins1*#, Jérémy DR Cherbuin1,2#, Thatcha Yimthin1,2, Lukas Eggerschwiler3, Fazal Adnan5 and Joerg Jores1,4
1Institute of Veterinary Bacteriology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland.
2Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
3Research Contracts Animals Group, Agroscope, 1725 Posieux, Switzerland
4Multidisciplinary Center for Infectious Diseases (MCID), University of Bern, Bern 3001, Switzerland
5Atta ur Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan
#Equal contribution as first authors
The rising spread of antimicrobial resistance challenges animal welfare, productivity and food supply with respect to bacterial infections in different livestock species. Bacteriophages offer alternative means to control infections with resistant bacteria. This work investigated the host immune responses towards lytic bacteriophages K and T1, acting respectively on Gram-positive or Gram-negative bacteria. We employed an ex vivo platform to decipher various immune responses elicited by primary blood cells of eight outbred cattle. Bacteriophage K was not recognized whereas bacteriophage T1 induced a profound immune response. Therefore, prior characterization of host immune responses towards therapeutic phages should be considered before therapy starts.
Host phase variation mediates the persistent co-existence of lytic bacteriophages with gut Bacteroidales
Adrián Cortés-Martín1,2, Colin Buttimer1, Jessie L Maier3, Ciara A Tobin1, Lorraine A Draper1, R Paul Ross1, Manuel Kleiner3, Colin Hill1, Andrey N Shkoporov1
1APC Microbiome Ireland & School of Microbiology, University College Cork, Cork, T12 YT20, Ireland
2Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
3Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America
Bacteriophages (phages) in the gut microbiome persist in long-term stable coexistence with their bacterial hosts driven by dynamic eco-evolutionary interactions. CrAss-like phages represent the most abundant group of bacteriophages in the human gut. They infect members of the order Bacteroidales and, despite their virulent nature, they can effectively co-exist with their host bacteria without dramatically impacting community structure or target bacterial numbers. In this study, we investigated the mechanisms underlying phage-bacteria co-existence through an in vitro multi-omics approach (transcriptomics, proteomics and metabolomics). We examined four phage-bacteria pairs: three Bacteroides strains paired with three crAss-like phages (Bacteroides intestinalis and фcrAss001, Bacteroides xylanisolvens and фcrAss002, and an acapsular mutant of Bacteroides thetaiotaomicron with DAC15), and Parabacteroides distasonis APCS2/PD with the siphovirus фPDS1. Our findings reveal that phase variation of individual capsular polysaccharides (CPSs) is the primary mechanism that promotes phage co-existence in Bacteroidales, but this is not the only strategy. Alternative resistance mechanisms, which also involve phase variation but less efficiently than changes in CPS expression, can be activated to enhance bacterial survival by regulating gene expression and resulting in metabolic adaptations, particularly in amino acid degradation pathways. In the absence of CPS, higher transcriptomic, proteomic, and metabolomic changes are observed since more factors are involved in achieving the equilibrium between bacterial and host populations. These mechanisms allow bacterial populations to survive in the presence of phages, and vice versa. These results advance our understanding of long-term phage-host interaction, offering insights into the long-term persistence of crAss-like phages and extending these observations to other phages, such as фPDS1.
Rational in vitro design of a two-phage cocktail against a contemporary A. baumannii strain recovered from a burned patient at CHUV
Hugues de Villiers de la Noue, Gwenaëlle Golliard, Xavier Vuattoux, Gregory Resch
Laboratory of Bacteriophages and Phage Therapy, Center for Research and Innovation in Clinical Pharmaceutical Sciences (CRISP), Lausanne University Hospital (CHUV), Switzerland
Acinetobacter baumannii is a major threat to human health. With the spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains, development of complementary strategies is needed. A complimentary strategy could be phage therapy, which uses bacteriophages (phages), i.e viruses that kill bacterial cells during their life cycle. We designed a two-phage cocktail highly efficient against an XDR A. baumannii isolate collected from a patient with burn wound infection at CHUV (termed Ab125). A first in vitro screen of our collection of 36 different phages identified only phage vB_AbaM_3098 as capable of lysing Ab125. However, quick (ca. 6 h) selection of phage-resistant clones (termed Ab139) occurred. Very interestingly, we observed that Ab139 became susceptible to six different phages in the collection, otherwise inactive on Ab125. Phage-resistance was also selected when Ab139 was challenged with either of the six phages, with bacterial regrowth observed between 12 h and 16 h. However, combination of vB_AbaM_3098 and phage vB_AbaM_3014 led to a clinically usable two-phage cocktail capable of totally inhibiting the growth of Ab125. Treatment with the phage cocktail led to 86.67% survival after 5 days in the in vivo Galleria Mellonella model of infectious diseases, compared to 0% in the non-treated group. Finally, the therapeutic potential of the assembled cocktail was tested in synergy with Standard-of-Care (SOC) antibiotics by both synograms and Time-kill assays, and a synergy with colistin was detected. We show that the combination of a phage that only slightly shifted the in vitro bacterial growth curve with an “inactive phage” led to the formulation of a highly bactericidal phage cocktail against an XDR A. baumannii clinical isolate. This work highlights the complexity sometimes involved in the assembly of potent phage cocktail, as well as their potential in difficult-to treat infections in combination with SOC antibiotics.
