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Vaibarova V, Kralova S, Palikova M, Schwarzerova J, Nejezchlebova J, Cejkova D, Cizek A. Genetic and phenotypic diversity of Flavobacterium psychrophilum isolates from Czech salmonid fish farms. BMC Microbiol 2024; 24:352. [PMID: 39294581 PMCID: PMC11409599 DOI: 10.1186/s12866-024-03490-3] [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: 06/06/2024] [Accepted: 09/02/2024] [Indexed: 09/20/2024] Open
Abstract
BACKGROUND The salmonid pathogen Flavobacterium psychrophilum poses a significant economic threat to global aquaculture, yet our understanding of its genetic and phenotypic diversity remains incomplete across much of its geographic range. In this study, we characterise the genetic and phenotypic diversity of 70 isolates collected from rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta m. fario) from fish farms in the Czech Republic between 2012 and 2019 to compare their genomic content with all draft or complete genomes present in the NCBI database (n = 187). RESULTS The Czech isolates underwent comprehensive evaluation, including multiplex PCR-based serotyping, genetic analysis, antimicrobial resistance testing, and assessment of selected virulence factors. Multiplex PCR serotyping revealed 43 isolates as Type 1, 23 as Type 2, with sporadic cases of Types 3 and 4. Multi-locus sequence typing unveiled 12 sequence types (ST), including seven newly described ones. Notably, 24 isolates were identified as ST329, a novel sequence type, while 22 were classified as the globally-distributed ST2. Phylogenetic analysis demonstrated clonal distribution of ST329 in the Czech Republic, with these isolates lacking a phage sequence in their genomes. Antimicrobial susceptibility testing revealed a high proportion of isolates classified as non-wild type with reduced susceptibility to oxolinic acid, oxytetracycline, flumequine, and enrofloxacin, while most isolates were classified as wild type for florfenicol, sulfamethoxazole-trimethoprim, and erythromycin. However, 31 isolates classified as wild type for florfenicol exhibited minimum inhibitory concentrations at the susceptibility breakpoint. CONCLUSION The prevalence of the Czech F. psychrophilum serotypes has evolved over time, likely influenced by the introduction of new isolates through international trade. Thus, it is crucial to monitor F. psychrophilum clones within and across countries using advanced methods such as MLST, serotyping, and genome sequencing. Given the open nature of the pan-genome, further sequencing of strains promises exciting discoveries in F. psychrophilum genomics.
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Affiliation(s)
- Vera Vaibarova
- Department of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Palackeho Trida 1946/1, 612 42, Brno, Czech Republic.
- Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute Brno, Brno, Czech Republic.
| | - Stanislava Kralova
- CEITEC VFU, University of Veterinary Sciences Brno, Brno, Czech Republic
| | - Miroslava Palikova
- Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic
- Department of Zoology, Fish Production, Hydrobiology and Apiculture, Faculty of Agriculture, Mendel University, Brno, Czech Republic
| | - Jana Schwarzerova
- Faculty of Electrical Engineering and Communication, Department of Biomedical Engineering, Brno University of Technology, 616 00, Brno, Czech Republic
- Molecular Systems Biology (MOSYS), Department of Functional and Evolutionary Ecology, Faculty of Life Sciences, University of Vienna, 1030, Vienna, Austria
- Department of Molecular and Clinical Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czech Republic
| | - Julie Nejezchlebova
- Faculty of Electrical Engineering and Communication, Department of Biomedical Engineering, Brno University of Technology, 616 00, Brno, Czech Republic
| | - Darina Cejkova
- Faculty of Electrical Engineering and Communication, Department of Biomedical Engineering, Brno University of Technology, 616 00, Brno, Czech Republic
| | - Alois Cizek
- Department of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Palackeho Trida 1946/1, 612 42, Brno, Czech Republic
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Oyejobi GK, Zhang X, Xiong D, Xue H, Shi M, Yang H, Wei H. Phage-Bacterial Interaction Alters Phenotypes Associated with Virulence in Acinetobacter baumannii. Viruses 2024; 16:743. [PMID: 38793624 PMCID: PMC11125765 DOI: 10.3390/v16050743] [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: 03/27/2024] [Revised: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024] Open
Abstract
Bacteriophages exert strong selection on their bacterial hosts to evolve resistance. At the same time, the fitness costs on bacteria following phage resistance may change their virulence, which may affect the therapeutic outcomes of phage therapy. In this study, we set out to assess the costs of phage resistance on the in vitro virulence of priority 1 nosocomial pathogenic bacterium, Acinetobacter baumannii. By subjecting phage-resistant variant Ev5-WHG of A. baumannii WHG40004 to several in vitro virulence profiles, we found that its resistance to phage is associated with reduced fitness in host microenvironments. Also, the mutant exhibited impaired adhesion and invasion to mammalian cells, as well as increased susceptibility to macrophage phagocytosis. Furthermore, the whole-genome sequencing of the mutant revealed that there exist multiple mutations which may play a role in phage resistance and altered virulence. Altogether, this study demonstrates that resistance to phage can significantly alter phenotypes associated with virulence in Acinetobacter baumannii.
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Affiliation(s)
- Greater Kayode Oyejobi
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (G.K.O.); (X.Z.); (D.X.); (H.X.); (M.S.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaoxu Zhang
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (G.K.O.); (X.Z.); (D.X.); (H.X.); (M.S.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dongyan Xiong
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (G.K.O.); (X.Z.); (D.X.); (H.X.); (M.S.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Heng Xue
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (G.K.O.); (X.Z.); (D.X.); (H.X.); (M.S.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mengjuan Shi
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (G.K.O.); (X.Z.); (D.X.); (H.X.); (M.S.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hang Yang
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (G.K.O.); (X.Z.); (D.X.); (H.X.); (M.S.)
| | - Hongping Wei
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (G.K.O.); (X.Z.); (D.X.); (H.X.); (M.S.)
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Thunes NC, Evenhuis JP, Lipscomb RS, Pérez-Pascual D, Stevick RJ, Birkett C, Ghigo JM, McBride MJ. Gliding motility proteins GldJ and SprB contribute to Flavobacterium columnare virulence. J Bacteriol 2024; 206:e0006824. [PMID: 38517170 PMCID: PMC11025331 DOI: 10.1128/jb.00068-24] [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: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024] Open
Abstract
Flavobacterium columnare causes columnaris disease in fish. Columnaris disease is incompletely understood, and adequate control measures are lacking. The type IX secretion system (T9SS) is required for F. columnare gliding motility and virulence. The T9SS and gliding motility machineries share some, but not all, components. GldN (required for gliding and for secretion) and PorV (involved in secretion but not required for gliding) are both needed for virulence, implicating T9SS-mediated secretion in virulence. The role of motility in virulence is uncertain. We constructed and analyzed sprB, sprF, and gldJ mutants that were defective for motility but that maintained T9SS function to understand the role of motility in virulence. Wild-type cells moved rapidly and formed spreading colonies. In contrast, sprB and sprF deletion mutants were partially defective in gliding and formed nonspreading colonies. Both mutants exhibited reduced virulence in rainbow trout fry. A gldJ deletion mutant was nonmotile, secretion deficient, and avirulent in rainbow trout fry. To separate the roles of GldJ in secretion and in motility, we generated gldJ truncation mutants that produce nearly full-length GldJ. Mutant gldJ563, which produces GldJ truncated at amino acid 563, was defective for gliding but was competent for secretion as measured by extracellular proteolytic activity. This mutant displayed reduced virulence in rainbow trout fry, suggesting that motility contributes to virulence. Fish that survived exposure to the sprB deletion mutant or the gldJ563 mutant exhibited partial resistance to later challenge with wild-type cells. The results aid our understanding of columnaris disease and may suggest control strategies.IMPORTANCEFlavobacterium columnare causes columnaris disease in many species of freshwater fish in the wild and in aquaculture systems. Fish mortalities resulting from columnaris disease are a major problem for aquaculture. F. columnare virulence is incompletely understood, and control measures are inadequate. Gliding motility and protein secretion have been suggested to contribute to columnaris disease, but evidence directly linking motility to disease was lacking. We isolated and analyzed mutants that were competent for secretion but defective for motility. Some of these mutants exhibited decreased virulence. Fish that had been exposed to these mutants were partially protected from later exposure to the wild type. The results contribute to our understanding of columnaris disease and may aid development of control strategies.
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Affiliation(s)
- Nicole C. Thunes
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Jason P. Evenhuis
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Ryan S. Lipscomb
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - David Pérez-Pascual
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Rebecca J. Stevick
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Clayton Birkett
- National Center for Cool and Cold Water Aquaculture, Agricultural Research Service, USDA, Kearneysville, West Virginia, USA
| | - Jean-Marc Ghigo
- Institut Pasteur, Université Paris-Cité, CNRS UMR 6047, Genetics of Biofilms Laboratory, Paris, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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Skliros D, Droubogiannis S, Kalloniati C, Katharios P, Flemetakis E. Perturbation of Quorum Sensing after the Acquisition of Bacteriophage Resistance Could Contribute to Novel Traits in Vibrio alginolyticus. Microorganisms 2023; 11:2273. [PMID: 37764117 PMCID: PMC10535087 DOI: 10.3390/microorganisms11092273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Bacteria employ a wide range of molecular mechanisms to confer resistance to bacteriophages, and these mechanisms are continuously being discovered and characterized. However, there are instances where certain bacterial species, despite lacking these known mechanisms, can still develop bacteriophage resistance through intricate metabolic adaptation strategies, potentially involving mutations in transcriptional regulators or phage receptors. Vibrio species have been particularly useful for studying the orchestrated metabolic responses of Gram-negative marine bacteria in various challenges. In a previous study, we demonstrated that Vibrio alginolyticus downregulates the expression of specific receptors and transporters in its membrane, which may enable the bacterium to evade infection by lytic bacteriophages. In our current study, our objective was to explore how the development of bacteriophage resistance in Vibrio species disrupts the quorum-sensing cascade, subsequently affecting bacterial physiology and metabolic capacity. Using a real-time quantitative PCR (rt-QPCR) platform, we examined the expression pattern of quorum-sensing genes, auto-inducer biosynthesis genes, and cell density regulatory proteins in phage-resistant strains. Our results revealed that bacteriophage-resistant bacteria downregulate the expression of quorum-sensing regulatory proteins, such as LuxM, LuxN, and LuxP. This downregulation attenuates the normal perception of quorum-sensing peptides and subsequently diminishes the expression of cell density regulatory proteins, including LuxU, aphA, and LuxR. These findings align with the diverse phenotypic traits observed in the phage-resistant strains, such as altered biofilm formation, reduced planktonic growth, and reduced virulence. Moreover, the transcriptional depletion of aphA, the master regulator associated with low cell density, was linked to the downregulation of genes related to virulence. This phenomenon appears to be phage-specific, suggesting a finely tuned metabolic adaptation driven by phage-host interaction. These findings contribute to our understanding of the role of Vibrio species in microbial marine ecology and highlight the complex interplay between phage resistance, quorum sensing, and bacterial physiology.
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Affiliation(s)
- Dimitrios Skliros
- Laboratory of Molecular Biology, Department of Biotechnology, School of Applied Biology and Biotechnology, Agricultural University of Athens, 11855 Athens, Greece; (D.S.); (C.K.)
| | - Stavros Droubogiannis
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, 71500 Heraklion, Greece; (S.D.); (P.K.)
| | - Chrysanthi Kalloniati
- Laboratory of Molecular Biology, Department of Biotechnology, School of Applied Biology and Biotechnology, Agricultural University of Athens, 11855 Athens, Greece; (D.S.); (C.K.)
- Department of Marine Sciences, University of the Aegean, 81100 Mytilene, Greece
| | - Pantelis Katharios
- Institute of Marine Biology, Biotechnology and Aquaculture, Hellenic Centre for Marine Research, 71500 Heraklion, Greece; (S.D.); (P.K.)
| | - Emmanouil Flemetakis
- Laboratory of Molecular Biology, Department of Biotechnology, School of Applied Biology and Biotechnology, Agricultural University of Athens, 11855 Athens, Greece; (D.S.); (C.K.)
