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Wen Q, Chen X, Xu M, Liu R, Lian W, Ma Y, Ibrahim AA. Selection and characterization of spontaneous phage-resistant mutant of Limosilactobacillus fermentum. Int J Food Microbiol 2024; 423:110833. [PMID: 39079450 DOI: 10.1016/j.ijfoodmicro.2024.110833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 07/14/2024] [Accepted: 07/21/2024] [Indexed: 08/18/2024]
Abstract
Phage infection remains a major cause of fermentation failures in the dairy industry. The development of phage-resistant mutants of important fermentation strains is an effective measure used to address phage-related issues. This study employed the secondary culture method to screen for spontaneous phage-resistant mutants from the phage sensitive strain Limosilactobacillus fermentum IMAU32646 (L. fermentum IMAU32646). The phenotypic characteristics, technological attributes, probiotic characterization, adsorption characteristics and mutant genes were investigated. The results showed that the mutant strain displayed a high degree of phage-resistance and stability. The mutant strain produced more lactic acid during fermentation than the sensitive strain, while maintaining identical cell structure and morphologies. The mutant strain exhibited superior tolerance to acid and bile salts compared to the sensitive strain. Furthermore, the adsorption rate of phage LFP01 on the mutant strain was significantly lower than that of the sensitive strain. Following genome re-sequencing analysis showed that adsorption interference and blocked DNA injection were responsible for its phage-resistance. These results may provide a new strategy for avoiding phage contamination and industrial application of phage-resistant strains with good characteristics.
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Affiliation(s)
- Qiannan Wen
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Xia Chen
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
| | - Ming Xu
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Runze Liu
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Weiqi Lian
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Yang Ma
- Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot 010018, China; Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot 010018, China; Inner Mongolia Key Laboratory of Dairy Biotechnology and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Amel A Ibrahim
- Dairy Science and Technology Department, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt
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Worthan SB, McCarthy RDP, Delaleau M, Stikeleather R, Bratton BP, Boudvillain M, Behringer MG. Evolution of pH-sensitive transcription termination in Escherichia coli during adaptation to repeated long-term starvation. Proc Natl Acad Sci U S A 2024; 121:e2405546121. [PMID: 39298488 PMCID: PMC11441560 DOI: 10.1073/pnas.2405546121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 08/19/2024] [Indexed: 09/21/2024] Open
Abstract
Fluctuating environments that consist of regular cycles of co-occurring stress are a common challenge faced by cellular populations. For a population to thrive in constantly changing conditions, an ability to coordinate a rapid cellular response is essential. Here, we identify a mutation conferring an arginine-to-histidine (Arg to His) substitution in the transcription terminator Rho. The rho R109H mutation frequently arose in Escherichia coli populations experimentally evolved under repeated long-term starvation conditions, during which the accumulation of metabolic waste followed by transfer into fresh media results in drastic environmental pH fluctuations associated with feast and famine. Metagenomic sequencing revealed that populations containing the rho mutation also possess putative loss-of-function mutations in ydcI, which encodes a recently characterized transcription factor associated with pH homeostasis. Genetic reconstructions of these mutations show that the rho allele confers plasticity via an alkaline-induced reduction of Rho function that, when found in tandem with a ΔydcI allele, leads to intracellular alkalization and genetic assimilation of Rho mutant function. We further identify Arg to His substitutions at analogous sites in rho alleles from species that regularly experience neutral to alkaline pH fluctuations in their environments. Our results suggest that Arg to His substitutions in Rho may serve to rapidly coordinate complex physiological responses through pH sensing and shed light on how cellular populations use environmental cues to coordinate rapid responses to complex, fluctuating environments.