Multispecies phage cocktail for improved efficacy in bacterial control
João Duarte1, Carla Pereira1, Ricardo Calado2, Adelaide Almeida1
1CESAM & Department of Biology, University of Aveiro, Aveiro, Portugal
2ECOMARE, CESAM & Department of Biology, University of Aveiro, Aveiro, Portugal
Bacterial infections remain a significant threat to human healthcare and industries such as food production, crop farming, animal husbandry and aquaculture. Bacteriophages have been widely explored as an alternative for controlling bacterial infections and proliferation. However, a major limitation is their narrow host range, often restricted to the bacterial strain used for phage isolation. Furthermore, bacteria can develop resistance to phages through various mechanisms, allowing bacterial survival and the emergence of resistant mutants. To address this issue, a phage cocktail can be an efficient strategy to overcome resistance. In this approach, phages with different properties were combined to reduce the likelihood of resistance. To evaluate whether phage cocktails provide superior outcomes, formulations were prepared using phages previously studied by our research group. Our collection was screened for phages infecting Aeromonas hydrophila, Salmonella enterica Typhimurium, Escherichia coli and Vibrio parahaemolyticus, based on previously reported host ranges. Four phages were selected: AH-1, ECA2, phSE-5 and SH. As SH was unable to infect other target strains but produced lysins, an initial cocktail excluding SH was prepared (CK3), followed by a second one including it (CK4). Efficacy was evaluated in vitro by monitoring bacterial kill curves via plate counts. Cups with 30 mL tryptic soy broth were inoculated with bacteria and phages and incubated for 12 h at 25 °C without shaking. Additionally, two cups were only inoculated with bacteria or phage (control). Aliquots were taken every 2 h, plated in triplicate in solid media (colony counts) and by the double agar layer (plaque forming units), and incubated for 16 h. Each experiment was repeated three times. Kill curves were statistically compared, with all cocktails showing significant bacterial reduction vs. individual phages. While CK3 and CK4 performed similarly, CK4 showed superior control of S. Typhimurium.
Phage collateral sensitivity: An evolutionary trade-off in phage resistance mechanisms
Wenbo Zhao, Xiang-Dang Du
International Joint Research Center for National Animal Immunology, Ministry of Education Key Laboratory for Animal Pathogens and Biosafety, College of Veterinary Medicine, Henan Agricultural University, PR China
The ST65-K2-type carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-HvKP) strain 20K-303 is of particular concern due to its multidrug-resistant nature. This poses a significant challenge to clinical treatment and underscores the urgent need for the development of phage therapy. This study focused on ST65-K64 CR-HvKP 20K-303, conducting continuous phage resistance induction experiments using phage libraries. These experiments revealed the evolutionary trade-offs, particularly the collateral sensitivity phenomenon, during the strain’s acquisition of phage tolerance. Throughout the experiment, the lysis spectrum of 20K-303 exhibited a dynamic ‘broadening-narrowing-rebroadening’ pattern. At the R3 evolutionary stage, 20 phages could still form plaques on double-layer plates, but failed to lyse the host bacteria effectively in liquid co-culture. Thus, R3 was designated as the induction endpoint. Interestingly, collateral sensitivity was observed among 20K-303, R1, R2 and R3: the acquisition of phage resistance came at the cost of compromised defence against other phages. Gene function validation revealed that the heightened host susceptibility of phage P98 resulted from ISKpn14-mediated insertion into the wcaJ gene, which is crucial for capsule formation. This mutation broadened the phage lysis spectrum, but reduced the virulence of the HvKP. As for phage P101, its increased host susceptibility was found to be linked to the host’s repair mechanisms. Additionally, glycosyltransferase GT-4 mutations were found to be associated with phage tolerance, likely by altering bacterial surface glycosylation and affecting phage adsorption. In summary, this study provides valuable insights into the evolution of CR-HvKP phage resistance and the role of collateral sensitivity.
