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Cossart P, Hacker J, Holden DH, Normark S, Vogel J. Meeting report 'Microbiology 2023: from single cell to microbiome and host', an international interacademy conference in Würzburg. Microlife 2024; 5:uqae008. [PMID: 38665235 PMCID: PMC11044969 DOI: 10.1093/femsml/uqae008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024]
Abstract
On September 20-22 September 2023, the international conference 'Microbiology 2023: from single cell to microbiome and host' convened microbiologists from across the globe for a very successful symposium, showcasing cutting-edge research in the field. Invited lecturers delivered exceptional presentations covering a wide range of topics, with a major emphasis on phages and microbiomes, on the relevant bacteria within these ecosystems, and their multifaceted roles in diverse environments. Discussions also spanned the intricate analysis of fundamental bacterial processes, such as cell division, stress resistance, and interactions with phages. Organized by four renowned Academies, the German Leopoldina, the French Académie des sciences, the Royal Society UK, and the Royal Swedish Academy of Sciences, the symposium provided a dynamic platform for experts to share insights and discoveries, leaving participants inspired and eager to integrate new knowledge into their respective projects. The success of Microbiology 2023 prompted the decision to host the next quadrennial academic meeting in Sweden. This choice underscores the commitment to fostering international collaboration and advancing the frontiers of microbiological knowledge. The transition to Sweden promises to be an exciting step in the ongoing global dialogue and specific collaborations on microbiology, a field where researchers will continue to push the boundaries of knowledge, understanding, and innovation not only in health and disease but also in ecology.
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Affiliation(s)
| | - Jörg Hacker
- German National Academy of Science Leopoldina, Jägerberg 1, D-06108 Halle, Germany
| | - David H Holden
- Department of Infectious Disease, Centre for Bacterial Resistance Biology, Flowers Building, South Kensington Campus, Exhibition Road, Imperial College London, London SW7 2AZ, United Kingdom
| | - Staffan Normark
- Karolinska Institute, Tumor-och-cellbiologi, C1 Microbial Pathogenesis, 17177 Stockholm, Sweden
| | - Jörg Vogel
- Faculty of Medicine, Institute for Molecular Infection Biology (IMIB), University of Würzburg, D-97080 Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Josef-Schneider-Str2/Gebaude D15; É. D-97080 Würzburg, Germany
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Farmand S, Sender V, Karlsson J, Merkl P, Normark S, Henriques-Normark B. STAT3 Deficiency Alters the Macrophage Activation Pattern and Enhances Matrix Metalloproteinase 9 Expression during Staphylococcal Pneumonia. J Immunol 2024; 212:69-80. [PMID: 37982695 PMCID: PMC10733582 DOI: 10.4049/jimmunol.2300151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 10/19/2023] [Indexed: 11/21/2023]
Abstract
Staphylococcus aureus is a significant cause of morbidity and mortality in pulmonary infections. Patients with autosomal-dominant hyper-IgE syndrome due to STAT3 deficiency are particularly susceptible to acquiring staphylococcal pneumonia associated with lung tissue destruction. Because macrophages are involved in both pathogen defense and inflammation, we investigated the impact of murine myeloid STAT3 deficiency on the macrophage phenotype in vitro and on pathogen clearance and inflammation during murine staphylococcal pneumonia. Murine bone marrow-derived macrophages (BMDM) from STAT3 LysMCre+ knockout or Cre- wild-type littermate controls were challenged with S. aureus, LPS, IL-4, or vehicle control in vitro. Pro- and anti-inflammatory responses as well as polarization and activation markers were analyzed. Mice were infected intratracheally with S. aureus, bronchoalveolar lavage and lungs were harvested, and immunohistofluorescence was performed on lung sections. S. aureus infection of STAT3-deficient BMDM led to an increased proinflammatory cytokine release and to enhanced upregulation of costimulatory MHC class II and CD86. Murine myeloid STAT3 deficiency did not affect pathogen clearance in vitro or in vivo. Matrix metalloproteinase 9 was upregulated in Staphylococcus-treated STAT3-deficient BMDM and in lung tissues of STAT3 knockout mice infected with S. aureus. Moreover, the expression of miR-155 was increased. The enhanced inflammatory responses and upregulation of matrix metalloproteinase 9 and miR-155 expression in murine STAT3-deficient as compared with wild-type macrophages during S. aureus infections may contribute to tissue damage as observed in STAT3-deficient patients during staphylococcal pneumonia.
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Affiliation(s)
- Susan Farmand
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Division of Pediatric Stem Cell Transplantation and Immunology, Clinic of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Vicky Sender
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Clinical Microbiology, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Jens Karlsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Clinical Microbiology, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Padryk Merkl
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Clinical Microbiology, Karolinska University Hospital Solna, Stockholm, Sweden
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Nakamoto R, Bamyaci S, Blomqvist K, Normark S, Henriques-Normark B, Sham LT. The divisome but not the elongasome organizes capsule synthesis in Streptococcus pneumoniae. Nat Commun 2023; 14:3170. [PMID: 37264013 DOI: 10.1038/s41467-023-38904-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 05/16/2023] [Indexed: 06/03/2023] Open
Abstract
The bacterial cell envelope consists of multiple layers, including the peptidoglycan cell wall, one or two membranes, and often an external layer composed of capsular polysaccharides (CPS) or other components. How the synthesis of all these layers is precisely coordinated remains unclear. Here, we identify a mechanism that coordinates the synthesis of CPS and peptidoglycan in Streptococcus pneumoniae. We show that CPS synthesis initiates from the division septum and propagates along the long axis of the cell, organized by the tyrosine kinase system CpsCD. CpsC and the rest of the CPS synthesis complex are recruited to the septum by proteins associated with the divisome (a complex involved in septal peptidoglycan synthesis) but not the elongasome (involved in peripheral peptidoglycan synthesis). Assembly of the CPS complex starts with CpsCD, then CpsA and CpsH, the glycosyltransferases, and finally CpsJ. Remarkably, targeting CpsC to the cell pole is sufficient to reposition CPS synthesis, leading to diplococci that lack CPS at the septum. We propose that septal CPS synthesis is important for chain formation and complement evasion, thereby promoting bacterial survival inside the host.
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Affiliation(s)
- Rei Nakamoto
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Sarp Bamyaci
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Karin Blomqvist
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
- Clinical Microbiology, Karolinska University Hospital Solna, SE-17176, Stockholm, Sweden
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, SE-17177, Sweden
- Clinical Microbiology, Karolinska University Hospital Solna, SE-17176, Stockholm, Sweden
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
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Iovino F, Nannapaneni P, Henriques-Normark B, Normark S. The impact of the ancillary pilus-1 protein RrgA of Streptococcus pneumoniae on colonization and disease. Mol Microbiol 2020; 113:650-658. [PMID: 32185835 DOI: 10.1111/mmi.14451] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/11/2022]
Abstract
The Gram-positive bacterium Streptococcus pneumoniae, the pneumococcus, is an important commensal resident of the human nasopharynx. Carriage is usually asymptomatic, however, S. pneumoniae can become invasive and spread from the upper respiratory tract to the lungs causing pneumonia, and to other organs to cause severe diseases such as bacteremia and meningitis. Several pneumococcal proteins important for its disease-causing capability have been described and many are expressed on the bacterial surface. The surface located pneumococcal type-1 pilus has been associated with virulence and the inflammatory response, and it is present in 20%-30% of clinical isolates. Its tip protein RrgA has been shown to be a major adhesin to human cells and to promote invasion through the blood-brain barrier. In this review we discuss recent findings of the impact of RrgA on bacterial colonization of the upper respiratory tract and on pneumococcal virulence, and use epidemiological data and genome-mining to suggest trade-off mechanisms potentially explaining the rather low prevalence of pilus-1 expressing pneumococci in humans.