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Affiliation(s)
- Sarah B. Worthan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN37232
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN37232
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN37232
| | | | - Mildred Delaleau
- Centre de Biophysique Moléculaire, CNRS UPR4301, affiliated with Université d’Orléans, Orléans Cedex 245071, France
| | - Ryan Stikeleather
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ85281
| | - Benjamin P. Bratton
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN37232
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN37232
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN37232
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, affiliated with Université d’Orléans, Orléans Cedex 245071, France
| | - Megan G. Behringer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN37232
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN37232
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN37232
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
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3
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Hellwig P, Dittrich A, Heyer R, Reichl U, Benndorf D. Detection, isolation and characterization of phage-host complexes using BONCAT and click chemistry. Front Microbiol 2024; 15:1434301. [PMID: 39296306 PMCID: PMC11409252 DOI: 10.3389/fmicb.2024.1434301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 08/15/2024] [Indexed: 09/21/2024] Open
Abstract
Introduction Phages are viruses that infect prokaryotes and can shape microbial communities by lysis, thus offering applications in various fields. However, challenges exist in sampling, isolation and accurate prediction of the host specificity of phages as well as in the identification of newly replicated virions in response to environmental challenges. Methods A new workflow using biorthogonal non-canonical amino acid tagging (BONCAT) and click chemistry (CC) allowed the combined analysis of phages and their hosts, the identification of newly replicated virions, and the specific tagging of phages with biotin for affinity chromatography. Results Replication of phage λ in Escherichia coli was selected as a model for workflow development. Specific labeling of phage λ proteins with the non-canonical amino acid 4-azido-L-homoalanine (AHA) during phage development in E. coli was confirmed by LC-MS/MS. Subsequent tagging of AHA with fluorescent dyes via CC allowed the visualization of phages adsorbed to the cell surface by fluorescence microscopy. Flow cytometry enabled the automated detection of these fluorescent phage-host complexes. Alternatively, AHA-labeled phages were tagged with biotin for purification by affinity chromatography. Despite biotinylation the tagged phages could be purified and were infectious after purification. Discussion Applying this approach to environmental samples would enable host screening without cultivation. A flexible and powerful workflow for the detection and enrichment of phages and their hosts in pure cultures has been established. The developed method lays the groundwork for future workflows that could enable the isolation of phage-host complexes from diverse complex microbial communities using fluorescence-activated cell sorting or biotin purification. The ability to expand and customize the workflow through the growing range of compounds for CC offers the potential to develop a versatile toolbox in phage research. This work provides a starting point for these further studies by providing a comprehensive standard operating procedure.
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Affiliation(s)
- Patrick Hellwig
- Chair of Bioprocess Engineering, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg, Magdeburg, Germany
| | - Anna Dittrich
- Department of Systems Biology, Institute of Biology, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Robert Heyer
- Multidimensional Omics Analyses Group, Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Dortmund, Germany
- Multidimensional Omics Analyses Group, Faculty of Technology, Bielefeld University, Universitätsstraße, Bielefeld, Germany
| | - Udo Reichl
- Chair of Bioprocess Engineering, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg, Magdeburg, Germany
| | - Dirk Benndorf
- Chair of Bioprocess Engineering, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
- Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg, Magdeburg, Germany
- Department of Microbiology, Anhalt University of Applied Sciences, Köthen, Germany
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Deng T, Wu W, Zhou J, Zeng Q, Wang H, Deng C. An electrochemical biosensor for sensitive detection of live Salmonella in food via MXene amplified methylene blue signals and electrostatic immobilization of bacteriophages. Mikrochim Acta 2024; 191:550. [PMID: 39167218 DOI: 10.1007/s00604-024-06610-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Accepted: 08/05/2024] [Indexed: 08/23/2024]
Abstract
A novel bacteriophage-targeted electrochemical biosensor designed for accurate and quantitative detection of live Salmonella in food samples is presented. The biosensor is simply constructed by electrostatic immobilizing bacteriophages on MXene-nanostructured electrodes. MXene, renowned for its high surface area, biocompatibility, and conductivity, serves as an ideal platform for bacteriophage immobilization. This allows for a high-density immobilization of bacteriophage particles, achieving approximately 71 pcs μm-2. Remarkably, the bacteriophages immobilized MXene nanostructured electrodes still maintain their viability and functionality, ensuring their effectiveness in pathogen detection. Therefore, the proposed biosensor exhibited enhanced sensitivity with a low limit of detection (LOD) of 5 CFU mL-1. Notably, the biosensor shows excellent specificity in the presence of other bacteria that commonly contaminate food and can distinguish live Salmonella from a mixed population. Furthermore, it is applicable in detecting live Salmonella in food samples, which highlights its potential in food safety monitoring. This biosensor offers simplicity, convenience, and suitability for resource-limited environments, making it a promising tool for on-site monitoring of foodborne pathogenic bacteria.
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Affiliation(s)
- Tingliu Deng
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Wuming Wu
- School of Electronic Science and Engineering, Hunan University of Information Technology, Changsha, 410151, China
| | - Jingjing Zhou
- Beijing Key Laboratory of Maternal-Fetal Medicine and Fetal Heart Disease & Echocardiography Department, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100069, China
| | - Qin Zeng
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Heye Wang
- Key Laboratory of Food Quality and Safety of Jiangsu Province, State Key Laboratory Breeding Base, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.
- State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co., Ltd., Shanghai, 200436, China.
| | - Chunyan Deng
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China.