Prophage-mediated anti-phage defense in clinically relevant Acinetobacter baumannii
Bálint Dénes Eszenyi1,2, Apjok Gábor1, Bálint Csörgő1
1HUN-REN Biological Research Centre, Szeged, 6726 Szeged, Temesvári krt. 62, Hungary
2University of Szeged Faculty of Science and Informatics, Ph.D. School in Biology, 6726 Szeged, Közép fasor 52, Hungary
The emergence of antibiotic resistance in many clinical pathogens has raised awareness of the need for alternative therapies to treat these infections. One promising approach is the use of bacteriophages (phages). The use of these bacterial viruses, called phage therapy has received considerable attention in recent years. Concerns regarding its use and the need to understand the underlying mechanisms of phage-bacterium interactions have led to numerous discoveries about how bacteria defend themselves against viral infection. One strategy involves employing an arsenal of bacterial defense systems that act as immune systems for these microorganisms. Many defense systems have been described in recent years, but most studies focus on traditionally used bacterial model strains. In our study, we focus on Acinetobacter baumannii, a multidrug-resistant bacterium that causes many infections and is becoming increasingly difficult to treat. We recently identified a defense system present in many clinical isolates that shows little homology to known defense systems. In this study, we aim to describe the numerous mechanisms of bacterial defense in this pathogen with a primary focus on the characterization of this possibly novel defense system.
A Sequential Phage Application for Respiratory Infection approach to phage therapy clinical trials
Christian Fitch1, Carlos Pereira Chilima2*, Julie Fletcher1, Sophie Whiteley1,2, Francesca Hodges3, Alex Chan5,6, Marie Noelle Vieu7, Spyridon Megremis8, Richard Fitzgerald9, Harriet Mok10, Stephanie Ellis11, Dorothy Grogono12, Freddie Frost6, Jo Fothergill4, Helen Quinn1,2, Phil Mitchelmore2, Ben Temperton1
1Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
2Department of Respiratory Medicine, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
3Innovate UK Business Connect, London, UK
4Department of Clinical Infection, Microbiology and Immunology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
5Pharmacy Department, Liverpool Heart & Chest Hospital NHS Foundation Trust, Liverpool, UK
6Liverpool Centre for Cardiovascular Sciences, Liverpool Heart & Chest Hospital NHS Foundation Trust and University of Liverpool, Liverpool, UK
7Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
8Becky Mayer Centre for Phage Research, University of Leicester, Leicester, UK
9NIHR Royal Liverpool and Broadgreen CRF, Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
10LifeArc, Lynton House, London, UK
11Cambridge Central Research Ethics Committee, Health Research Authority, Nottingham, UK
12Cambridge Centre for Lung Infection, Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK
In response to the antibiotic resistance crisis, bacteriophages are frequently proposed as an alternative therapeutic option. However, despite a remarkable safety profile, many successful case studies/series, and a century of historical use, phage therapy clinical trials often fail to meet efficacy endpoints. As positive efficacy data was regarded as essential to UK phage therapy in the recent Government reports, these failures hinder its widespread adoption in the UK. Furthermore, repeated trial failures may reduce confidence in the therapy, limiting scope for future trial funding and delay an effective antimicrobial strategy as the prevalence of antibiotic resistance further increases. To address this, a multidisciplinary meeting was convened including clinicians, academics, pharmacists, funders, patients, and analysts to discuss barriers to phage therapy trial success and propose a route to achieve this. Here, we report our requirements for a robust clinical trial framework and propose a trial design to treat patients with chronic bronchitis associated with Pseudomonas aeruginosa infection. To bring systematic phage therapy in line with the more successful case studies and series, our suggested design utilises an adaptive platform with sufficient flexibility to incorporate ongoing advancements in phage production and regulation. The single sequential approach, tested in comparison to a multi-phage cocktail in initial phases, matches phages from a defined initial panel prior to application also supports a precision-based methodology to phage therapy and presents opportunities for phage steering approaches. In the report, we highlight the major obstacles to phage therapy trials, how these obstacles may be overcome at scale, and discuss the immediate future steps to develop the proposed trial, all with the goal of establishing a solid evidence base for the clinical use of phage therapy.
Characterization of bacteriophages against uropathogenic Klebsiella pneumoniae
Sandra Pacios-Michelena1, Alexia Nakoutsi1, Amandine Hendrickx1, Johan Quintens2, Bob G Blasdel2 and Annika Gillis1
1Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Université catholique de Louvain, Croix du Sud 2, box L7.05.12, 1348 Louvain-la-Neuve, Belgium
2Inteliphage, Monnet Innovation Center, Av. Jean Monnet 1, 1348 Louvain-la-Neuve, Belgium
Urinary tract infections (UTIs) affect approximately 150 million people globally each year. Complicated UTIs are particularly challenging to treat due to the presence of multidrug-resistant pathogens. Gram-negative bacilli, including Klebsiella pneumoniae, are the leading cause and can resist commonly used antibiotics. Thus, alternative non-antibiotic treatments are urgently needed, and bacteriophages (phages) represent a promising option. This study aims to isolate, characterize and evaluate phages with therapeutic potential against uropathogenic K. pneumoniae. Of the 19 phages isolated from wastewater sources in Belgium, six were selected for further assessment based on their host range. In vitro bactericidal activity was evaluated using time-kill assays, which demonstrated a significant reduction in bacterial growth following phage treatment. Stability in artificial urine and antibiofilm activity, evaluated using the crystal violet method, were also assessed. Phage stability over 24 hours in artificial urine showed no significant loss in phage activity in five of the six phages evaluated. Compared to the control, phage-treated samples showed inhibited biofilm formation and disruption of mature biofilms. However, this effect depended on both bacterial strain and phage dose. These findings support the development of phage-based therapies against antibiotic-resistant bacteria.
