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Shiga T, Kono M, Murakami D, Sakatani H, Ogura K, Hotomi M. Traditional Japanese herbal medicine Hochuekkito protects development of sepsis after nasal colonization in mice. J Infect Chemother 2024:S1341-321X(24)00123-5. [PMID: 38677389 DOI: 10.1016/j.jiac.2024.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/01/2024] [Accepted: 04/24/2024] [Indexed: 04/29/2024]
Abstract
INTRODUCTION Streptococcus pneumoniae, a commensal in the nasopharynx, can cause invasive pneumococcal diseases (IPDs). To prevent the aggravation of IPDs, it is important to enhance host immune defense against S. pneumoniae. Hochuekkito (HET) is expected to have an immunostimulatory effect against infections. METHODS HET was administrated by gavage to adult BALB/cA mice before and after intranasal inoculation of S. pneumoniae. We evaluated the effect of HET on pneumococcal nasal colonization and subsequent development of lethal pneumococcal infections. RESULTS No effect on nasal colonization was observed, but HET significantly reduced bacterial count in the blood, decreased the incidence of bacteremia, and improved survival. HET also reduced nasal tissue damage 3 days after intranasal infection. Neutrophils from HET-treated mice showed significantly higher bactericidal activity against S. pneumoniae in the presence of the serum from the HET group compared with from the control group. CONCLUSIONS The non-specific immunostimulatory effect of HET is suggested by this study to be effective in preventing the progression in IPDs and provided insights into novel strategy in the post-pneumococcal vaccine era.
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Affiliation(s)
- Tatsuya Shiga
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Kimiidera 811-1 Wakayama-shi, 641-8509, Wakayama, Japan
| | - Masamitsu Kono
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Kimiidera 811-1 Wakayama-shi, 641-8509, Wakayama, Japan
| | - Daichi Murakami
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Kimiidera 811-1 Wakayama-shi, 641-8509, Wakayama, Japan
| | - Hideki Sakatani
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Kimiidera 811-1 Wakayama-shi, 641-8509, Wakayama, Japan
| | - Keisuke Ogura
- Tsumura Kampo Research Laboratories, Kampo Research & Development Division, Tsumura & Co., 3586 Yoshiwara, Ami-machi, Inashiki-gun, 300-1192, Ibaraki, Japan
| | - Muneki Hotomi
- Department of Otorhinolaryngology-Head and Neck Surgery, Wakayama Medical University, Kimiidera 811-1 Wakayama-shi, 641-8509, Wakayama, Japan.
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A Unique Case of Purulent Malignant Otitis Externa Causing Community-Acquired Klebsiella Pneumonia Meningitis in a Marshallese Male. INFECTIOUS DISEASES IN CLINICAL PRACTICE 2023. [DOI: 10.1097/ipc.0000000000001239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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3
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Streptococcus pneumoniae Rapidly Translocate from the Nasopharynx through the Cribriform Plate to Invade the Outer Meninges. mBio 2022; 13:e0102422. [PMID: 35924840 PMCID: PMC9426477 DOI: 10.1128/mbio.01024-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The entry routes and translocation mechanisms of microorganisms or particulate materials into the central nervous system remain obscure We report here that Streptococcus pneumoniae (pneumococcus), or polystyrene microspheres of similar size, appear in the meninges of the dorsal cortex of mice within minutes of inhaled delivery. Recovery of viable bacteria from dissected tissue and fluorescence microscopy show that up to at least 72 h, pneumococci and microspheres were predominantly found in the outer of the two meninges: the pachymeninx. No pneumococci were found in blood or cerebrospinal fluid. Intravital imaging through the skull, aligned with flow cytometry showed recruitment and activation of LysM+ cells in the dorsal pachymeninx at 5 and 10 hours following intranasal infection. Imaging of the cribriform plate suggested that both pneumococci and microspheres entered through the foramina via an inward flow of fluid connecting the nose to the pachymeninx. Our findings bring new insight into the varied mechanisms of pneumococcal invasion of the central nervous system, but they are also pertinent to the delivery of drugs to the brain and the entry of airborne particulate matter into the cranium.
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Lempinen L, Laulajainen‐Hongisto A, Aarnisalo AA, Bernardino L, Peltola H, Pitkäranta A, Pelkonen T, Jero J. Hearing impairment in Angolan children with acute bacterial meningitis with and without otitis media. Acta Paediatr 2022; 111:1585-1593. [PMID: 35500132 DOI: 10.1111/apa.16383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 04/20/2022] [Accepted: 04/29/2022] [Indexed: 11/28/2022]
Abstract
AIM Bacterial meningitis (BM) is a common cause of hearing loss in childhood. Our aim was to investigate bacterial aetiology, hearing impairment and outcome in childhood BM with vs. without otitis media (OM) in Angola. METHODS Hearing was tested by auditory brainstem response in 391 (76%) children with confirmed BM. The bacteria identified from the ear discharge were compared to those from cerebrospinal fluid (CSF). The hearing findings were compared among children with vs. without OM on days 1 and 7 of hospitalization, and at follow-ups of 1, 3 and 6 month(s). RESULTS No correlation was found in bacteriology between the ear discharge and CSF. On day 7 in hospital, hearing impairment (>40 dB) was common, regardless of whether concomitant OM or not (in 27% vs. 30%, respectively). Any hearing deficit on day 7 was associated with a higher risk of complicated or fatal clinical course (OR 2.76, CI95% 1.43-5.29, p = 0.002). CONCLUSION No significant difference prevailed in hearing thresholds between children with or without OM in hospital on day 7 or at later follow-ups. Any hearing impairment during hospital stay associated with a higher risk for complicated clinical course or death.