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Affiliation(s)
- Federico Iovino
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Priyanka Nannapaneni
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and Lee Kong Chian School of Medicine (LKC), Nanyang Technological University (NTU), Singapore, Singapore
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and Lee Kong Chian School of Medicine (LKC), Nanyang Technological University (NTU), Singapore, Singapore
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Affiliation(s)
- Marie-Stéphanie Aschtgen
- From the, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC), Singapore Centre on Environmental LifeSciences Engineering (SCELSE), Nanyang Technological University, Singapore City, Singapore
| | - Birgitta Henriques-Normark
- From the, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC), Singapore Centre on Environmental LifeSciences Engineering (SCELSE), Nanyang Technological University, Singapore City, Singapore.,Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Staffan Normark
- From the, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC), Singapore Centre on Environmental LifeSciences Engineering (SCELSE), Nanyang Technological University, Singapore City, Singapore.,Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
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Subramanian K, Henriques-Normark B, Normark S. Emerging concepts in the pathogenesis of the Streptococcus pneumoniae: From nasopharyngeal colonizer to intracellular pathogen. Cell Microbiol 2019; 21:e13077. [PMID: 31251447 PMCID: PMC6899785 DOI: 10.1111/cmi.13077] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/17/2019] [Accepted: 06/21/2019] [Indexed: 12/19/2022]
Abstract
Streptococcus pneumoniae (the pneumococcus) is a human respiratory tract pathogen and a major cause of morbidity and mortality globally. Although the pneumococcus is a commensal bacterium that colonizes the nasopharynx, it also causes lethal diseases such as meningitis, sepsis, and pneumonia, especially in immunocompromised patients, in the elderly, and in young children. Due to the acquisition of antibiotic resistance and the emergence of nonvaccine serotypes, the pneumococcus has been classified as one of the priority pathogens for which new antibacterials are urgently required by the World Health Organization, 2017. Understanding molecular mechanisms behind the pathogenesis of pneumococcal infections and bacterial interactions within the host is crucial to developing novel therapeutics. Previously considered to be an extracellular pathogen, it is becoming evident that pneumococci may also occasionally establish intracellular niches within the body to escape immune surveillance and spread within the host. Intracellular survival within host cells also enables pneumococci to resist many antibiotics. Within the host cell, the bacteria exist in unique vacuoles, thereby avoiding degradation by the acidic lysosomes, and modulate the expression of its virulence genes to adapt to the intracellular environment. To invade and survive intracellularly, the pneumococcus utilizes a combination of virulence factors such as pneumolysin (PLY), pneumococcal surface protein A (PspA), pneumococcal adhesion and virulence protein B (PavB), the pilus‐1 adhesin RrgA, pyruvate oxidase (SpxB), and metalloprotease (ZmpB). In this review, we discuss recent findings showing the intracellular persistence of Streptococcus pneumoniae and its underlying mechanisms.
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Affiliation(s)
- Karthik Subramanian
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC) and Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC) and Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore
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Feldman C, Normark S, Henriques-Normark B, Anderson R. Pathogenesis and prevention of risk of cardiovascular events in patients with pneumococcal community-acquired pneumonia. J Intern Med 2019; 285:635-652. [PMID: 30584680 DOI: 10.1111/joim.12875] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It is now well recognized that cardiovascular events (CVE) occur quite commonly, both in the acute phase and in the long-term, in patients with community-acquired pneumonia (CAP). CVE have been noted in up to 30% of patients hospitalized with all-cause CAP. One systematic review and meta-analysis of hospitalized patients with all-cause CAP noted that the incidence rates for overall cardiac events were 17.7%, for incident heart failure were 14.1%, for acute coronary syndromes were 5.3% and for incident cardiac arrhythmias were 4.7%. In the case of pneumococcal CAP, almost 20% of patients studied had one or more of these cardiac events. Recent research has provided insights into the pathogenesis of the acute cardiac events occurring in pneumococcal infections. With respect to the former, key involvements of the major pneumococcal protein virulence factor, pneumolysin, are now well documented, whilst systemic platelet-driven neutrophil activation may also contribute. However, events involved in the pathogenesis of the long-term cardiovascular sequelae remain largely unexplored. Emerging evidence suggests that persistent antigenaemia may predispose to the development of a systemic pro-inflammatory/prothrombotic phenotype underpinning the risk of future cardiovascular events. The current manuscript briefly reviews the occurrence of cardiovascular events in patients with all-cause CAP, as well as in pneumococcal and influenza infections. It highlights the close interaction between influenza and pneumococcal pneumonia. It also includes a brief discussion of mechanisms of the acute cardiac events in CAP. However, the primary focus is on the prevalence, pathogenesis and prevention of the longer-term cardiac sequelae of severe pneumococcal disease, particularly in the context of persistent antigenaemia and associated inflammation.
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Affiliation(s)
- C Feldman
- Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - S Normark
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden.,Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC), Singapore Centre on Environmental Life Sciences Engineering (SCELCE), Nanyang Technical University, Singapore, Singapore
| | - B Henriques-Normark
- Department of Microbiology, Tumor and Cell biology, Karolinska Institutet, Stockholm, Sweden.,Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Lee Kong Chian School of Medicine (LKC), Singapore Centre on Environmental Life Sciences Engineering (SCELCE), Nanyang Technical University, Singapore, Singapore
| | - R Anderson
- Department of Immunology and Institute of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
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Henriques-Normark B, Normark S. Streptococcal M1 Strikes by Neutralizing Cathelicidins. Cell Host Microbe 2016; 18:390-1. [PMID: 26468741 DOI: 10.1016/j.chom.2015.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Virulent group A streptococci have become a serious threat, with the emergence of the hypervirulent lineage M1T1. In this issue of Cell Host & Microbe, LaRock et al. (2015), uncover a role for the streptococcal M1 protein in neutralizing a key human antimicrobial peptide, cathelicidin.
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Affiliation(s)
- Birgitta Henriques-Normark
- Department of Microbiology, Cell Biology and Tumorbiology, Karolinska Institutet, 171 77 Stockholm, Sweden; Department of Clinical Microbiology, Karolinska University Hospital, 171 76 Stockholm, Sweden.
| | - Staffan Normark
- Department of Microbiology, Cell Biology and Tumorbiology, Karolinska Institutet, 171 77 Stockholm, Sweden; Department of Clinical Microbiology, Karolinska University Hospital, 171 76 Stockholm, Sweden
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Schulte T, Löfling J, Mikaelsson C, Kikhney A, Hentrich K, Diamante A, Ebel C, Normark S, Svergun D, Henriques-Normark B, Achour A. The keratin-10 binding region of the pneumococcal serine rich repeat protein (PsrP) forms a domain-swapped dimer and intermolecular β-sheets – implications for biofilm formation of Streptococcus pneumoniae. Acta Crystallogr A Found Adv 2015. [DOI: 10.1107/s2053273315095765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Affiliation(s)
- Staffan Normark
- Editor-in-Chief Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Muschiol S, Balaban M, Normark S, Henriques-Normark B. Uptake of extracellular DNA: competence induced pili in natural transformation of Streptococcus pneumoniae. Bioessays 2015; 37:426-35. [PMID: 25640084 PMCID: PMC4405041 DOI: 10.1002/bies.201400125] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Transport of DNA across bacterial membranes involves complex DNA uptake systems. In Gram-positive bacteria, the DNA uptake machinery shares fundamental similarities with type IV pili and type II secretion systems. Although dedicated pilus structures, such as type IV pili in Gram-negative bacteria, are necessary for efficient DNA uptake, the role of similar structures in Gram-positive bacteria is just beginning to emerge. Recently two essentially very different pilus structures composed of the same major pilin protein ComGC were proposed to be involved in transformation of the Gram-positive bacterium Streptococcus pneumoniae – one is a long, thin, type IV pilus-like fiber with DNA binding capacity and the other one is a pilus structure that was thicker, much shorter and not able to bind DNA. Here we discuss how competence induced pili, either by pilus retraction or by a transient pilus-related opening in the cell wall, may mediate DNA uptake in S. pneumoniae.
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Affiliation(s)
- Sandra Muschiol
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
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Affiliation(s)
- U Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Abstract
Spread of antibiotic resistance is mediated by clonal lineages of bacteria that besides being resistant also possess other properties promoting their success. Some vaccines already in use, such as the pneumococcal conjugate vaccines, have had an effect on these successful clones, but at the same time have allowed for the expansion and resistance evolution of previously minor clones not covered by the vaccine. Since resistance frequently is horizontally transferred it will be difficult to generate a vaccine that covers all possible genetic lineages prone to develop resistance unless the vaccine target(s) is absolutely necessary for spread and/or disease development. Targeting the resistance mechanism itself by a vaccine is an interesting but hitherto unexplored approach.
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Affiliation(s)
- Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden
- Karolinska University Hospital, 171 76 Stockholm, Sweden
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden
- Karolinska University Hospital, 171 76 Stockholm, Sweden
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Syk A, Norman M, Fernebro J, Gallotta M, Farmand S, Sandgren A, Normark S, Henriques-Normark B. Emergence of hypervirulent mutants resistant to early clearance during systemic serotype 1 pneumococcal infection in mice and humans. J Infect Dis 2014; 210:4-13. [PMID: 24443543 PMCID: PMC4054898 DOI: 10.1093/infdis/jiu038] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Streptococcus pneumoniae serotype 1 has a high likelihood of causing invasive disease. Serotype 1 isolates belonging to CC228 are associated with low mortality, while CC217 isolates exhibit high mortality in patients. METHODS Clinical pneumococcal isolates and mutants were evaluated in wild-type C57BL/6 mice, macrophage-depleted mice, neutrophil-depleted mice, and SIGN-R1 knockout mice. In vitro models included binding and phagocytosis by THP-1 cells, capsule measurements, hydrogen peroxide production, and viability assays. RESULTS During early systemic infection in mice with serotype 1, large-colony variants appeared in blood. Similar large colonies were found in blood specimens from patients with invasive disease. Large morphotypes contained higher numbers of viable bacteria, grew faster, produced no or little hydrogen peroxide, and contained mutations in the spxB gene. spxB mutants were considerably more virulent in wild-type mice, less susceptible to early host clearance than wild-type strains after intravenous infection, but impaired in colonization. spxB mutants were less efficiently phagocytosed by macrophages than wild-type bacteria, which, in contrast to spxB mutants, caused more-severe disease when macrophages or SIGN-R1 were depleted. CONCLUSIONS Hypervirulent spxB mutants are selected in both mice and patients and are resistant to early macrophage-mediated clearance.