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Umarje SC, Banerjee SK. Non-traditional approaches for control of antibiotic resistance. Expert Opin Biol Ther 2023; 23:1113-1135. [PMID: 38007617 DOI: 10.1080/14712598.2023.2279644] [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: 08/28/2023] [Accepted: 11/01/2023] [Indexed: 11/27/2023]
Abstract
INTRODUCTION The drying up of antibiotic pipeline has necessitated the development of alternative therapeutic strategies to control the problem of antimicrobial resistance (AMR) that is expected to kill 10-million people annually by 2050. Newer therapeutic approaches address the shortcomings of traditional small-molecule antibiotics - the lack of specificity, evolvability, and susceptibility to mutation-based resistance. These 'non-traditional' molecules are biologicals having a complex structure and mode(s) of action that makes them resilient to resistance. AREAS COVERED This review aims to provide information about the non-traditional drug development approaches to tackle the problem of antimicrobial resistance, from the pre-antibiotic era to the latest developments. We have covered the molecules under development in the clinic with literature sourced from reviewed scholarly articles, official company websites involved in innovation of concerned therapeutics, press releases from the regulatory bodies, and clinical trial databases. EXPERT OPINION Formal introduction of non-traditional therapies in general practice can be quick and feasible only if supported with companion diagnostics and used in conjunction with established therapies. Owing to relatively higher development costs, non-traditional therapeutics require more funding as well as well as clarity in regulatory and clinical path. We are hopeful these issues are adequately addressed before AMR develops into a pandemic.
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Affiliation(s)
- Siddharth C Umarje
- Department of Proteomics, AbGenics Life Sciences Pvt. Ltd., Pune, India
- AbGenics Life Sciences Pvt. Ltd., Pune, India
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6
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Chen F, Wang D, Lu T, Li S. Identification of a novel type II-C Cas9 from the fish pathogen Flavobacterium psychrophilum. Front Microbiol 2023; 14:1181303. [PMID: 37396349 PMCID: PMC10309648 DOI: 10.3389/fmicb.2023.1181303] [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: 03/07/2023] [Accepted: 05/26/2023] [Indexed: 07/04/2023] Open
Abstract
Flavobacterium psychrophilum is the causative agent of rainbow trout fry syndrome and bacterial cold-water disease in salmonid fish worldwide. As an important fish pathogen, F. psychrophilum is frequently exposed to multiple invading genetic elements in natural environments. Endonuclease Cas9 provides bacteria with adaptive interference against invading genetic elements. Previous studies revealed that several F. psychrophilum strains harbored a type II-C Cas9 called Fp1Cas9, but little is known about the potential role of this endonuclease against invading genetic elements. In this work, we identified a gene encoding a novel type II-C Cas9 called Fp2Cas9 from F. psychrophilum strain CN46. Through bacterial RNA sequencing, we demonstrated active transcription of both Fp2Cas9 and pre-crRNAs in strain CN46. Bioinformatics analysis further revealed that the transcription of Fp2Cas9 and pre-crRNAs was driven by a newly integrated promoter sequence and a promoter element embedded within each CRISPR repeat, respectively. To formally demonstrate that Fp2Cas9 and associated crRNAs yielded functional interference in strain CN46, a plasmid interference assay was performed, resulting in adaptive immunity to target DNA sequences in Flavobacterium bacteriophages. Phylogenetic analysis demonstrated that Fp2Cas9 was present only in several F. psychrophilum isolates. Phylogenetic analysis revealed that this novel endonuclease was probably acquired through horizontal gene transfer from the CRISPR-Cas9 system in an unidentified Flavobacterium species. Comparative genomics analysis further showed that the Fp2Cas9 was integrated into the type II-C CRISPR-Cas locus in strain CN38 instead of the original Fp1Cas9. Taken together, our results shed light on the origin and evolution of Fp2Cas9 gene and demonstrated that this novel endonuclease provided adaptive interference against bacteriophage infections.
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Affiliation(s)
- Fuguang Chen
- Department of Aquatic Animal Health, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, China
- Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China
| | - Di Wang
- Department of Aquatic Animal Health, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, China
- Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China
| | - Tongyan Lu
- Department of Aquatic Animal Health, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, China
- Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China
| | - Shaowu Li
- Department of Aquatic Animal Health, Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin, China
- Key Laboratory of Aquatic Animal Diseases and Immune Technology of Heilongjiang Province, Harbin, China
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Oyejobi GK, Zhang X, Xiong D, Ogolla F, Xue H, Wei H. Phage-bacterial evolutionary interactions: experimental models and complications. Crit Rev Microbiol 2023; 49:283-296. [PMID: 35358006 DOI: 10.1080/1040841x.2022.2052793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Phage treatment of bacterial infections has offered some hope even as the crisis of antimicrobial resistance continues to be on the rise. However, bacterial resistance to phage is another looming challenge capable of undermining the effectiveness of phage therapy. Moreover, the consideration of including phage therapy in modern medicine calls for more careful research around every aspect of phage study. In an attempt to adequately prepare for the events of phage resistance, many studies have attempted to experimentally evolve phage resistance in different bacterial strains, as well as train phages to evolve counter-infectivity of resistant bacterial mutants, in view of answering such questions as coevolutionary dynamics between phage and bacteria, mechanisms of phage resistance, fitness costs of phage resistance on bacteria, etc. In this review, we summarised many such studies and by careful examination, highlighted critical issues to the outcome of phage therapy. We also discuss the insufficiency of many of these in vitro studies to represent actual disease conditions during phage application, alongside other complications that exist in phage-bacterial evolutionary interactions. Conclusively, we present the exploitation of phage-bacterial interactions for successful infection managements, as well as some future perspectives to direct phage research.
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Affiliation(s)
- Greater Kayode Oyejobi
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,International College, University of Chinese Academy of Sciences, Beijing, China.,Department of Microbiology, Osun State University, Osogbo, Nigeria.,Organization of African Academic Doctors, Nairobi, Kenya
| | - Xiaoxu Zhang
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,International College, University of Chinese Academy of Sciences, Beijing, China
| | - Dongyan Xiong
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,International College, University of Chinese Academy of Sciences, Beijing, China
| | - Faith Ogolla
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,International College, University of Chinese Academy of Sciences, Beijing, China.,Organization of African Academic Doctors, Nairobi, Kenya.,Sino-Africa Joint Research Center, Nairobi, Kenya
| | - Heng Xue
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,International College, University of Chinese Academy of Sciences, Beijing, China
| | - Hongping Wei
- Key Laboratory of Special Pathogens and Biosafety, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,Sino-Africa Joint Research Center, Nairobi, Kenya
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Kondo Y, Ohara K, Fujii R, Nakai Y, Sato C, Naito M, Tsukuba T, Kadowaki T, Sato K. Transposon mutagenesis and genome sequencing identify two novel, tandem genes involved in the colony spreading of Flavobacterium collinsii, isolated from an ayu fish, Plecoglossus altivelis. Front Cell Infect Microbiol 2023; 13:1095919. [PMID: 36844397 PMCID: PMC9950754 DOI: 10.3389/fcimb.2023.1095919] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/16/2023] [Indexed: 02/12/2023] Open
Abstract
Bacteria of the family Flavobacteriaceae (flavobacteria) primarily comprise nonpathogenic bacteria that inhabit soil and water (both marine and freshwater). However, some bacterial species in the family, including Flavobacterium psychrophilum and Flavobacterium columnare, are known to be pathogenic to fish. Flavobacteria, including the abovementioned pathogenic bacteria, belong to the phylum Bacteroidota and possess two phylum-specific features, gliding motility and a protein secretion system, which are energized by a common motor complex. Herein, we focused on Flavobacterium collinsii (GiFuPREF103) isolated from a diseased fish (Plecoglossus altivelis). Genomic analysis of F. collinsii GiFuPREF103 revealed the presence of a type IX secretion system and additional genes associated with gliding motility and spreading. Using transposon mutagenesis, we isolated two mutants with altered colony morphology and colony spreading ability; these mutants had transposon insertions in pep25 and lbp26. The glycosylation material profiles revealed that these mutants lacked the high-molecular-weight glycosylated materials present in the wild-type strain. In addition, the wild-type strains exhibited fast cell population movement at the edge of the spreading colony, whereas reduced cell population behavior was observed in the pep25- and lbp26-mutant strains. In the aqueous environment, the surface layers of these mutant strains were more hydrophobic, and they formed biofilms with enhanced microcolony growth compared to those with the wild-type. In Flavobacterium johnsoniae, the Fjoh_0352 and Fjoh_0353 mutant strains were generated, which were based on the ortholog genes of pep25 and lbp26. In these F. johnsoniae mutants, as in F. collinsii GiFuPREF103, colonies with diminished spreading capacity were formed. Furthermore, cell population migration was observed at the edge of the colony in wild-type F. johnsoniae, whereas individual cells, and not cell populations, migrated in these mutant strains. The findings of the present study indicate that pep25 and lbp26 contribute to the colony spreading of F. collinsii.
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Affiliation(s)
- Yoshio Kondo
- Department of Pediatric Dentistry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan,*Correspondence: Yoshio Kondo, ; Keiko Sato,
| | - Kenichi Ohara
- Gifu Prefectural Research Institute for Fisheries and Aquatic Environments, Gifu, Japan
| | - Ryoji Fujii
- Gifu Prefectural Research Institute for Fisheries and Aquatic Environments, Gifu, Japan
| | - Yudai Nakai
- Department of Frontier Oral Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Chikara Sato
- School of Integrative and Global Majors (SIGMA), University of Tsukuba, Ibaraki, Japan,Biological Science Course, Graduate School of Science and Engineering, Aoyama Gakuin University, Kanagawa, Japan,Division of Immune Homeostasis, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan,Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan
| | - Mariko Naito
- Department of Microbiology and Oral Infection, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Takayuki Tsukuba
- Department of Dental Pharmacology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Tomoko Kadowaki
- Department of Frontier Oral Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Keiko Sato
- Department of Frontier Oral Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan,*Correspondence: Yoshio Kondo, ; Keiko Sato,
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Development and Evaluation of Bacteriophage Cocktail to Eradicate Biofilms Formed by an Extensively Drug-Resistant (XDR) Pseudomonas aeruginosa. Viruses 2023; 15:v15020427. [PMID: 36851640 PMCID: PMC9965693 DOI: 10.3390/v15020427] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/22/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Extensive and multiple drug resistance in P. aeruginosa combined with the formation of biofilms is responsible for its high persistence in nosocomial infections. A sequential method to devise a suitable phage cocktail with a broad host range and high lytic efficiency against a biofilm forming XDR P. aeruginosa strain is presented here. Out of a total thirteen phages isolated against P. aeruginosa, five were selected on the basis of their high lytic spectra assessed using spot assay and productivity by efficiency of plating assay. Phages, after selection, were tested individually and in combinations of two-, three-, four-, and five-phage cocktails using liquid infection model. Out of total 22 combinations tested, the cocktail comprising four phages viz. φPA170, φPA172, φPA177, and φPA180 significantly inhibited the bacterial growth in liquid infection model (p < 0.0001). The minimal inhibitory dose of each phage in a cocktail was effectively reduced to >10 times than the individual dose in the inhibition of XDR P. aeruginosa host. Field emission-scanning electron microscopy was used to visualize phage cocktail mediated eradication of 4-day-old multi-layers of XDR P. aeruginosa biofilms from urinary catheters and glass cover slips, and was confirmed by absence of any viable cells. Differential bacterial inhibition was observed with different phage combinations where multiple phages were found to enhance the cocktail's lytic range, but the addition of too many phages reduced the overall inhibition. This study elaborates an effective and sequential method for the preparation of a phage cocktail and evaluates its antimicrobial potential against biofilm forming XDR strains of P. aeruginosa.