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5
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Parmar K, Fackler JR, Rivas Z, Mandrekar J, Greenwood-Quaintance KE, Patel R. A comparison of phage susceptibility testing with two liquid high-throughput methods. Front Microbiol 2024; 15:1386245. [PMID: 39171268 PMCID: PMC11335653 DOI: 10.3389/fmicb.2024.1386245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 07/09/2024] [Indexed: 08/23/2024] Open
Abstract
Phage therapy is a promising antibacterial strategy, especially given that drug-resistant bacterial infections are escalating worldwide. Because phages are not active against all strains of a given species, phages being considered for therapeutic use would ideally be tested against bacterial isolates from individual patients prior to administration. Standardized, clinically validated phage susceptibility testing (PST) methods are needed for assessing in vitro phage activity. This study compared two high-throughput liquid-based PST assays. The first, using the Biolog Omnilog™, assessed changes in microbial respiration leading to color changes based on a tetrazolium dye. The second, Agilent BioTek Cytation 7, assessed changes in optical density. Both used 96-well microtiter plate formats. A total of 55 diverse phages with activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, or Enterococcus faecalis were studied against their respective susceptible bacterial hosts and non-susceptible controls, with susceptibility defined based on plaque assay. PST was performed by both assays in replicates, with results compared in terms of hold times (time through which bacterial growth is inhibited by phage compared to controls). Coefficients of variance and interclass correlation coefficients were used to assess inter- and intra-assay reproducibility. Based on a ≤50% coefficient of variance cutpoint, 87% of Biolog and 84% of Agilent assays were considered valid for susceptible bacteria, with 100% considered valid for non-susceptible bacteria by both systems. Using a 8 h hold time cutpoint, 100% of the results matched between the two assays. The interclass correlation coefficient showed 26% excellent agreement, 35% good agreement, and 17% moderate agreement between the two assays for susceptible isolates and 100% excellent agreement for non-susceptible isolates. Overall, the assays compared provided good/fair statistical reproducibility for the assessment of phage susceptibility.
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Affiliation(s)
- Krupa Parmar
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Joseph R. Fackler
- Adaptive Phage Therapeutics, Inc. (APT), Gaithersburg, MD, United States
| | - Zuriel Rivas
- Adaptive Phage Therapeutics, Inc. (APT), Gaithersburg, MD, United States
| | - Jay Mandrekar
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN, United States
| | - Kerryl E. Greenwood-Quaintance
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
- Division of Public Health, Infectious Diseases, and Occupational Medicine, Department of Medicine, Mayo Clinic, Rochester, MN, United States
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6
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Esteves NC, Scharf BE. Serratia marcescens ATCC 274 increases production of the red pigment prodigiosin in response to Chi phage infection. Sci Rep 2024; 14:17750. [PMID: 39085460 PMCID: PMC11291754 DOI: 10.1038/s41598-024-68747-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 07/26/2024] [Indexed: 08/02/2024] Open
Abstract
Serratia marcescens is an opportunistic human pathogen that produces a vibrant red pigment called prodigiosin. Prodigiosin has implications in virulence of S. marcescens and promising clinical applications. We discovered that addition of the virulent flagellotropic bacteriophage χ (Chi) to a culture of S. marcescens stimulates a greater than fivefold overproduction of prodigiosin. Active phage infection is required for the effect, as a χ-resistant strain lacking flagella does not respond to phage presence. Via a reporter fusion assay, we have determined that the addition of a χ-induced S. marcescens cell lysate to an uninfected culture causes a threefold increase in transcription of the pig operon, containing genes essential for pigment biosynthesis. Replacement of the pig promoter with a constitutive promoter abolished the pigmentation increase, indicating that regulatory elements present in the pig promoter likely mediate the phenomenon. We hypothesize that S. marcescens detects the threat of phage-mediated cell death and reacts by producing prodigiosin as a stress response. Our findings are of clinical significance for two main reasons: (i) elucidating complex phage-host interactions is crucial for development of therapeutic phage treatments, and (ii) overproduction of prodigiosin in response to phage could be exploited for its biosynthesis and use as a pharmaceutical.
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Affiliation(s)
- Nathaniel C Esteves
- Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Birgit E Scharf
- Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
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7
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Ibrahim HM, Mohammed GM, Sayed RH, Elshoky HA, Ahmed MM, El Sayed MF, Elsaady SA. Polymeric nanocarrier-based adjuvants to enhance a locally produced mucosal coryza vaccine in chicken. Sci Rep 2024; 14:15262. [PMID: 38961116 PMCID: PMC11222434 DOI: 10.1038/s41598-024-65267-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 06/18/2024] [Indexed: 07/05/2024] Open
Abstract
Infectious coryza (IC) is an acute upper respiratory disease of chicken caused by Avibacterium (A.) paragallinarum. This disease results in an increased culling rate in meat chicken and a marked decrease in egg production (10% to more than 40%) in laying and breeding hens. Vaccines were first used against IC and effectively controlled the disease. Nanotechnology provides an excellent way to develop a new generation of vaccines. NPs have been widely used in vaccine design as adjuvants and antigen delivery vehicles and as antibacterial agents; thus, they can be used as inactivators for bacterial culture. In this research, the antibacterial effects of several nanoparticles (NPs), such as silicon dioxide with chitosan (SiO2-CS), oleoyl-chitosan (O.CS), silicon dioxide (SiO2), and iron oxide (Fe3O4), on A. paragallinarum were studied. Additionally, different A. paragallinarum vaccines were made using the same nanomaterials at a concentration of 400 µg/ml to help control infectious coryza disease in chicken. A concentration of 400 µg/ml of all the NPs tested was the best concentration for the inactivation of A. paragallinarum. Additionally, this study showed that the infectious coryza vaccine adjuvanted with SiO2 NPs had the highest immune response, followed by the infectious coryza vaccine adjuvanted with Fe3O4 NPs, the infectious coryza vaccine adjuvanted with SiO2-CS NPs, and the infectious coryza vaccine adjuvanted with O.CS NPs in comparison with the infectious coryza vaccine adjuvanted with liquid paraffin (a commercial vaccine).