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Affiliation(s)
- Laura Lempinen
- Department of Otorhinolaryngology, Head and Neck Surgery University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Anu Laulajainen‐Hongisto
- Department of Otorhinolaryngology, Head and Neck Surgery University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Antti A. Aarnisalo
- Department of Otorhinolaryngology, Head and Neck Surgery University of Helsinki and Helsinki University Hospital Helsinki Finland
| | | | - Heikki Peltola
- Children’s Hospital University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Anne Pitkäranta
- Department of Otorhinolaryngology, Head and Neck Surgery University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Tuula Pelkonen
- Pediatric Hospital David Bernardino Luanda Angola
- Children’s Hospital University of Helsinki and Helsinki University Hospital Helsinki Finland
| | - Jussi Jero
- University of Helsinki and Helsinki University Hospital Helsinki Finland
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5
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MacDougall M, El-Hajj Sleiman J, Beauchemin P, Rangachari M. SARS-CoV-2 and Multiple Sclerosis: Potential for Disease Exacerbation. Front Immunol 2022; 13:871276. [PMID: 35572514 PMCID: PMC9102605 DOI: 10.3389/fimmu.2022.871276] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/21/2022] [Indexed: 12/15/2022] Open
Abstract
While the respiratory tract is the primary route of entry for SARS-CoV-2, evidence shows that the virus also impacts the central nervous system. Intriguingly, case reports have documented SARS-CoV-2 patients presenting with demyelinating lesions in the brain, spinal cord, and optic nerve, suggesting possible implications in neuroimmune disorders such as multiple sclerosis (MS) and other related neuroimmune disorders. However, the cellular mechanisms underpinning these observations remain poorly defined. The goal of this paper was to review the literature to date regarding possible links between SARS-CoV-2 infection and neuroimmune demyelinating diseases such as MS and its related disorders, with the aim of positing a hypothesis for disease exacerbation. The literature suggests that SARS-CoV, SARS-CoV-2, and orthologous murine coronaviruses invade the CNS via the olfactory bulb, spreading to connected structures via retrograde transport. We hypothesize that a glial inflammatory response may contribute to damaged oligodendrocytes and blood brain barrier (BBB) breakdown, allowing a second route for CNS invasion and lymphocyte infiltration. Potential for molecular mimicry and the stimulation of autoreactive T cells against myelin is also described. It is imperative that further studies on SARS-CoV-2 neuroinvasion address the adverse effects of the virus on myelin and exacerbation of MS symptoms, as nearly 3 million people suffer from MS worldwide.
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Affiliation(s)
- Madison MacDougall
- Department of Biological Sciences, Salisbury University, Salisbury, MD, United States
- Department of Psychology, Salisbury University, Salisbury, MD, United States
| | - Jad El-Hajj Sleiman
- Division of Neurology, Department of Medicine, CHU de Québec – Université Laval, Quebec City, QC, Canada
| | - Philippe Beauchemin
- Division of Neurology, Department of Medicine, CHU de Québec – Université Laval, Quebec City, QC, Canada
| | - Manu Rangachari
- Axe Neurosciences, Centre de Recherche du CHU de Québec – Université Laval, Quebec City, QC, Canada
- Department of Molecular Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
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6
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Agnew HN, Brazel EB, Tikhomirova A, van der Linden M, McLean KT, Paton JC, Trappetti C. Streptococcus pneumoniae Strains Isolated From a Single Pediatric Patient Display Distinct Phenotypes. Front Cell Infect Microbiol 2022; 12:866259. [PMID: 35433506 PMCID: PMC9008571 DOI: 10.3389/fcimb.2022.866259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/08/2022] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae is the leading cause of bacterial paediatric meningitis after the neonatal period worldwide, but the bacterial factors and pathophysiology that drive pneumococcal meningitis are not fully understood. In this work, we have identified differences in raffinose utilization by S. pneumoniae isolates of identical serotype and sequence type from the blood and cerebrospinal fluid (CSF) of a single pediatric patient with meningitis. The blood isolate displayed defective raffinose metabolism, reduced transcription of the raffinose utilization pathway genes, and an inability to grow in vitro when raffinose was the sole carbon source. The fitness of these strains was then assessed using a murine intranasal infection model. Compared with the CSF isolate, mice infected with the blood isolate displayed higher bacterial numbers in the nose, but this strain was unable to invade the ears of infected mice. A premature stop codon was identified in the aga gene in the raffinose locus, suggesting that this protein likely displays impaired alpha-galactosidase activity. These closely related strains were assessed by Illumina sequencing, which did not identify any single nucleotide polymorphisms (SNPs) between the two strains. However, these wider genomic analyses identified the presence of an alternative alpha-galactosidase gene that appeared to display altered sequence coverage between the strains, which may account for the observed differences in raffinose metabolic capacity. Together, these studies support previous findings that raffinose utilization capacity contributes to disease progression, and provide insight into a possible alternative means by which perturbation of this pathway may influence the behavior of pneumococci in the host environment, particularly in meningitis.