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10
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Zhu Y, Lechardeur D, Bernardet JF, Kerouault B, Guérin C, Rigaudeau D, Nicolas P, Duchaud E, Rochat T. Two functionally distinct heme/iron transport systems are virulence determinants of the fish pathogen Flavobacterium psychrophilum. Virulence 2022; 13:1221-1241. [PMID: 35880611 PMCID: PMC9331221 DOI: 10.1080/21505594.2022.2101197] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/02/2022] [Accepted: 07/08/2022] [Indexed: 10/26/2022] Open
Abstract
Bacterial pathogens have a critical impact on aquaculture, a sector that accounts for half of the human fish consumption. Flavobacterium psychrophilum (phylum Bacteroidetes) is responsible for bacterial cold-water disease in salmonids worldwide. The molecular factors involved in host invasion, colonization and haemorrhagic septicaemia are mostly unknown. In this study, we identified two new TonB-dependent receptors, HfpR and BfpR, that are required for adaptation to iron conditions encountered during infection and for virulence in rainbow trout. Transcriptional analyses revealed that their expression is tightly controlled and upregulated under specific iron sources and concentrations. Characterization of deletion mutants showed that they act without redundancy: BfpR is required for optimal growth in the presence of high haemoglobin level, while HfpR confers the capacity to acquire nutrient iron from haem or haemoglobin under iron scarcity. The gene hfpY, co-transcribed with hfpR, encodes a protein related to the HmuY family. We demonstrated that HfpY binds haem and contributes significantly to host colonization and disease severity. Overall, these results are consistent with a model in which both BfpR and Hfp systems promote haem uptake and respond to distinct signals to adapt iron acquisition to the different stages of pathogenesis. Our findings give insight into the molecular basis of pathogenicity of a serious pathogen belonging to the understudied family Flavobacteriaceae and point to the newly identified haem receptors as promising targets for antibacterial development.
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Affiliation(s)
- Yueying Zhu
- INRAE, UVSQ, VIM, Université Paris-Saclay, Jouy-en-Josas, France
| | - Delphine Lechardeur
- INRAE, AgroParisTech, Micalis Institute, Université Paris-Saclay, Jouy-en-Josas, France
| | | | | | - Cyprien Guérin
- INRAE, MaIAGE, Université Paris-Saclay, Jouy-en-Josas, France
| | | | - Pierre Nicolas
- INRAE, MaIAGE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Eric Duchaud
- INRAE, UVSQ, VIM, Université Paris-Saclay, Jouy-en-Josas, France
| | - Tatiana Rochat
- INRAE, UVSQ, VIM, Université Paris-Saclay, Jouy-en-Josas, France
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11
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Vallenas-Sánchez YPA, Bautista-Valles MF, Llaque-Chávarri F, Mendoza-Coello ME. Bacteriophage cocktail as a substitute for antimicrobials in companion animal dermatology. JOURNAL OF THE SELVA ANDINA ANIMAL SCIENCE 2022. [DOI: 10.36610/j.jsaas.2022.090200097x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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12
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Vallenas-Sánchez YPA, Bautista-Valles MF, Llaque-Chávarri F, Mendoza-Coello ME. Cóctel de bacteriófagos como sustituto de antimicrobianos en dermatología de animales de compañía. JOURNAL OF THE SELVA ANDINA ANIMAL SCIENCE 2022. [DOI: 10.36610/j.jsaas.2022.090200097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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13
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Jørgensen J, Sundell K, Castillo D, Dramshøj LS, Jørgensen NB, Madsen SB, Landor L, Wiklund T, Donati VL, Madsen L, Dalsgaard I, Middelboe M. Reversible mutations in gliding motility and virulence genes: A flexible and efficient phage defence mechanism in Flavobacterium psychrophilum. Environ Microbiol 2022; 24:4915-4930. [PMID: 35837851 DOI: 10.1111/1462-2920.16126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/27/2022] [Accepted: 07/04/2022] [Indexed: 01/07/2023]
Abstract
Flavobacteria are among the most important pathogens in freshwater salmonid aquaculture worldwide. Due to concerns regarding development of antibiotic resistance, phage therapy has been proposed as a solution to decrease pathogen load. However, application of phages is challenged by the development of phage resistance, and knowledge of the mechanisms and implications of phage resistance is therefore required. To study this, 27 phage-resistant isolates of F. psychrophilum were genome sequenced and characterized to identify genetic modifications and evaluate changes in phenotypic traits, including virulence against rainbow trout. Phage-resistant isolates showed reduction or loss of gliding motility, proteolytic activity, and adhesion to surfaces, and most isolates were completely non-virulent against rainbow trout fry. Genomic analysis revealed that most phage-resistant isolates had mutations in genes associated with gliding motility and virulence. Reversal of these mutations in a sub-set of isolates led to regained motility, proteolytic activity, virulence and phage susceptibility. Although costly, the fast generation of phage resistance driven by single, reversible mutations likely represents a flexible and efficient phage defence mechanism in F. psychrophilum. The results further suggest that phage administration in aquaculture systems to prevent F. psychrophilum outbreaks selects for non-virulent phage-resistant phenotypes.
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Affiliation(s)
| | - Krister Sundell
- Laboratory of Aquatic Pathobiology, Åbo Akademi University, Turku, Finland
| | - Daniel Castillo
- Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Liv S Dramshøj
- Department of Biology, University of Copenhagen, Helsingør, Denmark
| | | | - Susie B Madsen
- Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Lotta Landor
- Laboratory of Aquatic Pathobiology, Åbo Akademi University, Turku, Finland.,Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Tom Wiklund
- Laboratory of Aquatic Pathobiology, Åbo Akademi University, Turku, Finland
| | - Valentina L Donati
- National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lone Madsen
- National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Inger Dalsgaard
- National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
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14
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Biofilm eradication ability of phage cocktail against Listeria monocytogenes biofilms formed on food contact materials and effect on virulence-related genes and biofilm structure. Food Res Int 2022; 157:111367. [DOI: 10.1016/j.foodres.2022.111367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/08/2022] [Accepted: 05/10/2022] [Indexed: 11/23/2022]
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15
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Huang L, Guo W, Lu J, Pan W, Song F, Wang P. Enterococcus faecalis Bacteriophage vB_EfaS_efap05-1 Targets the Surface Polysaccharide and ComEA Protein as the Receptors. Front Microbiol 2022; 13:866382. [PMID: 35432223 PMCID: PMC9009173 DOI: 10.3389/fmicb.2022.866382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/08/2022] [Indexed: 11/13/2022] Open
Abstract
Enterococcus faecalis is a Gram-positive opportunistic pathogen that causes nosocomial infections in humans. Due to the growing threat of antibiotic resistance of E. faecalis, bacteriophage therapy is a promising option for treating of E. faecalis infection. Here, we characterized a lytic E. faecalis bacteriophage vB_EfaS_efap05-1 with a dsDNA genome of 56,563 bp. Phage vB_EfaS_efap05-1 had a prolate head and a tail, and belongs to Saphexavirus which is a member of Siphoviridae. Efap05-1 uses either surface polysaccharide or membrane protein ComEA as the receptor because the mutation of both genes (ComEA and UDP-glucose 4-epimerase galE) prevents phage adsorption and leads to phage resistance, and complementation of ComEA or galE could recover its phage sensitivity. Our results provided a comprehensive analysis of a new E. faecalis phage and suggest efap05-1 as a potential antimicrobial agent.
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Affiliation(s)
- Lingqiong Huang
- Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Yunnan Institute of Endemic Diseases Control and Prevention, Dali, China
- School of Public Health, Dali University, Dali, China
| | - Wenqiong Guo
- School of Nursing, Chengdu Medical College, Chengdu, China
| | - Jiahui Lu
- School of Clinical Medicine, Chengdu Medical College, Chengdu, China
| | - Wuliang Pan
- School of Pharmacy, Chengdu Medical College, Chengdu, China
| | - Fuqiang Song
- Department of Medical Laboratory, The General Hospital of Western Theater Command, Chengdu, China
- *Correspondence: Fuqiang Song,
| | - Peng Wang
- Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Yunnan Institute of Endemic Diseases Control and Prevention, Dali, China
- Peng Wang,
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16
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Castillo D, Højsting AR, Roosvall A, Smyrlis G, Jørgensen J, Middelboe M. In Vitro Evolution of Specific Phages Infecting the Fish Pathogen Flavobacterium psychrophilum. PHAGE 2022; 3:28-37. [PMID: 37025924 PMCID: PMC10071593 DOI: 10.1089/phage.2022.0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Background Flavobacterium psychrophilum is the causative agent of the bacterial cold-water disease and rainbow trout fry syndrome. Owing to the issues associated with increasing use of antibiotics to control the diseases, phage therapy has been proposed as an alternative method to control Flavobacterium infection within the industry. Materials and Methods We explored two simple and fast in vitro strategies for the isolation of evolved F. psychrophilum phages, using three well-characterized phages FpV4, FpV9, and FPSV-S20. Results During in vitro serial transfer experiments, 12 evolved phages were selected 72-96 h after phage exposure in the first or second week. Phenotype analysis showed improvement of host range and efficiency of plating and adsorption constants. Comparative genomic analysis of the evolved phages identified 13 independent point mutations causing amino acid changes mostly in hypothetical proteins. Conclusions These results confirmed the reliability and effectivity of two strategies to isolate evolved F. psychrophilum phages, which may be used to expand phage-host range and target phage-resistant pathogens in phage therapy applications against Flavobacterium infections.
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Affiliation(s)
- Daniel Castillo
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
- Instituto de Investigación Interdisciplinar en Ciencias Biomédicas SEK (I3CBSEK), Universidad SEK, Santiago, Chile
| | | | - Andrea Roosvall
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Giorgos Smyrlis
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Johanna Jørgensen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Mathias Middelboe
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
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17
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Mekasha S, Linke D. Secretion Systems in Gram-Negative Bacterial Fish Pathogens. Front Microbiol 2022; 12:782673. [PMID: 34975803 PMCID: PMC8714846 DOI: 10.3389/fmicb.2021.782673] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/24/2021] [Indexed: 12/17/2022] Open
Abstract
Bacterial fish pathogens are one of the key challenges in the aquaculture industry, one of the fast-growing industries worldwide. These pathogens rely on arsenal of virulence factors such as toxins, adhesins, effectors and enzymes to promote colonization and infection. Translocation of virulence factors across the membrane to either the extracellular environment or directly into the host cells is performed by single or multiple dedicated secretion systems. These secretion systems are often key to the infection process. They can range from simple single-protein systems to complex injection needles made from dozens of subunits. Here, we review the different types of secretion systems in Gram-negative bacterial fish pathogens and describe their putative roles in pathogenicity. We find that the available information is fragmented and often descriptive, and hope that our overview will help researchers to more systematically learn from the similarities and differences between the virulence factors and secretion systems of the fish-pathogenic species described here.
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Affiliation(s)
- Sophanit Mekasha
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Dirk Linke
- Section for Genetics and Evolutionary Biology, Department of Biosciences, University of Oslo, Oslo, Norway
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18
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Zhou W, Li Y, Li Z, Ma B, Jiang X, Hu C, Ai Y, Luo P. Genomic Changes and Genetic Divergence of Vibrio alginolyticus Under Phage Infection Stress Revealed by Whole-Genome Sequencing and Resequencing. Front Microbiol 2021; 12:710262. [PMID: 34671325 PMCID: PMC8521149 DOI: 10.3389/fmicb.2021.710262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 09/14/2021] [Indexed: 11/13/2022] Open
Abstract
Bacteriophages (phages) and their bacterial hosts were the most abundant and genetically highly diverse organisms on the earth. In this study, a series of phage-resistant mutant (PRM) strains derived from Vibrio alginolyticus were isolated and Infrequent-restriction-site PCR (IRS-PCR) was used to investigate the genetic diversity of the PRM strains. Phenotypic variations of eight PRM strains were analyzed using profiles of utilizing carbon sources and chemical sensitivity. Genetic variations of eight PRM strains and coevolved V. alginolyticus populations with phages were analyzed by whole-genome sequencing and resequencing, respectively. The results indicated that eight genetically discrepant PRM stains exhibited abundant and abundant phenotypic variations. Eight PRM strains and coevolved V. alginolyticus populations (VE1, VE2, and VE3) contained numerous single nucleotide variations (SNVs) and insertions/indels (InDels) and exhibited obvious genetic divergence. Most of the SNVs and InDels in coding genes were related to the synthesis of flagellar, extracellular polysaccharide (EPS), which often served as the receptors of phage invasion. The PRM strains and the coevolved cell populations also contained frequent mutations in tRNA and rRNA genes. Two out of three coevolved populations (VE1 and VE2) contained a large mutation segment severely deconstructing gene nrdA, which was predictably responsible for the booming of mutation rate in the genome. In summary, numerous mutations and genetic divergence were detected in the genomes of V. alginolyticus PRM strains and in coevolved cell populations of V. alginolyticus under phage infection stress. The phage infection stress may provide an important force driving genomic evolution of V. alginolyticus.