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Affiliation(s)
- Hazem M Ibrahim
- Veterinary Serum and Vaccine Research Institute (VSVRI), Agricultural Research Center (ARC), Cairo, Egypt
| | - Gina M Mohammed
- Central Laboratory for Evaluation of Veterinary Biologics (CLEVB), Agricultural Research Center (ARC), Cairo, Egypt
| | - Rafik Hamed Sayed
- Central Laboratory for Evaluation of Veterinary Biologics (CLEVB), Agricultural Research Center (ARC), Cairo, Egypt
| | - Hisham A Elshoky
- Nanotechnology and Advanced Materials Central Lab, Agricultural Research Center, Giza, Egypt.
- Regional Center for Food and Feed, Agricultural Research Center, Giza, Egypt.
| | - Marwa M Ahmed
- Veterinary Serum and Vaccine Research Institute (VSVRI), Agricultural Research Center (ARC), Cairo, Egypt
| | - Marwa Fathy El Sayed
- Central Laboratory for Evaluation of Veterinary Biologics (CLEVB), Agricultural Research Center (ARC), Cairo, Egypt
| | - Shaimaa Abdelall Elsaady
- Central Laboratory for Evaluation of Veterinary Biologics (CLEVB), Agricultural Research Center (ARC), Cairo, Egypt
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8
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Bisen M, Kharga K, Mehta S, Jabi N, Kumar L. Bacteriophages in nature: recent advances in research tools and diverse environmental and biotechnological applications. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:22199-22242. [PMID: 38411907 DOI: 10.1007/s11356-024-32535-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/15/2024] [Indexed: 02/28/2024]
Abstract
Bacteriophages infect and replicate within bacteria and play a key role in the environment, particularly in microbial ecosystems and bacterial population dynamics. The increasing recognition of their significance stems from their wide array of environmental and biotechnological uses, which encompass the mounting issue of antimicrobial resistance (AMR). Beyond their therapeutic potential in combating antibiotic-resistant infections, bacteriophages also find vast applications such as water quality monitoring, bioremediation, and nutrient cycling within environmental sciences. Researchers are actively involved in isolating and characterizing bacteriophages from different natural sources to explore their applications. Gaining insights into key aspects such as the life cycle of bacteriophages, their host range, immune interactions, and physical stability is vital to enhance their application potential. The establishment of diverse phage libraries has become indispensable to facilitate their wide-ranging uses. Consequently, numerous protocols, ranging from traditional to cutting-edge techniques, have been developed for the isolation, detection, purification, and characterization of bacteriophages from diverse environmental sources. This review offers an exploration of tools, delves into the methods of isolation, characterization, and the extensive environmental applications of bacteriophages, particularly in areas like water quality assessment, the food sector, therapeutic interventions, and the phage therapy in various infections and diseases.
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Affiliation(s)
- Monish Bisen
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh, 173229, India
| | - Kusum Kharga
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh, 173229, India
| | - Sakshi Mehta
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh, 173229, India
| | - Nashra Jabi
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh, 173229, India
| | - Lokender Kumar
- School of Biotechnology, Faculty of Applied Sciences and Biotechnology, Shoolini University, Solan, Himachal Pradesh, 173229, India.
- Cancer Biology Laboratory, Raj Khosla Centre for Cancer Research, Shoolini University, Himachal Pradesh, Solan, 173229, India.