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Affiliation(s)
- Hannah N. Agnew
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SAAustralia
| | - Erin B. Brazel
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SAAustralia
| | - Alexandra Tikhomirova
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SAAustralia
| | - Mark van der Linden
- German National Reference Center for Streptoccocci, University Hospital Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Aachen, Germany
| | - Kimberley T. McLean
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SAAustralia
| | - James C. Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SAAustralia
- *Correspondence: Claudia Trappetti, ; James C. Paton,
| | - Claudia Trappetti
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SAAustralia
- *Correspondence: Claudia Trappetti, ; James C. Paton,
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7
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Neila-Ibáñez C, Brogaard L, Pailler-García L, Martínez J, Segalés J, Segura M, Heegaard PMH, Aragon V. Piglet innate immune response to Streptococcus suis colonization is modulated by the virulence of the strain. Vet Res 2021; 52:145. [PMID: 34924012 PMCID: PMC8684544 DOI: 10.1186/s13567-021-01013-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/21/2021] [Indexed: 12/21/2022] Open
Abstract
Streptococcus suis is a zoonotic pathogen of swine involved in arthritis, polyserositis, and meningitis. Colonization of piglets by S. suis is very common and occurs early in life. The clinical outcome of infection is influenced by the virulence of the S. suis strains and the immunity of the animals. Here, the role of innate immunity was studied in cesarean-derived colostrum-deprived piglets inoculated intranasally with either virulent S. suis strain 10 (S10) or non-virulent S. suis strain T15. Colonization of the inoculated piglets was confirmed at the end of the study by PCR and immunohistochemistry. Fever (≥40.5 °C) was more prevalent in piglets inoculated with S10 compared to T15 at 4 h after inoculation. During the 3 days of monitoring, no other major clinical signs were detected. Accordingly, only small changes in transcription of genes associated with the antibacterial innate immune response were observed at systemic sites, with S10 inducing an earlier response than T15 in blood. Local inflammatory response to the inoculation, evaluated by transcriptional analysis of selected genes in nasal swabs, was more sustained in piglets inoculated with the virulent S10, as demonstrated by transcription of inflammation-related genes, such as IL1B, IL1A, and IRF7. In contrast, most of the gene expression changes in trachea, lungs, and associated lymph nodes were observed in response to the non-virulent T15 strain. Thus, S. suis colonization in the absence of systemic infection induces an innate immune response in piglets that appears to be related to the virulence potential of the colonizing strain.
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Affiliation(s)
- Carlos Neila-Ibáñez
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Bellaterra, Barcelona, Spain
| | - Louise Brogaard
- Section for Protein Science and Biotherapeutics, DTU Bioengineering, Technical University of Denmark, Kongens Lyngby, Denmark.,Current Affiliation: Section for Animal Genetics, Bioinformatics and Breeding, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Lola Pailler-García
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Bellaterra, Barcelona, Spain
| | - Jorge Martínez
- OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Bellaterra, Barcelona, Spain.,UAB, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,Departament de Sanitat I Anatomia Animals, Facultat de Veterinària, UAB, 08193, Bellaterra, Barcelona, Spain
| | - Joaquim Segalés
- OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Bellaterra, Barcelona, Spain.,UAB, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain.,Departament de Sanitat I Anatomia Animals, Facultat de Veterinària, UAB, 08193, Bellaterra, Barcelona, Spain
| | - Mariela Segura
- Research Group On Infectious Diseases in Production Animals and Swine and Poultry Infectious Diseases Research Centre, Faculty of Veterinary Medicine, University of Montreal, St-Hyacinthe, QC, J2S 2M2, Canada
| | - Peter M H Heegaard
- Innate Immunology Group, Center for Diagnostics, DTU Health Tech, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Virginia Aragon
- IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain. .,OIE Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Bellaterra, Barcelona, Spain.
