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Takala TM, Mokhtari S, Ahonen SL, Wan X, Saris PEJ. Wild-type Lactococcus lactis producing bacteriocin-like prophage lysins. Front Microbiol 2023; 14:1219723. [PMID: 37520360 PMCID: PMC10377672 DOI: 10.3389/fmicb.2023.1219723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/26/2023] [Indexed: 08/01/2023] Open
Abstract
Introduction Lactococcus is a genus of lactic acid bacteria used in the dairy industry as a starter. Lactococci have been found to produce altogether more than 40 different bacteriocins, ribosomally synthesized antimicrobial proteins. All known Lactococcus spp. bacteriocins belong to classes I and II, which are mainly heat-resistant peptides. No class III bacteriocins, bigger heat-sensitive proteins, including phage tail-like bacteriocins, have been found from the Lactococcus spp. Unlike phage tail-like bacteriocins, prophage lysins have not been regarded as bacteriocins, possibly because phage lysins contribute to autolysis, degrading the host's own cell wall. Methods Wild-type Lactococcus lactis strain LAC460, isolated from spontaneously fermented idli batter, was examined for its antimicrobial activity. We sequenced the genome, searched phage lysins from the culture supernatant, and created knock-out mutants to find out the source of the antimicrobial activity. Results and discussion The strain LAC460 was shown to kill other Lactococcus strains with protease- and heat-sensitive lytic activity. Three phage lysins were identified in the culture supernatant. The genes encoding the three lysins were localized in different prophage regions in the chromosome. By knock-out mutants, two of the lysins, namely LysL and LysP, were demonstrated to be responsible for the antimicrobial activity. The strain LAC460 was found to be resistant to the lytic action of its own culture supernatant, and as a consequence, the phage lysins could behave like bacteriocins targeting and killing other closely related bacteria. Hence, similar to phage tail-like bacteriocins, phage lysin-like bacteriocins could be regarded as a novel type of class III bacteriocins.
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Affiliation(s)
- Timo M. Takala
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Samira Mokhtari
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Susanna L. Ahonen
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
- Expert Microbiology Unit, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Xing Wan
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Per E. J. Saris
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
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2
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Tonkin-Hill G, Ling C, Chaguza C, Salter SJ, Hinfonthong P, Nikolaou E, Tate N, Pastusiak A, Turner C, Chewapreecha C, Frost SDW, Corander J, Croucher NJ, Turner P, Bentley SD. Pneumococcal within-host diversity during colonization, transmission and treatment. Nat Microbiol 2022; 7:1791-1804. [PMID: 36216891 PMCID: PMC9613479 DOI: 10.1038/s41564-022-01238-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022]
Abstract
Characterizing the genetic diversity of pathogens within the host promises to greatly improve surveillance and reconstruction of transmission chains. For bacteria, it also informs our understanding of inter-strain competition and how this shapes the distribution of resistant and sensitive bacteria. Here we study the genetic diversity of Streptococcus pneumoniae within 468 infants and 145 of their mothers by deep sequencing whole pneumococcal populations from 3,761 longitudinal nasopharyngeal samples. We demonstrate that deep sequencing has unsurpassed sensitivity for detecting multiple colonization, doubling the rate at which highly invasive serotype 1 bacteria were detected in carriage compared with gold-standard methods. The greater resolution identified an elevated rate of transmission from mothers to their children in the first year of the child's life. Comprehensive treatment data demonstrated that infants were at an elevated risk of both the acquisition and persistent colonization of a multidrug-resistant bacterium following antimicrobial treatment. Some alleles were enriched after antimicrobial treatment, suggesting that they aided persistence, but generally purifying selection dominated within-host evolution. Rates of co-colonization imply that in the absence of treatment, susceptible lineages outcompeted resistant lineages within the host. These results demonstrate the many benefits of deep sequencing for the genomic surveillance of bacterial pathogens.
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Affiliation(s)
- Gerry Tonkin-Hill
- grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK ,grid.5510.10000 0004 1936 8921Department of Biostatistics, University of Oslo, Blindern, Norway
| | - Clare Ling
- grid.10223.320000 0004 1937 0490Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand ,grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Chrispin Chaguza
- grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK ,grid.47100.320000000419368710Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT USA
| | - Susannah J. Salter
- grid.5335.00000000121885934Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Pattaraporn Hinfonthong
- grid.10223.320000 0004 1937 0490Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Elissavet Nikolaou
- grid.48004.380000 0004 1936 9764Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK ,grid.1058.c0000 0000 9442 535XInfection and Immunity, Murdoch Children’s Research Institute, Melbourne, Victoria Australia ,grid.1008.90000 0001 2179 088XDepartment of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria Australia
| | - Natalie Tate
- grid.48004.380000 0004 1936 9764Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Claudia Turner
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.459332.a0000 0004 0418 5364Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Claire Chewapreecha
- grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK ,grid.10223.320000 0004 1937 0490Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Simon D. W. Frost
- grid.419815.00000 0001 2181 3404Microsoft Research, Redmond, WA USA ,grid.8991.90000 0004 0425 469XLondon School of Hygiene and Tropical Medicine, London, UK
| | - Jukka Corander
- grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK ,grid.5510.10000 0004 1936 8921Department of Biostatistics, University of Oslo, Blindern, Norway ,grid.7737.40000 0004 0410 2071Helsinki Institute for Information Technology HIIT, Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
| | - Nicholas J. Croucher
- grid.7445.20000 0001 2113 8111MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Paul Turner
- grid.4991.50000 0004 1936 8948Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK ,grid.459332.a0000 0004 0418 5364Cambodia-Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
| | - Stephen D. Bentley
- grid.10306.340000 0004 0606 5382Parasites and Microbes, Wellcome Sanger Institute, Cambridge, UK
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3
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Xiao Y, Chen R, Li M, Qi Z, Yu Y, Pan Z, Yao H, Feng Z, Zhang W. The effectiveness of extended binding affinity of prophage lysin PlyARI against Streptococcus suis infection. Arch Microbiol 2021; 203:5163-5172. [PMID: 34338822 DOI: 10.1007/s00203-021-02438-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 01/21/2023]
