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Ayoola MB, Shack LA, Phanstiel O, Nanduri B. Impact of Difluoromethylornithine and AMXT 1501 on Gene Expression and Capsule Regulation in Streptococcus pneumoniae. Biomolecules 2024; 14:178. [PMID: 38397415 PMCID: PMC10887117 DOI: 10.3390/biom14020178] [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: 12/31/2023] [Revised: 01/27/2024] [Accepted: 01/31/2024] [Indexed: 02/25/2024] Open
Abstract
Streptococcus pneumoniae (Spn), a Gram-positive bacterium, poses a significant threat to human health, causing mild respiratory infections to severe invasive conditions. Despite the availability of vaccines, challenges persist due to serotype replacement and antibiotic resistance, emphasizing the need for alternative therapeutic strategies. This study explores the intriguing role of polyamines, ubiquitous, small organic cations, in modulating virulence factors, especially the capsule, a crucial determinant of Spn's pathogenicity. Using chemical inhibitors, difluoromethylornithine (DFMO) and AMXT 1501, this research unveils distinct regulatory effects on the gene expression of the Spn D39 serotype in response to altered polyamine homeostasis. DFMO inhibits polyamine biosynthesis, disrupting pathways associated with glucose import and the interconversion of sugars. In contrast, AMXT 1501, targeting polyamine transport, enhances the expression of polyamine and glucose biosynthesis genes, presenting a novel avenue for regulating the capsule independent of glucose availability. Despite ample glucose availability, AMXT 1501 treatment downregulates the glycolytic pathway, fatty acid synthesis, and ATP synthase, crucial for energy production, while upregulating two-component systems responsible for stress management. This suggests a potential shutdown of energy production and capsule biosynthesis, redirecting resources towards stress management. Following DFMO and AMXT 1501 treatments, countermeasures, such as upregulation of stress response genes and ribosomal protein, were observed but appear to be insufficient to overcome the deleterious effects on capsule production. This study highlights the complexity of polyamine-mediated regulation in S. pneumoniae, particularly capsule biosynthesis. Our findings offer valuable insights into potential therapeutic targets for modulating capsules in a polyamine-dependent manner, a promising avenue for intervention against S. pneumoniae infections.
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Affiliation(s)
- Moses B Ayoola
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Leslie A Shack
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
| | - Otto Phanstiel
- Department of Medical Education, College of Medicine, University of Central Florida, Orlando, FL 32826, USA
| | - Bindu Nanduri
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA
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2
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Murray GGR, Hossain ASMM, Miller EL, Bruchmann S, Balmer AJ, Matuszewska M, Herbert J, Hadjirin NF, Mugabi R, Li G, Ferrando ML, Fernandes de Oliveira IM, Nguyen T, Yen PLK, Phuc HD, Zaw Moe A, Su Wai T, Gottschalk M, Aragon V, Valentin-Weigand P, Heegaard PMH, Vrieling M, Thein Maw M, Thidar Myint H, Tun Win Y, Thi Hoa N, Bentley SD, Clavijo MJ, Wells JM, Tucker AW, Weinert LA. The emergence and diversification of a zoonotic pathogen from within the microbiota of intensively farmed pigs. Proc Natl Acad Sci U S A 2023; 120:e2307773120. [PMID: 37963246 PMCID: PMC10666105 DOI: 10.1073/pnas.2307773120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 10/02/2023] [Indexed: 11/16/2023] Open
Abstract
The expansion and intensification of livestock production is predicted to promote the emergence of pathogens. As pathogens sometimes jump between species, this can affect the health of humans as well as livestock. Here, we investigate how livestock microbiota can act as a source of these emerging pathogens through analysis of Streptococcus suis, a ubiquitous component of the respiratory microbiota of pigs that is also a major cause of disease on pig farms and an important zoonotic pathogen. Combining molecular dating, phylogeography, and comparative genomic analyses of a large collection of isolates, we find that several pathogenic lineages of S. suis emerged in the 19th and 20th centuries, during an early period of growth in pig farming. These lineages have since spread between countries and continents, mirroring trade in live pigs. They are distinguished by the presence of three genomic islands with putative roles in metabolism and cell adhesion, and an ongoing reduction in genome size, which may reflect their recent shift to a more pathogenic ecology. Reconstructions of the evolutionary histories of these islands reveal constraints on pathogen emergence that could inform control strategies, with pathogenic lineages consistently emerging from one subpopulation of S. suis and acquiring genes through horizontal transfer from other pathogenic lineages. These results shed light on the capacity of the microbiota to rapidly evolve to exploit changes in their host population and suggest that the impact of changes in farming on the pathogenicity and zoonotic potential of S. suis is yet to be fully realized.