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Affiliation(s)
- Wenjie Zhou
- College of Animal Science, Jilin University, Changchun, China
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Yingying Li
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- Geological Survey Institute of Guangzhou, Guangzhou, China
| | - Zhuobo Li
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bo Ma
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiao Jiang
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Chaoqun Hu
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Yongxing Ai
- College of Animal Science, Jilin University, Changchun, China
| | - Peng Luo
- CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
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19
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Ramos-Vivas J, Superio J, Galindo-Villegas J, Acosta F. Phage Therapy as a Focused Management Strategy in Aquaculture. Int J Mol Sci 2021; 22:10436. [PMID: 34638776 PMCID: PMC8508683 DOI: 10.3390/ijms221910436] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 12/12/2022] Open
Abstract
Therapeutic bacteriophages, commonly called as phages, are a promising potential alternative to antibiotics in the management of bacterial infections of a wide range of organisms including cultured fish. Their natural immunogenicity often induces the modulation of a variated collection of immune responses within several types of immunocytes while promoting specific mechanisms of bacterial clearance. However, to achieve standardized treatments at the practical level and avoid possible side effects in cultivated fish, several improvements in the understanding of their biology and the associated genomes are required. Interestingly, a particular feature with therapeutic potential among all phages is the production of lytic enzymes. The use of such enzymes against human and livestock pathogens has already provided in vitro and in vivo promissory results. So far, the best-understood phages utilized to fight against either Gram-negative or Gram-positive bacterial species in fish culture are mainly restricted to the Myoviridae and Podoviridae, and the Siphoviridae, respectively. However, the current functional use of phages against bacterial pathogens of cultured fish is still in its infancy. Based on the available data, in this review, we summarize the current knowledge about phage, identify gaps, and provide insights into the possible bacterial control strategies they might represent for managing aquaculture-related bacterial diseases.
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Affiliation(s)
- José Ramos-Vivas
- Grupo de Investigación en Acuicultura, Universidad de Las Palmas de Gran Canaria, 35214 Las Palmas de Gran Canaria, Spain; (J.R.-V.); (F.A.)
- Research Group on Foods, Nutritional Biochemistry and Health, Universidad Europea del Atlántico, 39011 Santander, Spain
- Department of Project Management, Universidad Internacional Iberoamericana, Campeche 24560, Mexico
| | - Joshua Superio
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway;
| | | | - Félix Acosta
- Grupo de Investigación en Acuicultura, Universidad de Las Palmas de Gran Canaria, 35214 Las Palmas de Gran Canaria, Spain; (J.R.-V.); (F.A.)
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20
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Lindsay RJ, Jepson A, Butt L, Holder PJ, Smug BJ, Gudelj I. Would that it were so simple: Interactions between multiple traits undermine classical single-trait-based predictions of microbial community function and evolution. Ecol Lett 2021; 24:2775-2795. [PMID: 34453399 DOI: 10.1111/ele.13861] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/11/2021] [Accepted: 07/27/2021] [Indexed: 12/15/2022]
Abstract
Understanding how microbial traits affect the evolution and functioning of microbial communities is fundamental for improving the management of harmful microorganisms, while promoting those that are beneficial. Decades of evolutionary ecology research has focused on examining microbial cooperation, diversity, productivity and virulence but with one crucial limitation. The traits under consideration, such as public good production and resistance to antibiotics or predation, are often assumed to act in isolation. Yet, in reality, multiple traits frequently interact, which can lead to unexpected and undesired outcomes for the health of macroorganisms and ecosystem functioning. This is because many predictions generated in a single-trait context aimed at promoting diversity, reducing virulence or controlling antibiotic resistance can fail for systems where multiple traits interact. Here, we provide a much needed discussion and synthesis of the most recent research to reveal the widespread and diverse nature of multi-trait interactions and their consequences for predicting and controlling microbial community dynamics. Importantly, we argue that synthetic microbial communities and multi-trait mathematical models are powerful tools for managing the beneficial and detrimental impacts of microbial communities, such that past mistakes, like those made regarding the stewardship of antimicrobials, are not repeated.
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Affiliation(s)
- Richard J Lindsay
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Alys Jepson
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Lisa Butt
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Philippa J Holder
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
| | - Bogna J Smug
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ivana Gudelj
- Biosciences and Living Systems Institute, University of Exeter, Exeter, UK
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21
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Comparative Genomic Analyses of Flavobacterium psychrophilum Isolates Reveals New Putative Genetic Determinants of Virulence Traits. Microorganisms 2021; 9:microorganisms9081658. [PMID: 34442736 PMCID: PMC8400371 DOI: 10.3390/microorganisms9081658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/23/2021] [Accepted: 07/29/2021] [Indexed: 11/29/2022] Open
Abstract
The fish pathogen Flavobacterium psychrophilum is currently one of the main pathogenic bacteria hampering the productivity of salmonid farming worldwide. Although putative virulence determinants have been identified, the genetic basis for variation in virulence of F. psychrophilum is not fully understood. In this study, we analyzed whole-genome sequences of a collection of 25 F. psychrophilum isolates from Baltic Sea countries and compared genomic information with a previous determination of their virulence in juvenile rainbow trout. The results revealed a conserved population of F. psychrophilum that were consistently present across the Baltic Sea countries, with no clear association between genomic repertoire, phylogenomic, or gene distribution and virulence traits. However, analysis of the entire genome of four F. psychrophilum isolates by hybrid assembly provided an unprecedented resolution for discriminating even highly related isolates. The results showed that isolates with different virulence phenotypes harbored genetic variances on a number of consecutive leucine-rich repeat (LRR) proteins, repetitive motifs in gliding motility-associated protein, and the insertion of transposable elements into intergenic and genic regions. Thus, these findings provide novel insights into the genetic variation of these elements and their putative role in the modulation of F. psychrophilum virulence.
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22
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Kunttu HMT, Runtuvuori-Salmela A, Sundell K, Wiklund T, Middelboe M, Landor L, Ashrafi R, Hoikkala V, Sundberg LR. Bacteriophage Resistance Affects Flavobacterium columnare Virulence Partly via Mutations in Genes Related to Gliding Motility and the Type IX Secretion System. Appl Environ Microbiol 2021; 87:e0081221. [PMID: 34106011 PMCID: PMC8315173 DOI: 10.1128/aem.00812-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 05/30/2021] [Indexed: 02/08/2023] Open
Abstract
Increasing problems with antibiotic resistance have directed interest toward phage therapy in the aquaculture industry. However, phage resistance evolving in target bacteria is considered a challenge. To investigate how phage resistance influences the fish pathogen Flavobacterium columnare, two wild-type bacterial isolates, FCO-F2 and FCO-F9, were exposed to phages (FCO-F2 to FCOV-F2, FCOV-F5, and FCOV-F25, and FCO-F9 to FCL-2, FCOV-F13, and FCOV-F45), and resulting phenotypic and genetic changes in bacteria were analyzed. Bacterial viability first decreased in the exposure cultures but started to increase after 1 to 2 days, along with a change in colony morphology from original rhizoid to rough, leading to 98% prevalence of the rough morphotype. Twenty-four isolates (including four isolates from no-phage treatments) were further characterized for phage resistance, antibiotic susceptibility, motility, adhesion, and biofilm formation, protease activity, whole-genome sequencing, and virulence in rainbow trout fry. The rough isolates arising in phage exposure were phage resistant with low virulence, whereas rhizoid isolates maintained phage susceptibility and high virulence. Gliding motility and protease activity were also related to the phage susceptibility. Observed mutations in phage-resistant isolates were mostly located in genes encoding the type IX secretion system, a component of the Bacteroidetes gliding motility machinery. However, not all phage-resistant isolates had mutations, indicating that phage resistance in F. columnare is a multifactorial process, including both genetic mutations and changes in gene expression. Phage resistance may not, however, be a challenge for development of phage therapy against F. columnare infections since phage resistance is associated with decreases in bacterial virulence. IMPORTANCE Phage resistance of infectious bacteria is a common phenomenon posing challenges for the development of phage therapy. Along with a growing world population and the need for increased food production, constantly intensifying animal farming has to face increasing problems of infectious diseases. Columnaris disease, caused by Flavobacterium columnare, is a worldwide threat for salmonid fry and juvenile farming. Without antibiotic treatments, infections can lead to 100% mortality in a fish stock. Phage therapy of columnaris disease would reduce the development of antibiotic-resistant bacteria and antibiotic loads by the aquaculture industry, but phage-resistant bacterial isolates may become a risk. However, phenotypic and genetic characterization of phage-resistant F. columnare isolates in this study revealed that they are less virulent than phage-susceptible isolates and thus not a challenge for phage therapy against columnaris disease. This is valuable information for the fish farming industry globally when considering phage-based prevention and curing methods for F. columnare infections.
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Affiliation(s)
- Heidi M. T. Kunttu
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Anniina Runtuvuori-Salmela
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Krister Sundell
- Laboratory of Aquatic Pathobiology, Åbo Akademi University, Turku, Finland
| | - Tom Wiklund
- Laboratory of Aquatic Pathobiology, Åbo Akademi University, Turku, Finland
| | - Mathias Middelboe
- Department of Biology, Marine Biological Section, University of Copenhagen, Helsingør, Denmark
| | - Lotta Landor
- Laboratory of Aquatic Pathobiology, Åbo Akademi University, Turku, Finland
| | - Roghaieh Ashrafi
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Ville Hoikkala
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Lotta-Riina Sundberg
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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23
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Guérin C, Lee BH, Fradet B, van Dijk E, Mirauta B, Thermes C, Bernardet JF, Repoila F, Duchaud E, Nicolas P, Rochat T. Transcriptome architecture and regulation at environmental transitions in flavobacteria: the case of an important fish pathogen. ISME COMMUNICATIONS 2021; 1:33. [PMID: 36739365 PMCID: PMC9723704 DOI: 10.1038/s43705-021-00029-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/07/2021] [Indexed: 02/06/2023]
Abstract
The family Flavobacteriaceae (phylum Bacteroidetes) is a major component of soil, marine and freshwater ecosystems. In this understudied family, Flavobacterium psychrophilum is a freshwater pathogen that infects salmonid fish worldwide, with critical environmental and economic impact. Here, we report an extensive transcriptome analysis that established the genome map of transcription start sites and transcribed regions, predicted alternative sigma factor regulons and regulatory RNAs, and documented gene expression profiles across 32 biological conditions mimicking the pathogen life cycle. The results link genes to environmental conditions and phenotypic traits and provide insights into gene regulation, highlighting similarities with better known bacteria and original characteristics linked to the phylogenetic position and the ecological niche of the bacterium. In particular, osmolarity appears as a signal for transition between free-living and within-host programs and expression patterns of secreted proteins shed light on probable virulence factors. Further investigations showed that a newly discovered sRNA widely conserved in the genus, Rfp18, is required for precise expression of proteases. By pointing proteins and regulatory elements probably involved in host-pathogen interactions, metabolic pathways, and molecular machineries, the results suggest many directions for future research; a website is made available to facilitate their use to fill knowledge gaps on flavobacteria.