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8
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Anil A, Banerjee A. Pneumococcal Encounter With the Blood-Brain Barrier Endothelium. Front Cell Infect Microbiol 2020; 10:590682. [PMID: 33224900 PMCID: PMC7669544 DOI: 10.3389/fcimb.2020.590682] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 09/22/2020] [Indexed: 12/27/2022] Open
Abstract
Meningitis, the inflammation of the protective membrane surrounding the brain and spinal cord (known as meninges), is a condition associated with high mortality rates and permanent neurological sequelae in a significant proportion of survivors. The opportunistic pathogen Streptococcus pneumoniae (SPN/pneumococcus) is the leading cause of bacterial meningitis in adults and older children. Following infection of the lower respiratory tract and subsequent bloodstream invasion, SPN breaches the blood-brain barrier endothelium for invasion of the central nervous system. Transcytosis, a mode of passage through the endothelial cells has been identified as the predominant route of pneumococcal blood-brain barrier trafficking. Herein, we review the interactions enabling SPN invasion into the brain endothelial cells, events involved in the tug-of-war between pneumococcal virulence factors and host intracellular defense machineries and pneumococcal strategies for evasion of host defenses and successful transendothelial trafficking.
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Affiliation(s)
| | - Anirban Banerjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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9
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Abstract
BACKGROUND Polysaccharide conjugate vaccines (PCVs) target the pneumococcal capsular types that most commonly cause fatal pneumonia and sepsis. Because these types were eliminated by the vaccines, it became apparent that in immunized populations, most invasive pneumococcal diseases, including bacteremia, sepsis and complicated pneumonia, were greatly reduced. However, the protective effects of PCVs against another invasive disease, meningitis, has shown much less or no decrease in disease incidence. METHODS References were identified through searches of PubMed for articles published from January 1930 to the present by use of specific search terms. Relevant articles were also identified through searches in Google and Google Scholar. Relevant references cited in those articles were also reviewed. RESULTS Even in the presence of the PCVs, meningitis rates in children have been reported globally to be as high as 13 per 100,000 annually. Widespread use of vaccines resulted in the emergence of a broad diversity of replacement non-PCV type strains. These strains generally failed to cause sepsis, but caused meningitis of comparable severity and levels similar to, or in excess of, prior pneumococcal meningitis rates. This is probably because these non-PCV type strains do not survive well in the blood, therefore possibly entering the brain through nonhematogenous routes. CONCLUSIONS Because virtually all cases of pneumococcal meningitis lead to either permanent neurologic sequelae or death, it would be well worth the effort to develop a new vaccine capable of preventing pneumococcal meningitis regardless of capsular type. Such a vaccine would need to protect against colonization with most, if not all, pneumococci.
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Affiliation(s)
| | - David E Briles
- Department of Microbiology and Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
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10
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Synthetic directions towards capsular polysaccharide of Streptococcus pneumoniae serotype 18C. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2019.151153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Kim BJ, Shusta EV, Doran KS. Past and Current Perspectives in Modeling Bacteria and Blood-Brain Barrier Interactions. Front Microbiol 2019; 10:1336. [PMID: 31263460 PMCID: PMC6585309 DOI: 10.3389/fmicb.2019.01336] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/29/2019] [Indexed: 01/18/2023] Open
Abstract
The central nervous system (CNS) barriers are highly specialized cellular barriers that promote brain homeostasis while restricting pathogen and toxin entry. The primary cellular constituent regulating pathogen entry in most of these brain barriers is the brain endothelial cell (BEC) that exhibits properties that allow for tight regulation of CNS entry. Bacterial meningoencephalitis is a serious infection of the CNS and occurs when bacteria can cross specialized brain barriers and cause inflammation. Models have been developed to understand the bacterial - BEC interaction that lead to pathogen crossing into the CNS, however, these have been met with challenges due to these highly specialized BEC phenotypes. This perspective provides a brief overview and outlook of the in vivo and in vitro models currently being used to study bacterial brain penetration, and opinion on improved models for the future.