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Affiliation(s)
- Gemma G. R. Murray
- Department of Genetics, Evolution and Environment, University College London, LondonWC1E 6BT, United Kingdom
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | | | - Eric L. Miller
- Department of Biology, Haverford College, Haverford, PA19041
| | - Sebastian Bruchmann
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | - Andrew J. Balmer
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | - Marta Matuszewska
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
- Department of Medicine, University of Cambridge, CambridgeCB2 2QQ, United Kingdom
| | - Josephine Herbert
- Centre for Enzyme Innovation, University of Portsmouth, PortsmouthPO1 2DD, United Kingdom
| | - Nazreen F. Hadjirin
- Nuffield Department of Population Health, University of Oxford, OxfordOX3 7LF, United Kingdom
| | - Robert Mugabi
- College of Veterinary Medicine, Iowa State University, Ames, IA50011
| | - Ganwu Li
- College of Veterinary Medicine, Iowa State University, Ames, IA50011
| | - Maria Laura Ferrando
- Animal Sciences Department, Wageningen University, 6700 AHWageningen, The Netherlands
| | | | - Thanh Nguyen
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Phung L. K. Yen
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Ho D. Phuc
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Aung Zaw Moe
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | - Thiri Su Wai
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | - Marcelo Gottschalk
- Département de Pathologie et Microbiologie, Université de Montréal, QuébecJ2S 2M2, Canada
| | - Virginia Aragon
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal, Campus de la Universitat Autònoma de Barcelona, Barcelona08193, Spain
- OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Barcelona08193, Spain
| | - Peter Valentin-Weigand
- Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover30559, Germany
| | - Peter M. H. Heegaard
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby2800, Denmark
| | - Manouk Vrieling
- Wageningen Bioveterinary Research, 8221 RALelystad, The Netherlands
| | - Min Thein Maw
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | | | - Ye Tun Win
- Livestock Breeding and Veterinary Department, Yangon, Myanmar
| | - Ngo Thi Hoa
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, OxfordOX3 7LG, United Kingdom
- Microbiology Department and Center for Tropical Medicine Research, Ngoc Thach University of Medicine, Ho Chi Minh City, Vietnam
| | - Stephen D. Bentley
- Parasites and Microbes Programme, Wellcome Sanger Institute, CambridgeCB10 1RQ, United Kingdom
| | - Maria J. Clavijo
- College of Veterinary Medicine, Iowa State University, Ames, IA50011
| | - Jerry M. Wells
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
- Animal Sciences Department, Wageningen University, 6700 AHWageningen, The Netherlands
| | - Alexander W. Tucker
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | - Lucy A. Weinert
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
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3
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Rueff AS, van Raaphorst R, Aggarwal SD, Santos-Moreno J, Laloux G, Schaerli Y, Weiser JN, Veening JW. Synthetic genetic oscillators demonstrate the functional importance of phenotypic variation in pneumococcal-host interactions. Nat Commun 2023; 14:7454. [PMID: 37978173 PMCID: PMC10656556 DOI: 10.1038/s41467-023-43241-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023] Open
Abstract
Phenotypic variation is the phenomenon in which clonal cells display different traits even under identical environmental conditions. This plasticity is thought to be important for processes including bacterial virulence, but direct evidence for its relevance is often lacking. For instance, variation in capsule production in the human pathogen Streptococcus pneumoniae has been linked to different clinical outcomes, but the exact relationship between variation and pathogenesis is not well understood due to complex natural regulation. In this study, we use synthetic oscillatory gene regulatory networks (GRNs) based on CRISPR interference (CRISPRi) together with live cell imaging and cell tracking within microfluidics devices to mimic and test the biological function of bacterial phenotypic variation. We provide a universally applicable approach for engineering intricate GRNs using only two components: dCas9 and extended sgRNAs (ext-sgRNAs). Our findings demonstrate that variation in capsule production is beneficial for pneumococcal fitness in traits associated with pathogenesis providing conclusive evidence for this longstanding question.
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Affiliation(s)
- Anne-Stéphanie Rueff
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
| | - Renske van Raaphorst
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
- de Duve Institute, UCLouvain, 75 Avenue Hippocrate, 1200, Brussels, Belgium
| | - Surya D Aggarwal
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Javier Santos-Moreno
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
- Pompeu Fabra University, Barcelona, Spain
| | - Géraldine Laloux
- de Duve Institute, UCLouvain, 75 Avenue Hippocrate, 1200, Brussels, Belgium
| | - Yolanda Schaerli
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
| | - Jeffrey N Weiser
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland.
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA.
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA.
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4
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Klabunde B, Wesener A, Bertrams W, Beinborn I, Paczia N, Surmann K, Blankenburg S, Wilhelm J, Serrania J, Knoops K, Elsayed EM, Laakmann K, Jung AL, Kirschbaum A, Hammerschmidt S, Alshaar B, Gisch N, Abu Mraheil M, Becker A, Völker U, Vollmeister E, Benedikter BJ, Schmeck B. NAD + metabolism is a key modulator of bacterial respiratory epithelial infections. Nat Commun 2023; 14:5818. [PMID: 37783679 PMCID: PMC10545792 DOI: 10.1038/s41467-023-41372-w] [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: 03/29/2023] [Accepted: 08/30/2023] [Indexed: 10/04/2023] Open
Abstract
Lower respiratory tract infections caused by Streptococcus pneumoniae (Spn) are a leading cause of death globally. Here we investigate the bronchial epithelial cellular response to Spn infection on a transcriptomic, proteomic and metabolic level. We found the NAD+ salvage pathway to be dysregulated upon infection in a cell line model, primary human lung tissue and in vivo in rodents, leading to a reduced production of NAD+. Knockdown of NAD+ salvage enzymes (NAMPT, NMNAT1) increased bacterial replication. NAD+ treatment of Spn inhibited its growth while growth of other respiratory pathogens improved. Boosting NAD+ production increased NAD+ levels in immortalized and primary cells and decreased bacterial replication upon infection. NAD+ treatment of Spn dysregulated the bacterial metabolism and reduced intrabacterial ATP. Enhancing the bacterial ATP metabolism abolished the antibacterial effect of NAD+. Thus, we identified the NAD+ salvage pathway as an antibacterial pathway in Spn infections, predicting an antibacterial mechanism of NAD+.