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Affiliation(s)
- Anna Syk
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Martin Norman
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Jenny Fernebro
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
| | - Marilena Gallotta
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
| | - Susan Farmand
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Andreas Sandgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet
- Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
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Schulte T, Löfling J, Mikaelsson C, Kikhney A, Hentrich K, Diamante A, Ebel C, Normark S, Svergun D, Henriques-Normark B, Achour A. The basic keratin 10-binding domain of the virulence-associated pneumococcal serine-rich protein PsrP adopts a novel MSCRAMM fold. Open Biol 2014; 4:130090. [PMID: 24430336 PMCID: PMC3909270 DOI: 10.1098/rsob.130090] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Streptococcus pneumoniae is a major human pathogen, and a leading cause of disease and death worldwide. Pneumococcal invasive disease is triggered by initial asymptomatic colonization of the human upper respiratory tract. The pneumococcal serine-rich repeat protein (PsrP) is a lung-specific virulence factor whose functional binding region (BR) binds to keratin-10 (KRT10) and promotes pneumococcal biofilm formation through self-oligomerization. We present the crystal structure of the KRT10-binding domain of PsrP (BR187–385) determined to 2.0 Å resolution. BR187–385 adopts a novel variant of the DEv-IgG fold, typical for microbial surface components recognizing adhesive matrix molecules adhesins, despite very low sequence identity. An extended β-sheet on one side of the compressed, two-sided barrel presents a basic groove that possibly binds to the acidic helical rod domain of KRT10. Our study also demonstrates the importance of the other side of the barrel, formed by extensive well-ordered loops and stabilized by short β-strands, for interaction with KRT10.
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Affiliation(s)
- Tim Schulte
- Science for Life Laboratory, Center for Infectious Medicine (CIM), Department of Medicine, Karolinska University Hospital Huddinge, Karolinska Institutet Science Park, Tomtebodavägen 23A Solna, Stockholm 17165, Sweden
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Croucher NJ, Mitchell AM, Gould KA, Inverarity D, Barquist L, Feltwell T, Fookes MC, Harris SR, Dordel J, Salter SJ, Browall S, Zemlickova H, Parkhill J, Normark S, Henriques-Normark B, Hinds J, Mitchell TJ, Bentley SD. Dominant role of nucleotide substitution in the diversification of serotype 3 pneumococci over decades and during a single infection. PLoS Genet 2013; 9:e1003868. [PMID: 24130509 PMCID: PMC3794909 DOI: 10.1371/journal.pgen.1003868] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 08/24/2013] [Indexed: 01/12/2023] Open
Abstract
Streptococcus pneumoniae of serotype 3 possess a mucoid capsule and cause disease associated with high mortality rates relative to other pneumococci. Phylogenetic analysis of a complete reference genome and 81 draft sequences from clonal complex 180, the predominant serotype 3 clone in much of the world, found most sampled isolates belonged to a clade affected by few diversifying recombinations. However, other isolates indicate significant genetic variation has accumulated over the clonal complex's entire history. Two closely related genomes, one from the blood and another from the cerebrospinal fluid, were obtained from a patient with meningitis. The pair differed in their behaviour in a mouse model of disease and in their susceptibility to antimicrobials, with at least some of these changes attributable to a mutation that up-regulated the patAB efflux pump. This indicates clinically important phenotypic variation can accumulate rapidly through small alterations to the genotype.
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Affiliation(s)
- Nicholas J. Croucher
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- * E-mail: (NJC); (TJM)
| | - Andrea M. Mitchell
- Institute of Microbiology and Infection and School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Katherine A. Gould
- Bacterial Microarray Group, Division of Clinical Sciences, St. George's Hospital, University of London, London, United Kingdom
| | - Donald Inverarity
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Lars Barquist
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Theresa Feltwell
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Maria C. Fookes
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Simon R. Harris
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Janina Dordel
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Susannah J. Salter
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Sarah Browall
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Dept. of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | | | - Julian Parkhill
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Staffan Normark
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Dept. of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Dept. of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Jason Hinds
- Bacterial Microarray Group, Division of Clinical Sciences, St. George's Hospital, University of London, London, United Kingdom
| | - Tim J. Mitchell
- Institute of Microbiology and Infection and School of Immunity and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- * E-mail: (NJC); (TJM)
| | - Stephen D. Bentley
- Pathogen Genomics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
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17
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Browall S, Norman M, Tångrot J, Galanis I, Sjöström K, Dagerhamn J, Hellberg C, Pathak A, Spadafina T, Sandgren A, Bättig P, Franzén O, Andersson B, Örtqvist Å, Normark S, Henriques-Normark B. Intraclonal variations among Streptococcus pneumoniae isolates influence the likelihood of invasive disease in children. J Infect Dis 2013; 209:377-88. [PMID: 24009156 PMCID: PMC4014860 DOI: 10.1093/infdis/jit481] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Background. Pneumococcal serotypes are represented by
a varying number of clonal lineages with different genetic contents, potentially affecting
invasiveness. However, genetic variation within the same genetic lineage may be larger
than anticipated. Methods. A total of 715 invasive and carriage isolates
from children in the same region and during the same period were compared using
pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Bacterial genome
sequencing, functional assays, and in vivo virulence mice studies were performed. Results. Clonal types of the same serotype but also
intraclonal variants within clonal complexes (CCs) showed differences in invasive-disease
potential. CC138, a common CC, was divided into several PFGE patterns, partly explained by
number, location, and type of temperate bacteriophages. Whole-genome sequencing of 4 CC138
isolates representing PFGE clones with different invasive-disease potentials revealed
intraclonal sequence variations of the virulence-associated proteins pneumococcal surface
protein A (PspA) and pneumococcal choline-binding protein C (PspC). A carrier isolate
lacking PcpA exhibited decreased virulence in mice, and there was a differential binding
of human factor H, depending on invasiveness. Conclusions. Pneumococcal clonal types but also
intraclonal variants exhibited different invasive-disease potentials in children.
Intraclonal variants, reflecting different prophage contents, showed differences in major
surface antigens. This suggests ongoing immune selection, such as that due to
PspC-mediated complement resistance through varied human factor H binding, that may affect
invasiveness in children.
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18
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Kuri T, Sörensen AS, Thomas S, Karlsson Hedestam GB, Normark S, Henriques-Normark B, McInerney GM, Plant L. Influenza A virus-mediated priming enhances cytokine secretion by human dendritic cells infected with Streptococcus pneumoniae. Cell Microbiol 2013; 15:1385-400. [PMID: 23421931 PMCID: PMC3798092 DOI: 10.1111/cmi.12122] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 01/23/2013] [Accepted: 02/04/2013] [Indexed: 12/22/2022]
Abstract
Secondary infections with Streptococcus pneumoniae (SP) are frequently observed following influenza A virus (IAV) infection and have a substantial impact on global health. Despite this, the basis for the disease progression is incompletely understood. To investigate the effect of co-infection on human monocyte-derived dendritic cells (MDDCs) we analysed the expression of clinically important pro-inflammatory and immune-modulatory cytokines. IAV infection or treatment with supernatants from IAV-infected cell cultures resulted in priming of the DCs which subsequently influenced the production of IL-12p70, as well as IL-6, following SP infection. Co-infection of the same cell was not required but this effect was dependent on the time, dose and duration of the infections, as well as pathogen viability, bacterial uptake and endosome acidification. Bacterially infected cells were characterized as the main producers of IL-12p70. Finally, we showed that type I interferons were primarily responsible for the priming of IL-12p70 that was observed by infection with IAV. These results provide a probable mechanism for the elevated levels of particular cytokines observed in IAV and SP co-infected cell cultures with implications for the pathogenic outcome observed during in vivo infection.
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Affiliation(s)
- Thomas Kuri
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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19
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Mellroth P, Daniels R, Eberhardt A, Rönnlund D, Blom H, Widengren J, Normark S, Henriques-Normark B. LytA, major autolysin of Streptococcus pneumoniae, requires access to nascent peptidoglycan. J Biol Chem 2012; 287:11018-29. [PMID: 22334685 PMCID: PMC3322828 DOI: 10.1074/jbc.m111.318584] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The pneumococcal autolysin LytA is a virulence factor involved in autolysis as well as in fratricidal- and penicillin-induced lysis. In this study, we used biochemical and molecular biological approaches to elucidate which factors control the cytoplasmic translocation and lytic activation of LytA. We show that LytA is mainly localized intracellularly, as only a small fraction was found attached to the extracellular cell wall. By manipulating the extracellular concentration of LytA, we found that the cells were protected from lysis during exponential growth, but not in the stationary phase, and that a defined threshold concentration of extracellular LytA dictates the onset of autolysis. Stalling growth through nutrient depletion, or the specific arrest of cell wall synthesis, sensitized cells for LytA-mediated lysis. Inhibition of cell wall association via the choline binding domain of an exogenously added enzymatically inactive form of LytA revealed a potential substrate for the amidase domain within the cell wall where the formation of nascent peptidoglycan occurs.
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Affiliation(s)
- Peter Mellroth
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, 17177 Stockholm, Sweden.