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Affiliation(s)
- Cyprien Guérin
- Université Paris-Saclay, INRAE, MaIAGE, 78350, Jouy-en-Josas, France
| | - Bo-Hyung Lee
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Benjamin Fradet
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Erwin van Dijk
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Bogdan Mirauta
- Sorbonne Université, CNRS, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005, Paris, France
| | - Claude Thermes
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | | | - Francis Repoila
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Eric Duchaud
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Pierre Nicolas
- Université Paris-Saclay, INRAE, MaIAGE, 78350, Jouy-en-Josas, France.
| | - Tatiana Rochat
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France.
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Daniel C, Johanna J, Krister S, Lone M, Inger D, Tom W, Mathias M. Genome-informed approach to identify genetic determinants of Flavobacterium psychrophilum phage susceptibility. Environ Microbiol 2021; 23:4185-4199. [PMID: 33989443 DOI: 10.1111/1462-2920.15593] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/08/2021] [Accepted: 05/11/2021] [Indexed: 12/17/2022]
Abstract
The fish pathogen Flavobacterium psychrophilum infects farmed salmonids worldwide, and application of bacteriophages has been suggested for controlling disease outbreaks in aquaculture. Successful application of phages requires detailed knowledge about the variability in phage susceptibility of the host communities. In this study, we analysed the genetic diversity of F. psychrophilum hosts and phages from the Baltic Sea area to identify genetic determinants of phage-host interaction patterns. A host range analysis of 103 phages tested against 177 F. psychrophilum strains (18 231 phage-host interactions) identified nine phage clusters, infecting from 10% to 91% of the strain collection. The core genome-based comparison of 35 F. psychrophilum isolates revealed an extremely low overall genomic diversity (>99.5% similarity). However, a small subset of 16 ORFs, including genes involved in the type IX secretion system (T9SS), gliding motility and hypothetical cell-surface related proteins, exhibited a highly elevated genetic diversity. These specific genetic variations were linked to variability in phage infection patterns obtained from experimental studies, indicating that these genes are key determinants of phage susceptibility. These findings provide novel insights on the molecular mechanisms determining phage susceptibility in F. psychrophilum and emphasizes the importance of phages as drivers of core genomic diversity in this pathogen.
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Affiliation(s)
- Castillo Daniel
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.,Instituto de Investigación Interdisciplinar en Ciencias Biomédicas SEK (I3CBSEK), Universidad SEK, Santiago, Chile
| | - Jørgensen Johanna
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Sundell Krister
- Laboratory of Aquatic Pathobiology, Marine and Environmental Biology, Åbo Akademi University, Turku, Finland
| | - Madsen Lone
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Dalsgaard Inger
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Wiklund Tom
- Laboratory of Aquatic Pathobiology, Marine and Environmental Biology, Åbo Akademi University, Turku, Finland
| | - Middelboe Mathias
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
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The Development of Bacteriophage Resistance in Vibrio alginolyticus Depends on a Complex Metabolic Adaptation Strategy. Viruses 2021; 13:v13040656. [PMID: 33920240 PMCID: PMC8069663 DOI: 10.3390/v13040656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 12/23/2022] Open
Abstract
Lytic bacteriophages have been well documented to play a pivotal role in microbial ecology due to their complex interactions with bacterial species, especially in aquatic habitats. Although the use of phages as antimicrobial agents, known as phage therapy, in the aquatic environment has been increasing, recent research has revealed drawbacks due to the development of phage-resistant strains among Gram-negative species. Acquired phage resistance in marine Vibrios has been proven to be a very complicated process utilizing biochemical, metabolic, and molecular adaptation strategies. The results of our multi-omics approach, incorporating transcriptome and metabolome analyses of Vibrio alginolyticus phage-resistant strains, corroborate this prospect. Our results provide insights into phage-tolerant strains diminishing the expression of phage receptors ompF, lamB, and btuB. The same pattern was observed for genes encoding natural nutrient channels, such as rbsA, ptsG, tryP, livH, lysE, and hisp, meaning that the cell needs to readjust its biochemistry to achieve phage resistance. The results showed reprogramming of bacterial metabolism by transcript regulations in key-metabolic pathways, such as the tricarboxylic acid cycle (TCA) and lysine biosynthesis, as well as the content of intracellular metabolites belonging to processes that could also significantly affect the cell physiology. Finally, SNP analysis in resistant strains revealed no evidence of amino acid alterations in the studied putative bacterial phage receptors, but several SNPs were detected in genes involved in transcriptional regulation. This phenomenon appears to be a phage-specific, fine-tuned metabolic engineering, imposed by the different phage genera the bacteria have interacted with, updating the role of lytic phages in microbial marine ecology.
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Yu Z, Schwarz C, Zhu L, Chen L, Shen Y, Yu P. Hitchhiking Behavior in Bacteriophages Facilitates Phage Infection and Enhances Carrier Bacteria Colonization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2462-2472. [PMID: 33381966 DOI: 10.1021/acs.est.0c06969] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Interactions between bacteriophages (phages) and biofilms remain poorly understood despite the broad implications for microbial ecology, water quality, and microbiome engineering. Here, we demonstrate that lytic coliphage PHH01 can hitchhike on carrier bacteria Bacillus cereus to facilitate its infection of host bacteria, Escherichia coli, in biofilms. Specifically, PHH01 could adsorb onto the flagella of B. cereus, and thus phage motility was increased, resulting in 4.36-fold more effective infection of E. coli in biofilm relative to free PHH01 alone. Moreover, phage infection mitigated interspecies competition and enhanced B. cereus colonization; the fraction of B. cereus in the final biofilm increased from 9% without phages to 43% with phages. The mutualistic relationship between the coliphage and carrier bacteria was substantiated by migration tests on an E. coli lawn: the conjugation of PHH01 and B. cereus enhanced B. cereus colonization by 6.54-fold compared to B. cereus alone (6.15 vs 0.94 cm2 in 24 h) and PHH01 migration by 5.15-fold compared to PHH01 alone (10.3 vs 2.0 mm in 24 h). Metagenomic and electron microscopic analysis revealed that the phages of diverse taxonomies and different morphologies could be adsorbed by the flagella of B. cereus, suggesting hitchhiking on flagellated bacteria might be a widespread strategy in aquatic phage populations. Overall, our study highlights that hitchhiking behavior in phages can facilitate phage infection of biofilm bacteria, promote carrier bacteria colonization, and thus significantly influence biofilm composition, which holds promise for mediating biofilm functions and moderating associated risks.
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Affiliation(s)
- Zhuodong Yu
- School of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Cory Schwarz
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
| | - Liang Zhu
- School of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Linlin Chen
- School of Environment and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yun Shen
- Department of Chemical and Environmental Engineering, University of California, Riverside, California 92521, United States
| | - Pingfeng Yu
- Department of Civil and Environmental Engineering, Rice University, Houston, Texas 77005, United States
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Sundell K, Landor L, Castillo D, Middelboe M, Wiklund T. Bacteriophages as Biocontrol Agents for Flavobacterium psychrophilum Biofilms and Rainbow Trout Infections. ACTA ACUST UNITED AC 2020; 1:198-204. [PMID: 33409498 PMCID: PMC7774876 DOI: 10.1089/phage.2020.0021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Background: Bacteriophages (phages) have been proposed as an alternative to antibiotics and surface disinfectants for treatment of Flavobacterium psychrophilum biofilms and fish infections in aquaculture settings. The aim of the study was to estimate the minimal phage:host ratio (PHR) required for the control of in vitro biofilm formation and mortalities caused by F. psychrophilum in experimentally infected fish. Materials and Methods: F. psychrophilum cells in different stages of biofilm formation were exposed to the lytic phage FPSV-D22 at different PHRs. Results: Our results show that an initial PHR of 0.01 is sufficient for more than an 80% inhibition of attachment and colonization, and disruption of maturated F. psychrophilum biofilms, whereas greater ratios resulted in almost complete interruption of the different biofilm stages. Interestingly, a similar response was observed in a phage therapy trial with live rainbow trout (Oncorhynchus mykiss), where treatment of F. psychrophilum-infected fish by injection of serial bacteriophage doses resulted in significantly (***p ≤ 0.001) higher survival already at a PHR of 0.02. Conclusions: These results indicate that phages have the potential to be effective for control and treatment of F. psychrophilum infections in fish farms even when applied in concentrations lower than previously expected.
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Affiliation(s)
- Krister Sundell
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
| | - Lotta Landor
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
| | - Daniel Castillo
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Mathias Middelboe
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Tom Wiklund
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
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28
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Hu M, Zhang H, Gu D, Ma Y, Zhou X. Identification of a novel bacterial receptor that binds tail tubular proteins and mediates phage infection of Vibrio parahaemolyticus. Emerg Microbes Infect 2020; 9:855-867. [PMID: 32306848 PMCID: PMC7241545 DOI: 10.1080/22221751.2020.1754134] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The adsorption of phages to hosts is the first step of phage infection. Studies have shown that tailed phages use tail fibres or spikes to recognize bacterial receptors and mediate adsorption. However, whether other phage tail components can also recognize host receptors is unknown. To identify potential receptors, we screened a transposon mutagenesis library of the marine pathogen Vibrio parahaemolyticus and discovered that a vp0980 mutant (vp0980 encodes a predicted transmembrane protein) could not be lysed by phage OWB. Complementation of this mutant with wild-type vp0980 in trans restored phage-mediated lysis. Phage adsorption and confocal microscopy assays demonstrated that phage OWB had dramatically reduced adsorption to the vp0980 mutant compared to that to the wild type. Pulldown assays showed that phage tail tubular proteins A and B (TTPA and TTPB) interact with Vp0980, suggesting that Vp0980 is a TTPA and TTPB receptor. Vp0980 lacking the outer membrane region (aa 114–127) could not bind to TTPA and TTPB, resulting in reduced phage adsorption. These results strongly indicated that TTPA and TTPB binding with their receptor Vp0980 mediates phage adsorption and subsequent bacterial lysis. To the best of our knowledge, this study is the first report of a bacterial receptor for phage tail tubular proteins.
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Affiliation(s)
- Maozhi Hu
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, USA
| | - Hui Zhang
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, USA
| | - Dan Gu
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, USA
| | - Yi Ma
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, USA
| | - Xiaohui Zhou
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, CT, USA
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29
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Computational Identification of Repeat-Containing Proteins and Systems. QRB DISCOVERY 2020. [PMID: 37528961 PMCID: PMC10392669 DOI: 10.1017/qrd.2020.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
AbstractRepetitive sequence elements in proteins and nucleic acids are often signatures of adaptive or reprogrammable systems in nature. Known examples of these systems, such as transcriptional activator-like effectors (TALE) and CRISPR, have been harnessed as powerful molecular tools with a wide range of applications including genome editing. The continued expansion of genomic sequence databases raises the possibility of prospectively identifying new such systems by computational mining. By leveraging sequence repeats as an organizing principle, here we develop a systematic genome mining approach to explore new types of naturally adaptive systems, five of which are discussed in greater detail. These results highlight the existence of a diverse range of intriguing systems in nature that remain to be explored and also provide a framework for future discovery efforts.
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30
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Einarsdottir T, Guttormsdottir G, Connaghan D, Hjartardottir S. Longitudinal survey of Flavobacterium species in Icelandic salmonid fish farms. DISEASES OF AQUATIC ORGANISMS 2020; 141:15-24. [PMID: 32940247 DOI: 10.3354/dao03508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Flavobacterium species cause significant disease in salmonid farming worldwide, typically seen as mortality in sac fry and later as necrosis and ulceration in fingerlings and fry. In this study, we sampled Atlantic salmon Salmo salar and Arctic char Salvelinus alpinus from 5 Icelandic fish farms in 2014 and 2017, where flavobacteria were suspected to cause disease. The objective of the study was to identify and characterise the bacteria by sequencing the 16S rRNA gene and multilocus sequence type housekeeping genes. We found 5 distinct groups of flavobacteria: 3 that were homogeneous and appeared to persist in the fish farms between 2014 and 2017 and 2 that were heterogeneous and transient. Flavobacterium psychrophilum could be isolated from diseased Arctic char from all 5 fish farms in both 2014 and 2017. However, while the other 4 Flavobacterium sp. groups were isolated from Atlantic salmon, water and roe, F. psychrophilum could not be isolated from these samples. This indicates that flavobacteria other than F. psychrophilum may be the primary cause of fin and tail rot in Icelandic Atlantic salmon fry.