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Affiliation(s)
- Björn Klabunde
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany
| | - André Wesener
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany
| | - Wilhelm Bertrams
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany
| | - Isabell Beinborn
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany
| | - Nicole Paczia
- Core Facility for Metabolomics and Small Molecule Mass Spectrometry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Kristin Surmann
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Sascha Blankenburg
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Jochen Wilhelm
- Institute for Lung Health (ILH), Giessen, Germany
- Universities of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig-Universität Giessen, German Center for Lung Research (DZL), Giessen, Germany
| | - Javier Serrania
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
| | - Kèvin Knoops
- Microscopy CORE Lab, Maastricht Multimodal Molecular Imaging Institute (M4I), Maastricht University, Universiteitssingel 50, 6229 ER, Maastricht, The Netherlands
| | - Eslam M Elsayed
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Katrin Laakmann
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany
| | - Anna Lena Jung
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany
- Core Facility Flow Cytometry - Bacterial Vesicles, Philipps-Universität Marburg, Marburg, Germany
| | - Andreas Kirschbaum
- Department of Visceral, Thoracic and Vascular Surgery, University Hospital Gießen and Marburg (UKGM), Marburg, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Belal Alshaar
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Mobarak Abu Mraheil
- Institute for Medical Microbiology, Justus-Liebig Universität Giessen, Giessen, Germany
| | - Anke Becker
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
| | - Uwe Völker
- Department of Functional Genomics, Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Evelyn Vollmeister
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany
| | - Birke J Benedikter
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany.
- University Eye Clinic Maastricht, Maastricht University Medical Center (MUMC+), School for Mental Health and Neuroscience, Maastricht University, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands.
| | - Bernd Schmeck
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Philipps-Universität Marburg, Marburg, Germany.
- Institute for Lung Health (ILH), Giessen, Germany.
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany.
- Core Facility Flow Cytometry - Bacterial Vesicles, Philipps-Universität Marburg, Marburg, Germany.
- Department of Medicine, Pulmonary and Critical Care Medicine, University Medical Center Marburg, Philipps-Universität Marburg, Marburg, Germany.
- Member of the German Center for Infectious Disease Research (DZIF), Marburg, Germany.
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5
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Glanville DG, Gazioglu O, Marra M, Tokars VL, Kushnir T, Habtom M, Croucher NJ, Nebenzahl YM, Mondragón A, Yesilkaya H, Ulijasz AT. Pneumococcal capsule expression is controlled through a conserved, distal cis-regulatory element during infection. PLoS Pathog 2023; 19:e1011035. [PMID: 36719895 PMCID: PMC9888711 DOI: 10.1371/journal.ppat.1011035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 11/29/2022] [Indexed: 02/01/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is the major cause of bacterial pneumonia in the US and worldwide. Studies have shown that the differing chemical make-up between serotypes of its most important virulence factor, the capsule, can dictate disease severity. Here we demonstrate that control of capsule synthesis is also critical for infection and facilitated by two broadly conserved transcription factors, SpxR and CpsR, through a distal cis-regulatory element we name the 37-CE. Strikingly, changing only three nucleotides within this sequence is sufficient to render pneumococcus avirulent. Using in vivo and in vitro approaches, we present a model where SpxR interacts as a unique trimeric quaternary structure with the 37-CE to enable capsule repression in the airways. Considering its dramatic effect on infection, variation of the 37-CE between serotypes suggests this molecular switch could be a critical contributing factor to this pathogen's serotype-specific disease outcomes.