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20
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Zheng Z, Andersson AF, Ye W, Nyrén O, Normark S, Engstrand L. A method for metagenomics of Helicobacter pylori from archived formalin-fixed gastric biopsies permitting longitudinal studies of carcinogenic risk. PLoS One 2011; 6:e26442. [PMID: 22031833 PMCID: PMC3198776 DOI: 10.1371/journal.pone.0026442] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 09/27/2011] [Indexed: 12/22/2022] Open
Abstract
The human microbiota has come into focus in the search for component causes of chronic diseases, such as gastrointestinal cancers. Presumably long induction periods and altered local environments after disease onset call for the development of methods for characterization of microorganisms colonizing the host decades before disease onset. Sequencing of microbial genomes in old formalin-fixed and paraffin-embedded (FFPE) gastrointestinal biopsies provides a means for such studies but is still challenging. Here we report a method based on laser capture micro-dissection and modified Roche 454 high-throughput pyrosequencing to obtain metagenomic profiles of Helicobacter pylori. We applied this method to two 15 year old FFPE biopsies from two patients. Frozen homogenized biopsies from the same gastroscopy sessions were also available for comparison after re-culture of H. pylori. For both patients, H. pylori DNA dissected from FFPE sections had ∼96.4% identity with culture DNA from the same patients, while only ∼92.5% identity with GenBank reference genomes, and with culture DNA from the other patient. About 82% and 60% of the predicted genes in the two genomes were captured by at least a single sequencing read. Along with sequences displaying high similarity to known H. pylori genes, novel and highly variant H. pylori sequences were identified in the FFPE sections by our physical enrichment approach, which would likely not have been detected by a sequence capture approach. The study demonstrates the feasibility of longitudinal metagenomic studies of H. pylori using decade-preserved FFPE biopsies.
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Affiliation(s)
- Zongli Zheng
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Anders F. Andersson
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Weimin Ye
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Olof Nyrén
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Swedish Institute for Communicable Disease Control, Solna, Sweden
| | - Lars Engstrand
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Swedish Institute for Communicable Disease Control, Solna, Sweden
- * E-mail:
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21
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Bergman P, Linde C, Pütsep K, Pohanka A, Normark S, Henriques-Normark B, Andersson J, Björkhem-Bergman L. Studies on the antibacterial effects of statins--in vitro and in vivo. PLoS One 2011; 6:e24394. [PMID: 21912631 PMCID: PMC3166163 DOI: 10.1371/journal.pone.0024394] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 08/09/2011] [Indexed: 11/18/2022] Open
Abstract
Background Statin treatment has been associated with a beneficial outcome on respiratory tract infections. In addition, previous in vitro and in vivo experiments have indicated favorable effects of statins in bacterial infections. Aim The aim of the present study was to elucidate possible antibacterial effects of statins against primary pathogens of the respiratory tract. Methods MIC-values for simvastatin, fluvastatin and pravastatin against S. pneumoniae, M. catarrhalis and H. influenzae were determined by traditional antibacterial assays. A BioScreen instrument was used to monitor effects of statins on bacterial growth and to assess possible synergistic effects with penicillin. Bacterial growth in whole blood and serum from healthy volunteers before and after a single dose of simvastatin, fluvastatin and penicillin (positive control) was determined using a blood culture system (BactAlert). Findings The MIC-value for simvastatin against S pneumoniae and M catarrhalis was 15 µg/mL (36 mmol/L). Fluvastatin and Pravastatin showed no antibacterial effect in concentrations up to 100 µg/mL (230 µmol/L). Statins did not affect growth or viability of H influenzae. Single doses of statins given to healthy volunteers did not affect growth of pneumococci, whereas penicillin efficiently killed all bacteria. Conclusions Simvastatin at high concentrations 15 µg/mL (36 µmol/L) rapidly kills S pneumoniae and M catarrhalis. However, these concentrations by far exceed the concentrations detected in human blood during simvastatin therapy (1–15 nmol/L) and single doses of statins given to healthy volunteers did not improve antibacterial effects of whole blood. Thus, a direct bactericidal effect of statins in vivo is probably not the mechanism behind the observed beneficial effect of statins against various infections.
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Affiliation(s)
- Peter Bergman
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
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22
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Hagström A, Larsson U, Hörstedt P, Normark S. Frequency of dividing cells, a new approach to the determination of bacterial growth rates in aquatic environments. Appl Environ Microbiol 2010; 37:805-12. [PMID: 16345378 PMCID: PMC243306 DOI: 10.1128/aem.37.5.805-812.1979] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Frequency of dividing cells is suggested to be an indirect measure of the mean growth rate of an aquatic bacterial community. Seasonal changes in frequency of dividing cells were found which covariated with the bacterial uptake of C-labeled phytoplankton exudates. Batch and continuous culture growth experiments, using brackish water bacteria in pure and mixed enrichment cultures, were performed to establish a relationship between frequency of dividing cells and growth rate. An improved technique for bacterial direct counts, using fluorescent staining and epifluorescence microscopy, is presented. Based on a 6-month survey in a coastal area of the Baltic Sea, the bacterial production in the photic zone is estimated. Compared to the total primary production in the area, the bacterial population during this period utilized approximately 25% of the amount of carbon originally fixed by the primary producers.
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Affiliation(s)
- A Hagström
- The National Environmental Protection Board, Brackish Water Toxicology Laboratory, Studsvik, S-611 01 Nyköping
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23
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Wikner J, Andersson A, Normark S, Hagström A. Use of genetically marked minicells as a probe in measurement of predation on bacteria in aquatic environments. Appl Environ Microbiol 2010; 52:4-8. [PMID: 16347116 PMCID: PMC203384 DOI: 10.1128/aem.52.1.4-8.1986] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Minicells produced by Escherichia coli M2141 were used as probes to measure predation on pelagic bacteria in situ. The minicells, labeled with [S]methionine in one specific protein, were shown to disappear in the presence of a microflagellate (Ochromonas sp.), as seen by a decrease in the amount of labeled marker protein with time. Incubation in filtered (pore size, 0.2 mum) and autoclaved seawater did not affect the amount of labeled marker protein in the minicell. The generation time of flagellates feeding on minicells was determined to be similar to that found for flagellates grown on seawater bacteria or living E. coli NC3. Data indicate that minicells are seen as true food particles by the flagellates. The minicell probe was used in recapture experiments, in which predation in situ on pelagic bacteria was demonstrated. The rate of bacterial production showed a clear covariation with the rate of predation, both in different sea areas and in depth profiles. The obtained results (11 field experiments) showed that the rate of predation, on average, accounts for the consumption of 62% of the bacteria produced.
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Affiliation(s)
- J Wikner
- Department of Microbiology, University of Umeå, S-901 87 Umeå, Sweden
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24
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Henriques-Normark B, Normark S. Commensal pathogens, with a focus on Streptococcus pneumoniae, and interactions with the human host. Exp Cell Res 2010; 316:1408-14. [PMID: 20227406 DOI: 10.1016/j.yexcr.2010.03.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/05/2010] [Indexed: 01/29/2023]
Abstract
Many important pathogens have humans as their normal ecological niche where healthy carriage dominates over disease. The ability of these commensal pathogens, such as Streptococcus pneumoniae, to cause disease depends on a series of microbial factors as well as of genetic and environmental factors in the human host affecting the clearing capacity mediated by the innate and adaptive immune system. This delicate interplay between microbe and host affects not only the likelihood for a commensal pathogen to cause disease, but also disease type and disease severity.
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25
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Littmann M, Albiger B, Frentzen A, Normark S, Henriques-Normark B, Plant L. Streptococcus pneumoniae evades human dendritic cell surveillance by pneumolysin expression. EMBO Mol Med 2010; 1:211-22. [PMID: 20049723 PMCID: PMC3378134 DOI: 10.1002/emmm.200900025] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dendritic cells (DCs) protect the respiratory epithelium via induction of innate immune responses and priming of naïve T cells during the initiation of adaptive immunity. Streptococcus pneumoniae, a commonly carried asymptomatic member of the human nasopharyngeal microflora, can cause invasive and inflammatory diseases and the cholesterol-dependent cytotoxin pneumolysin is a major pneumococcal virulence factor implicated in compounding tissue damage and mediating inflammatory responses. While most studies examining the impact of pneumolysin have been based on murine models, we have focused this study on human DC responses. We show that expression of haemolytic pneumolysin inhibits human DC maturation, induction of proinflammatory cytokines and activation of the inflammasome. Furthermore, intracellular production of pneumolysin induces caspase-dependent apoptosis in infected DCs. Similarly, clinical isolates with non-haemolytic pneumolysin were more proinflammatory and caused less apoptosis compared to clonally related strains with active pneumolysin. This study describes a novel role of pneumolysin in the evasion of human DC surveillance that could have a profound clinical impact upon inflammatory disease progression and highlights the need to study human responses to human-specific pathogens.