Abstract
Streptococcus suis is an important zoonotic pathogen. An increase in multi-drug-resistant strains has led to poor performance of traditional antibiotic therapies. Thus, alternative antibacterial agents are urgently needed. In this study, we identified a recombined and expressed lysin PlyARI derived from the novel serotype S. suis (Chz) prophage PhiARI0460-1. The recombinant PlyARI at a concentration of 10 µg/mL showed high bacteriolytic activity against 30 S. suis isolates. The minimum inhibitory concentration (MIC) of PlyARI against S. suis was found to be as low as 2 µg/mL, and the lytic efficiency could be maintained between the range of pH 4 and 12. Additionally, in a mouse infection model, a dose of 0.5 mg of PlyARI protected 10 out of 10 mice that were challenged with highly virulent S. suis strain HA9801. Furthermore, the binding specificity of PlyARI was evaluated by constructing a green fluorescent protein (GFP-ARIb), where GFP was fused with the PlyARI-SH3b (cell wall-binding domain, CBD), revealing a high affinity to S. suis, Staphylococcus aureus, and Streptococcus equi along with exhibiting a medium affinity to Streptococcus pneumoniae as well as Streptococcus agalactiae. Overall, our findings indicated that PlyARI may be an alternative antibacterial agent that was useful in treating and possibly the prevention of Streptococcal infections.
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Affiliation(s)
- Yuyi Xiao
- OIE Reference Lab for Swine Streptococcosis, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China.,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Rong Chen
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Min Li
- OIE Reference Lab for Swine Streptococcosis, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China.,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zitai Qi
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yanfei Yu
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Zihao Pan
- OIE Reference Lab for Swine Streptococcosis, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China.,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Huochun Yao
- OIE Reference Lab for Swine Streptococcosis, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China.,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhixin Feng
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Wei Zhang
- OIE Reference Lab for Swine Streptococcosis, Nanjing, 210095, China. .,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China. .,College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
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Tzani-Tzanopoulou P, Skliros D, Megremis S, Xepapadaki P, Andreakos E, Chanishvili N, Flemetakis E, Kaltsas G, Taka S, Lebessi E, Doudoulakakis A, Papadopoulos NG. Interactions of Bacteriophages and Bacteria at the Airway Mucosa: New Insights Into the Pathophysiology of Asthma. FRONTIERS IN ALLERGY 2021; 1:617240. [PMID: 35386933 PMCID: PMC8974763 DOI: 10.3389/falgy.2020.617240] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/29/2020] [Indexed: 12/16/2022] Open
Abstract
The airway epithelium is the primary site where inhaled and resident microbiota interacts between themselves and the host, potentially playing an important role on allergic asthma development and pathophysiology. With the advent of culture independent molecular techniques and high throughput technologies, the complex composition and diversity of bacterial communities of the airways has been well-documented and the notion of the lungs' sterility definitively rejected. Recent studies indicate that the microbial composition of the asthmatic airways across the spectrum of disease severity, differ significantly compared with healthy individuals. In parallel, a growing body of evidence suggests that bacterial viruses (bacteriophages or simply phages), regulating bacterial populations, are present in almost every niche of the human body and can also interact directly with the eukaryotic cells. The triptych of airway epithelial cells, bacterial symbionts and resident phages should be considered as a functional and interdependent unit with direct implications on the respiratory and overall homeostasis. While the role of epithelial cells in asthma pathophysiology is well-established, the tripartite interactions between epithelial cells, bacteria and phages should be scrutinized, both to better understand asthma as a system disorder and to explore potential interventions.
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Affiliation(s)
- Panagiota Tzani-Tzanopoulou
- Allergy and Clinical Immunology Unit, 2nd Pediatric Clinic, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitrios Skliros
- Laboratory of Molecular Biology, Department of Biotechnology, School of Food, Biotechnology and Development, Agricultural University of Athens, Athens, Greece
| | - Spyridon Megremis
- Division of Evolution and Genomic Sciences, University of Manchester, Manchester, United Kingdom
| | - Paraskevi Xepapadaki
- Allergy and Clinical Immunology Unit, 2nd Pediatric Clinic, National and Kapodistrian University of Athens, Athens, Greece
| | - Evangelos Andreakos
- Center for Clinical, Experimental Surgery and Translational Research of the Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Nina Chanishvili
- Laboratory for Genetics of Microorganisms and Bacteriophages, Eliava Institute of Bacteriophage, Microbiology & Virology, Tbilisi, GA, United States
| | - Emmanouil Flemetakis
- Laboratory of Molecular Biology, Department of Biotechnology, School of Food, Biotechnology and Development, Agricultural University of Athens, Athens, Greece
| | - Grigoris Kaltsas
- Department of Electrical and Electronic Engineering, University of West Attica, Athens, Greece
| | - Styliani Taka
- Allergy and Clinical Immunology Unit, 2nd Pediatric Clinic, National and Kapodistrian University of Athens, Athens, Greece
| | - Evangelia Lebessi
- Department of Microbiology, P. & A. Kyriakou Children's Hospital, Athens, Greece
| | | | - Nikolaos G Papadopoulos
- Allergy and Clinical Immunology Unit, 2nd Pediatric Clinic, National and Kapodistrian University of Athens, Athens, Greece.,Division of Evolution and Genomic Sciences, University of Manchester, Manchester, United Kingdom
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5
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Garriss G, Henriques-Normark B. Lysogeny in Streptococcus pneumoniae. Microorganisms 2020; 8:E1546. [PMID: 33036379 PMCID: PMC7600539 DOI: 10.3390/microorganisms8101546] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 10/05/2020] [Indexed: 12/31/2022] Open
Abstract
Bacterial viruses, or bacteriophages, are major contributors to the evolution, pathogenesis and overall biology of their host bacteria. During their life cycle, temperate bacteriophages form stable associations with their host by integrating into the chromosome, a process called lysogeny. Isolates of the human pathogen Streptococcus pneumoniae are frequently lysogenic, and genomic studies have allowed the classification of these phages into distinct phylogenetic groups. Here, we review the recent advances in the characterization of temperate pneumococcal phages, with a focus on their genetic features and chromosomal integration loci. We also discuss the contribution of phages, and specific phage-encoded features, to colonization and virulence. Finally, we discuss interesting research perspectives in this field.