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Affiliation(s)
- David G. Glanville
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Ozcan Gazioglu
- Department of Respiratory Sciences, University of Leicester, University Road, Leicester, United Kingdom
| | - Michela Marra
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Valerie L. Tokars
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Tatyana Kushnir
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of The Negev, Beer-Sheva, Israel
| | - Medhanie Habtom
- Department of Respiratory Sciences, University of Leicester, University Road, Leicester, United Kingdom
| | - Nicholas J. Croucher
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Sir Michael Uren Hub, Imperial College London, London, United Kingdom
| | - Yaffa Mizrachi Nebenzahl
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences, Ben-Gurion University of The Negev, Beer-Sheva, Israel
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Hasan Yesilkaya
- Department of Respiratory Sciences, University of Leicester, University Road, Leicester, United Kingdom
| | - Andrew T. Ulijasz
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois, United States of America
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6
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Fuji N, Pichichero M, Kaur R. Pathogenesis of Streptococcus pneumoniae serotype 3 during natural colonization and infections among children and its IgG correlate of protection in a mouse model. Vaccine 2022; 40:6412-6421. [PMID: 36192274 DOI: 10.1016/j.vaccine.2022.09.062] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 09/07/2022] [Accepted: 09/20/2022] [Indexed: 01/27/2023]
Abstract
Current licensed pneumococcal conjugate vaccines (PCVs) are effective against pneumococcal diseases caused by the serotypes contained in the PCvs However; several studies evaluating pneumococcal colonization and acute otitis-media (AOM) prevention in young children vaccinated with PCV13, observed less effectiveness against serotype-3. One possible reason for less effectiveness may be release of the capsular polysaccharide (CPS) of serotype-3 (CPS-3) as an immune evasion mechanism. Here we evaluated free CPS-3 levels released from 6 clinical isolates from young children compared to WU2 strain and to serotype-19A CPS (CPS-19A) released in vitro when interacting with nasopharyngeal, middle-ear and lung cell-lines. Clinical serotype-3 strains showed greater release of CPS than WU2 with the interaction to 2 cell-lines and all 6 clinical serotype-19A strains. We next evaluated CPS-3 vs CPS-19A levels in middle-ear fluid (MEF) and the nasopharynx (NP) of young children and found higher levels of CPS-3 compared to CPS-19A in MEF during AOM but not in NP secretions during colonization. With anti-CPS-3 IgG in MEF and NP secretions at time of health and onset of AOM, a significant negative correlation (r = -0.75, p < 0.05) between unbound anti-CPS-3 IgG levels and free- anti-CPS-3 in MEF were found, and a significant lower detection of unbound anti-CPS-3 IgG in NP at the time of health with serotype-3 SPN (p < 0.05) compared to irrelevant SPN serotypes were found. In a mouse model of AOM and pneumonia, we sought a correlate of protection against serotype-3 infection using human serum-derived anti-CPS-3 IgG. We conclude that serotype-3 clinical isolates from children release more capsule than WU2 strains or 19A strains during in vitro testing; release more capsule in the MEF of children during AOM than serotype 19A; unbound anti-CPS-3 IgG levels negatively correlate with free-anti-CPS-3; and a level of 2.8 µg/ml anti-CPS-3 antibody protects mice from AOM and pneumonia but not colonization.
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Affiliation(s)
- Naoko Fuji
- Center for Infectious Diseases and Immunology, Rochester General Hospital Research Institute, Rochester, NY, United States
| | - Michael Pichichero
- Center for Infectious Diseases and Immunology, Rochester General Hospital Research Institute, Rochester, NY, United States
| | - Ravinder Kaur
- Center for Infectious Diseases and Immunology, Rochester General Hospital Research Institute, Rochester, NY, United States.
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7
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Differential Pneumococcal Growth Features in Severe Invasive Disease Manifestations. Microbiol Spectr 2022; 10:e0005022. [PMID: 35678554 PMCID: PMC9241771 DOI: 10.1128/spectrum.00050-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The nasopharyngeal commensal Streptococcus pneumoniae can become invasive and cause metastatic infection. This requires the pneumococcus to have the ability to adapt, grow, and reside in diverse host environments. Therefore, we studied whether the likelihood of severe disease manifestations was related to pneumococcal growth kinetics. For 383 S. pneumoniae blood isolates and 25 experimental mutants, we observed highly reproducible growth curves in nutrient-rich medium. The derived growth features were lag time, maximum growth rate, maximum density, and stationary-phase time before lysis. First, the pathogenicity of each growth feature was probed by comparing isolates from patients with and without marked preexisting comorbidity. Then, growth features were related to the propensity of causing severe manifestations of invasive pneumococcal disease (IPD). A high maximum bacterial density was the most pronounced pathogenic growth feature, which was also an independent predictor of 30-day mortality (P = 0.03). Serotypes with an epidemiologically higher propensity for causing meningitis displayed a relatively high maximum density (P < 0.005) and a short stationary phase (P < 0.005). Correspondingly, isolates from patients diagnosed with meningitis showed an especially high maximum density and short stationary phase compared to isolates from the same serotype that had caused uncomplicated bacteremic pneumonia. In contrast, empyema-associated strains were characterized by a relatively long lag phase (P < 0.0005), and slower growth (P < 0.005). The course and dissemination of IPD may partly be attributable to the pneumococcal growth features involved. If confirmed, we should tailor the prevention and treatment strategies for the different infection sites that can complicate IPD. IMPORTANCEStreptococcus pneumoniae is a leading infectious cause of deaths worldwide. To understand the course and outcome of pneumococcal infection, most research has focused on the host and its response to contain bacterial growth. However, bacterial epidemiology suggest that certain pneumococcal serotypes are particularly prone to causing complicated infections. Therefore, we took the bacterial point of view, simply examining in vitro growth features for hundreds of pneumococcal blood isolates. Their growth curves were very reproducible. Certain poles of pneumococcal growth features were indeed associated with specific clinical manifestations like meningitis or pleural empyema. This indicates that bacterial growth style potentially affects the progression of infection. Further research on bacterial growth and adaptation to different host environments may therefore provide key insight into pathogenesis of complicated invasive disease. Such knowledge could lead to more tailored vaccine targets or therapeutic approaches to reduce the million deaths that are caused by pneumococcal disease every year.