Rapid, high-throughput microcapillary platform allows phage-host measurements alongside direct-from-urine antimicrobial susceptibility testing
Julie Hart1,2, Sarah H Needs1,2, Oliver Hancox1,2, Alexander D Edwards2,3
1School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6UR, UK
2Astratus Limited, Blagrave Street, Reading, RG1 1PL, UK
3School of Electronics and Computer Science, University of Southampton, University Road, Southampton, SO17 1BJ, UK
Standard culture methods for phage-host measurements, such as phage lysis and plaque assays, are manual, slow and labour-intensive. To realise the full potential of phage therapies, better and more rapid phage-host and phage sensitivity assays are required. Current manual antimicrobial susceptibility testing (AST) methods also take 2-3 days to obtain a result at low throughput. Therefore faster, easier-to-use, digital, automated phage sensitivity and AST methods are urgently required. Astratus Limited, a University of Reading spin out, has developed a rapid, automated platform. We present here a novel dual microcapillary assay for performing both phage-host measurements and AST. Proof-of-concept data demonstrates the microcapillary platform’s capability for detecting phage lysis and counting phage plaques. Dark field imaging combined with LED illumination permits label-free quantitation of bacterial light scattering following bacteriophage lysis of Escherichia coli. We can determine host specificity for lytic bacteriophage and perform bacterial measurements including growth kinetics, sedimentation and phage lysis of both low and high bacterial cell densities. Importantly, the phage sensitivity assays can be performed alongside rapid, high-throughput, direct-from-urine AST making the fully customisable microcapillary platform the ideal technology to rapidly evaluate and screen combination therapies. The intended users of our platform are NHS, private hospital and veterinary laboratories and researchers involved in therapeutic phage and bacteriophage research. Our solution aligns with the UK strategy for confronting antimicrobial resistance (AMR) by prioritising new approaches to diagnose and treat infections and supports the One Health approach to tackling AMR. By incorporating both phage and antibiotic selection into one single platform, our goal is to make personalised therapies available for difficult-to-treat UTI patients who currently lack treatment options.
Applications of Bacteriophages as Biocontrol Agents against Spoilage-Causing Pseudomonads
Chiara Krühne, Stefanie Gieschler-Lübbehüsen, Erik Brinks, Charles MAP Franz, Frank Hille
Max Rubner-Institute, Department of Microbiology and Biotechnology, Hermann-Weigmann-Str. 1, 24103 Kiel, Germany
Heat-stable enzymes produced by spoilage-causing Pseudomonas species remain a major challenge for the dairy industry, despite strict hygienic regulations. These enzymes degrade milk fats and proteins, leading to quality deterioration and shortened shelf life. A particular challenge in combating pseudomonads is their ability to form biofilms. Bacteriophages – viruses that specifically infect and lyse bacteria – offer a promising biocontrol strategy.We classified and characterized 16 newly isolated Pseudomonas phages, assessing their host range and ability to lyse planktonic cells and biofilms. The results show a large taxonomic and morphological diversity of phages, with the majority being head-tail phages belonging to the class Caudoviricetes. The host spectrum analysis showed that jumbo phages (>200 kb genome) exhibited the largest host spectra, whereas smaller phages infected only a few bacterial strains. Initial biofilm experiments with single phages and phage cocktails did not yield a significant reduction of host cells, but showed that the phages were still able to penetrate biofilms and infect embedded host cells. In contrast, a preventive phage application on early-stage biofilms revealed a strong inhibition of further biofilm formation. Additional experiments will provide insight into the optimal application strategy required for efficient phage treatment and the minimization of biofilm growth of a variety of spoilage-relevant pseudomonads.