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Affiliation(s)
- Geneviève Garriss
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden
- Clinical Microbiology, Karolinska University Hospital, Bioclinicum, 171 76 Stockholm, Sweden
- Lee Kong Chian School of Medicine (LKC) and Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 639798, Singapore
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6
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Putra RD, Lyrawati D. Interactions between Bacteriophages and Eukaryotic Cells. SCIENTIFICA 2020; 2020:3589316. [PMID: 32582449 PMCID: PMC7301238 DOI: 10.1155/2020/3589316] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/02/2020] [Accepted: 05/18/2020] [Indexed: 05/30/2023]
Abstract
As the name implies, bacteriophage is a bacterium-specific virus. It infects and kills the bacterial host. Bacteriophages have gained attention as alternative antimicrobial entities in the science community in the western world since the alarming rise of antibiotic resistance among microbes. Although generally considered as prokaryote-specific viruses, recent studies indicate that bacteriophages can interact with eukaryotic organisms, including humans. In the current review, these interactions are divided into two categories, i.e., indirect and direct interactions, with the involvement of bacteriophages, bacteria, and eukaryotes. We discuss bacteriophage-related diseases, transcytosis of bacteriophages, bacteriophage interactions with cancer cells, collaboration of bacteriophages and eukaryotes against bacterial infections, and horizontal gene transfer between bacteriophages and eukaryotes. Such interactions are crucial for understanding and developing bacteriophages as the therapeutic agents and pharmaceutical delivery systems. With the advancement and combination of in silico, in vitro, and in vivo approaches and clinical trials, bacteriophages definitely serve as useful repertoire for biologic target-based drug development to manage many complex diseases in the future.
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Affiliation(s)
| | - Diana Lyrawati
- Department of Pharmacy, Faculty of Medicine, Brawijaya University, Malang 65145, Indonesia
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7
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Pacífico C, Hilbert M, Sofka D, Dinhopl N, Pap IJ, Aspöck C, Hilbert F. Characterization of Bacteria and Inducible Phages in an Intensive Care Unit. J Clin Med 2019; 8:E1433. [PMID: 31510095 PMCID: PMC6780966 DOI: 10.3390/jcm8091433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 09/08/2019] [Indexed: 12/29/2022] Open
Abstract
Intensive care units (ICUs) are critical locations for the transmission of pathogenic and opportunistic microorganisms. Bacteria may develop a synergistic relationship with bacteriophages and more effectively resist various stresses, enabling them to persist despite disinfection and antimicrobial treatment. We collected 77 environmental samples from the surroundings of 12 patients with infection/colonizations by Escherichia coli, Staphylococcus aureus or Klebsiella spp in an ICU in Austria. Surface swabs were tested for lytic phages and bacterial isolates for mitomycin C-inducible prophages. No lytic bacteriophages were detected, but S. aureus was isolated from the surroundings of all patients. About 85% of the colonies isolated from surface samples were resistant to antimicrobials, with 94% of them multidrug resistant. Two inducible temperate bacteriophages-myovirus vB_EcoM_P5 and siphovirus vB_SauS_P9-were recovered from two clinical isolates. Staphylococci phage vB_SauS_P9 lysed S. aureus isolates from the surface swabs collected from the surroundings of three patients. No transductants were obtained on propagation in phage-sensitive antimicrobial-resistant isolates. The two phages were sensitive to 0.25% (v/v) of the disinfectant TPH Protect, which eliminated viable phages after 15 min. Coliphage vB_EcoM_P5 was inactivated at 70 °C and staphylococci phage vB_SauS_P9 at 60 °C after 60 min.
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Affiliation(s)
- Cátia Pacífico
- Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine, 1210 Vienna, Austria
- Karl Landsteiner University of Health Sciences, 3500 Krems an der Donau, Austria
| | - Miriam Hilbert
- Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine, 1210 Vienna, Austria
- Karl Landsteiner University of Health Sciences, 3500 Krems an der Donau, Austria
| | - Dmitrij Sofka
- Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Nora Dinhopl
- Department of Pathobiology, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Ildiko-Julia Pap
- Institute of Hygiene and Microbiology, University Clinic St. Pölten, 3100 St. Pölten, Austria
| | - Christoph Aspöck
- Karl Landsteiner University of Health Sciences, 3500 Krems an der Donau, Austria
- Institute of Hygiene and Microbiology, University Clinic St. Pölten, 3100 St. Pölten, Austria
| | - Friederike Hilbert
- Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine, 1210 Vienna, Austria.