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8
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The Role of luxS in the Middle Ear Streptococcus pneumoniae Isolate 947. Pathogens 2022; 11:pathogens11020216. [PMID: 35215159 PMCID: PMC8877971 DOI: 10.3390/pathogens11020216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 02/04/2023] Open
Abstract
The LuxS protein, encoded by luxS, is required for the production of autoinducer 2 (AI-2) in Streptococcus pneumoniae. The AI-2 molecule serves as a quorum sensing signal, and thus regulates cellular processes such as carbohydrate utilisation and biofilm formation, as well as impacting virulence. The role of luxS in S. pneumoniae biology and lifestyle has been predominantly assessed in the laboratory strain D39. However, as biofilm formation, which is regulated by luxS, is critical for the ability of S. pneumoniae to cause otitis media, we investigated the role of luxS in a middle ear isolate, strain 947. Our results identified luxS to have a role in prevention of S. pneumoniae transition from colonisation of the nasopharynx to the ear, and in facilitating adherence to host epithelial cells.
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Willen L, Ekinci E, Cuypers L, Theeten H, Desmet S. Infant Pneumococcal Carriage in Belgium Not Affected by COVID-19 Containment Measures. Front Cell Infect Microbiol 2022; 11:825427. [PMID: 35111700 PMCID: PMC8801737 DOI: 10.3389/fcimb.2021.825427] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 12/30/2021] [Indexed: 12/31/2022] Open
Abstract
Streptococcus pneumoniae is an important and frequently carried respiratory pathogen that has the potential to cause serious invasive diseases, such as pneumonia, meningitis, and sepsis. Young children and older adults are among the most vulnerable to developing serious disease. With the arrival of the COVID-19 pandemic and the concomitant restrictive measures, invasive disease cases caused by respiratory bacterial species, including pneumococci, decreased substantially. Notably, the stringency of the containment measures as well as the visible reduction in the movement of people appeared to coincide with the drop in invasive disease cases. One could argue that wearing protective masks and adhering to social distancing guidelines to halt the spread of the SARS-CoV-2 virus, also led to a reduction in the person-to-person transmission of respiratory bacterial species. Although plausible, this conjecture is challenged by novel data obtained from our nasopharyngeal carriage study which is performed yearly in healthy daycare center attending children. A sustained and high pneumococcal carriage rate was observed amid periods of stringent restrictive measures. This finding prompts us to revisit the connection between nasopharyngeal colonization and invasion and invites us to look closer at the nasopharyngeal microbiome as a whole.
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Affiliation(s)
- Laura Willen
- Centre for the Evaluation of Vaccination, Vaccine and Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium
- *Correspondence: Laura Willen,
| | - Esra Ekinci
- Centre for the Evaluation of Vaccination, Vaccine and Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium
| | - Lize Cuypers
- Department of Laboratory Medicine, National Reference Centre for Pneumococci, University Hospitals Leuven, Leuven, Belgium
| | - Heidi Theeten
- Centre for the Evaluation of Vaccination, Vaccine and Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium
| | - Stefanie Desmet
- Department of Laboratory Medicine, National Reference Centre for Pneumococci, University Hospitals Leuven, Leuven, Belgium
- Laboratory of Clinical Bacteriology and Mycology, Department of Microbiology, Immunology and Transplantation, Katholieke Universiteit Leuven, Leuven, Belgium
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10
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High-Throughput Mutagenesis and Cross-Complementation Experiments Reveal Substrate Preference and Critical Residues of the Capsule Transporters in Streptococcus pneumoniae. mBio 2021; 12:e0261521. [PMID: 34724815 PMCID: PMC8561386 DOI: 10.1128/mbio.02615-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MOP (Multidrug/Oligosaccharidyl-lipid/Polysaccharide) family transporters are found in almost all life forms. They are responsible for transporting lipid-linked precursors across the cell membrane to support the synthesis of various glycoconjugates. While significant progress has been made in elucidating their transport mechanism, how these transporters select their substrates remains unclear. Here, we systematically tested the MOP transporters in the Streptococcus pneumoniae capsule pathway for their ability to translocate noncognate capsule precursors. Sequence similarity cannot predict whether these transporters are interchangeable. We showed that subtle changes in the central aqueous cavity of the transporter are sufficient to accommodate a different cargo. These changes can occur naturally, suggesting a potential mechanism of expanding substrate selectivity. A directed evolution experiment was performed to identify gain-of-function variants that translocate a noncognate cargo. Coupled with a high-throughput mutagenesis and sequencing (Mut-seq) experiment, residues that are functionally important for the capsule transporter were revealed. Lastly, we showed that the expression of a flippase that can transport unfinished precursors resulted in an increased susceptibility to bacitracin and mild cell shape defects, which may be a driving force to maintain transporter specificity. IMPORTANCE All licensed pneumococcal vaccines target the capsular polysaccharide (CPS). This layer is highly variable and is important for virulence in many bacterial pathogens. Most of the CPSs are produced by the Wzx/Wzy mechanism. In this pathway, CPS repeating units are synthesized in the cytoplasm, which must be flipped across the cytoplasmic membrane before polymerization. This step is mediated by the widely conserved MOP (Multidrug/Oligosaccharidyl-lipid/Polysaccharide) family transporters. Here, we systematically evaluated the interchangeability of these transporters and identified the residues important for substrate specificity and function. Understanding how CPS is synthesized will inform glycoengineering, vaccine development, and antimicrobial discovery.