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9
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Wang R, Yeh YJ, An YN, Virly. Engineering pH-sensitive erodible chitosan hydrogel composite containing bacteriophage: An interplay between hydrogel and bacteriophage against Staphylococcus aureus. Int J Biol Macromol 2023; 253:127371. [PMID: 37827407 DOI: 10.1016/j.ijbiomac.2023.127371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/25/2023] [Accepted: 10/09/2023] [Indexed: 10/14/2023]
Abstract
Encapsulation of phages represents a key approach for improving phage stability and controlling phage delivery dosage. The hydrogel made from positively charged quaternized chitosan (QCS) and multivalent crosslinker, aldehyde-modified poly(xylitol sebacate)-co-poly(ethylene glycol) (APP) was introduced for the first time for drug (phage 44AHJD) delivery. The freeze-thawing (FT) treatment enhanced the porous structure and the stress resistance of native hydrogel with increased compression stress (stiffness) from 10 to 20 kPa. The stiffness of the phage-loaded hydrogel (FTP) was suitable for the proper release of phage particles and polymer chains, both working synergistically against bacterial growth. The FTP followed the Korsmeyer-Peppas model's anomalous diffusion of phage particles at different temperatures (30-45 °C) and pH (6.6-8.5) conditions. FTP was sensitive to pH, which released more phage particles at pH-neutral conditions, while the release under acidic and alkaline conditions was more based on gel degradation. The high biocompatibility of FTP hydrogel at its working concentration of 30 mg mL-1 was demonstrated through a hemolysis ratio of <2 %. Sixty percent of the total encapsulated phages and 6 mg mL-1 of hydrogel debris were released after 10 h of hydrogel submerge treatment, which can fight the growing bacteria and the emergence of phage-resistant bacteria.
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Affiliation(s)
- Reuben Wang
- Institute of Food Safety and Health, National Taiwan University, Taipei City, Taiwan; Master of Public Health (MPH) Program, National Taiwan University, Taipei City, Taiwan; GIP-TRIAD Master's Degree in Agro-Biomedical Science, National Taiwan University, Taipei City, Taiwan.
| | - Yu-Jia Yeh
- Institute of Food Safety and Health, National Taiwan University, Taipei City, Taiwan
| | - Yu-Ning An
- Institute of Food Safety and Health, National Taiwan University, Taipei City, Taiwan
| | - Virly
- Global Health Program, College of Public Health, National Taiwan University, Taipei City, Taiwan; Department of Food Technology, Faculty of Agricultural Technology, Widya Mandala Surabaya Catholic University, Surabaya, Indonesia
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10
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Uyttebroek S, Bessems L, Metsemakers WJ, Debaveye Y, Van Gerven L, Dupont L, Depypere M, Wagemans J, Lavigne R, Merabishvili M, Pirnay JP, Devolder D, Spriet I, Onsea J. Stability of magistral phage preparations before therapeutic application in patients with chronic rhinosinusitis, sepsis, pulmonary, and musculoskeletal infections. Microbiol Spectr 2023; 11:e0290723. [PMID: 37819122 PMCID: PMC10715222 DOI: 10.1128/spectrum.02907-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/30/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE As antimicrobial resistance becomes more prevalent, the application of (bacterio)phage therapy as an alternative treatment for difficult-to-treat infections is (re)gaining popularity. Over the past decade, numerous promising case reports and series have been published demonstrating the therapeutic potential of phage therapy. However, important questions remain regarding the optimal treatment protocol and, unlike for medicinal products, there are currently no predefined quality standards for the stability of phage preparations. Phage titers can be influenced by several factors which could lead to reduced titers after preparation and storage and, ultimately, subtherapeutic applications. Determining the stability of different phages in different recipients according to the route of administration is therefore one of the first important steps in establishing a standardized protocol for phage therapy.
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Affiliation(s)
- Saartje Uyttebroek
- Department of Otorhinolaryngology, Head and Neck surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Experimental Otorhinolaryngology, Rhinology Research, KU Leuven, Leuven, Belgium
| | - Laura Bessems
- Department of Trauma Surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Willem-Jan Metsemakers
- Department of Trauma Surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Yves Debaveye
- Department of Intensive Care Medicine, University Hospitals Leuven, Leuven, Belgium
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Laura Van Gerven
- Department of Otorhinolaryngology, Head and Neck surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Neurosciences, Experimental Otorhinolaryngology, Rhinology Research, KU Leuven, Leuven, Belgium
- Department of Microbiology, Immunology and Transplantation, Allergy and Clinical Immunology Research Group, KU Leuven, Leuven, Belgium
| | - Lieven Dupont
- Department of Pneumology, University Hospitals Leuven, Leuven, Belgium
- Department of Chronic Diseases and Metabolism, Respiratory Diseases and Thoracic Surgery, KU Leuven, Leuven, Belgium
| | - Melissa Depypere
- Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
- Department of Microbiology, Immunology and Transplantation, Laboratory of Clinical Bacteriology and Mycology, KU Leuven, Leuven, Belgium
| | - Jeroen Wagemans