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Affiliation(s)
- Marie Littmann
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, Stockholm SE-171 77, Sweden
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26
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Zheng Z, Andersson AF, Ye W, Nyr�n O, Normark S, Engstrand L. Metagenomic study of Helicobacter pylori microdissected from archived formalin-fixed paraffin-embedded biopsy sections. Genome Biol 2010. [PMCID: PMC3026273 DOI: 10.1186/gb-2010-11-s1-p42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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27
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Daniels R, Mellroth P, Bernsel A, Neiers F, Normark S, von Heijne G, Henriques-Normark B. Disulfide bond formation and cysteine exclusion in gram-positive bacteria. J Biol Chem 2009; 285:3300-9. [PMID: 19940132 PMCID: PMC2823432 DOI: 10.1074/jbc.m109.081398] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Most secretion pathways in bacteria and eukaryotic cells are challenged by the requirement for their substrate proteins to mature after they traverse a membrane barrier and enter a reactive oxidizing environment. For Gram-positive bacteria, the mechanisms that protect their exported proteins from misoxidation during their post-translocation maturation are poorly understood. To address this, we separated numerous bacterial species according to their tolerance for oxygen and divided their proteomes based on the predicted subcellular localization of their proteins. We then applied a previously established computational approach that utilizes cysteine incorporation patterns in proteins as an indicator of enzymatic systems that may exist in each species. The Sec-dependent exported proteins from aerobic Gram-positive Actinobacteria were found to encode cysteines in an even-biased pattern indicative of a functional disulfide bond formation system. In contrast, aerobic Gram-positive Firmicutes favor the exclusion of cysteines from both their cytoplasmic proteins and their substantially longer exported proteins. Supporting these findings, we show that Firmicutes, but not Actinobacteria, tolerate growth in reductant. We further demonstrate that the actinobacterium Corynebacterium glutamicum possesses disulfide-bonded proteins and two dimeric Dsb-like enzymes that can efficiently catalyze the formation of disulfide bonds. Our results suggest that cysteine exclusion is an important adaptive strategy against the challenges presented by oxidative environments.
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Affiliation(s)
- Robert Daniels
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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28
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Neiers F, Madhurantakam C, Fälker S, Manzano C, Dessen A, Normark S, Henriques-Normark B, Achour A. Two crystal structures of pneumococcal pilus sortase C provide novel insights into catalysis and substrate specificity. J Mol Biol 2009; 393:704-16. [PMID: 19729023 DOI: 10.1016/j.jmb.2009.08.058] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 08/24/2009] [Accepted: 08/25/2009] [Indexed: 01/28/2023]
Abstract
The respiratory tract pathogen Streptococcus pneumoniae is a primary cause of morbidity and mortality worldwide. Pili enhance initial adhesion as well as the capacity of pneumococci to cause pneumonia and bacteremia. Pilus-associated sortases (SrtB, SrtC, and SrtD) are involved in the biogenesis of pneumococcal pili, composed of repeating units of RrgB that create the stalk to which the RrgA adhesin and the preferential pilus tip subunit RrgC are covalently associated. Using single sortase-expressing strains, we demonstrate that both pilin-polymerizing sortases SrtB and SrtC can covalently link pili to the peptidoglycan cell wall, a property shared with the non-pilus-polymerizing enzyme SrtD and the housekeeping sortase SrtA. Comparative analysis of the crystal structures of S. pneumoniae SrtC and SrtB revealed structural differences explaining the incapacity of SrtC, but not of SrtB, to incorporate RrgC into the pilus. Accordingly, site-directed mutagenesis of Thr(160) in SrtB to an arginine as in SrtC (Arg(160)) partially converted its substrate specificity into that of SrtC. Solving two crystal structures for SrtC suggests that an opening of a flexible lid and a concomitant cysteine rotation are important for catalysis and the activation of the catalytic cysteine of pilus-associated sortases.
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Affiliation(s)
- Fabrice Neiers
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
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29
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Normark S, Boman HG, Bloom GD. Cell division in a chain-forming envA mutant of Escherichia coli K12. Fine structure of division sites and effects of EDTA, lysozyme and ampicillin. Acta Pathol Microbiol Scand B Microbiol Immunol 2009; 79:651-64. [PMID: 4999789 DOI: 10.1111/j.1699-0463.1971.tb00093.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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30
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Kline KA, Fälker S, Dahlberg S, Normark S, Henriques-Normark B. Bacterial adhesins in host-microbe interactions. Cell Host Microbe 2009; 5:580-92. [PMID: 19527885 DOI: 10.1016/j.chom.2009.05.011] [Citation(s) in RCA: 406] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 05/23/2009] [Accepted: 05/27/2009] [Indexed: 02/09/2023]
Abstract
Most commensal and pathogenic bacteria interacting with eukaryotic hosts express adhesive molecules on their surfaces that promote interaction with host cell receptors or with soluble macromolecules. Even though bacterial attachment to epithelial cells may be beneficial for bacterial colonization, adhesion may come at a cost because bacterial attachment to immune cells can facilitate phagocytosis and clearing. Many pathogenic bacteria have solved this dilemma by producing an antiphagocytic surface layer usually consisting of polysaccharide and by expressing their adhesins on polymeric structures that extend out from the cell surface. In this review, we will focus on the interaction between bacterial adhesins and the host, with an emphasis on pilus-like structures.
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Affiliation(s)
- Kimberly A Kline
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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31
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Skoglund A, Bäckhed HK, Nilsson C, Björkholm B, Normark S, Engstrand L. A changing gastric environment leads to adaptation of lipopolysaccharide variants in Helicobacter pylori populations during colonization. PLoS One 2009; 4:e5885. [PMID: 19517017 PMCID: PMC2690825 DOI: 10.1371/journal.pone.0005885] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 05/14/2009] [Indexed: 12/13/2022] Open
Abstract
The human gastric pathogen Helicobacter pylori colonizes the stomachs of half of the human population, and causes development of peptic ulcer disease and gastric adenocarcinoma. H. pylori-associated chronic atrophic gastritis (ChAG) with loss of the acid-producing parietal cells, is correlated with an increased risk for development of gastric adenocarcinoma. The majority of H. pylori isolates produce lipopolysaccharides (LPS) decorated with human-related Lewis epitopes, which have been shown to phase-vary in response to different environmental conditions. We have characterized the adaptations of H. pylori LPS and Lewis antigen expression to varying gastric conditions; in H. pylori isolates from mice with low or high gastric pH, respectively; in 482 clinical isolates from healthy individuals and from individuals with ChAG obtained at two time points with a four-year interval between endoscopies; and finally in isolates grown at different pH in vitro. Here we show that the gastric environment can contribute to a switch in Lewis phenotype in the two experimental mouse models. The clinical isolates from different human individuals showed that intra-individual isolates varied in Lewis antigen expression although the LPS diversity was relatively stable within each individual over time. Moreover, the isolates demonstrated considerable diversity in the levels of glycosylation and in the sizes of fucosylated O-antigen chains both within and between individuals. Thus our data suggest that different LPS variants exist in the colonizing H. pylori population, which can adapt to changes in the gastric environment and provide a means to regulate the inflammatory response of the host during disease progression.
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Affiliation(s)
- Anna Skoglund
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Helene Kling Bäckhed
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Christina Nilsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Solna, Sweden
| | | | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Lars Engstrand
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden
- Swedish Institute for Infectious Disease Control, Solna, Sweden
- * E-mail:
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Muschiol S, Normark S, Henriques-Normark B, Subtil A. Small molecule inhibitors of the Yersinia type III secretion system impair the development of Chlamydia after entry into host cells. BMC Microbiol 2009; 9:75. [PMID: 19383140 PMCID: PMC2679026 DOI: 10.1186/1471-2180-9-75] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 04/21/2009] [Indexed: 01/07/2023] Open
Abstract
Background Chlamydiae are obligate intracellular pathogens that possess a type III secretion system to deliver proteins into the host cell during infection. Small molecule inhibitors of type III secretion in Yersinia, termed INPs (Innate Pharmaceuticals AB) were reported to strongly inhibit Chlamydia growth in epithelial cells. In this study we have analyzed the effect of these drugs on bacterial invasiveness. Results We demonstrate that INPs affect Chlamydia growth in a dose dependent manner after bacterial invasion. The efficiency of C. trachomatis L2 and C. caviae GPIC entry into host cells was not altered in the presence of INPs. In C. caviae, entry appears to proceed normally with recruitment of actin and the small GTPases Rac, Cdc42 and Arf6 to the site of bacterial entry. Conclusion INPs have a strong inhibitory effect on Chlamydia growth. However, bacterial invasion is not altered in the presence of these drugs. In the light of these results, we discuss several hypotheses regarding the mode of action of INPs on type III secretion during the Chlamydia infectious cycle.
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Affiliation(s)
- Sandra Muschiol
- Institut Pasteur, Unité de Biologie des Interactions Cellulaires, CNRS URA 2582, Paris, France.