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11
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Cellular Mn/Zn Ratio Influences Phosphoglucomutase Activity and Capsule Production in Streptococcus pneumoniae D39. J Bacteriol 2021; 203:e0060220. [PMID: 33875543 PMCID: PMC8316032 DOI: 10.1128/jb.00602-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Capsular polysaccharide (CPS) is a major virulence determinant for many human-pathogenic bacteria. Although the essential functional roles for CPS in bacterial virulence have been established, knowledge of how CPS production is regulated remains limited. Streptococcus pneumoniae (pneumococcus) CPS expression levels and overall thickness change in response to available oxygen and carbohydrate. These nutrients in addition to transition metal ions can vary significantly between host environmental niches and infection stage. Since the pneumococcus must modulate CPS expression among various host niches during disease progression, we examined the impact of the nutritional transition metal availability of manganese (Mn) and zinc (Zn) on CPS production. We demonstrate that increased Mn/Zn ratios increase CPS production via Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway in a transcription-independent manner. Furthermore, we find that the downstream CPS protein CpsB, an Mn-dependent phosphatase, does not promote aberrant dephosphorylation of its target capsule-tyrosine kinase CpsD during Mn stress. Together, these data reveal a direct role for cellular Mn/Zn ratios in the regulation of CPS biosynthesis via the direct activation of Pgm. We propose a multilayer mechanism used by the pneumococcus in regulating CPS levels across various host niches. IMPORTANCE Evolving evidence strongly indicates that maintenance of metal homeostasis is essential for establishing colonization and continued growth of bacterial pathogens in the vertebrate host. In this study, we demonstrate the impact of cellular manganese/zinc (Mn/Zn) ratios on bacterial capsular polysaccharide (CPS) production, an important virulence determinant of many human-pathogenic bacteria, including Streptococcus pneumoniae. We show that higher Mn/Zn ratios increase CPS production via the Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway. The findings provide a direct role for Mn/Zn homeostasis in the regulation of CPS expression levels and further support the ability of metal cations to act as important cellular signaling mediators in bacteria.
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12
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Morimura A, Hamaguchi S, Akeda Y, Tomono K. Mechanisms Underlying Pneumococcal Transmission and Factors Influencing Host-Pneumococcus Interaction: A Review. Front Cell Infect Microbiol 2021; 11:639450. [PMID: 33996623 PMCID: PMC8113816 DOI: 10.3389/fcimb.2021.639450] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 04/06/2021] [Indexed: 01/21/2023] Open
Abstract
Streptococcus pneumoniae (also called pneumococcus) is not only a commensal that frequently colonizes the human upper respiratory tract but also a pathogen that causes pneumonia, sepsis, and meningitis. The mechanism of pneumococcal infection has been extensively studied, but the process of transmission has not been fully elucidated because of the lack of tractable animal models. Novel animal models of transmission have enabled further progress in investigating pneumococcal transmission mechanisms including the processes such as pneumococcal shedding, survival in the external environment, and adherence to the nasopharynx of a new host. Herein, we present a review on these animal models, recent research findings about pneumococcal transmission, and factors influencing the host-pneumococcus interaction.
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Affiliation(s)
- Ayumi Morimura
- Department of Infection Control and Prevention, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Shigeto Hamaguchi
- Department of Infection Control and Prevention, Osaka University Graduate School of Medicine, Osaka, Japan.,Division of Infection Control and Prevention, Osaka University Hospital, Osaka, Japan
| | - Yukihiro Akeda
- Department of Infection Control and Prevention, Osaka University Graduate School of Medicine, Osaka, Japan.,Division of Infection Control and Prevention, Osaka University Hospital, Osaka, Japan.,Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Kazunori Tomono
- Department of Infection Control and Prevention, Osaka University Graduate School of Medicine, Osaka, Japan.,Division of Infection Control and Prevention, Osaka University Hospital, Osaka, Japan
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13
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Buffet A, Rocha EPC, Rendueles O. Nutrient conditions are primary drivers of bacterial capsule maintenance in Klebsiella. Proc Biol Sci 2021; 288:20202876. [PMID: 33653142 PMCID: PMC7935059 DOI: 10.1098/rspb.2020.2876] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 02/05/2021] [Indexed: 02/06/2023] Open
Abstract
The fitness cost associated with the production of bacterial capsules is considered to be offset by the protection provided by these extracellular structures against biotic aggressions or abiotic stress. However, it is unknown if the capsule contributes to fitness in the absence of these. Here, we explored conditions favouring the maintenance of the capsule in Klebsiella pneumoniae, where the capsule is known to be a major virulence factor. Using short-term experimental evolution on different Klebsiella strains, we showed that small environmental variations have a strong impact on the maintenance of the capsule. Capsule inactivation is frequent in nutrient-rich, but scarce in nutrient-poor media. Competitions between wild-type and capsule mutants in nine different strains confirmed that the capsule is costly in nutrient-rich media. Surprisingly, these results also showed that the presence of a capsule provides a clear fitness advantage in nutrient-poor conditions by increasing both growth rates and population yields. The comparative analyses of the wild-type and capsule mutants reveal complex interactions between the environment, genetic background and serotype even in relation to traits known to be relevant during pathogenesis. In conclusion, our data suggest there are novel roles for bacterial capsules yet to be discovered and further supports the notion that the capsule's role in virulence may be a by-product of its contribution to bacterial adaptation outside the host.