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8
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Methylation Warfare: Interaction of Pneumococcal Bacteriophages with Their Host. J Bacteriol 2019; 201:JB.00370-19. [PMID: 31285240 PMCID: PMC6755750 DOI: 10.1128/jb.00370-19] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/01/2019] [Indexed: 12/15/2022] Open
Abstract
With antimicrobial drug resistance becoming an increasing burden on human health, much attention has been focused on the potential use of bacteriophages and their enzymes as therapeutics. However, the investigations into the physiology of the complex interactions of bacteriophages with their hosts have attracted far less attention, in comparison. This work describes the molecular characterization of the infectious cycle of a bacteriophage in the important human pathogen Streptococcus pneumoniae and explores the intricate relationship between phase-variable host defense mechanisms and the virus. This is the first report showing how a phase-variable type I restriction-modification system is involved in bacteriophage restriction while it also provides an additional level of infection control through abortive infection. Virus-host interactions are regulated by complex coevolutionary dynamics. In Streptococcus pneumoniae, phase-variable type I restriction-modification (R-M) systems are part of the core genome. We hypothesized that the ability of the R-M systems to switch between six target DNA specificities also has a key role in preventing the spread of bacteriophages. Using the streptococcal temperate bacteriophage SpSL1, we show that the variants of both the SpnIII and SpnIV R-M systems are able to restrict invading bacteriophage with an efficiency approximately proportional to the number of target sites in the bacteriophage genome. In addition to restriction of lytic replication, SpnIII also led to abortive infection in the majority of host cells. During lytic infection, transcriptional analysis found evidence of phage-host interaction through the strong upregulation of the nrdR nucleotide biosynthesis regulon. During lysogeny, the phage had less of an effect on host gene regulation. This research demonstrates a novel combined bacteriophage restriction and abortive infection mechanism, highlighting the importance that the phase-variable type I R-M systems have in the multifunctional defense against bacteriophage infection in the respiratory pathogen S. pneumoniae. IMPORTANCE With antimicrobial drug resistance becoming an increasing burden on human health, much attention has been focused on the potential use of bacteriophages and their enzymes as therapeutics. However, the investigations into the physiology of the complex interactions of bacteriophages with their hosts have attracted far less attention, in comparison. This work describes the molecular characterization of the infectious cycle of a bacteriophage in the important human pathogen Streptococcus pneumoniae and explores the intricate relationship between phase-variable host defense mechanisms and the virus. This is the first report showing how a phase-variable type I restriction-modification system is involved in bacteriophage restriction while it also provides an additional level of infection control through abortive infection.
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9
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Shen P, Lees JA, Bee GCW, Brown SP, Weiser JN. Pneumococcal quorum sensing drives an asymmetric owner-intruder competitive strategy during carriage via the competence regulon. Nat Microbiol 2018; 4:198-208. [PMID: 30546100 DOI: 10.1038/s41564-018-0314-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/30/2018] [Indexed: 11/09/2022]
Abstract
Competition among microorganisms is a key determinant of successful host colonization and persistence. For Streptococcus pneumoniae, lower than predicted rates of co-colonizing strains suggest a competitive advantage for resident bacteria over newcomers. In light of evolutionary theory, we hypothesized that S. pneumoniae use owner-intruder asymmetries to settle contests, leading to the disproportionate success of the initial resident 'owner', regardless of the genetic identity of the 'intruder'. We investigated the determinants of within-host competitive success utilizing S. pneumoniae colonization of the upper respiratory tract of infant mice. Within 6 h, colonization by the resident inhibited colonization by an isogenic challenger. The competitive advantage of the resident was dependent on quorum sensing via the competence (Com) regulon and downstream choline binding protein D (CbpD) and on the competence-induced bacteriocins A and B (CibAB) implicated in fratricide. CbpD and CibAB are highly conserved across pneumococcal lineages, indicating evolutionary advantages for asymmetric competitive strategies within the species. Mathematical modelling supported a significant role for quorum sensing via the Com regulon in competition, even for strains with different competitive advantages. Our study suggests that asymmetric owner-intruder competitive strategies do not require complex cognition and are used by a major human pathogen to determine 'ownership' of human hosts.
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Affiliation(s)
- Pamela Shen
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - John A Lees
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Gavyn Chern Wei Bee
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Sam P Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jeffrey N Weiser
- Department of Microbiology, New York University School of Medicine, New York, NY, USA.