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Blomberg C, Dagerhamn J, Dahlberg S, Browall S, Fernebro J, Albiger B, Morfeldt E, Normark S, Henriques-Normark B. Pattern of Accessory Regions and Invasive Disease Potential inStreptococcus pneumoniae. J Infect Dis 2009; 199:1032-42. [PMID: 19203261 DOI: 10.1086/597205] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- C Blomberg
- Swedish Institute for Infectious Disease Control, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
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Persson OP, Pinhassi J, Riemann L, Marklund BI, Rhen M, Normark S, González JM, Hagström A. High abundance of virulence gene homologues in marine bacteria. Environ Microbiol 2009; 11:1348-57. [PMID: 19207573 PMCID: PMC2702493 DOI: 10.1111/j.1462-2920.2008.01861.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Marine bacteria can cause harm to single-celled and multicellular eukaryotes. However, relatively little is known about the underlying genetic basis for marine bacterial interactions with higher organisms. We examined whole-genome sequences from a large number of marine bacteria for the prevalence of homologues to virulence genes and pathogenicity islands known from bacteria that are pathogenic to terrestrial animals and plants. As many as 60 out of 119 genomes of marine bacteria, with no known association to infectious disease, harboured genes of virulence-associated types III, IV, V and VI protein secretion systems. Type III secretion was relatively uncommon, while type IV was widespread among alphaproteobacteria (particularly among roseobacters) and type VI was primarily found among gammaproteobacteria. Other examples included homologues of the Yersinia murine toxin and a phage-related ‘antifeeding’ island. Analysis of the Global Ocean Sampling metagenomic data indicated that virulence genes were present in up to 8% of the planktonic bacteria, with highest values in productive waters. From a marine ecology perspective, expression of these widely distributed genes would indicate that some bacteria infect or even consume live cells, that is, generate a previously unrecognized flow of organic matter and nutrients directly from eukaryotes to bacteria.
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Affiliation(s)
- Olof P Persson
- Marine Microbiology, Department of Natural Sciences, University of Kalmar, Kalmar, Sweden
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Neiers F, Madhurantakam C, Fälker S, Normark S, Henriques-Normark B, Achour A. Cloning, expression, purification, crystallization and preliminary X-ray analysis of the pilus-associated sortase C from Streptococcus pneumoniae. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:55-8. [PMID: 19153457 PMCID: PMC2628848 DOI: 10.1107/s1744309108040025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Accepted: 11/27/2008] [Indexed: 11/10/2022]
Abstract
The pilus-associated sortase C from Streptococcus pneumoniae (SrtC or Srt-2) acts as a polymerase for the pilus subunit proteins RrgA and RrgB. Here, the crystallization and preliminary X-ray diffraction analysis of three crystal forms of SrtC are reported. One crystal form belongs to space group P2(1)2(1)2(1), with unit-cell parameters a = 48.9, b = 96.9, c = 98.9 A, alpha = beta = gamma = 90 degrees . The other two crystal forms belong to space group P222, with unit-cell parameters a = 48.8, b = 97.2, c = 99.2 A, alpha = beta = gamma = 90 degrees and a = 48.6, b = 96.5, c = 98.8 A, alpha = beta = gamma = 90 degrees , respectively. Preliminary analysis indicates the presence of two molecules in the asymmetric unit of the crystal for all three forms.
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Affiliation(s)
- F. Neiers
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, SE-171 77 Solna, Sweden
- Centre for Infectious Medicine, F59, Department of Medicine Huddinge, Karolinska University Hospital Huddinge, Karolinska Institutet, SE-141 86 Stockholm, Sweden
| | - C. Madhurantakam
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, SE-171 77 Solna, Sweden
- Centre for Infectious Medicine, F59, Department of Medicine Huddinge, Karolinska University Hospital Huddinge, Karolinska Institutet, SE-141 86 Stockholm, Sweden
| | - S. Fälker
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, SE-171 77 Solna, Sweden
| | - S. Normark
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, SE-171 77 Solna, Sweden
| | - B. Henriques-Normark
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, SE-171 77 Solna, Sweden
| | - A. Achour
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, SE-171 77 Solna, Sweden
- Centre for Infectious Medicine, F59, Department of Medicine Huddinge, Karolinska University Hospital Huddinge, Karolinska Institutet, SE-141 86 Stockholm, Sweden
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Nilsson C, Skoglund A, Moran AP, Annuk H, Engstrand L, Normark S. Lipopolysaccharide diversity evolving in Helicobacter pylori communities through genetic modifications in fucosyltransferases. PLoS One 2008; 3:e3811. [PMID: 19043574 PMCID: PMC2583950 DOI: 10.1371/journal.pone.0003811] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 11/04/2008] [Indexed: 01/16/2023] Open
Abstract
Helicobacter pylori persistently colonizes the gastric mucosa of half the human population. It is one of the most genetically diverse bacterial organisms and subvariants are continuously emerging within an H. pylori population. In this study we characterized a number of single-colony isolates from H. pylori communities in various environmental settings, namely persistent human gastric infection, in vitro bacterial subcultures on agar medium, and experimental in vivo infection in mice. The lipopolysaccharide (LPS) O-antigen chain revealed considerable phenotypic diversity between individual cells in the studied bacterial communities, as demonstrated by size variable O-antigen chains and different levels of Lewis glycosylation. Absence of high-molecular-weight O-antigen chains was notable in a number of experimentally passaged isolates in vitro and in vivo. This phenotype was not evident in bacteria obtained from a human gastric biopsy, where all cells expressed high-molecular-weight O-antigen chains, which thus may be the preferred phenotype for H. pylori colonizing human gastric mucosa. Genotypic variability was monitored in the two genes encoding α1,3-fucosyltransferases, futA and futB, that are involved in Lewis antigen expression. Genetic modifications that could be attributable to recombination events within and between the two genes were commonly detected and created a diversity, which together with phase variation, contributed to divergent LPS expression. Our data suggest that the surrounding environment imposes a selective pressure on H. pylori to express certain LPS phenotypes. Thus, the milieu in a host will select for bacterial variants with particular characteristics that facilitate adaptation and survival in the gastric mucosa of that individual, and will shape the bacterial community structure.
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Affiliation(s)
- Christina Nilsson
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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Henriques-Normark B, Blomberg C, Dagerhamn J, Bättig P, Normark S. The rise and fall of bacterial clones: Streptococcus pneumoniae. Nat Rev Microbiol 2008; 6:827-37. [DOI: 10.1038/nrmicro2011] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Fälker S, Nelson AL, Morfeldt E, Jonas K, Hultenby K, Ries J, Melefors O, Normark S, Henriques-Normark B. Sortase-mediated assembly and surface topology of adhesive pneumococcal pili. Mol Microbiol 2008; 70:595-607. [PMID: 18761697 PMCID: PMC2680257 DOI: 10.1111/j.1365-2958.2008.06396.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The rlrA genetic islet encodes an extracellular pilus in the Gram-positive pathogen Streptococcus pneumoniae. Of the three genes for structural subunits, rrgB encodes the major pilin, while rrgA and rrgC encode ancillary pilin subunits decorating the pilus shaft and tip. Deletion of all three pilus-associated sortase genes, srtB, srtC and srtD, completely prevents pilus biogenesis. Expression of srtB alone is sufficient to covalently associate RrgB subunits to one another as well as linking the RrgA adhesin and the RrgC subunit into the polymer. The active-site cysteine residue of SrtB (Cys 177) is crucial for incorporating RrgC, even when the two other sortase genes are expressed. SrtC is redundant to SrtB in permitting RrgB polymerization, and in linking RrgA to the RrgB filament, but SrtC is insufficient to incorporate RrgC. In contrast, expression of srtD alone fails to mediate RrgB polymerization, and a srtD mutant assembles heterotrimeric pilus indistinguishable from wild type. Topological studies demonstrate that pilus antigens are localized to symmetric foci at the cell surface in the presence of all three sortases. This symmetric focal presentation is abrogated in the absence of either srtB or srtD, while deletion of srtC had no effect. In addition, strains expressing srtB alone or srtC alone also displayed disrupted antigen localization, despite polymerizing subunits. Our data suggest that both SrtB and SrtC act as pilus subunit polymerases, with SrtB processing all three pilus subunit proteins, while SrtC only RrgB and RrgA. In contrast, SrtD does not act as a pilus subunit polymerase, but instead is required for wild-type focal presentation of the pilus at the cell surface.
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Affiliation(s)
- Stefan Fälker
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
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Abstract
The chaperone/usher pathway is responsible for the assembly of adhesive pili on the surface of gram-negative pathogenic bacteria. In this issue, Remaut et al. (2008) present the crystal structure of the PapC usher translocation domain and images of the FimD usher bound to a pilus translocation intermediate. These new structures provide the first detailed view of a translocase in action.