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Affiliation(s)
- Amandine Buffet
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris 75015, France
| | - Eduardo P. C. Rocha
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris 75015, France
| | - Olaya Rendueles
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris 75015, France
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Mike LA, Stark AJ, Forsyth VS, Vornhagen J, Smith SN, Bachman MA, Mobley HLT. A systematic analysis of hypermucoviscosity and capsule reveals distinct and overlapping genes that impact Klebsiella pneumoniae fitness. PLoS Pathog 2021; 17:e1009376. [PMID: 33720976 PMCID: PMC7993769 DOI: 10.1371/journal.ppat.1009376] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/25/2021] [Accepted: 02/12/2021] [Indexed: 12/11/2022] Open
Abstract
Hypervirulent K. pneumoniae (hvKp) is a distinct pathotype that causes invasive community-acquired infections in healthy individuals. Hypermucoviscosity (hmv) is a major phenotype associated with hvKp characterized by copious capsule production and poor sedimentation. Dissecting the individual functions of CPS production and hmv in hvKp has been hindered by the conflation of these two properties. Although hmv requires capsular polysaccharide (CPS) biosynthesis, other cellular factors may also be required and some fitness phenotypes ascribed to CPS may be distinctly attributed to hmv. To address this challenge, we systematically identified genes that impact capsule and hmv. We generated a condensed, ordered transposon library in hypervirulent strain KPPR1, then evaluated the CPS production and hmv phenotypes of the 3,733 transposon mutants, representing 72% of all open reading frames in the genome. We employed forward and reverse genetic screens to evaluate effects of novel and known genes on CPS biosynthesis and hmv. These screens expand our understanding of core genes that coordinate CPS biosynthesis and hmv, as well as identify central metabolism genes that distinctly impact CPS biosynthesis or hmv, specifically those related to purine metabolism, pyruvate metabolism and the TCA cycle. Six representative mutants, with varying effect on CPS biosynthesis and hmv, were evaluated for their impact on CPS thickness, serum resistance, host cell association, and fitness in a murine model of disseminating pneumonia. Altogether, these data demonstrate that hmv requires both CPS biosynthesis and other cellular factors, and that hmv and CPS may serve distinct functions during pathogenesis. The integration of hmv and CPS to the metabolic status of the cell suggests that hvKp may require certain nutrients to specifically cause deep tissue infections.
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Affiliation(s)
- Laura A. Mike
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Andrew J. Stark
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Valerie S. Forsyth
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jay Vornhagen
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sara N. Smith
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Michael A. Bachman
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Harry L. T. Mobley
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
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15
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Abstract
Influenza A virus (IAV) is a major pathogen of the human respiratory tract, where the virus coexists and interacts with bacterial populations comprising the respiratory tract microbiome. Synergies between IAV and respiratory bacterial pathogens promote enhanced inflammation and disease burden that exacerbate morbidity and mortality. We demonstrate that direct interactions between IAV and encapsulated bacteria commonly found in the respiratory tract promote environmental stability and infectivity of IAV. Antibiotic-mediated depletion of the respiratory bacterial flora abrogated IAV transmission in ferret models, indicating that these virus-bacterium interactions are operative for airborne transmission of IAV. Restoring IAV airborne transmission in antibiotic-treated ferrets by coinfection with Streptococcus pneumoniae confirmed a role for specific members of the bacterial respiratory community in promoting IAV transmission. These results implicate a role for the bacterial respiratory flora in promoting airborne transmission of IAV.IMPORTANCE Infection with influenza A virus (IAV), especially when complicated with a secondary bacterial infection, is a leading cause of global mortality and morbidity. Gaining a greater understanding of the transmission dynamics of IAV is important during seasonal IAV epidemics and in the event of a pandemic. Direct bacterium-virus interactions are a recently appreciated aspect of infectious disease biology. Direct interactions between IAV and specific bacterial species of the human upper respiratory tract were found to promote the stability and infectivity of IAV during desiccation stress. Viral environmental stability is an important aspect during transmission, suggesting a potential role for bacterial respiratory communities in IAV transmission. Airborne transmission of IAV was abrogated upon depletion of nasal bacterial flora with topical antibiotics. This defect could be functionally complemented by S. pneumoniae coinfection. These data suggest that bacterial coinfection may be an underappreciated aspect of IAV transmission dynamics.
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16
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Disruption of the cpsE and endA Genes Attenuates Streptococcus pneumoniae Virulence: Towards the Development of a Live Attenuated Vaccine Candidate. Vaccines (Basel) 2020; 8:vaccines8020187. [PMID: 32326482 PMCID: PMC7349068 DOI: 10.3390/vaccines8020187] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/27/2020] [Accepted: 04/07/2020] [Indexed: 12/15/2022] Open
Abstract
The majority of deaths due to Streptococcus pneumoniae infections are in developing countries. Although polysaccharide-based pneumococcal vaccines are available, newer types of vaccines are needed to increase vaccine affordability, particularly in developing countries, and to provide broader protection across all pneumococcal serotypes. To attenuate pneumococcal virulence with the aim of engineering candidate live attenuated vaccines (LAVs), we constructed knockouts in S. pneumoniae D39 of one of the capsular biosynthetic genes, cpsE that encodes glycosyltransferase, and the endonuclease gene, endA, that had been implicated in the uptake of DNA from the environment as well as bacterial escape from neutrophil-mediated killing. The cpsE gene knockout significantly lowered peak bacterial density, BALB/c mice nasopharyngeal (NP) colonisation but increased biofilm formation when compared to the wild-type D39 strain as well as the endA gene knockout mutant. All constructed mutant strains were able to induce significantly high serum and mucosal antibody response in BALB/c mice. However, the cpsE-endA double mutant strain, designated SPEC, was able to protect mice from high dose mucosal challenge of the D39 wild-type. Furthermore, SPEC showed 23-fold attenuation of virulence compared to the wild-type. Thus, the cpsE-endA double-mutant strain could be a promising candidate for further development of a LAV for S. pneumoniae.