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Rob Lavigne
- Department of Biosystems, Laboratory of Gene Technology, KU Leuven, Leuven, Belgium
| | - Maya Merabishvili
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Brussels, Belgium
| | - Jean-Paul Pirnay
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Brussels, Belgium
| | - David Devolder
- Pharmacy Department, University Hospitals Leuven, Leuven, Belgium
| | - Isabel Spriet
- Pharmacy Department, University Hospitals Leuven, Leuven, Belgium
- Department of Pharmaceutical and Pharmacological Sciences, Clinical Pharmacology and Pharmacotherapy, KU Leuven, Leuven, Belgium
| | - Jolien Onsea
- Department of Trauma Surgery, University Hospitals Leuven, Leuven, Belgium
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium
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11
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Yerushalmy O, Braunstein R, Alkalay-Oren S, Rimon A, Coppenhagn-Glazer S, Onallah H, Nir-Paz R, Hazan R. Towards Standardization of Phage Susceptibility Testing: The Israeli Phage Therapy Center "Clinical Phage Microbiology"-A Pipeline Proposal. Clin Infect Dis 2023; 77:S337-S351. [PMID: 37932122 DOI: 10.1093/cid/ciad514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023] Open
Abstract
Using phages as salvage therapy for nonhealing infections is gaining recognition as a viable solution for patients with such infections. The escalating issue of antibiotic resistance further emphasizes the significance of using phages in treating bacterial infections, encompassing compassionate-use scenarios and clinical trials. Given the high specificity of phages, selecting the suitable phage(s) targeting the causative bacteria becomes critical for achieving treatment success. However, in contrast to conventional antibiotics, where susceptibility-testing procedures were well established for phage therapy, there is a lack of standard frameworks for matching phages from a panel to target bacterial strains and assessing their interactions with antibiotics or other agents. This review discusses and compares published methods for clinical phage microbiology, also known as phage susceptibility testing, and proposes guidelines for establishing a standard pipeline based on our findings over the past 5 years of phage therapy at the Israeli Phage Therapy Center.
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Affiliation(s)
- Ortal Yerushalmy
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- Faculty of Dental Medicine, Institute of Biomedical and Oral Research (IBOR), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ron Braunstein
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- Faculty of Dental Medicine, Institute of Biomedical and Oral Research (IBOR), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sivan Alkalay-Oren
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- Faculty of Dental Medicine, Institute of Biomedical and Oral Research (IBOR), The Hebrew University of Jerusalem, Jerusalem, Israel
- The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Amit Rimon
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- Faculty of Dental Medicine, Institute of Biomedical and Oral Research (IBOR), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shunit Coppenhagn-Glazer
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- Faculty of Dental Medicine, Institute of Biomedical and Oral Research (IBOR), The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hadil Onallah
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ran Nir-Paz
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ronen Hazan
- The Israeli Phage Therapy Center (IPTC) of Hadassah Medical Center and the Hebrew University, Jerusalem, Israel
- Faculty of Dental Medicine, Institute of Biomedical and Oral Research (IBOR), The Hebrew University of Jerusalem, Jerusalem, Israel
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12
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Egido JE, Toner-Bartelds C, Costa AR, Brouns SJJ, Rooijakkers SHM, Bardoel BW, Haas PJ. Monitoring phage-induced lysis of gram-negatives in real time using a fluorescent DNA dye. Sci Rep 2023; 13:856. [PMID: 36646746 PMCID: PMC9842612 DOI: 10.1038/s41598-023-27734-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 01/06/2023] [Indexed: 01/18/2023] Open
Abstract
Bacteriophages (phages) are viruses that specifically attack bacteria. Their use as therapeutics, which constitutes a promising alternative to antibiotics, heavily relies on selecting effective lytic phages against the pathogen of interest. Current selection techniques are laborious and do not allow for direct visualization of phage infection dynamics. Here, we present a method that circumvents these limitations. It can be scaled for high-throughput and permits monitoring of the phage infection in real time via a fluorescence signal readout. This is achieved through the use of a membrane-impermeant nucleic acid dye that stains the DNA of damaged or lysed bacteria and new phage progeny. We have tested the method on Pseudomonas aeruginosa and Klebsiella pneumoniae and show that an increase in fluorescence reflects phage-mediated killing. This is confirmed by other techniques including spot tests, colony plating, flow cytometry and metabolic activity measurements. Furthermore, we illustrate how our method may be used to compare the activity of different phages and to screen the susceptibility of clinical isolates to phage. Altogether, we present a fast, reliable way of selecting phages against Gram-negative bacteria, which may be valuable in optimizing the process of selecting phages for therapeutic use.