Comparison of pharmacodynamic and pharmacokinetic aspects in systemic and local infection during phage therapy in a murine model
Ivana Mašlaňová1, Lucie Kuntová1, Gabriela Ambrožová2, Soňa Smetanová3, Edita Jeklová4, Hana Šiměčková1, Adam Vinco1, Peter Makovický5, Břetislav Lipový6 and Roman Pantůček1
1Masaryk University, Faculty of Science, Department of Experimental Biology, Brno, Czech Republic
2Department of Biophysics of Immune System, Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic
3Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
4Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czech Republic
5Department of Histology and Embryology, Faculty of Medicine, University of Ostrava, Ostrava, Czech Republic
6Department of Burns Medicine, Third Faculty of Medicine, Charles University and University Hospital Kralovske Vinohrady, Vinohrady, Prague, Czech Republic
Although the use of bacteriophages in treating bacterial infections has a long history and the growing international crisis of resistance to standard antibiotics supports alternative treatment approaches, phage therapy is not currently used as a standard medical approach. One explanation for why phage therapy has not been the subject of broader implementation into clinical practice is that pharmacological data regarding preclinical and clinical testing of phages is still lacking. In the context of phage therapy, this means understanding how phages reach the target bacteria and how effectively they destroy these bacteria. A lack of awareness of these aspects can lead to issues such as insufficient concentration of phages at the infection site or ineffectiveness against certain bacterial strains. Our study compares the pharmacological aspects of phage therapy in a murine model of open wound, where systemic infection occurs, and in a murine model of abscess, which simulates local infection. The pharmacological and pharmacokinetic aspects of phage therapy were studied in 170 mice for 5 days in the infection abscess model. We demonstrated the immunomodulatory effect of phages. The expression of anti-inflammatory and pro-inflammatory markers was monitored in the tested groups of animals using RT-PCR and Western Blotting. We quantified the presence of inducible nitric oxide synthase (iNOS) as a pro-inflammatory marker in the liver. The expression of this marker was increased in groups of animals infected with Staphylococcus aureus and decreased in the phage-treated group. Phage kinetics were monitored using qPCR and plaque titration methods throughout the experiment. The immune system clears bacteriophages from the bloodstream within an hour after administration. Our study provides a comprehensive view of the pharmacological aspects of phage therapy. These findings could lead to a broader use of this therapy in clinical practice. Acknowledgment: Supported by MEYS of the CR (LX22NPO5103) and MZ CR (NU22-05-00042).
Characterisation of four novel Bacillus anthracis bacteriophages
Catriona Matthews1,2, Ertelt Moritz3, Georgie Metters1, Chris Jenkins1, Peter Braun3, Izzy Norville1, Les Bailey2, Philip Ireland1
1Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
2Cardiff School of Pharmacy and Pharmaceutical Sciences, King Edward VII Avenue, Cardiff University, Cardiff CF10 3NB, UK
3Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Immunology, Infection and Pandemic Research, 80799 Munich, Germany
Bacillus anthracis, a Gram-positive, spore-forming bacterium, is the causative agent of anthrax, a zoonotic disease found worldwide with significant implications for both animal and human health. The disease most commonly affects livestock and wild animals but can also infect humans with the route of infection influencing disease progression and severity. While there are existing tools for B. anthracis detection, treatment and decontamination, bacteriophages present a promising alternative and complement to these methods. Phages offer numerous advantages such as their high specificity, reduced disruption to existing microbial flora, ability to replicate over the course of a treatment and greater environmental sustainability, making them an attractive option for enhancing existing strategies. This project focuses on the characterisation of four novel bacteriophages LC1H911, RW, AB1 and 3B6 which were isolated from soil samples in Wales and were found to infect a range of B. anthracis strains, including isolates previously identified as phage resistant. Sequencing and genomic analysis of the four phages revealed three novel Basilisk-like phages – LC1H911, 3B6 and AB1, and phage RW, which was almost identical to the diagnostic γ phage. Preliminary investigations have optimised propagation and revealed phages LC1H911 and 3B6 to be highly lytic against B. anthracis. B. anthracis phage-resistant mutants were isolated to identify the underlying mutations. The most frequently observed mutations occurred in the csaB gene, which encodes a polysaccharide pyruvyl transferase essential for surface layer arrangement in B. anthracis, providing an early indication of the surface properties that may be required for host cell interaction. © Crown Copyright 2025, Dstl. This material is licensed under the terms of the Open Government Licence.
Development of an in vitro culture system to study the lung microcosm in airway diseases
Miles O Oke1, Leah F Cuthbertson2, Martha RJ Clokie1, Spyridon Megremis1
1Becky Mayer Centre for Phage Research, University of Leicester, University Road, Leicester, LE1 7RH, UK
2University of Leicester, University Road, Leicester, LE1 7RH, UK
Chronic respiratory diseases (CRDs) are the third leading cause of death globally, responsible for approximately 4 million deaths in 2019. Across England one in five people are affected by CRDs, with lung cancer, pneumonia, and chronic obstructive pulmonary disease (COPD) being the biggest causes of death. The combined annual economic burden of just asthma and COPD on the NHS is estimated at almost £5 billion. The lung microbiome is home to a diverse ecosystem of microbial communities, including bacteria, fungi, and viruses, and is constantly alternating between states of low microbial presence and resilient microbial colonization, representing a unique, dynamic system. Lung ecology has been linked with CRDs and the wide range of pathophysiological mechanisms they encompass, highlighting the importance of microbial ecology in disease development. Though tremendous advances have been made in identifying microbiome disease states and differentially abundant species, there remains a vague understanding of what drives these microbiome shifts, as well as the link between microbial ecology, microbiome assembly, and disease pathophysiology. Currently, there is a lack of model systems that allow testing of microbial ecology and the extent to which they contribute to disease. These gaps in insight represent major barriers in being able to translate research discoveries to applicable microbiome-based interventions for improved health outcomes. Through developing a model system to study microbial communities through an ecological framework, we hope to address these gaps to identify disease-specific niches and characterise microbial interactions. By understanding the roles of community interactions among relevant species in CRDs, and the impact of bacteriophages on communities, we also aim to develop potential microbiome-based interventions such as bacteriophage therapy.