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10
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Azarian T, Mitchell PK, Georgieva M, Thompson CM, Ghouila A, Pollard AJ, von Gottberg A, du Plessis M, Antonio M, Kwambana-Adams BA, Clarke SC, Everett D, Cornick J, Sadowy E, Hryniewicz W, Skoczynska A, Moïsi JC, McGee L, Beall B, Metcalf BJ, Breiman RF, Ho PL, Reid R, O’Brien KL, Gladstone RA, Bentley SD, Hanage WP. Global emergence and population dynamics of divergent serotype 3 CC180 pneumococci. PLoS Pathog 2018; 14:e1007438. [PMID: 30475919 PMCID: PMC6283594 DOI: 10.1371/journal.ppat.1007438] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 12/06/2018] [Accepted: 10/25/2018] [Indexed: 12/23/2022] Open
Abstract
Streptococcus pneumoniae serotype 3 remains a significant cause of morbidity and mortality worldwide, despite inclusion in the 13-valent pneumococcal conjugate vaccine (PCV13). Serotype 3 increased in carriage since the implementation of PCV13 in the USA, while invasive disease rates remain unchanged. We investigated the persistence of serotype 3 in carriage and disease, through genomic analyses of a global sample of 301 serotype 3 isolates of the Netherlands3-31 (PMEN31) clone CC180, combined with associated patient data and PCV utilization among countries of isolate collection. We assessed phenotypic variation between dominant clades in capsule charge (zeta potential), capsular polysaccharide shedding, and susceptibility to opsonophagocytic killing, which have previously been associated with carriage duration, invasiveness, and vaccine escape. We identified a recent shift in the CC180 population attributed to a lineage termed Clade II, which was estimated by Bayesian coalescent analysis to have first appeared in 1968 [95% HPD: 1939-1989] and increased in prevalence and effective population size thereafter. Clade II isolates are divergent from the pre-PCV13 serotype 3 population in non-capsular antigenic composition, competence, and antibiotic susceptibility, the last of which resulting from the acquisition of a Tn916-like conjugative transposon. Differences in recombination rates among clades correlated with variations in the ATP-binding subunit of Clp protease, as well as amino acid substitutions in the comCDE operon. Opsonophagocytic killing assays elucidated the low observed efficacy of PCV13 against serotype 3. Variation in PCV13 use among sampled countries was not independently correlated with the CC180 population shift; therefore, genotypic and phenotypic differences in protein antigens and, in particular, antibiotic resistance may have contributed to the increase of Clade II. Our analysis emphasizes the need for routine, representative sampling of isolates from disperse geographic regions, including historically under-sampled areas. We also highlight the value of genomics in resolving antigenic and epidemiological variations within a serotype, which may have implications for future vaccine development.
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Affiliation(s)
- Taj Azarian
- Center for Communicable Disease Dynamics, Department of Epidemiology, T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Patrick K. Mitchell
- Center for Communicable Disease Dynamics, Department of Epidemiology, T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Maria Georgieva
- Center for Communicable Disease Dynamics, Department of Epidemiology, T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Claudette M. Thompson
- Center for Communicable Disease Dynamics, Department of Epidemiology, T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Amel Ghouila
- Institut Pasteur de Tunis, LR11IPT02, Laboratory of Transmission, Control and Immunobiology of Infections (LTCII), Tunis-Belvédère, Tunisia
| | - Andrew J. Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford; NIHR Oxford Biomedical Research Centre, Centre for Clinical Vaccinology and Tropical Medicine (CCVTM), Churchill Hospital, Oxford, United Kingdom
| | - Anne von Gottberg
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Mignon du Plessis
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Martin Antonio
- Medical Research Council Unit The Gambia, Fajara, The Gambia
| | | | - Stuart C. Clarke
- Faculty of Medicine and Institute for Life Sciences and Global Health Research Institute, University of Southampton, Southampton, United Kingdom
- NIHR Southampton Biomedical Research Centre, Southampton General Hospital, Southampton, United Kingdom
| | - Dean Everett
- Queens Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Jennifer Cornick
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Ewa Sadowy
- National Medicines Institute, Warsaw, Poland
| | | | | | - Jennifer C. Moïsi
- Pfizer Vaccines, Medical Development, Scientific and Clinical Affairs, Paris, France
| | - Lesley McGee
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Bernard Beall
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Benjamin J. Metcalf
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Robert F. Breiman
- Global Health Institute, Emory University, Atlanta, Georgia, United States of America
| | - PL Ho
- Department of Microbiology, Queen Mary Hospital University of Hong Kong, Hong Kong, People’s Republic of China
| | - Raymond Reid
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Katherine L. O’Brien
- Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Rebecca A. Gladstone
- Wellcome Trust, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Stephen D. Bentley
- Wellcome Trust, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - William P. Hanage
- Center for Communicable Disease Dynamics, Department of Epidemiology, T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
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11
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Hiller NL, Sá-Leão R. Puzzling Over the Pneumococcal Pangenome. Front Microbiol 2018; 9:2580. [PMID: 30425695 PMCID: PMC6218428 DOI: 10.3389/fmicb.2018.02580] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/09/2018] [Indexed: 12/11/2022] Open
Abstract
The Gram positive bacterium Streptococcus pneumoniae (pneumococcus) is a major human pathogen. It is a common colonizer of the human host, and in the nasopharynx, sinus, and middle ear it survives as a biofilm. This mode of growth is optimal for multi-strain colonization and genetic exchange. Over the last decades, the far-reaching use of antibiotics and the widespread implementation of pneumococcal multivalent conjugate vaccines have posed considerable selective pressure on pneumococci. This scenario provides an exceptional opportunity to study the evolution of the pangenome of a clinically important bacterium, and has the potential to serve as a case study for other species. The goal of this review is to highlight key findings in the studies of pneumococcal genomic diversity and plasticity.