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Affiliation(s)
- Julia E Egido
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Catherine Toner-Bartelds
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Ana Rita Costa
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft, The Netherlands
- Fagenbank, Delft, The Netherlands
| | - Stan J J Brouns
- Department of Bionanoscience, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft, The Netherlands
- Fagenbank, Delft, The Netherlands
| | - Suzan H M Rooijakkers
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Bart W Bardoel
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Pieter-Jan Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
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13
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Patpatia S, Schaedig E, Dirks A, Paasonen L, Skurnik M, Kiljunen S. Rapid hydrogel-based phage susceptibility test for pathogenic bacteria. Front Cell Infect Microbiol 2022; 12:1032052. [PMID: 36569196 PMCID: PMC9771388 DOI: 10.3389/fcimb.2022.1032052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Phage therapy is one alternative to cure infections caused by antibiotic resistant bacteria. Due to the narrow host range of phages, hundreds to thousands of phages are required to cover the diversity of bacterial pathogens. In personalized phage therapy, fast selection of the phages for individual patients is essential for successful therapy. The aims of this study were to set up a rapid hydrogel-based liquid phage susceptibility assay (PST) for the selection of phages for therapeutic use and to establish a "ready-to-screen" plate concept, where phages are readily stored in hydrogel as small droplets in microtiter plate wells. We first tested four commercially available hydrogels (GrowDex, Askina, Purilon, and Intrasite) for their suitability as phage matrices in PSTs with four phages, two of which infecting Escherichia coli and two Staphylococcus aureus. Of these four hydrogels, GrowDex was the best matrix for PST, as it did not inhibit bacterial growth, released phages quickly when mixed with bacterial culture, and maintained phage viability well. We then optimized the assay for both optical density and microscopy readers using GrowDex as matrix with 23 bacterial strains representing 10 different species and 23 phages possessing different morphologies and genome sizes. When the bacterial growth was monitored by microscopy reader, the PST was executed in just 3 hours, and there was no need for overnight culturing bacterial cells prior to the assay, whereas using optical density reader, bacteria had to be pre-cultured overnight, and the assay time was five hours. Finally, we evaluated the effect of three different chemical stabilizers (trehalose, hyaluronic acid, and gelatin) in a six-month stability assay with six model phages. These phages assay behaved very differently in respect to the chemical stabilizers, and there was not a single stabilizer suitable for all phages. However, when gelatin (0.01%) or hyaluronic acid (0.2 mg/ml) was used as stabilizer, all tested phages were still considered as positives in PST after a six-month storage in 1 ml volume. In "ready-to-screen" plates, the differences in phage stabilities were even more profound, varying from two to six months for the most and least stable phages, respectively.
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Affiliation(s)
- Sheetal Patpatia
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Eric Schaedig
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anna Dirks
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | | | - Mikael Skurnik
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland,Division of Clinical Microbiology, HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Saija Kiljunen
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland,Division of Clinical Microbiology, HUSLAB, Helsinki University Hospital, Helsinki, Finland,*Correspondence: Saija Kiljunen,
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14
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Daubie V, Chalhoub H, Blasdel B, Dahma H, Merabishvili M, Glonti T, De Vos N, Quintens J, Pirnay JP, Hallin M, Vandenberg O. Determination of phage susceptibility as a clinical diagnostic tool: A routine perspective. Front Cell Infect Microbiol 2022; 12:1000721. [PMID: 36211951 PMCID: PMC9532704 DOI: 10.3389/fcimb.2022.1000721] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
As the global burden of disease caused by multidrug resistant bacteria is a major source of concern, credible clinical alternatives to antibiotic therapy, such as personalized phage therapy, are actively explored. Although phage therapy has been used for more than a century, the issue of an easy to implement diagnostic tool for determining phage susceptibility that meets current routine clinical needs is still open. In this Review, we summarize the existing methods used for determining phage activity on bacteria, including the three reference methods: the spot test, the double agar overlay plaque assay, and the Appelmans method. The first two methods rely on the principle of challenging the overnight growth of a lawn of bacteria in an agar matrix to a known relative phage to bacteria concentration and represent good screening tools to determine if the tested phage can be used for a “passive” and or “active” treatment. Beside these methods, several techniques, based on “real-time” growth kinetics assays (GKA) have been developed or are under development. They all monitor the growth of clinical isolates in the presence of phages, but use various detection methods, from classical optical density to more sophisticated techniques such as computer-assisted imagery, flow-cytometry, quantitative real-time polymerase chain reaction (qPCR) or metabolic indicators. Practical considerations as well as information provided about phage activity are reviewed for each technique. Finally, we also discuss the analytical and interpretative requirements for the implementation of a phage susceptibility testing tool in routine clinical microbiology.