A competitive fish gelatin formulation for phage delivery
Haoyu Wang1,2; Oluyemi O. Awolusi1; Nikola Chalashkanov2; Saravana K. Jaganathan3; Nick Tucker2; Bukola A Onarinde1
1School of Agrifood Technology and Manufacturing, University of Lincoln, UK
2School of Engineering and Physical Sciences, University of Lincoln, UK
3School of Engineering, University of Leicester, UK
Antimicrobial resistance crisis has prompted renewed interest in bacteriophage therapy as an alternative to antibiotics. Bacteriophages offer several advantages including high specificity, self-replication, and minimal disruption of the host microbiome. However, despite their long history of clinical application, there are ongoing challenges in optimising phage formulations and delivery methods. Electrospinning has emerged as a promising approach for encapsulating and delivering bacteriophages within nanofibers. However, while electrospinning holds significant potential for phage delivery, preserving phage structural integrity and biological activity during the process remains a key obstacle. In our study, we used fish gelatin to encapsulate and deliver bacteriophages via electrospinning. Fish gelatin offers excellent compatibility with bacteriophages and contains less hydroxyproline than mammal-derived gelatin, allowing it to remain fluid in aqueous solutions and eliminating the need for organic solvents during electrospinning. It also possesses good spinnability. In addition, we employed acoustic levitation to hold phage containing gelatin/PBS droplets in mid-air before electrospinning, demonstrating contactless fabrication. We tested the system using bacteriophage K and Staphylococcus aureus. The resulting electrospun phage-loaded fibers showed uniform, smooth morphology (0.48±0.17 μm) and compared with gelatin-only fibers, reduced crystallisation during solidification, embedding phages in a predominantly amorphous structure (69.7%). Antimicrobial testing revealed a clear inhibition zone on day 1, and the encapsulated bacteriophages retained detectable infectivity for at least 14 days, with viability decreasing from 1,633 PFU/cm² initially to 1,265 and 977 PFU/cm² at days 3 and 7, respectively. Our formulation offers a promising approach for phage delivery, and our findings indicate that food‑derived fish gelatin has strong potential for biomedical applications.
Phage product development for non-clinical applications – From laboratory to field
Nethravathi A Poonacha and Team GangaGen
GangaGen Biotechnologies Pvt Ltd., Bengaluru, India
Antibiotic resistance is recognized as a “One Health” challenge because of the rapid emergence and dissemination of resistant bacteria and genes among humans, animals and the environment on a global scale. With the increasing ineffectiveness of antibiotics against drug-resistant bacteria, alternative therapies are gaining attention. Bacteriophage therapy is re-emerging as a promising solution. The presentation will cover GangaGen’s pursuit in using bacteriophage technology to develop novel products using wild-type bacteriophages for use in veterinary settings. Understanding the need to create sustainable and environmentally friendly strategy, and as a substitute for antibiotic in the veterinary area, we isolated broad host range lytic phages against Salmonella strains pathogenic to poultry. We have optimized the manufacturing conditions for industrial scale production of these phages. A placebo-controlled field trial revealed that the phage cocktail was as effective as antibiotics in maintaining the health of broilers, suggesting that phages have the potential to replace antibiotics in poultry management. Similarly, we investigated the potential of phages to control vibriosis in shrimps caused by luminous Vibrio harveyi. In a laboratory model simulating typical hatchery conditions, phage improved survival of shrimp post-larval stage by 40 to 60% against a pathogenic strain of V. harveyi. These results suggest the usefulness of phage-based prophylactics in shrimp hatcheries. Despite the promising advances, several challenges such as narrow host range and specificity, environmental sensitivity, phage formulation and delivery issues, and regulatory hurdles have to be addressed to fully realize the potential of phages. The transitioning of the technique from the lab to the field will be discussed.