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31
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Sieiro C, Areal-Hermida L, Pichardo-Gallardo Á, Almuiña-González R, de Miguel T, Sánchez S, Sánchez-Pérez Á, Villa TG. A Hundred Years of Bacteriophages: Can Phages Replace Antibiotics in Agriculture and Aquaculture? Antibiotics (Basel) 2020; 9:E493. [PMID: 32784768 PMCID: PMC7460141 DOI: 10.3390/antibiotics9080493] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 12/12/2022] Open
Abstract
Agriculture, together with aquaculture, supplies most of the foodstuffs required by the world human population to survive. Hence, bacterial diseases affecting either agricultural crops, fish, or shellfish not only cause large economic losses to producers but can even create food shortages, resulting in malnutrition, or even famine, in vulnerable populations. Years of antibiotic use in the prevention and the treatment of these infections have greatly contributed to the emergence and the proliferation of multidrug-resistant bacteria. This review addresses the urgent need for alternative strategies for the use of antibiotics, focusing on the use of bacteriophages (phages) as biocontrol agents. Phages are viruses that specifically infect bacteria; they are highly host-specific and represent an environmentally-friendly alternative to antibiotics to control and kill pathogenic bacteria. The information evaluated here highlights the effectiveness of phages in the control of numerous major pathogens that affect both agriculture and aquaculture, with special emphasis on scientific and technological aspects still requiring further development to establish phagotherapy as a real universal alternative to antibiotic treatment.
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Affiliation(s)
- Carmen Sieiro
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Lara Areal-Hermida
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Ángeles Pichardo-Gallardo
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Raquel Almuiña-González
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Trinidad de Miguel
- Department of Microbiology and Parasitology, University of Santiago de Compostela, 5706 Santiago de Compostela, Spain; (T.d.M.); (S.S.)
| | - Sandra Sánchez
- Department of Microbiology and Parasitology, University of Santiago de Compostela, 5706 Santiago de Compostela, Spain; (T.d.M.); (S.S.)
| | - Ángeles Sánchez-Pérez
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydnay NSN 2006, Australia;
| | - Tomás G. Villa
- Department of Microbiology and Parasitology, University of Santiago de Compostela, 5706 Santiago de Compostela, Spain; (T.d.M.); (S.S.)
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Castillo D, Rørbo N, Jørgensen J, Lange J, Tan D, Kalatzis PG, Svenningsen SL, Middelboe M. Phage defense mechanisms and their genomic and phenotypic implications in the fish pathogen Vibrio anguillarum. FEMS Microbiol Ecol 2020; 95:5281231. [PMID: 30624625 DOI: 10.1093/femsec/fiz004] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/08/2019] [Indexed: 01/21/2023] Open
Abstract
Vibrio anguillarum is a marine bacterium that can cause vibriosis in many fish and shellfish species. Although phage therapy has been proposed as an alternative treatment, the defense mechanisms against phage infection in V. anguillarum and their impact on host function are not fully understood. Here, we examined phage defense strategies in four V. anguillarum strains during exposure to the broad-host-range bacteriophage KVP40. Whole-genome sequences of phage-resistant V. anguillarum isolates showed mutations causing premature stop codons, frameshifts and amino acid changes in the OmpK phage receptor. Moreover, certain phage-resistant variants recovered susceptibility to phage infection following re-culturing, suggesting alternative protection mechanisms, such as formation of biofilm, receptor downregulation and phage inactivation by proteases. Also, the lack of phage production by some strains despite strong phage control suggested an abortive infection mechanism was in play. In addition, examination of the virulence properties and extracellular enzyme secretion of the phage-resistant variants suggested that phage resistance was associated with reduced virulence in V. anguillarum. Altogether, the results identified a variety of phage resistance mechanisms in V. anguillarum including both mutational and non-mutational defenses and demonstrated a significant fitness loss associated with mutational changes, which may explain the selection for alternative defense mechanisms.
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Affiliation(s)
- Daniel Castillo
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, DK-3000, Helsingør, Denmark
| | - Nanna Rørbo
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, DK-3000, Helsingør, Denmark
| | - Jóhanna Jørgensen
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, DK-3000, Helsingør, Denmark
| | - Janina Lange
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, DK-3000, Helsingør, Denmark.,Zoological Institute, Christian-Albrechts-University, Am botanischen Garten 1-9, G-24116 Kiel, Germany
| | - Demeng Tan
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, DK-3000, Helsingør, Denmark.,Section for Biomolecular Science, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, København N, Denmark
| | - Panos G Kalatzis
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, DK-3000, Helsingør, Denmark
| | - Sine Lo Svenningsen
- Section for Biomolecular Science, University of Copenhagen, Ole Maaløes Vej 5, DK-2200, København N, Denmark
| | - Mathias Middelboe
- Marine Biological Section, University of Copenhagen, Strandpromenaden 5, DK-3000, Helsingør, Denmark
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Characterization and Genomic Analysis of ValSw3-3, a New Siphoviridae Bacteriophage Infecting Vibrio alginolyticus. J Virol 2020; 94:JVI.00066-20. [PMID: 32132234 PMCID: PMC7199398 DOI: 10.1128/jvi.00066-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/25/2020] [Indexed: 02/08/2023] Open
Abstract
A novel lytic bacteriophage, ValSw3-3, which efficiently infects pathogenic strains of Vibrio alginolyticus, was isolated from sewage water and characterized by microbiological and in silico genomic analyses. Transmission electron microscopy indicated that ValSw3-3 has the morphology of siphoviruses. This phage can infect four species in the Vibrio genus and has a latent period of 15 min and a burst size of 95 ± 2 PFU/infected bacterium. Genome sequencing results show that ValSw3-3 has a 39,846-bp double-stranded DNA genome with a GC content of 43.1%. The similarity between the genome sequences of ValSw3-3 and those of other phages recorded in the GenBank database was below 50% (42%), suggesting that ValSw3-3 significantly differs from previously reported phages at the DNA level. Multiple genome comparisons and phylogenetic analysis based on the major capsid protein revealed that phage ValSw3-3 is grouped in a clade with five other phages, including Listonella phage phiHSIC (GenBank accession no. NC_006953.1), Vibrio phage P23 (MK097141.1), Vibrio phage pYD8-B (NC_021561.1), Vibrio phage 2E1 (KX507045.1), and Vibrio phage 12G5 (HQ632860.1), and is distinct from all known genera within the Siphoviridae family that have been ratified by the International Committee on Taxonomy of Viruses (ICTV). An in silico proteomic comparison of diverse phages from the Siphoviridae family supported this clustering result and suggested that ValSw3-3, phiHSIC, P23, pYD8-B, 2E1, and 12G5 should be classified as a novel genus cluster of Siphoviridae A subsequent analysis of core genes also revealed the common genes shared within this new cluster. Overall, these results provide a characterization of Vibrio phage ValSw3-3 and support our proposal of a new viral genus within the family Siphoviridae IMPORTANCE Phage therapy has been considered a potential alternative to antibiotic therapy in treating bacterial infections. For controlling the vibriosis-causing pathogen Vibrio alginolyticus, well-documented phage candidates are still lacking. Here, we characterize a novel lytic Vibrio phage, ValSw3-3, based on its morphology, host range and infectivity, growth characteristics, stability under various conditions, and genomic features. Our results show that ValSw3-3 could be a potent candidate for phage therapy to treat V. alginolyticus infections due to its stronger infectivity and better pH and thermal stability than those of previously reported Vibrio phages. Moreover, genome sequence alignments, phylogenetic analysis, in silico proteomic comparison, and core gene analysis all support that this novel phage, ValSw3-3, and five unclassified phages form a clade distant from those of other known genera ratified by the ICTV. Thus, we propose a new viral genus within the Siphoviridae family to accommodate this clade, with ValSw3-3 as a representative member.
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35
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Kumru S, Tekedar HC, Blom J, Lawrence ML, Karsi A. Genomic diversity in flavobacterial pathogens of aquatic origin. Microb Pathog 2020; 142:104053. [PMID: 32058022 DOI: 10.1016/j.micpath.2020.104053] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/07/2020] [Accepted: 02/07/2020] [Indexed: 12/15/2022]
Abstract
Flavobacterium species are considered important fish pathogens in wild and cultured fish throughout the world. They can cause acute, subacute, and chronic infections, which are mainly characterized by gill damage, skin lesions, and deep necrotic ulcerations. Primarily, three Flavobacterium species, F. branchiophilum, F. columnare, and F. psychrophilum, have been reported to cause substantial losses to freshwater fish. In this study, we evaluated genomes of 86 Flavobacterium species isolated from aquatic hosts (mainly fish) to identify their unique and shared genome features. Our results showed that F. columnare genomes cluster into four different genetic groups. In silico secretion system analysis identified that all genomes carry type I (T1SS) and type IX (T9SS) secretion systems, but the number of type I secretion system genes shows diversity between species. F. branchiophilum, F. araucananum, F. chilense, F. spartansii, and F. tructae genomes have full type VI secretion system (T6SS). F. columnare, F. hydatis, and F. plurextorum carry partial T6SS with some of the T6SS genes missing. F. columnare, F. araucananum, F. chilense, F. spartansii, F. araucananum, F. tructae, Flavobacterium sp., F. crassostreae, F. succinicans, F. hydatis, and F. plurextorum carry most of the type IV secretion system genes (T4SS). F. columnare genetic groups 1 and 2, Flavobacterium sp., and F. crassostreae encode the least number of antibiotic resistance elements. F. hydatis, F. chilense, and F. plurextorum encode the greatest number of antibiotic resistance genes. Additionally, F. spartansii, F. araucananum, and chilense encode the greatest number of virulence genes while Flavobacterium sp. and F. crassostreae encode the least number of virulence genes. In conclusion, comparative genomics of Flavobacterium species of aquatic origin will help our understanding of Flavobacterium pathogenesis.
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Affiliation(s)
- Salih Kumru
- Faculty of Fisheries, Recep Tayyip Erdogan University, Rize, Turkey
| | - Hasan C Tekedar
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Hesse, Germany
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States.
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Wang CH, Hsieh YH, Powers ZM, Kao CY. Defeating Antibiotic-Resistant Bacteria: Exploring Alternative Therapies for a Post-Antibiotic Era. Int J Mol Sci 2020; 21:E1061. [PMID: 32033477 PMCID: PMC7037027 DOI: 10.3390/ijms21031061] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/04/2020] [Accepted: 02/04/2020] [Indexed: 12/11/2022] Open
Abstract
Antibiotics are one of the greatest medical advances of the 20th century, however, they are quickly becoming useless due to antibiotic resistance that has been augmented by poor antibiotic stewardship and a void in novel antibiotic discovery. Few novel classes of antibiotics have been discovered since 1960, and the pipeline of antibiotics under development is limited. We therefore are heading for a post-antibiotic era in which common infections become untreatable and once again deadly. There is thus an emergent need for both novel classes of antibiotics and novel approaches to treatment, including the repurposing of existing drugs or preclinical compounds and expanded implementation of combination therapies. In this review, we highlight to utilize alternative drug targets/therapies such as combinational therapy, anti-regulator, anti-signal transduction, anti-virulence, anti-toxin, engineered bacteriophages, and microbiome, to defeat antibiotic-resistant bacteria.