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Affiliation(s)
- Brandon J Kim
- Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Eric V Shusta
- Department of Chemical and Biological Engineering, University of Wisconsin, Madison, WI, United States
| | - Kelly S Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States
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12
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Cools F, Torfs E, Vanhoutte B, de Macedo MB, Bonofiglio L, Mollerach M, Maes L, Caljon G, Delputte P, Cappoen D, Cos P. Streptococcus pneumoniae galU gene mutation has a direct effect on biofilm growth, adherence and phagocytosis in vitro and pathogenicity in vivo. Pathog Dis 2018; 76:5078866. [DOI: 10.1093/femspd/fty069] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/22/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- F Cools
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - E Torfs
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - B Vanhoutte
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - M Bidart de Macedo
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - L Bonofiglio
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética. Cátedra de Microbiología. Junín 956. Ciudad Autónoma de Buenos Aires, Argentina
| | - M Mollerach
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética. Cátedra de Microbiología. Junín 956. Ciudad Autónoma de Buenos Aires, Argentina
| | - L Maes
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - G Caljon
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - P Delputte
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - D Cappoen
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - P Cos
- University of Antwerp, Laboratory of Microbiology, Parasitology and Hygiene. Universiteitsplein 1, 2610 Wilrijk, Belgium
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13
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Threshold level of Riemerella anatipestifer crossing blood-brain barrier and expression profiles of immune-related proteins in blood and brain tissue from infected ducks. Vet Immunol Immunopathol 2018; 200:26-31. [DOI: 10.1016/j.vetimm.2018.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 02/11/2018] [Accepted: 04/09/2018] [Indexed: 12/13/2022]
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14
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Animal models of acute otitis media - A review with practical implications for laboratory research. Eur Ann Otorhinolaryngol Head Neck Dis 2018; 135:183-190. [PMID: 29656888 DOI: 10.1016/j.anorl.2017.06.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 06/08/2017] [Accepted: 06/12/2017] [Indexed: 11/23/2022]
Abstract
Considerable animal research has focused on developing new strategies for the prevention and treatment of acute otitis media (AOM). Several experimental models of AOM have thus been developed. A PubMed search of the English literature was conducted from 1975 to July 2016 using the search terms "animal model" and "otitis media" from which 91 published studies were included for analysis, yielding 123 animal models. The rat, mouse and chinchilla are the preferred animals for experimental AOM models with their individual advantages and disadvantages. The most common pathogens used to create AOM are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Streptococcus pneumoniae (types 3, 23 and 6A) and non-typeable Haemophilus influenzae (NTHi) are best options for inoculation into rat and mouse models. Adding viral pathogens such as RSV and Influenza A virus, along with creating ET dysfunction, are useful adjuncts in animal models of AOM. Antibiotic prophylaxis may interfere with the inflammatory response without a significant reduction in animal mortality.
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15
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Concise Synthesis of the Phosphoglycerylated Tetrasaccharide Repeating Unit of the Capsular Polysaccharide ofStreptococcus pneumoniaeSerotype 11 A. ChemistrySelect 2017. [DOI: 10.1002/slct.201702500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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16
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Zavala A, Kovacec V, Levín G, Moglioni A, Miranda MV, García E, Bonofiglio L, Mollerach M. Screening assay for inhibitors of a recombinant Streptococcus pneumoniae UDP-glucose pyrophosphorylase. J Enzyme Inhib Med Chem 2017; 32:203-207. [PMID: 28114831 PMCID: PMC6009895 DOI: 10.1080/14756366.2016.1247055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The UDP-glucose pyrophosphorylase of Streptococcus pneumoniae (GalUSpn) is absolutely required for the biosynthesis of capsular polysaccharide, the sine qua non virulence factor of pneumococcus. Since the eukaryotic enzymes are completely unrelated to their prokaryotic counterparts, we propose that the GalU enzyme is a critical target to fight the pneumococcal disease. A recombinant GalUSpn was overexpressed and purified. An enzymatic assay that is rapid, sensitive and easy to perform was developed. This assay was appropriate for screening chemical libraries for searching GalU inhibitors. This work represents a fundamental step in the exploration of novel antipneumococcal drugs.
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Affiliation(s)
- Agustín Zavala
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Verónica Kovacec
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Gustavo Levín
- b Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Biotecnología , Buenos Aires , Argentina
| | - Albertina Moglioni
- c Departamento de Farmacología, Facultad de Farmacia y Bioquímica , Cátedra de Química Medicinal, Universidad de Buenos Aires , Buenos Aires , Argentina
| | - María Victoria Miranda
- b Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Biotecnología , Buenos Aires , Argentina
| | - Ernesto García
- d Centro de Investigaciones Biológicas, CSIC and CIBER de Enfermedades Respiratorias (CIBERES) , Madrid , Spain
| | - Laura Bonofiglio
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Marta Mollerach
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
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Abstract
Over the past several decades, the incidence of bacterial meningitis in children has decreased but there remains a significant burden of disease in adults, with a mortality of up to 30%. Although the pathogenesis of bacterial meningitis is not completely understood, knowledge of bacterial invasion and entry into the CNS is improving. Clinical features alone cannot determine whether meningitis is present and analysis of cerebrospinal fluid is essential for diagnosis. Newer technologies, such as multiplex PCR, and novel diagnostic platforms that incorporate proteomics and genetic sequencing, might help provide a quicker and more accurate diagnosis. Even with appropriate antimicrobial therapy, mortality is high and so attention has focused on adjunctive therapies; adjunctive corticosteroids are beneficial in certain circumstances. Any further improvements in outcome are likely to come from either modulation of the host response or novel approaches to therapy, rather than new antibiotics. Ultimately, the best hope to reduce the disease burden is with broadly protective vaccines.
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Affiliation(s)
- Fiona McGill
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK; NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, UK; Leeds University Hospitals NHS Trust, Leeds, UK; Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, UK
| | - Robert S Heyderman
- Malawi-Liverpool-Wellcome Trust, Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi; Division of Infection and Immunity, University College London, London, UK
| | - Stavros Panagiotou
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Allan R Tunkel
- Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Tom Solomon
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK; The Walton Centre NHS Foundation Trust, Liverpool, UK; NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, UK; Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, UK.