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17
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Müller A, Salmen A, Aebi S, de Gouveia L, von Gottberg A, Hathaway LJ. Pneumococcal serotype determines growth and capsule size in human cerebrospinal fluid. BMC Microbiol 2020; 20:16. [PMID: 31959125 PMCID: PMC6971925 DOI: 10.1186/s12866-020-1700-7] [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: 07/14/2019] [Accepted: 01/09/2020] [Indexed: 12/02/2022] Open
Abstract
Background The polysaccharide capsule is a major virulence factor of S. pneumoniae in diseases such as meningitis. While some capsular serotypes are more often found in invasive disease, high case fatality rates are associated with those serotypes more commonly found in asymptomatic colonization. We tested whether growth patterns and capsule size in human cerebrospinal fluid depends on serotype using a clinical isolate of S. pneumoniae and its capsule switch mutants. Results We found that the growth pattern differed markedly from that in culture medium by lacking the exponential and lysis phases. Growth in human cerebrospinal fluid was reduced when strains lost their capsules. When a capsule was present, growth was serotype-specific: high carriage serotypes (6B, 9 V, 19F and 23F) grew better than low carriage serotypes (7F, 14, 15B/C and 18C). Growth correlated with the case-fatality rates of serotypes reported in the literature. Capsule size in human cerebrospinal fluid also depended on serotype. Conclusions We propose that serotype-specific differences in disease severity observed in meningitis patients may, at least in part, be explained by differences in growth and capsule size in human cerebrospinal fluid. This information could be useful to guide future vaccine design.
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Affiliation(s)
- Annelies Müller
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Anke Salmen
- Department of Neurology, Inselspital, University Hospital Bern and University of Bern, Bern, Switzerland
| | - Suzanne Aebi
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland
| | - Linda de Gouveia
- National Institute for Communicable Diseases: Division of the National Health Laboratory Service, Johannesburg, South Africa
| | - Anne von Gottberg
- National Institute for Communicable Diseases: Division of the National Health Laboratory Service, Johannesburg, South Africa.,Faculty of Health Sciences, School of Pathology, University of Witwatersrand, Johannesburg, South Africa
| | - Lucy J Hathaway
- Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3001, Bern, Switzerland.
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18
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Biosynthesis and regulation mechanisms of the Pasteurella multocida capsule. Res Vet Sci 2019; 127:82-90. [PMID: 31678457 DOI: 10.1016/j.rvsc.2019.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 09/05/2019] [Accepted: 10/21/2019] [Indexed: 12/27/2022]
Abstract
Pasteurella multocida possesses a polysaccharide capsule composed of a viscous surface layer that acts as a critical structural component and virulence factor. Capsular polysaccharides are structurally similar to vertebrate glycosaminoglycans, providing an immunological mechanism for bacterial molecular mimicry, resistance to phagocytosis, and immune evasion during the infection process. In recent years, a series of important research advances have been made in understanding the biosynthesis and regulatory aspects of the P. multocida capsule. This review systematically examines the serogroups, polysaccharide composition and structures, biosynthetic loci and functions, biosynthesis pathways, and expression regulation mechanisms of the P. multocida capsule, supplying a theoretical basis for the molecular pathogenesis of the P. multocida capsule and the future development of capsular polysaccharide vaccines.
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19
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Microencapsulation for Delivery of Probiotic Bacteria. NANOBIOTECHNOLOGY IN BIOFORMULATIONS 2019. [DOI: 10.1007/978-3-030-17061-5_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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20
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Weiser JN, Ferreira DM, Paton JC. Streptococcus pneumoniae: transmission, colonization and invasion. Nat Rev Microbiol 2018; 16:355-367. [PMID: 29599457 PMCID: PMC5949087 DOI: 10.1038/s41579-018-0001-8] [Citation(s) in RCA: 521] [Impact Index Per Article: 86.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Streptococcus pneumoniae has a complex relationship with its obligate human host. On the one hand, the pneumococci are highly adapted commensals, and their main reservoir on the mucosal surface of the upper airways of carriers enables transmission. On the other hand, they can cause severe disease when bacterial and host factors allow them to invade essentially sterile sites, such as the middle ear spaces, lungs, bloodstream and meninges. Transmission, colonization and invasion depend on the remarkable ability of S. pneumoniae to evade or take advantage of the host inflammatory and immune responses. The different stages of pneumococcal carriage and disease have been investigated in detail in animal models and, more recently, in experimental human infection. Furthermore, widespread vaccination and the resulting immune pressure have shed light on pneumococcal population dynamics and pathogenesis. Here, we review the mechanistic insights provided by these studies on the multiple and varied interactions of the pneumococcus and its host.
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