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Affiliation(s)
- Chih-Hung Wang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan;
| | - Yi-Hsien Hsieh
- Institute of Biochemistry, Microbiology and Immunology, Chung Shan Medical University, Taichung 40201, Taiwan;
| | - Zachary M. Powers
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA;
| | - Cheng-Yen Kao
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei 11221, Taiwan
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Diversity and Host Interactions Among Virulent and Temperate Baltic Sea Flavobacterium Phages. Viruses 2020; 12:v12020158. [PMID: 32019073 PMCID: PMC7077304 DOI: 10.3390/v12020158] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/24/2020] [Accepted: 01/28/2020] [Indexed: 02/06/2023] Open
Abstract
Viruses in aquatic environments play a key role in microbial population dynamics and nutrient cycling. In particular, bacteria of the phylum Bacteriodetes are known to participate in recycling algal blooms. Studies of phage–host interactions involving this phylum are hence important to understand the processes shaping bacterial and viral communities in the ocean as well as nutrient cycling. In this study, we isolated and sequenced three strains of flavobacteria—LMO6, LMO9, LMO8—and 38 virulent phages infecting them. These phages represent 15 species, occupying three novel genera. Additionally, one temperate phage was induced from LMO6 and was found to be competent at infecting LMO9. Functions could be predicted for a limited number of phage genes, mainly representing roles in DNA replication and virus particle formation. No metabolic genes were detected. While the phages isolated on LMO8 could infect all three bacterial strains, the LMO6 and LMO9 phages could not infect LMO8. Of the phages isolated on LMO9, several showed a host-derived reduced efficiency of plating on LMO6, potentially due to differences in DNA methyltransferase genes. Overall, these phage–host systems contribute novel genetic information to our sequence databases and present valuable tools for the study of both virulent and temperate phages.
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Papadopoulou A, Dalsgaard I, Wiklund T. Inhibition Activity of Compounds and Bacteriophages against Flavobacterium psychrophilum Biofilms In Vitro. JOURNAL OF AQUATIC ANIMAL HEALTH 2019; 31:225-238. [PMID: 31216387 DOI: 10.1002/aah.10069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 03/24/2019] [Indexed: 06/09/2023]
Abstract
Flavobacterium psychrophilum produces biofilms under laboratory conditions, and it has been inconclusively suggested that F. psychrophilum biofilms can be a potential reservoir for transmission of the pathogen to a fish population under fish farming conditions. Therefore, there is a need for anti-biofilm compounds. The main aim of this study was to determine the anti-biofilm properties of certain compounds and bacteriophages on F. psychrophilum biofilms under static conditions using a standard 96-well microtiter plate biofilm assay in vitro. Eight compounds (A-type proanthocyanidins, D-leucine, EDTA, emodin, fucoidan, L-alliin, parthenolide, and 2-aminoimidazole) at three sub-minimum inhibitory concentrations (sub-MICs), four bacteriophages (Fpv-3, Fpv-9, Fpv-10, and Fpv-21), and a phage combination (Fpv-9 + Fpv-10) were tested for inhibition of biofilm formation and reduction of the biomass of mature biofilms formed by two smooth isolates (P7-9/10 and P1-10B/10) and two rough isolates (P7-9/2R/10 and P1-10B/2R/10) of F. psychrophilum. The crystal violet staining method was used to stain the biofilms. Most of the compounds at sub-MICs inhibited the biofilm formation of mainly smooth isolates, attaining up to 80% inhibition. Additionally, the same reduction trend was also observed for 2-aminoimidazole, emodin, parthenolide, and D-leucine on the biomass of mature biofilms in a concentration-dependent manner. The anti-biofilm properties of the compounds are believed to lie in their ability to disturb the cellular interactions during biofilm formation and probably to cause cell dispersal in already formed biofilms. Lytic bacteriophages efficiently inhibited biofilm formation of F. psychrophilum, while they partially reduced the biomass of mature biofilms. However, the phage combination (Fpv-9 + Fpv-10) showed a successful reduction in the biomass of F. psychrophilum mature biofilms. We conclude that inhibiting compounds together with bacteriophages may supplement the use of disinfectants against bacterial biofilms (e.g., F. psychrophilum biofilms), leading to a reduced occurrence of bacterial coldwater disease outbreaks at fish farms.
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Affiliation(s)
- Anna Papadopoulou
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Tykistokatu 6, FI-20520, Turku, Finland
| | - Inger Dalsgaard
- National Institute of Aquatic Resources, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Tom Wiklund
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Tykistokatu 6, FI-20520, Turku, Finland
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Sundell K, Landor L, Nicolas P, Jørgensen J, Castillo D, Middelboe M, Dalsgaard I, Donati VL, Madsen L, Wiklund T. Phenotypic and Genetic Predictors of Pathogenicity and Virulence in Flavobacterium psychrophilum. Front Microbiol 2019; 10:1711. [PMID: 31396199 PMCID: PMC6668605 DOI: 10.3389/fmicb.2019.01711] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/11/2019] [Indexed: 02/05/2023] Open
Abstract
Flavobacterium psychrophilum causes bacterial cold-water disease (BCWD) in farmed rainbow trout (Oncorhynchus mykiss), with the multilocus sequence typing (MLST) clonal complex (CC) CC-ST10 accounting for the majority of outbreaks globally. The development of alternative strategies to antibiotic treatment of BCWD using bacteriophage-based control of F. psychrophilum, or virulence factors as targets for therapy, requires knowledge of the phage-sensitivity of outbreak strains and of universal traits contributing to their pathogenicity. To examine the association between virulence and both genetic (MLST sequence type (ST) and PCR-serotype) and phenotypic characteristics (adherence, antibiotic resistance, colony spreading motility, hemolytic and proteolytic activity), the median lethal dose (LD50) of 26 geographically disparate F. psychrophilum isolates was determined in rainbow trout. Furthermore, the in vitro sensitivity of the isolates against five bacteriophages was determined by the efficiency of plating (EOP). The tested F. psychrophilum isolates were mainly represented by CC-ST10 genotypes (22 out of 26) and showed up to 3-log differences in LD50 (8.9 × 103 to 3.1 × 106 CFU). No association between MLST ST and virulence was found because of a high variation in LD50 within STs. All identified serotypes (0, 1, and 2) were pathogenic, but ten most virulent isolates belonged to serotype 1 or 2. Isolates of high (LD50 < 105 CFU), moderate (LD50 = 105–106 CFU), and weak (LD50 > 106 CFU) virulence were similar in phenotypic characteristics in vitro. However, the only non-virulent CC-ST10 isolate was deficient in spreading motility and proteolytic activity, indicating that the characteristics are required for pathogenicity in F. psychrophilum. Univariate correlation studies found only non-significant associations between LD50 and the measured phenotypic characteristics, and the multivariable analysis did neither reveal any significant predictors of virulence. The majority of isolates (16 out of 26) were sensitive to at least four bacteriophages, with up to a 6-log variation in the EOP. Most CC-ST10 isolates (16 out of 22) were sensitive to the examined phages, including 5 out of the 7 most virulent isolates represented by prevalent and antibiotic-resistant STs. Our findings suggest that control of BCWD using lytic phages or interventions targeting shared characteristics of pathogenic F. psychrophilum strains should be further explored.
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Affiliation(s)
- Krister Sundell
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
| | - Lotta Landor
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
| | - Pierre Nicolas
- Unité Mathématiques et Informatique Appliquées du Génome à l'Environnement (MaIAGE), Institut National de la Recherche Agronomique, Université Paris-Saclay, Jouy-en-Josas, France
| | - Jóhanna Jørgensen
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Daniel Castillo
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Mathias Middelboe
- Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark
| | - Inger Dalsgaard
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Valentina Laura Donati
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lone Madsen
- Unit for Fish and Shellfish Diseases, National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Tom Wiklund
- Laboratory of Aquatic Pathobiology, Environmental and Marine Biology, Åbo Akademi University, Turku, Finland
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Hoikkala V, Almeida GMF, Laanto E, Sundberg LR. Aquaculture as a source of empirical evidence for coevolution between CRISPR-Cas and phage. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180100. [PMID: 30905289 PMCID: PMC6452259 DOI: 10.1098/rstb.2018.0100] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2018] [Indexed: 12/20/2022] Open
Abstract
So far, studies on the bacterial immune system CRISPR-Cas and its ecological and evolutionary effects have been largely limited to laboratory conditions. While providing crucial information on the constituents of CRISPR-Cas, such studies may overlook fundamental components that affect bacterial immunity in natural habitats. Translating laboratory-derived predictions to nature is not a trivial task, owing partly to the instability of natural communities and difficulties in repeated sampling. To this end, we review how aquaculture, the farming of fishes and other aquatic species, may provide suitable semi-natural laboratories for examining the role of CRISPR-Cas in phage/bacterium coevolution. Existing data from disease surveillance conducted in aquaculture, coupled with growing interest towards phage therapy, may have already resulted in large collections of bacterium and phage isolates. These data, combined with premeditated efforts, can provide empirical evidence on phage-bacterium dynamics such as the bacteriophage adherence to mucus hypothesis, phage life cycles and their relationship with CRISPR-Cas and other immune defences. Typing of CRISPR spacer content in pathogenic bacteria can also provide practical information on diversity and origin of isolates during outbreaks. In addition to providing information of CRISPR functionality and phage-bacterium dynamics, aquaculture systems can significantly impact perspectives on design of phage-based disease treatment at the current era of increasing antibiotic resistance. This article is part of a discussion meeting issue 'The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems'.
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Affiliation(s)
| | | | | | - Lotta-Riina Sundberg
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, PO Box 35, 40014 Jyvaskyla, Finland
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Cisar JO, Bush CA, Wiens GD. Comparative Structural and Antigenic Characterization of Genetically Distinct Flavobacterium psychrophilum O-Polysaccharides. Front Microbiol 2019; 10:1041. [PMID: 31139169 PMCID: PMC6519341 DOI: 10.3389/fmicb.2019.01041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/25/2019] [Indexed: 11/25/2022] Open
Abstract
Little is known about the underlying basis of serotype specificity among strains of Flavobacterium psychrophilum, the agent of rainbow trout fry syndrome and bacterial cold-water disease. The identification of different heat-stable O-serotypes among strains of this gram-negative pathogen does, however, suggest structural variations in the O-polysaccharide (O-PS) moiety of cell surface lipopolysaccharide (LPS). A trisaccharide composed of L-rhamnose (L-Rha), 2-acetamido-2-deoxy-L-fucose (L-FucNAc) and 2-acetamido-4-R-2,4-dideoxy-D-quinovose (D-Qui2NAc4NR), where R represents a dihydroxyhexanamido derivative, was previously identified as the repeating unit of Fp CSF259-93 O-PS. Interestingly, the O-PS gene cluster of this strain and that of Fp 950106-1/1, which belongs to a different O-serotype, are identical except for wzy, which encodes the putative polymerase that links trisaccharide repeats into O-PS chains. We have now found from results of glycosyl composition analysis and high-resolution nuclear magnetic resonance, that the linkage of D-Qui2NAc4NR to L-Rha, which is α1-2 for Fp CSF259-93 versus β1-3 for Fp 950106-1/1, is the only structural difference between O-PS from these strains. The corresponding difference in O-serotype specificity was established from the reactions of rabbit and trout anti-F. psychrophilum antibody with purified O-PS and LPS. Moreover, LPS-based differences in antigenicity were noted between strains with O-PS loci identical to those of Fp CSF259-93 or Fp 950106-1/1, except for the genes predicted to direct synthesis of different R-groups in Qui2NAc4NR. The findings provide a framework for defining the genetic basis of O-PS structure and antigenicity and suggest that the repertoire of F. psychrophilum O-serotypes extends beyond what is presently recognized from serological studies of this important fish pathogen.