Phage-Derived Receptor Binding Proteins and Biolayer Interferometry: Improving Detection of Salmonella enterica
Renato Mota1, Maria J Costa1, Ana Brandão1, Ana Oliveira1,2 and Sílvio B Santos1,2
1CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
2LABBELS –Associate Laboratory, Braga/Guimarães, Portugal
Salmonella enterica remains a major global cause of foodborne illness, with S. Enteritidis and S. Typhimurium accounting for nearly 70% of human infections. Gold-standard culture-based detection methods require 3–5 days for confirmation—an impractical timeframe given the short shelf-life of poultry and perishable foods. Although molecular and immunological assays offer faster alternatives, they are often hindered by false positives, cross-reactivity, and high implementation costs. There is therefore a pressing need for rapid, robust, and highly specific detection technologies for food safety monitoring. Phage-derived receptor binding proteins (RBPs) are emerging as powerful tools for pathogen detection due to their natural specificity and affinity. Here, we identified and characterised a novel RBP from a Salmonella-infecting phage and evaluated its application in a label-free detection system using biolayer interferometry (BLI). The phage genome was investigated in silico using BLASTp, HHpred, and domain prediction tools (Pfam, InterProScan, Motif Search) to identify putative RBPs. Candidate genes were cloned as GFP fusion constructs and heterologously expressed in E. coli. Fluorescence-based binding assays enabled the identification of a functional RBP with strong affinity for S. enterica. Subsequent epifluorescence microscopy assays confirmed the high specificity of the RBP, which bound to nearly all tested strains of S. enterica subsp. enterica, with no detectable cross-reactivity to non-Salmonella foodborne or opportunistic pathogens. This RBP was then employed in a BLI-based assay, allowing real-time, label-free detection of bacterial cells in under 40 minutes. Overall, our results highlight the potential of this phage-derived RBP as a selective and rapid biorecognition element. When coupled with BLI, it offers a promising platform for the development of next-generation diagnostics to improve Salmonella detection in food safety and public health contexts.
Experimental evolution strategies to modulate bacteriophage life-history traits
Manuela Reuter1, Michael Sieber1, Octavio Reyes-Matte1, Christina Vasileiou1, Jordan Romeyer-Dherbey2, Christopher Böhmker1, Javier Lopez-Garrido1, Frederic Bertels1
1Max Planck Institute for Evolutionary Biology, Plön, Germany
2University of Cambridge, Cambridge, United Kingdom
The evolutionary success of lytic bacteriophages depends on key life-history traits, yet how these traits shape fitness across different environments remains poorly understood. Here, we explored this question in phage ΦX174 using a combination of experimental evolution, quantitative trait measurements, and mathematical modelling. By investigating how serial transfer conditions shape evolutionary outcomes in liquid culture, we found that the time between transfers imposes divergent selection on adsorption rate. Longer transfer intervals, which allow multiple infection cycles, favoured fast-adsorbing mutants. In contrast, shorter intervals, permitting only one infection cycle, selected for slower adsorption. Modelling revealed that slow adsorption minimises dead-end attachments, maximising the number of transferable virions in short-transfer regimes. These trade-offs resulted in distinct plaque phenotypes in solid media: fast adsorbers formed small plaques, while slow adsorbers formed large ones. A single point mutation in the major capsid protein drove changes in adsorption and, in fast adsorbers, also increased environmental persistence. These contrasting phenotypes, arising from closely related genotypes, highlight the influence of environmental structure on phage evolution. Our findings show how simple changes in propagation conditions can steer phage phenotypes, offering insights relevant to both evolutionary biology and phage therapy.
Identification of Genetic Determinants Driving Bacteriophage Translocation Through the Blood–Brain Barrier
Dóra Sala1, Gábor Apjok2, Bálint Kintses3, Bálint Csörgő4, Mária A Deli5, Ilona Gróf6
1,2,3HUN-REN Biological Research Centre, Szeged, Hungary, Synthetic and Systems Biology Unit, Laboratory of Translational Microbiology
4HUN-REN Biological Research Centre, Szeged, Hungary, Institute of Biochemistry, Synthetic and Systems Biology Unit, Gene Technology Research Group
5,6HUN-REN Biological Research Centre, Szeged, Hungary, Institute of Biophysics, Molecular Neurobiology Research Unit, Biological Barrier Research Group
The global rise of antibiotic-resistant bacterial pathogens presents a critical threat to public health. Bacteriophages (phages) have emerged as promising candidates for targeted antibacterial therapy. Recent evidence suggests that beyond their therapeutic applications, phages are integral components of the human microbiome and can be detected across multiple organs, including immunoprivileged and therapeutically inaccessible sites such as the central nervous system (CNS). The blood-brain barrier (BBB) is one of the most selective interfaces in the human body. It severely limits the translocation of most therapeutics, thereby complicating the treatment of CNS-related diseases, including infections caused by multidrug-resistant bacteria. Remarkably, certain phages have been shown to cross the BBB and exhibit antimicrobial activity within the CNS, offering a novel approach for treating infections in otherwise inaccessible neural tissues. However, the molecular mechanisms enabling this translocation remain unknown. In this study, we aimed to identify the genetic determinants driving BBB translocation of phages. Our analysis revealed the high prevalence of immunoglobulin (Ig)-like domains among BBB-permeable phages. These structural motifs are hypothesized to mediate interactions between the viral particles and human cells. To experimentally validate our findings, the identified genetic determinants were inserted into the genomes of phages that are unable to cross the BBB. The resulting engineered variants were then tested on humanized in vitro BBB models to evaluate their ability to reach the CNS. Our findings highlight a potential role for Ig-like domains in facilitating barrier crossing and lay the foundation for the development of genetically modified phages as therapeutic agents against CNS infections, or potentially even for treating other neurological disorders.