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Affiliation(s)
- N. Luisa Hiller
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States
- Center of Excellence in Biofilm Research, Allegheny Health Network, Pittsburgh, PA, United States
| | - Raquel Sá-Leão
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
- Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
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12
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Aucouturier A, Chain F, Langella P, Bidnenko E. Characterization of a Prophage-Free Derivative Strain of Lactococcus lactis ssp. lactis IL1403 Reveals the Importance of Prophages for Phenotypic Plasticity of the Host. Front Microbiol 2018; 9:2032. [PMID: 30233519 PMCID: PMC6127208 DOI: 10.3389/fmicb.2018.02032] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/13/2018] [Indexed: 12/16/2022] Open
Abstract
Lactococcus lactis is a lactic acid bacterium of major importance for the dairy industry and for human health. Recent sequencing surveys of this species have provided evidence that all lactococcal genomes contain prophages and prophage-like elements. The prophage-related sequences encompass up to 10% of the bacterial chromosomes and thus contribute significantly to the genetic diversity of lactococci. However, the impact of these resident prophages on the physiology of L. lactis is presently unknown. The genome of the first sequenced prototype strain, L. lactis ssp. lactis IL1403, contains six prophage-like elements which together represent 6.7% of the IL1403 chromosome. Diverse prophage genes other than those encoding phage repressors have been shown to be expressed in lysogenic conditions, suggesting that prophage genes are indeed able to modulate the physiology of their host. To elucidate the effect of resident prophages on the behavior of L. lactis in different growth conditions, we constructed and characterized, for the first time, a derivative strain of IL1403 that is prophage-free. This strain provides unique experimental opportunities for the study of different aspects of lactococcal physiology using the well-defined genetic background of IL1403. Here, we show that resident prophages modify the growth and survival of the host strain to a considerable extent in different conditions, including in the gastrointestinal environment. They also may affect cellular autolytic properties and the host cells' susceptibility to virulent bacteriophages and antimicrobial agents. It thus appears that prophages contribute significantly to lactococcal cell physiology and might play an important role in the adaptation of L. lactis to cultivation and environmental conditions.
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Affiliation(s)
- Anne Aucouturier
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Florian Chain
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Philippe Langella
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Elena Bidnenko
- MICALIS Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
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13
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Capsule Prolongs Survival of Streptococcus pneumoniae during Starvation. Infect Immun 2018; 86:IAI.00802-17. [PMID: 29311231 DOI: 10.1128/iai.00802-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/21/2017] [Indexed: 12/18/2022] Open
Abstract
Person-to-person transmission of Streptococcus pneumoniae (the pneumococcus) may occur via environmental sources in close contact with carriers. Pneumococcal polysaccharide capsules, the determinant of serotype (or type), are heterogeneous in structure and amount, and these differences affect rates of transmission. In this study, we examined the contribution of capsule and its variations to the maintenance of pneumococcal viability under starvation conditions. S. pneumoniae retained its ability to colonize infant mice even after incubation for 24 h in phosphate-buffered saline at 25°C. The expression of capsule by the cps locus prolonged survival under these and other nutrient-poor conditions. Analysis of capsule-switch constructs showed that strain-to-strain differences in survival were due to capsule type rather than genetic background. The addition of glucose was sufficient to rescue the survival defect of the capsule-deficient derivative, demonstrating that in the absence of capsule, survival depends upon nutrient availability. During starvation, there was a decrease in capsule size and amount of capsular polysaccharide that was dependent on bacterial viability and the presence of the cps locus. These observations suggest that pneumococci catabolize their own capsular polysaccharide using the genes involved in its biosynthesis to maintain viability when other carbon sources are unavailable. Our findings describe a new role of the pneumococcal capsule: the prolongation of viability under nutrient-limiting conditions as would be encountered during periods when the organism is between hosts.
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14
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Lees JA, Croucher NJ, Goldblatt D, Nosten F, Parkhill J, Turner C, Turner P, Bentley SD. Genome-wide identification of lineage and locus specific variation associated with pneumococcal carriage duration. eLife 2017; 6:e26255. [PMID: 28742023 PMCID: PMC5576492 DOI: 10.7554/elife.26255] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/21/2017] [Indexed: 01/04/2023] Open
Abstract
Streptococcus pneumoniae is a leading cause of invasive disease in infants, especially in low-income settings. Asymptomatic carriage in the nasopharynx is a prerequisite for disease, but variability in its duration is currently only understood at the serotype level. Here we developed a model to calculate the duration of carriage episodes from longitudinal swab data, and combined these results with whole genome sequence data. We estimated that pneumococcal genomic variation accounted for 63% of the phenotype variation, whereas the host traits considered here (age and previous carriage) accounted for less than 5%. We further partitioned this heritability into both lineage and locus effects, and quantified the amount attributable to the largest sources of variation in carriage duration: serotype (17%), drug-resistance (9%) and other significant locus effects (7%). A pan-genome-wide association study identified prophage sequences as being associated with decreased carriage duration independent of serotype, potentially by disruption of the competence mechanism. These findings support theoretical models of pneumococcal competition and antibiotic resistance.
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Affiliation(s)
- John A Lees
- Infection GenomicsWellcome Trust Sanger InstituteHinxtonUnited Kingdom
| | - Nicholas J Croucher
- Department of Infectious Disease EpidemiologySt. Mary’s Campus, Imperial College LondonLondonUnited Kingdom
| | - David Goldblatt
- Institute of Child HealthUniversity College LondonLondonUnited Kingdom
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityMae SotThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited Kingdom
| | - Julian Parkhill
- Infection GenomicsWellcome Trust Sanger InstituteHinxtonUnited Kingdom
| | - Claudia Turner
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityMae SotThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited Kingdom
| | - Paul Turner
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical MedicineMahidol UniversityMae SotThailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of MedicineUniversity of OxfordOxfordUnited Kingdom
| | - Stephen D Bentley
- Infection GenomicsWellcome Trust Sanger InstituteHinxtonUnited Kingdom
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15
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Characterization and interstrain transfer of prophage pp3 of Pseudomonas aeruginosa. PLoS One 2017; 12:e0174429. [PMID: 28346467 PMCID: PMC5367828 DOI: 10.1371/journal.pone.0174429] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/08/2017] [Indexed: 01/16/2023] Open
Abstract
Prophages are major contributors to horizontal gene transfer and drive the evolution and diversification of bacteria. Here, we describe the characterization of a prophage element designated pp3 in the clinical Pseudomonas aeruginosa isolate PA1. pp3 spontaneously excises from the PA1 genome and circularizes at a very high frequency of 25%. pp3 is likely to be a defective prophage due to its inability to form plaques on P. aeruginosa indicator strains, and no phage particles could be detected in PA1 supernatants. The pp3-encoded integrase is essential for excision by mediating site-specific recombination at the 26-bp attachment sequence. Using a filter mating experiment, we demonstrated that pp3 can transfer into P. aeruginosa recipient strains that do not possess this element naturally. Upon transfer, pp3 integrates into the same attachment site as in PA1 and maintains the ability to excise and circularize. Furthermore, pp3 significantly promotes biofilm formation in the recipient. Sequence alignment reveals that the 26-bp attachment site recognized by pp3 is conserved in all P. aeruginosa strains sequenced to date, making it possible that pp3 could be extensively disseminated in P. aeruginosa. This work improves our understanding of the ways in which prophages influence bacterial behavior and evolution.