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Affiliation(s)
- Valéry Daubie
- Innovation and Business Development Unit, LHUB-ULB, Université Libre de Bruxelles, Brussels, Belgium
- Department of Microbiology, LHUB-ULB, Université Libre de Bruxelles, Brussels, Belgium
| | - Houssein Chalhoub
- Innovation and Business Development Unit, LHUB-ULB, Université Libre de Bruxelles, Brussels, Belgium
- Centre for Environmental Health and Occupational Health, School of Public Health, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Bob Blasdel
- R&D department, Vesale Bioscience, Noville-sur-Mehaigne, Belgium
| | - Hafid Dahma
- Department of Microbiology, LHUB-ULB, Université Libre de Bruxelles, Brussels, Belgium
| | - Maya Merabishvili
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Brussels, Belgium
| | - Tea Glonti
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Brussels, Belgium
| | - Nathalie De Vos
- Department of Clinical Chemistry, LHUB-ULB, Université Libre de Bruxelles, Brussels, Belgium
| | - Johan Quintens
- R&D department, Vesale Bioscience, Noville-sur-Mehaigne, Belgium
| | - Jean-Paul Pirnay
- Laboratory for Molecular and Cellular Technology, Queen Astrid Military Hospital, Brussels, Belgium
| | - Marie Hallin
- Centre for Environmental Health and Occupational Health, School of Public Health, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Olivier Vandenberg
- Innovation and Business Development Unit, LHUB-ULB, Université Libre de Bruxelles, Brussels, Belgium
- Centre for Environmental Health and Occupational Health, School of Public Health, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Division of Infection and Immunity, Faculty of Medical Sciences, University College London, London, United Kingdom
- *Correspondence: Olivier Vandenberg,
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15
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Melo LDR, Monteiro R, Pires DP, Azeredo J. Phage-Host Interaction Analysis by Flow Cytometry Allows for Rapid and Efficient Screening of Phages. Antibiotics (Basel) 2022; 11:antibiotics11020164. [PMID: 35203767 PMCID: PMC8868278 DOI: 10.3390/antibiotics11020164] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/22/2022] [Accepted: 01/24/2022] [Indexed: 01/27/2023] Open
Abstract
Recently, phages have become popular as an alternative to antibiotics. This increased demand for phage therapy needs rapid and efficient methods to screen phages infecting specific hosts. Existing methods are time-consuming, and for clinical purposes, novel, quick, and reliable screening methods are highly needed. Flow cytometry (FC) allows a quick differentiation and enumeration of bacterial cell populations and has been used to assess in vitro the activity of antimicrobial compounds. In this work, we propose FC as a rapid and reliable method to assess the susceptibility of a bacterial population to phage infection. For that, the interaction of phages vB_PaeM_CEB_DP1 and vB_PaeP_PE3 with Pseudomonas aeruginosa PAO1 was characterized by FC. Synchronous infection assays were performed, and samples were collected at different time points and stained with SYTO BC and PI before analysis. Part of the collected samples was used to characterize the expression of early, middle, and late genes by qPCR. Both FC and qPCR results were correlated with phage propagation assays. Results showed that SYTO BC median fluorescence intensity (MFI) values increased in the first 25 min of PE3 and DP1 infection. The increase of fluorescence is due to the expression of phage genes observed by qPCR. Since SYTO BC MFI values increase with gene expression, it allows the determination of host susceptibility to a phage in a short period of time, avoiding false positives caused by lysis from without. In conclusion, this method may allow for a quick and high-throughput real-time screening of different phages to a specific host, which can be crucial for a quick phage selection in clinical practice.
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Affiliation(s)
- Luís D. R. Melo
- LIBRO—Laboratório de Investigação em Biofilmes Rosário Oliveira, Centre of Biological Engineering, Campus de Gualtar, University of Minho, 4700-057 Braga, Portugal; (R.M.); (D.P.P.)
- LABBELS—Associate Laboratory, Braga, 4800-122 Guimarães, Portugal
- Correspondence: (L.D.R.M.); (J.A.); Tel.: +351-253-601-989 (L.D.R.M.); +351-253-604-414 (J.A.)
| | - Rodrigo Monteiro
- LIBRO—Laboratório de Investigação em Biofilmes Rosário Oliveira, Centre of Biological Engineering, Campus de Gualtar, University of Minho, 4700-057 Braga, Portugal; (R.M.); (D.P.P.)
- LABBELS—Associate Laboratory, Braga, 4800-122 Guimarães, Portugal
| | - Diana P. Pires
- LIBRO—Laboratório de Investigação em Biofilmes Rosário Oliveira, Centre of Biological Engineering, Campus de Gualtar, University of Minho, 4700-057 Braga, Portugal; (R.M.); (D.P.P.)
- LABBELS—Associate Laboratory, Braga, 4800-122 Guimarães, Portugal
| | - Joana Azeredo
- LIBRO—Laboratório de Investigação em Biofilmes Rosário Oliveira, Centre of Biological Engineering, Campus de Gualtar, University of Minho, 4700-057 Braga, Portugal; (R.M.); (D.P.P.)
- LABBELS—Associate Laboratory, Braga, 4800-122 Guimarães, Portugal
- Correspondence: (L.D.R.M.); (J.A.); Tel.: +351-253-601-989 (L.D.R.M.); +351-253-604-414 (J.A.)
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