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Affiliation(s)
- Robert Daniels
- Swedish Institute for Infectious Disease Control, 171 82 Solna, Sweden
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Moschioni M, Donati C, Muzzi A, Masignani V, Censini S, Hanage WP, Bishop CJ, Reis JN, Normark S, Henriques-Normark B, Covacci A, Rappuoli R, Barocchi MA. Streptococcus pneumoniae contains 3 rlrA pilus variants that are clonally related. J Infect Dis 2008; 197:888-96. [PMID: 18269316 DOI: 10.1086/528375] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Pilus components of Streptococcus pneumoniae encoded by rlrA were recently shown to elicit protection in an animal model of infection. Limited data are available on the prevalence of the rlrA operon in pneumococci; therefore, we investigated its distribution and its antigenic variation among disease-causing strains. METHODS The prevalence of rlrA and its association with serotype and genotype were evaluated in a global panel of 424 pneumococci isolates (including the 26 drug-resistant clones described by the Pneumococcal Molecular Epidemiology Network). RESULTS The rlrA islet was found in 130 isolates (30.6%) of the defined collection. Sequence alignment of 15 rlrA islets defined the presence of 3 clade types, with an overall homology of 88%-92%. The presence or absence of a pilus-encoding operon correlated with S. pneumoniae genotype (P < .001), as determined by multilocus sequence typing, and not with serotype. Further investigation identified a positive trend of rlrA occurrence among antimicrobial-resistant pneumococci. CONCLUSIONS On the basis of S. pneumoniae genotype, it is possible to predict the incidence of the rlrA pilus operon in a collection of pneumococcal isolates. This will facilitate the development of a protein vaccine.
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Fernebro J, Blomberg C, Morfeldt E, Wolf-Watz H, Normark S, Normark BH. The influence of in vitro fitness defects on pneumococcal ability to colonize and to cause invasive disease. BMC Microbiol 2008; 8:65. [PMID: 18423011 PMCID: PMC2375889 DOI: 10.1186/1471-2180-8-65] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 04/18/2008] [Indexed: 11/16/2022] Open
Abstract
Background Streptococcus pneumoniae is a genetically diverse major human pathogen, yet a common colonizer of the nasopharynx. Here we analyzed the influence of defects affecting in vitro growth rate, on the ability of S. pneumoniae to colonize and to cause invasive disease in vivo. Results Of eleven different clinical isolates one serotype 14 carrier isolate showed a significantly longer generation time as compared to other isolates, and was severely attenuated in mice. To directly investigate the impact of growth rate on virulence, a panel of mutants in five non-essential housekeeping genes was constructed in the virulent TIGR4 background by insertion-deletion mutagenesis. Three of these mutants (ychF, hemK and yebC) were, to different degrees, growth defective, and showed a reduced invasiveness in an intranasal murine challenge model that correlated to their in vitro growth rate, but remained capable of colonizing the upper airways. The growth defect, as well as virulence defect of the hemK insertion-deletion mutant, was mediated by polarity effects on the downstream yrdC gene, encoding a probable chaperone in ribosome assembly. Conclusion We conclude that large fitness defects are needed to completely prevent pneumococci from causing invasive disease after intranasal challenge. However, even severe growth defects still allow pneumococci to persistently colonize the upper airways.
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Affiliation(s)
- Jenny Fernebro
- Swedish Institute for Infectious Disease Control, 171 82 Solna, Sweden.
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Meyer-Hoffert U, Hornef M, Henriques-Normark B, Normark S, Andersson M, Pütsep K. Identification of heparin/heparan sulfate interacting protein as a major broad-spectrum antimicrobial protein in lung and small intestine. FASEB J 2008; 22:2427-34. [PMID: 18299334 DOI: 10.1096/fj.07-103440] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The lungs are continuously exposed to a broad array of microbes through inhalation, and microorganisms that escape clearance by the upper airway mucociliary motion will deposit in the alveolar compartment of the lower airways. The pulmonary epithelium in the alveolar compartment is covered by a thin aqueous layer that contains surfactant proteins but also microbicidal components. We have here identified the epithelial cell surface-expressed heparin/heparan sulfate interacting protein (HIP/RPL29) by high-performance liquid chromatography-fractionation, N-terminal sequencing, and mass spectrometry analysis as a major antimicrobial component in extracts of mouse lung tissue. HIP/RPL29 was also detected in extracts of mouse small intestinal tissue. HIP/RPL29 exhibited broad antibacterial activity, notably against Pseudomonas aeruginosa strains. Human recombinant HIP/RPL29 exhibited killing activity in the same order of magnitude. The HIP/RPL29 protein was demonstrated to be localized to the epithelial cells and cell surface of the lungs and intestines by immunohistochemistry. We suggest that HIP/RPL29 fulfills a function as an abundant antibacterial factor of the epithelial innate defense shield against invading bacteria in both the lungs and the small intestine.
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Affiliation(s)
- Ulf Meyer-Hoffert
- Department of Microbiology Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden.
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Nelson AL, Ries J, Bagnoli F, Dahlberg S, Fälker S, Rounioja S, Tschöp J, Morfeldt E, Ferlenghi I, Hilleringmann M, Holden DW, Rappuoli R, Normark S, Barocchi MA, Henriques-Normark B. RrgA is a pilus-associated adhesin in Streptococcus pneumoniae. Mol Microbiol 2007; 66:329-40. [PMID: 17850254 PMCID: PMC2170534 DOI: 10.1111/j.1365-2958.2007.05908.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Adherence to host cells is important in microbial colonization of a mucosal surface, and Streptococcus pneumoniae adherence was significantly enhanced by expression of an extracellular pilus composed of three subunits, RrgA, RrgB and RrgC. We sought to determine which subunit(s) confers adherence. Bacteria deficient in RrgA are significantly less adherent than wild-type organisms, while overexpression of RrgA enhances adherence. Recombinant monomeric RrgA binds to respiratory cells, as does RrgC with less affinity, and pre-incubation of epithelial cells with RrgA reduces adherence of wild-type piliated pneumococci. Non-adherent RrgA-negative, RrgB- and RrgC-positive organisms produce pili, suggesting that pilus-mediated adherence is due to expression of RrgA, rather than the pilus backbone itself. In contrast, RrgA-positive strains with disrupted rrgB and rrgC genes exhibit wild-type adherence despite failure to produce pili by Western blot or immunoelectron microscopy. The density of bacteria colonizing the upper respiratory tract of mice inoculated with piliated RrgA-negative pneumococci was significantly less compared with wild-type; in contrast, non-piliated pneumococci expressing non-polymeric RrgA had similar numbers of bacteria in the nasopharynx as piliated wild-type bacteria. These data suggest that RrgA is central in pilus-mediated adherence and disease, even in the absence of polymeric pilus production.
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Affiliation(s)
- A L Nelson
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | - J Ries
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | | | - S Dahlberg
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | - S Fälker
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | - S Rounioja
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | - J Tschöp
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | - E Morfeldt
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | | | | | - D W Holden
- Centre for Molecular Microbiology and Infection, Imperial CollegeLondon, UK
| | | | - S Normark
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
| | | | - B Henriques-Normark
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska InstitutetStockholm, Sweden
- E-mail ; Tel. (+46) 8 457 24 13; Fax (+46) 8 30 25 66
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Sjöström K, Blomberg C, Fernebro J, Dagerhamn J, Morfeldt E, Barocchi MA, Browall S, Moschioni M, Andersson M, Henriques F, Albiger B, Rappuoli R, Normark S, Henriques-Normark B. Clonal success of piliated penicillin nonsusceptible pneumococci. Proc Natl Acad Sci U S A 2007; 104:12907-12. [PMID: 17644611 PMCID: PMC1929012 DOI: 10.1073/pnas.0705589104] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antibiotic resistance in pneumococci is due to the spread of strains belonging to a limited number of clones. The Spain(9V)-3 clone of sequence type (ST)156 is one of the most successful clones with reduced susceptibility to penicillin [pneumococci nonsusceptible to penicillin (PNSP)]. In Sweden during 2000-2003, a dramatic increase in the number of PNSP isolates was observed. Molecular characterization of these isolates showed that a single clone of sequence type ST156 increased from 40% to 80% of all serotype 14, thus causing the serotype expansion. Additionally, during the same time period, we examined the clonal composition of two serotypes 9V and 19F: all 9V and 20% of 19F isolates belonged to the clonal cluster of ST156, and overall approximately 50% of all PNSP belonged to the ST156 clonal cluster. Moreover, microarray and PCR analysis showed that all ST156 isolates, irrespective of capsular type, carried the rlrA pilus islet. This islet was also found to be present in the penicillin-sensitive ST162 clone, which is believed to be the drug-susceptible ancestor of ST156. Competitive experiments between related ST156 serotype 19F strains confirmed that those containing the rlrA pilus islet were more successful in an animal model of carriage. We conclude that the pilus island is an important biological factor common to ST156 isolates and other successful PNSP clones. In Sweden, a country where the low antibiotic usage does not explain the spread of resistant strains, at least 70% of all PNSP isolates collected during year 2003 carried the pilus islet.
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Affiliation(s)
- K. Sjöström
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - C. Blomberg
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - J. Fernebro
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - J. Dagerhamn
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - E. Morfeldt
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
| | | | - S. Browall
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
| | | | - M. Andersson
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
| | - F. Henriques
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
| | - B. Albiger
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
- Department of Clinical Microbiology, Lund University, SE-221 00 Malmö, Sweden
| | - Rino Rappuoli
- Novartis Vaccines, 53100 Siena, Italy; and
- To whom correspondence may be addressed. E-mail: or
| | - S. Normark
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - B. Henriques-Normark
- *Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
- To whom correspondence may be addressed. E-mail: or
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Abstract
The innate immunity plays a critical role in host protection against pathogens and it relies amongst others on pattern recognition receptors such as the Toll-like receptors (TLRs) and the nucleotide-binding oligomerization domains proteins (NOD-like receptors, NLRs) to alert the immune system of the presence of invading bacteria. Since their recent discovery less than a decade ago, both TLRs and NLRs have been shown to be crucial in host protection against microbial infections but also in homeostasis of the colonizing microflora. They recognize specific microbial ligands and with the use of distinct adaptor molecules, they activate different signalling pathways that in turns trigger subsequent inflammatory and immune responses that allows a immediate response towards bacterial infections and the initiation of the long-lasting adaptive immunity. In this review, we will focus on the role of the TLRs against bacterial infections in humans in contrast to mice that have been used extensively in experimental models of infections and discuss their role in controlling normal flora or nonpathogenic bacteria. We also highlight how bacteria can evade recognition by TLRs.