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Free Sialic Acid Acts as a Signal That Promotes Streptococcus pneumoniae Invasion of Nasal Tissue and Nonhematogenous Invasion of the Central Nervous System. Infect Immun 2016; 84:2607-15. [PMID: 27354445 DOI: 10.1128/iai.01514-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 06/18/2016] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is a leading cause of bacterial meningitis and neurological sequelae in children worldwide. Acute bacterial meningitis is widely considered to result from bacteremia that leads to blood-brain barrier breakdown and bacterial dissemination throughout the central nervous system (CNS). Previously, we showed that pneumococci can gain access to the CNS through a nonhematogenous route without peripheral blood infection. This access is thought to occur when the pneumococci in the upper sinus follow the olfactory nerves and enter the CNS through the olfactory bulbs. In this study, we determined whether the addition of exogenous sialic acid postcolonization promotes nonhematogenous invasion of the CNS. Previously, others showed that treatment with exogenous sialic acid post-pneumococcal infection increased the numbers of CFU recovered from an intranasal mouse model of infection. Using a pneumococcal colonization model, an in vivo imaging system, and a multiplex assay for cytokine expression, we demonstrated that sialic acid can increase the number of pneumococci recovered from the olfactory bulbs and brains of infected animals. We also show that pneumococci primarily localize to the olfactory bulb, leading to increased expression levels of proinflammatory cytokines and chemokines. These findings provide evidence that sialic acid can enhance the ability of pneumococci to disseminate into the CNS and provide details about the environment needed to establish nonhematogenous pneumococcal meningitis.
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Majhi A, Kundu K, Adhikary R, Banerjee M, Mahanti S, Basu A, Bishayi B. Combination therapy with ampicillin and azithromycin in an experimental pneumococcal pneumonia is bactericidal and effective in down regulating inflammation in mice. JOURNAL OF INFLAMMATION-LONDON 2014; 11:5. [PMID: 24565171 PMCID: PMC3936873 DOI: 10.1186/1476-9255-11-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 02/17/2014] [Indexed: 12/21/2022]
Abstract
Objectives Emergence of multidrug resistance among Streptococcus pneumoniae (SP), has limited the available options used to treat infections caused by this organism. The objective of this study was to compare the role of monotherapy and combination therapy with ampicillin (AMP) and azithromycin (AZM) in eradicating bacterial burden and down regulating lung inflammation in a murine experimental pneumococcal infection model. Methods Balb/C mice were infected with 106 CFU of SP. Treatments with intravenous ampicillin (200 mg/kg) and azithromycin (50 mg/kg) either alone or in combination was initiated 18 h post infection, animals were sacrificed from 0 – 6 h after initiation of treatment. AMP and AZM were quantified in serum by microbiological assay. Levels of TNF-α, IFN-γ IL-6, and IL-10 in serum and in lungs, along with myeloperoxidase, inflammatory cell count in broncho alveolar lavage fluid, COX-2 and histopathological changes in lungs were estimated. Results Combination therapy down regulated lung inflammation and accelerated bacterial clearance. This approach also significantly decreased TNF-α, IFN-γ, IL-6 and increased IL-10 level in serum and lungs along with decreased myeloperoxidase, pulmonary vascular permeability, inflammatory cell numbers and COX-2 levels in lungs. Conclusions Combinatorial therapy resulted in comparable bactericidal activity against the multi-drug resistant isolate and may represent an alternative dosing strategy, which may help to alleviate problems with pneumococcal pneumonia.
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Affiliation(s)
| | | | | | | | | | | | - Biswadev Bishayi
- Department of Physiology, Immunology laboratory, University of Calcutta, University Colleges of Science and Technology, 92 APC Road, Calcutta 700009, West Bengal,India.
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Frazão N, Hiller NL, Powell E, Earl J, Ahmed A, Sá-Leão R, de Lencastre H, Ehrlich GD, Tomasz A. Virulence potential and genome-wide characterization of drug resistant Streptococcus pneumoniae clones selected in vivo by the 7-valent pneumococcal conjugate vaccine. PLoS One 2013; 8:e74867. [PMID: 24069360 PMCID: PMC3777985 DOI: 10.1371/journal.pone.0074867] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 08/07/2013] [Indexed: 11/28/2022] Open
Abstract
We used mouse models of pneumococcal colonization and disease combined with full genome sequencing to characterize three major drug resistant clones of S. pneumoniae that were recovered from the nasopharynx of PCV7-immunized children in Portugal. The three clones--serotype 6A (ST2191), serotype 15A (ST63) and serotype 19A (ST276) carried some of the same drug resistance determinants already identified in nasopharyngeal isolates from the pre-PCV7 era. The three clones were able to colonize efficiently the mouse nasopharyngeal mucosa where populations of these pneumococci were retained for as long as 21 days. During this period, the three clones were able to asymptomatically invade the olfactory bulbs, brain, lungs and the middle ear mucosa and established populations in these tissues. The virulence potential of the three clones was poor even at high inoculum (10(5) CFU per mouse) concentrations in the mouse septicemia model and was undetectable in the pneumonia model. Capsular type 3 transformants of clones 6A and 19A prepared in the laboratory produced lethal infection at low cell concentration (10(3) CFU per mouse) but the same transformants became impaired in their potential to colonize, indicating the importance of the capsular polysaccharide in both disease and colonization. The three clones were compared to the genomes of 56 S. pneumoniae strains for which sequence information was available in the public databank. Clone 15A (ST63) only differed from the serotype 19F clone G54 in a very few genes including serotype so that this clone may be considered the product of a capsular switch. While no strain with comparable degree of similarity to clone 19A (ST276) was found among the sequenced isolates, by MLST this clone is a single locust variant (SLV) of Denmark14-ST230 international clone. Clone 6A (ST2191) was most similar to the penicillin resistant Hungarian serotype 19A clone.