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Affiliation(s)
- John O Cisar
- United States Department of Agriculture, Agricultural Research Service, National Center for Cool and Cold Water Aquaculture, Kearneysville, WV, United States
| | - C Allen Bush
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, MD, United States
| | - Gregory D Wiens
- United States Department of Agriculture, Agricultural Research Service, National Center for Cool and Cold Water Aquaculture, Kearneysville, WV, United States
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Wang J, Bai P, Li Q, Lin Y, Huo D, Ke F, Zhang Q, Li T, Zhao J. Interaction between cyanophage MaMV-DC and eight Microcystis strains, revealed by genetic defense systems. HARMFUL ALGAE 2019; 85:101699. [PMID: 31810530 DOI: 10.1016/j.hal.2019.101699] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
Cyanophage MaMV-DC is a member of Myoviridae that was reported to specifically infect and lyse Microcystis aeruginosa FACHB-524 among 21 selected cyanobacterial strains. We reidentified the infection specificity of MaMV-DC among seven other Microcystis strains of different species. In our experiments, MaMV-DC infected three Microcystis strains but did not form plaque in Microcystis lawns. This indicated that MaMV-DC is at least a genus- rather than strain-specific virus. Cyanophage MaMV-DC genes were transcribed in M. aeruginosa FACHB-524, M. flos-aquae TF09, M. aeruginosa TA09 and M. wesenbergii DW09, and the growth of these Microcystis strains was inhibited by the addition of MaMV-DC. The predicted defense of eight Microcystis strains by CRISPR-Cas systems has shown mixed consistency with the infection experiment results, suggesting other defense or anti-defense systems play roles during infection process. Restriction-modification (RM) system analysis revealed an abundance of four types of RM proteins that may play roles in defense against cyanophages.
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Affiliation(s)
- Juanping Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan 430071, China
| | - Peng Bai
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Yan Lin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Da Huo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Ke
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Qiya Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Tao Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Jindong Zhao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; State Key Laboratory of Protein and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China
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Kulikov EE, Golomidova AK, Prokhorov NS, Ivanov PA, Letarov AV. High-throughput LPS profiling as a tool for revealing of bacteriophage infection strategies. Sci Rep 2019; 9:2958. [PMID: 30814597 PMCID: PMC6393563 DOI: 10.1038/s41598-019-39590-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/25/2019] [Indexed: 12/25/2022] Open
Abstract
O-antigens of Gram-negative bacteria modulate the interactions of bacterial cells with diverse external factors, including the components of the immune system and bacteriophages. Some phages need to acquire specific adhesins to overcome the O-antigen layer. For other phages, O-antigen is required for phage infection. In this case, interaction of phage receptor binding proteins coupled with enzymatic degradation or modification of the O-antigen is followed by phage infection. Identification of the strategies used by newly isolated phages may be of importance in their consideration for various applications. Here we describe an approach based on screening for host LPS alterations caused by selection by bacteriophages. We describe an optimized LPS profiling procedure that is simple, rapid and suitable for mass screening of mutants. We demonstrate that the phage infection strategies identified using a set of engineered E. coli 4 s mutants with impaired or altered LPS synthesis are in good agreement with the results of simpler tests based on LPS profiling of phage-resistant spontaneous mutants.
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Affiliation(s)
- Eugene E Kulikov
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, prosp. 60-letiya Oktyabrya, 7 bld. 2, 117312, Moscow, Russian Federation
- Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, Moscow Region, 141701, Russian Federation
| | - Alla K Golomidova
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, prosp. 60-letiya Oktyabrya, 7 bld. 2, 117312, Moscow, Russian Federation
| | - Nikolai S Prokhorov
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, prosp. 60-letiya Oktyabrya, 7 bld. 2, 117312, Moscow, Russian Federation
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, 301 University Bulevard, Galveston, TX, USA
| | - Pavel A Ivanov
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, prosp. 60-letiya Oktyabrya, 7 bld. 2, 117312, Moscow, Russian Federation
| | - Andrey V Letarov
- Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, prosp. 60-letiya Oktyabrya, 7 bld. 2, 117312, Moscow, Russian Federation.
- Moscow Institute of Physics and Technology, Institutskiy per., 9, Dolgoprudny, Moscow Region, 141701, Russian Federation.
- Faculty of Biology, Lomonosov Moscow State University, ul. Leninskie Gory, 1, 119991, Moscow, Russia.
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Bacteriophage-host arm race: an update on the mechanism of phage resistance in bacteria and revenge of the phage with the perspective for phage therapy. Appl Microbiol Biotechnol 2019; 103:2121-2131. [PMID: 30680434 DOI: 10.1007/s00253-019-09629-x] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/25/2018] [Accepted: 12/27/2018] [Indexed: 12/20/2022]
Abstract
Due to a constant attack by phage, bacteria in the environment have evolved diverse mechanisms to defend themselves. Several reviews on phage resistance mechanisms have been published elsewhere. Thanks to the advancement of molecular techniques, several new phage resistance mechanisms were recently identified. For the practical phage therapy, the emergence of phage-resistant bacteria could be an obstacle. However, unlike antibiotic, phages could evolve a mechanism to counter-adapt against phage-resistant bacteria. In this review, we summarized the most recent studies of the phage-bacteria arm race with the perspective of future applications of phages as antimicrobial agents.
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The disparate effects of bacteriophages on antibiotic-resistant bacteria. Emerg Microbes Infect 2018; 7:168. [PMID: 30302018 PMCID: PMC6177407 DOI: 10.1038/s41426-018-0169-z] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 08/30/2018] [Accepted: 09/05/2018] [Indexed: 01/21/2023]
Abstract
Faced with the crisis of multidrug-resistant bacteria, bacteriophages, viruses that infect and replicate within bacteria, have been reported to have both beneficial and detrimental effects with respect to disease management. Bacteriophages (phages) have important ecological and evolutionary impacts on their bacterial hosts and have been associated with therapeutic use to kill bacterial pathogens, but can lead to the transmission of antibiotic resistance. Although the process known as transduction has been reported for many bacterial species by classic and modern genetic approaches, its contribution to the spread of antibiotic resistance in nature remains unclear. In addition, detailed molecular studies have identified phages residing in bacterial genomes, revealing unexpected interactions between phages and their bacterial hosts. Importantly, antibiotics can induce the production of phages and phage-encoded products, disseminating these viruses and virulence-related genes, which have dangerous consequences for disease severity. These unwanted side-effects of antibiotics cast doubt on the suitability of some antimicrobial treatments and may require new strategies to prevent and limit the selection for virulence. Foremost among these treatments is phage therapy, which could be used to treat many bacterial infectious diseases and confront the pressing problem of antibiotic resistance in pathogenic bacteria. This review discusses the interactions between bacteriophages, antibiotics, and bacteria and provides an integrated perspective that aims to inspire the development of successful antibacterial therapies.
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Investigation of O-polysaccharides from bacterial strains of Pseudomonas genus as potential receptors of bacteriophage BIM BV-45. Int J Biol Macromol 2018; 118:1065-1072. [DOI: 10.1016/j.ijbiomac.2018.06.165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/08/2018] [Accepted: 06/27/2018] [Indexed: 02/06/2023]
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Chen L, Yuan S, Liu Q, Mai G, Yang J, Deng D, Zhang B, Liu C, Ma Y. In Vitro Design and Evaluation of Phage Cocktails Against Aeromonas salmonicida. Front Microbiol 2018; 9:1476. [PMID: 30034378 PMCID: PMC6043867 DOI: 10.3389/fmicb.2018.01476] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/13/2018] [Indexed: 01/21/2023] Open
Abstract
As an alternative approach against multidrug-resistant bacterial infections, phages are now being increasingly investigated as effective therapeutic agents. Here, aiming to design an efficient phage cocktail against Aeromonas salmonicida infections, we isolated and characterized five lytic A. salmonicida phages, AS-szw, AS-yj, AS-zj, AS-sw, and AS-gz. The results of morphological and genomic analysis suggested that all these phages are affiliated to the T4virus genus of the Caudovirales order. Their heterogeneous lytic capacities against A. salmonicida strains were demonstrated by experiments. A series of phage cocktails were prepared and investigated in vitro. We observed that the cocktail combining AS-gz and AS-yj showed significantly higher antimicrobial activity than other cocktails and individual phages. Given the divergent genomes between the phages AS-yj and AS-gz, our results highlight that the heterogeneous mechanisms that phages use to infect their hosts likely lead to phage synergy in killing the host. Conclusively, our study described a strategy to develop an effective and promising phage cocktail as a therapeutic agent to combat A. salmonicida infections, and thereby to control the outbreak of relevant fish diseases. Our study suggests that in vitro investigations into phages are prerequisite to obtain satisfying phage cocktails prior to application in practice.
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Affiliation(s)
- Ling Chen
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Shengjian Yuan
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Quan Liu
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Guoqin Mai
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jinfang Yang
- R&D Center, Shenzhen Alpha Feed Co., Ltd., Shenzhen, China
| | - Deng Deng
- R&D Center, Shenzhen Alpha Feed Co., Ltd., Shenzhen, China
| | - Bingzhao Zhang
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Chenli Liu
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yingfei Ma
- Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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Penttinen R, Hoikkala V, Sundberg LR. Gliding Motility and Expression of Motility-Related Genes in Spreading and Non-spreading Colonies of Flavobacterium columnare. Front Microbiol 2018; 9:525. [PMID: 29632520 PMCID: PMC5879114 DOI: 10.3389/fmicb.2018.00525] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 03/08/2018] [Indexed: 11/13/2022] Open
Abstract
Gliding motility facilitates the movement of bacteria along surfaces in many Bacteroidetes species and results in spreading colonies. The adhesins required for the gliding are secreted through a gliding motility-associated protein secretion system, known as the type IX secretion system (T9SS). The fish pathogen Flavobacterium columnare produces spreading (rhizoid [Rz], soft [S]) and non-spreading (rough [R]) colony types, of which only the spreading Rz type is virulent. In this study, we explored the spreading behavior of these colony types by microscopic imaging and measured the expression of genes associated with gliding motility and T9SS (gldG, gldH, gldL, sprA, sprB, sprE, sprF, sprT, and porV) under high and low resource levels by using RT-qPCR (reverse transcription quantitative PCR). The spreading colony types responded to the low resource level with increased colony size. The non-spreading colony type, as well as the cells growing under high nutrient level expressed only moderate cell movements. Yet, a low nutrient level provoked more active gliding motility in individual cells and increased spreading by cooperative gliding. The gene expression survey demonstrated an increased expression level of sprA (a core component of T9SS) and sprF (needed for adhesin secretion) under low nutrient conditions. Surprisingly, the expression of gliding motility genes was not consistently associated with more active spreading behavior. Furthermore, no genetic differences were found between spreading and non-spreading colony types in the studied genes associated with gliding motility. Our study demonstrates that environmental nutrient level is an important regulator of both gliding motility and the expression of some of the associated genes. These results may help to understand the connections between nutrient concentration, gliding motility, and virulence of F. columnare.
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Affiliation(s)
- Reetta Penttinen
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Ville Hoikkala
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Lotta-Riina Sundberg
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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Bacteriophage Interactions with Marine Pathogenic Vibrios: Implications for Phage Therapy. Antibiotics (Basel) 2018; 7:antibiotics7010015. [PMID: 29495270 PMCID: PMC5872126 DOI: 10.3390/antibiotics7010015] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 02/19/2018] [Accepted: 02/21/2018] [Indexed: 12/27/2022] Open
Abstract
A global distribution in marine, brackish, and freshwater ecosystems, in combination with high abundances and biomass, make vibrios key players in aquatic environments, as well as important pathogens for humans and marine animals. Incidents of Vibrio-associated diseases (vibriosis) in marine aquaculture are being increasingly reported on a global scale, due to the fast growth of the industry over the past few decades years. The administration of antibiotics has been the most commonly applied therapy used to control vibriosis outbreaks, giving rise to concerns about development and spreading of antibiotic-resistant bacteria in the environment. Hence, the idea of using lytic bacteriophages as therapeutic agents against bacterial diseases has been revived during the last years. Bacteriophage therapy constitutes a promising alternative not only for treatment, but also for prevention of vibriosis in aquaculture. However, several scientific and technological challenges still need further investigation before reliable, reproducible treatments with commercial potential are available for the aquaculture industry. The potential and the challenges of phage-based alternatives to antibiotic treatment of vibriosis are addressed in this review.
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