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Affiliation(s)
- B Albiger
- Medical Microbiology, Department of Laboratory Medicine, Lund University, Malmö, Sweden
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Wartha F, Beiter K, Albiger B, Fernebro J, Zychlinsky A, Normark S, Henriques-Normark B. Capsule and D-alanylated lipoteichoic acids protect Streptococcus pneumoniae against neutrophil extracellular traps. Cell Microbiol 2007; 9:1162-71. [PMID: 17217430 DOI: 10.1111/j.1462-5822.2006.00857.x] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide. Pneumococci can counteract the action of neutrophils with an antiphagocytic capsule and through electrochemical repulsion of antimicrobial peptides via addition of positive charge to the surface. Pneumococci are captured, but not killed in neutrophil extracellular traps (NETs). Here, we study the role of the polysaccharide capsule and lipoteichoic acid (LTA) modification on pneumococcal interaction with NETs. Expression of capsule (serotypes 1, 2, 4 and 9V) significantly reduced trapping by NETs, but was not required for resistance to NET-mediated killing. Pneumococci contain a dlt operon that mediates the incorporation of d-alanine residues into LTAs, thereby introducing positive charge. Genetic inactivation of dltA in non-encapsulated pneumococci rendered the organism sensitive to killing by antimicrobial components present in NETs. However, the encapsulated dltA mutant remained resistant to NET-mediated killing in vitro. Nevertheless, in a murine model of pneumococcal pneumonia, the encapsulated dltA-mutant strain was outcompeted by the wild-type upon invasion into the lungs and bloodstream. This suggests a non-redundant role for LTA alanylation in pneumococcal virulence at the early stage of invasive disease when capsule expression has been shown to be low.
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Affiliation(s)
- Florian Wartha
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, Solna, Sweden
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Wartha F, Beiter K, Normark S, Henriques-Normark B. Neutrophil extracellular traps: casting the NET over pathogenesis. Curr Opin Microbiol 2007; 10:52-6. [PMID: 17208512 DOI: 10.1016/j.mib.2006.12.005] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Accepted: 12/19/2006] [Indexed: 12/31/2022]
Abstract
Neutrophil extracellular traps (NETs) are considered to be part of the human innate immunity because they trap and kill pathogens. NETs are formed by activated neutrophils and consist of a DNA backbone with embedded antimicrobial peptides and enzymes. They are involved in host defense during pneumococcal pneumonia, streptococcal necrotizing fasciitis, appendicitis and insemination. Recently, bacterial virulence factors that counteract NETs have been identified. These include the degradation of the NET-backbone by DNases enabling the liberation of bacteria from NETs, as well as capsule formation, which reduces bacterial trapping. Furthermore, pathogens can resist NET-mediated killing by adding positive charge to their cell surface.
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Affiliation(s)
- Florian Wartha
- Department of Bacteriology, Swedish Institute for Infectious Disease Control Nobelsväg 18, SE-171 82 Solna, Solna, Sweden
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Albiger B, Dahlberg S, Sandgren A, Wartha F, Beiter K, Katsuragi H, Akira S, Normark S, Henriques-Normark B. Toll-like receptor 9 acts at an early stage in host defence against pneumococcal infection. Cell Microbiol 2006; 9:633-44. [PMID: 17004992 DOI: 10.1111/j.1462-5822.2006.00814.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Toll-like receptor 9 (TLR9) induces an inflammatory response by recognition of unmethylated CpG dinucleotides, mainly present in prokaryotic DNA. So far, TLR9-deficient mice have been shown to be more sensitive than wild-type mice to viral, but not to bacterial infections. Here, we show that mice deficient in TLR9 but not in TLR1, TLR2, TLR4 and TLR6 or IL-1R/IL-18R are more susceptible to a respiratory tract bacterial infection caused by Streptococcus pneumoniae. Intranasal challenge studies revealed that TLR9 plays a protective role in the lungs at an early stage of infection prior to the entry of circulating inflammatory cells. Alveolar as well as bone marrow-derived macrophages deficient in either TLR9 or the myeloid adaptor differentiation protein MyD88 were impaired in pneumococcal uptake and in pneumococcal killing. Our data suggest that in the airways, pneumococcal infection triggers a TLR9 and MyD88-dependent activation of phagocytic activity from resident macrophages leading to an early clearance of bacteria from the lower respiratory tract.
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Affiliation(s)
- Barbara Albiger
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 18, SE-171 82 Solna, Sweden.
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Muschiol S, Bailey L, Gylfe Å, Sundin C, Hultenby K, Bergström S, Elofsson M, Wolf-Watz H, Normark S, Henriques-Normark B. A small-molecule inhibitor of type III secretion inhibits different stages of the infectious cycle of Chlamydia trachomatis. Proc Natl Acad Sci U S A 2006; 103:14566-71. [PMID: 16973741 PMCID: PMC1566191 DOI: 10.1073/pnas.0606412103] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The intracellular pathogen Chlamydia trachomatis possesses a type III secretion (TTS) system believed to deliver a series of effector proteins into the inclusion membrane (Inc-proteins) as well as into the host cytosol with perceived consequences for the pathogenicity of this common venereal pathogen. Recently, small molecules were shown to block the TTS system of Yersinia pseudotuberculosis. Here, we show that one of these compounds, INP0400, inhibits intracellular replication and infectivity of C. trachomatis at micromolar concentrations resulting in small inclusion bodies frequently containing only one or a few reticulate bodies (RBs). INP0400, at high concentration, given at the time of infection, partially blocked entry of elementary bodies into host cells. Early treatment inhibited the localization of the mammalian protein 14-3-3beta to the inclusions, indicative of absence of the early induced TTS effector IncG from the inclusion membrane. Treatment with INP0400 during chlamydial mid-cycle prevented secretion of the TTS effector IncA and homotypic vesicular fusions mediated by this protein. INP0400 given during the late phase resulted in the detachment of RBs from the inclusion membrane concomitant with an inhibition of RB to elementary body conversion causing a marked decrease in infectivity.
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Affiliation(s)
- Sandra Muschiol
- *Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Leslie Bailey
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Åsa Gylfe
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Charlotta Sundin
- Innate Pharmaceuticals, Umestan Företagspark, SE-903 47 Umeå, Sweden
| | - Kjell Hultenby
- Department of Laboratory Medicine, Karolinska Institutet, SE-141 86 Huddinge, Sweden; and
| | - Sven Bergström
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Mikael Elofsson
- Organic Chemistry, Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Hans Wolf-Watz
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
| | - Staffan Normark
- *Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Birgitta Henriques-Normark
- *Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden
- Department of Microbiology, Tumor Biology, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
- **To whom correspondence should be addressed at:
Department of Bacteriology, Swedish Institute for Infectious Disease Control, Nobels väg 18, SE-171 82 Solna, Sweden. E-mail:
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Beiter K, Wartha F, Albiger B, Normark S, Zychlinsky A, Henriques-Normark B. An endonuclease allows Streptococcus pneumoniae to escape from neutrophil extracellular traps. Curr Biol 2006; 16:401-7. [PMID: 16488875 DOI: 10.1016/j.cub.2006.01.056] [Citation(s) in RCA: 383] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Revised: 01/17/2006] [Accepted: 01/24/2006] [Indexed: 12/20/2022]
Abstract
Streptococcus pneumoniae (pneumococcus) is the most common cause of community-acquired pneumonia, with high morbidity and mortality worldwide. A major feature of pneumococcal pneumonia is an abundant neutrophil infiltration . It was recently shown that activated neutrophils release neutrophil extracellular traps (NETs), which contain antimicrobial proteins bound to a DNA scaffold. NETs provide a high local concentration of antimicrobial components and bind, disarm, and kill microbes extracellularly. Here, we show that pneumococci are trapped but, unlike many other pathogens, not killed by NETs. NET trapping in the lungs, however, may allow the host to confine the infection, reducing the likelihood for the pathogen to spread into the bloodstream. DNases are expressed by many Gram-positive bacterial pathogens, but their role in virulence is not clear. Expression of a surface endonuclease encoded by endA is a common feature of many pneumococcal strains. We show that EndA allows pneumococci to degrade the DNA scaffold of NETs and escape. Furthermore, we demonstrate that escaping NETs promotes spreading of pneumococci from the upper airways to the lungs and from the lungs into the bloodstream during pneumonia.
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Affiliation(s)
- Katharina Beiter
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, Solna SE-171 82, Sweden
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