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Affiliation(s)
- Nelson Frazão
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America
| | - N. Luisa Hiller
- Allegheny General Hospital, Allegheny-Singer Research Institute, Center for Genomic Sciences, Pittsburgh, Pennsylvania, United States of America
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Evan Powell
- Allegheny General Hospital, Allegheny-Singer Research Institute, Center for Genomic Sciences, Pittsburgh, Pennsylvania, United States of America
| | - Josh Earl
- Allegheny General Hospital, Allegheny-Singer Research Institute, Center for Genomic Sciences, Pittsburgh, Pennsylvania, United States of America
| | - Azad Ahmed
- Allegheny General Hospital, Allegheny-Singer Research Institute, Center for Genomic Sciences, Pittsburgh, Pennsylvania, United States of America
| | - Raquel Sá-Leão
- Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Hermínia de Lencastre
- Laboratory of Molecular Genetics, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America
| | - Garth D. Ehrlich
- Allegheny General Hospital, Allegheny-Singer Research Institute, Center for Genomic Sciences, Pittsburgh, Pennsylvania, United States of America
| | - Alexander Tomasz
- Laboratory of Microbiology, The Rockefeller University, New York, New York, United States of America
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Intracellular transport of Toxoplasma gondii through the blood-brain barrier. J Neuroimmunol 2010; 232:119-30. [PMID: 21106256 DOI: 10.1016/j.jneuroim.2010.10.029] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 08/29/2010] [Accepted: 10/25/2010] [Indexed: 12/29/2022]
Abstract
Toxoplasma gondii establishes latent infection in the central nervous system of immunocompentent hosts. Toxoplasmic encephalitis is a life threatening reactivation of latent infection in the brain of immunocompromised patients. To further understand the mechanisms of entry into the brain of T. gondii we investigated host molecules and cells involved in the passage of the parasite through the blood-brain barrier. First, using microarrays brain endothelial cells were found to upregulate, among others, chemokines and adhesion molecules following infection with tachyzoites. Using flow cytometry we observed upregulated ICAM-1 expression on the surface of brain endothelial cells following infection; ICAM-1 expression was further increased after pre-incubation with IFN-γ. Compared to RH tachyzoites, ME49 tachyzoites induced a stronger upregulation of ICAM-1 and an earlier and stronger IL-6 and MCP-1 secretion by brain endothelial cells. Using an in vitro coculture model of the BBB (primary glia cells and brain endothelial cells) we found a stronger migration of infected antigen-presenting cells compared to lymphocytes (4.63% vs. 0.6% of all cells) across the BBB. Among all antigen-presenting cells CD11b(+)/CD11c(+) cells showed the highest infection rate, whereas the majority of infected cells that migrated through the blood-brain barrier were CD11b(+)/CD11c(-) cells. Infection of PBMCs with type I or type II Toxoplasma strains resulted in similar patterns of cell migration across the in vitro BBB model. In conclusion, these results suggest that T. gondii modulates gene expression of brain endothelial cells to promote its own migration through the blood-brain barrier in a 'Trojan horse' manner. Cells expressing CD11b either with or without CD11c are likely candidate cells for the intracellular transport of T. gondii across the BBB. T. gondii type I and type II strains induced similar migration patterns of antigen-presenting cells across the in vitro BBB.
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Olfactory nerve--a novel invasion route of Neisseria meningitidis to reach the meninges. PLoS One 2010; 5:e14034. [PMID: 21124975 PMCID: PMC2987801 DOI: 10.1371/journal.pone.0014034] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 10/29/2010] [Indexed: 11/19/2022] Open
Abstract
Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS) is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent of the mice developed lethal meningitis even though no bacteria could be detected in blood. Upon bacterial infection, epithelial lesions and redistribution of intracellular junction protein N-cadherin were observed at the nasal epithelial mucosa, especially at the olfactory epithelium, which is functionally and anatomically connected to the CNS. Bacteria were detected in the submucosa of the olfactory epithelium, along olfactory nerves in the cribriform plate, at the olfactory bulb and subsequently at the meninges and subarachnoid space. Furthermore, our data suggest that a threshold level of bacteremia is required for the development of meningococcal sepsis. Taken together, N. meningitidis is able to pass directly from nasopharynx to meninges through the olfactory nerve system. This study enhances our understanding how N. meningitidis invades the meninges. The nasal olfactory nerve system may be a novel target for disease prevention that can improve outcome and survival.