Exploring Nanomotion Technology for Phage Therapy: A Novel Diagnostic Tool to Combat Antimicrobial Resistance
Anthony Vocat1, Amanda Luraschi-Eggemann2, Grzegorz Jóźwiak2, Julia Dolezel3, Zahra Azizi3, Shreyas Vasantham3, Salomé Gutiérrez3, Danuta Cichocka2, Alexander Sturm2, Gregory Resch1
1Centre for Research and Innovation in Clinical Pharmaceutical Sciences (CRISP), Lausanne University Hospital (CHUV), Lausanne, Switzerland
2Resistell AG, Muttenz, Switzerland
3Cellectric Biosciences GmbH, Vienna, Austria
Antimicrobial resistance (AMR) is an escalating global health threat, responsible for hundreds of thousands of deaths annually, with projections reaching 10 million fatalities per year by 2050 without effective interventions. Phage therapy, utilizing bacteriophages to target drug-resistant bacteria, presents a promising complementary approach to antibiotic treatments. This study explores the application of nanomotion technology for rapid, growth-independent in vitro phage susceptibility testing (PST). We developed Phenotech PST, an innovative technology that simplifies empirical drop test assays (DTA) by measuring the real-time nanomotions (vibrations) of living bacterial cells. These vibrations are detected via micromechanical sensors (cantilevers). Clinical isolates of Pseudomonas aeruginosa (n=47) were exposed to five distinct bacteriophages across 171 experiments. Machine learning algorithms were applied to analyze the resulting nanomotion data. Additionally, PST was performed directly on patient sputum samples, circumventing traditional bacterial isolation steps. Phenotech PST significantly reduced the time-to-result (TTR) from approximately 16 hours for standard DTA to just 6 hours. By analyzing variance slopes of nanomotion signals, the technology accurately classified phage activity, correlating with observed lysis patterns in DTA. While no significant signal differences were found between inactive phages and control samples (p > 0.99), Phenotech PST achieved 91% accuracy in distinguishing clear and turbid lysis outcomes, with 97.5% sensitivity and 83% specificity (p < 0.001). Preliminary sputum testing results were promising, though further optimization is needed for standardization. Nanomotion technology demonstrates significant potential for enhancing PST and guiding phage therapy decisions. By providing a rapid, reliable, and growth-independent readout, this method addresses key limitations of traditional assays. Future work will focus on refining sputum testing protocols, incorporating temperature-controlled conditions at 37°C, and optimizing TTR. Our findings contribute to the advancement of phage-based diagnostics, offering a valuable tool for combating AMR.
Genomic diversity and genetic exchange between prophages of Burkholderia pseudomallei, B. thailandensis and their free phages from soils
Patoo Withatanung1, Veerachat Muangsombut1, Sujintana Janesomboon1, Vanaporn Wuthiekanun2, Premjit Amornchai2, Sorujsiri Chareonsudjai3, Dave J. Baker4, Martha R.J. Clokie5, Edouard E. Galyov5, Ozan Gundogdu6, Sunee Korbsrisate1
1Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
2Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
3Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
4Science Operations, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
5Becky Mayer Centre for Bacteriophage Research, Department of Genetics, Genomics and Cancer Sciences, University of Leicester, Leicester, UK
6Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
Burkholderia pseudomallei, pathogenic bacterium that causes melioidosis, can be found coexisting with Burkholderia thailandensis and B. thailandensis capsule variant (BTCV) in the environment. Currently, most Burkholderia phage studies focus on in silico analyzes of clinical strains which are likely to reflect only a small subset of total diversity. This study aimed to investigate the genomes of induced prophages and soil-isolated free phages associated with Burkholderia spp. To achieve this, soil-isolated B. pseudomallei, B. thailandensis, and BTCV were induced with mitomycin C; resulting in the recovery of 66 culturable prophages. In addition, 16 phages were isolated from soil. Genomic analysis of these 82 Burkholderia-associated phages revealed a dynamic interplay between lysogenic and lytic phage lifestyles in the environment. The sequence homology and integrases presence in environmental free phages support the idea that they originate from prophages through environmental triggers. Three B. pseudomallei phage clades were identified: BP1 represents a novel group whereas clades BP2-3 showed homology with known B. pseudomallei phages. The finding that clades BP2 and BP3 share sequence similarity with phages isolated from melioidosis patients indicates that prophages can be induced and detected in patients. B. thailandensis and BTCV phages form seven clades (BT1-7), each clade contains various genes that promote bacterial survival, stress resistance and evolution. This pioneering study provides novel insights into Burkholderia phage dynamics, origins and their potential for horizontal transfer between environmental and clinical settings. Detection of B. pseudomallei phages in the environment has the potential to serve as ecological markers for B. pseudomallei surveillance.