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16
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Phage-Derived Protein Induces Increased Platelet Activation and Is Associated with Mortality in Patients with Invasive Pneumococcal Disease. mBio 2017; 8:mBio.01984-16. [PMID: 28096486 PMCID: PMC5241397 DOI: 10.1128/mbio.01984-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
To improve our understanding about the severity of invasive pneumococcal disease (IPD), we investigated the association between the genotype of Streptococcus pneumoniae and disease outcomes for 349 bacteremic patients. A pneumococcal genome-wide association study (GWAS) demonstrated a strong correlation between 30-day mortality and the presence of the phage-derived gene pblB, encoding a platelet-binding protein whose effects on platelet activation were previously unknown. Platelets are increasingly recognized as key players of the innate immune system, and in sepsis, excessive platelet activation contributes to microvascular obstruction, tissue hypoperfusion, and finally multiorgan failure, leading to mortality. Our in vitro studies revealed that pblB expression was induced by fluoroquinolones but not by the beta-lactam antibiotic penicillin G. Subsequently, we determined pblB induction and platelet activation by incubating whole blood with the wild type or a pblB knockout mutant in the presence or absence of antibiotics commonly administered to our patient cohort. pblB-dependent enhancement of platelet activation, as measured by increased expression of the α-granule protein P-selectin, the binding of fibrinogen to the activated αIIbβ3 receptor, and the formation of platelet-monocyte complex occurred irrespective of antibiotic exposure. In conclusion, the presence of pblB on the pneumococcal chromosome potentially leads to increased mortality in patients with an invasive S. pneumoniae infection, which may be explained by enhanced platelet activation. This study highlights the clinical utility of a bacterial GWAS, followed by functional characterization, to identify bacterial factors involved in disease severity. The exact mechanisms causing mortality in invasive pneumococcal disease (IPD) patients are not completely understood. We examined 349 patients with IPD and found in a bacterial genome-wide association study (GWAS) that the presence of the phage-derived gene pblB was associated with mortality in the first 30 days after hospitalization. Although pblB has been extensively studied in Streptococcus mitis, its consequence for the interaction between platelets and Streptococcus pneumoniae is largely unknown. Platelets are important in immunity and inflammation, and excessive platelet activation contributes to microvascular obstruction and multiorgan failure, leading to mortality. We therefore developed this study to assess whether the expression of pblB might increase the risk of death for IPD patients through its effect on enhanced platelet activation. This study also shows the value of integrating extensive bacterial genomics and clinical data in predicting and understanding pathogen virulence, which in turn will help to improve prognosis and therapy.
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17
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Zafar MA, Kono M, Wang Y, Zangari T, Weiser JN. Infant Mouse Model for the Study of Shedding and Transmission during Streptococcus pneumoniae Monoinfection. Infect Immun 2016; 84:2714-22. [PMID: 27400721 PMCID: PMC4995895 DOI: 10.1128/iai.00416-16] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/05/2016] [Indexed: 12/21/2022] Open
Abstract
One of the least understood aspects of the bacterium Streptococcus pneumoniae (pneumococcus) is its transmission from host to host, the critical first step in both the carrier state and the disease state. To date, transmission models have depended on influenza A virus coinfection, which greatly enhances pneumococcal shedding to levels that allow acquisition by a new host. Here, we describe an infant mouse model that can be utilized to study pneumococcal colonization, shedding, and transmission during bacterial monoinfection. Using this model, we demonstrated that the level of bacterial shedding is highest in pups infected intranasally at age 4 days and peaks over the first 4 days postchallenge. Shedding results differed among isolates of five different pneumococcal types. Colonization density was found to be a major factor in the level of pneumococcal shedding and required expression of capsule. Transmission within a litter occurred when there was a high ratio of colonized "index" pups to uncolonized "contact" pups. Transmission was observed for each of the well-colonizing pneumococcal isolates, with the rate of transmission proportional to the level of shedding. This model can be used to examine bacterial and host factors that contribute to pneumococcal transmission without the effects of viral coinfection.
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Affiliation(s)
- M Ammar Zafar
- Department of Microbiology, New York University, New York, New York, USA
| | - Masamitsu Kono
- Department of Microbiology, New York University, New York, New York, USA Department of Otolaryngology-Head and Neck Surgery, Wakayama Medical University, Wakayama, Japan
| | - Yang Wang
- Department of Microbiology, New York University, New York, New York, USA School of Medicine, Tsing Hua University, Beijing, China
| | - Tonia Zangari
- Department of Microbiology, New York University, New York, New York, USA
| | - Jeffrey N Weiser
- Department of Microbiology, New York University, New York, New York, USA
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18
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Friendly Fire: Biological Functions and Consequences of Chromosomal Targeting by CRISPR-Cas Systems. J Bacteriol 2016; 198:1481-6. [PMID: 26929301 DOI: 10.1128/jb.00086-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Clustered regularly interspaced short palindromic repeat (CRISPR)-associated (Cas) systems in bacteria and archaea target foreign elements, such as bacteriophages and conjugative plasmids, through the incorporation of short sequences (termed spacers) from the foreign element into the CRISPR array, thereby allowing sequence-specific targeting of the invader. Thus, CRISPR-Cas systems are typically considered a microbial adaptive immune system. While many of these incorporated spacers match targets on bacteriophages and plasmids, a noticeable number are derived from chromosomal DNA. While usually lethal to the self-targeting bacteria, in certain circumstances, these self-targeting spacers can have profound effects in regard to microbial biology, including functions beyond adaptive immunity. In this minireview, we discuss recent studies that focus on the functions and consequences of CRISPR-Cas self-targeting, including reshaping of the host population, group behavior modification, and the potential applications of CRISPR-Cas self-targeting as a tool in microbial biotechnology. Understanding the effects of CRISPR-Cas self-targeting is vital to fully understanding the spectrum of function of these systems.
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19
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Sensing of interleukin-1 cytokines during Streptococcus pneumoniae colonization contributes to macrophage recruitment and bacterial clearance. Infect Immun 2015; 83:3204-12. [PMID: 26034210 DOI: 10.1128/iai.00224-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/22/2015] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae (the pneumococcus), a leading cause of bacterial disease, is most commonly carried in the human nasopharynx. Colonization induces inflammation that promotes the organism's growth and transmission. This inflammatory response is dependent on intracellular sensing of bacterial components that access the cytosolic compartment via the pneumococcal pore-forming toxin pneumolysin. In vitro, cytosolic access results in cell death that includes release of the proinflammatory cytokine interleukin-1β (IL-1β). IL-1 family cytokines, including IL-1β, are secreted upon activation of inflammasomes, although the role of this activation in the host immune response to pneumococcal carriage is unknown. Using a murine model of pneumococcal nasopharyngeal colonization, we show that mice deficient in the interleukin-1 receptor type 1 (Il1r1(-/-)) have reduced numbers of neutrophils early after infection, fewer macrophages later in carriage, and prolonged bacterial colonization. Moreover, intranasal administration of Il-1β promoted clearance. Macrophages are the effectors of clearance, and characterization of macrophage chemokines in colonized mice revealed that Il1r1(-/-) mice have lower expression of the C-C motif chemokine ligand 6 (CCL6), correlating with reduced macrophage recruitment to the nasopharynx. IL-1 family cytokines are known to promote adaptive immunity; however, we observed no difference in the development of humoral or cellular immunity to pneumococcal colonization between wild-type and Il1r1(-/-) mice. Our findings show that sensing of IL-1 cytokines during colonization promotes inflammation without immunity, which may ultimately benefit the pneumococcus.
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20
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Giovanetti E, Brenciani A, Morroni G, Tiberi E, Pasquaroli S, Mingoia M, Varaldo PE. Transduction of the Streptococcus pyogenes bacteriophage Φm46.1, carrying resistance genes mef(A) and tet(O), to other Streptococcus species. Front Microbiol 2015; 5:746. [PMID: 25620959 PMCID: PMC4288039 DOI: 10.3389/fmicb.2014.00746] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/09/2014] [Indexed: 11/13/2022] Open
Abstract
Φm46.1 – Streptococcus pyogenes bacteriophage carrying mef(A) and tet(O), respectively, encoding resistance to macrolides (M phenotype) and tetracycline – is widespread in S. pyogenes but has not been reported outside this species. Φm46.1 is transferable in vitro among S. pyogenes isolates, but no information is available about its transferability to other Streptococcus species. We thus investigated Φm46.1 for its ability to be transduced in vitro to recipients of different Streptococcus species. Transductants were obtained from recipients of Streptococcus agalactiae, Streptococcus gordonii, and Streptococcus suis. Retransfer was always achieved, and from S. suis to S. pyogenes occurred at a much greater frequency than in the opposite direction. In transductants Φm46.1 retained its functional properties, such as inducibility with mitomycin C, presence both as a prophage and as a free circular form, and transferability. The transductants shared the same Φm46.1 chromosomal integration site as the donor, at the 3′ end of a conserved RNA uracil methyltransferase (rum) gene, which is an integration hotspot for a variety of genetic elements. No transfer occurred to recipients of Streptococcus pneumoniae, Streptococcus oralis, and Streptococcus salivarius, even though rum-like genes were also detected in the sequenced genomes of these species. A largely overlapping 18-bp critical sequence, where the site-specific recombination process presumably takes place, was identified in the rum genes of all recipients, including those of the species yielding no transductants. Growth assays to evaluate the fitness cost of Φm46.1 acquisition disclosed a negligible impact on S. pyogenes, S. agalactiae, and S. gordonii transductants and a noticeable fitness advantage in S. suis. The S. suis transductant also displayed marked overexpression of the autolysin-encoding gene atl.
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Affiliation(s)
- Eleonora Giovanetti
- Unit of Microbiology, Department of Life and Environmental Sciences, Polytechnic University of Marche Ancona, Italy
| | - Andrea Brenciani
- Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School Ancona, Italy
| | - Gianluca Morroni
- Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School Ancona, Italy
| | - Erika Tiberi
- Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School Ancona, Italy
| | - Sonia Pasquaroli
- Unit of Microbiology, Department of Life and Environmental Sciences, Polytechnic University of Marche Ancona, Italy
| | - Marina Mingoia
- Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School Ancona, Italy
| | - Pietro E Varaldo
- Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School Ancona, Italy
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