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Wei BP, Shepherd RK, Robins-Browne RM, Clark GM, O'Leary SJ. Pneumococcal meningitis post-cochlear implantation: Potential routes of infection and pathophysiology. Otolaryngol Head Neck Surg 2010. [DOI: 10.1177/019459981014305s07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective This review describes the current concept of pneumococcal meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of Streptococcus pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of pneumococcal meningitis in implant recipients. Data Sources Medline/PubMed database; English articles after 1960. Search terms: cochlear implants, meningitis, pneumococcus, streptococcus pneumonia. Review Methods Narrative review. All articles relating to post-implant meningitis without any restriction in study designs were assessed and information extracted. Results The incidence of pneumococcal meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for pneumococcal meningitis. Conclusion The laboratory data complement the existing clinical data on the risk of pneumococcal meningitis post-cochlear implantation.
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Affiliation(s)
- Benjamin P.C. Wei
- Bionic Ear Institute and the Department of Otolaryngology, University of Melbourne, Melbourne, Victoria, Australia
| | - Robert K. Shepherd
- Bionic Ear Institute and the Department of Otolaryngology, University of Melbourne, Melbourne, Victoria, Australia
| | - Roy M. Robins-Browne
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria, Australia
| | - Graeme M. Clark
- Bionic Ear Institute and the Department of Otolaryngology, University of Melbourne, Melbourne, Victoria, Australia
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Hamed SA, Hamed EA, Zakary MM. Oxidative stress and S-100B protein in children with bacterial meningitis. BMC Neurol 2009; 9:51. [PMID: 19814795 PMCID: PMC2768670 DOI: 10.1186/1471-2377-9-51] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Accepted: 10/08/2009] [Indexed: 12/22/2022] Open
Abstract
Background Bacterial meningitis is often associated with cerebral compromise which may be responsible for neurological sequelae in nearly half of the survivors. Little is known about the mechanisms of CNS involvement in bacterial meningitis. Several studies have provided substantial evidence for the key role of nitric oxide (NO) and reactive oxygen species in the complex pathophysiology of bacterial meningitis. Methods In the present study, serum and CSF levels of NO, lipid peroxide (LPO) (mediators for oxidative stress and lipid peroxidation); total thiol, superoxide dismutase (SOD) (antioxidant mediators) and S-100B protein (mediator of astrocytes activation and injury), were investigated in children with bacterial meningitis (n = 40). Albumin ratio (CSF/serum) is a marker of blood-CSF barriers integrity, while mediator index (mediator ratio/albumin ratio) is indicative of intrathecal synthesis. Results Compared to normal children (n = 20), patients had lower serum albumin but higher NO, LPO, total thiol, SOD and S-100B. The ratios and indices of NO and LPO indicate blood-CSF barriers dysfunction, while the ratio of S-100B indicates intrathecal synthesis. Changes were marked among patients with positive culture and those with neurological complications. Positive correlation was found between NO index with CSF WBCs (r = 0.319, p < 0.05); CSF-LPO with CSF-protein (r = 0.423, p < 0.01); total thiol with LPO indices (r = 0.725, p < 0.0001); S-100B and Pediatric Glasow Coma Scores (0.608, p < 0.0001); CSF-LPO with CSF-S-100B (r = 0.482, p < 0.002); serum-total thiol with serum S-100B (r = 0.423, p < 0.01). Conclusion This study suggests that loss of integrity of brain-CSF barriers, oxidative stress and S-100B may contribute to the severity and neurological complications of bacterial meningitis.
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Affiliation(s)
- Sherifa A Hamed
- Department of Neurology, Faculty of Medicine, Assiut University, Assiut, Egypt.
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Could proteomic research deliver the next generation of treatments for pneumococcal meningitis? Interdiscip Perspect Infect Dis 2009; 2009:214216. [PMID: 19503804 PMCID: PMC2688656 DOI: 10.1155/2009/214216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Accepted: 03/09/2009] [Indexed: 02/07/2023] Open
Abstract
Streptococcus pneumoniae is the most common bacterial cause of community-acquired meningitis worldwide. Despite optimal antibiotic therapy and supportive care, the mortality of this condition remains very high at 20–30% in the developed world and over 60% in under-resourced hospitals. In developed countries, approximately half of the survivors suffer intellectual impairment, hearing loss, or other neurological damage. There is an urgent need for more information about the mechanisms of brain damage and death in pneumococcal meningitis so that new treatments can be designed. Using proteomic techniques and bioinformatics, the protein content of cerebrospinal fluid can be examined in great detail. Animal models have added greatly to our knowledge of possible mechanisms and shown that hippocampal apoptosis and cortical necrosis are distinct mechanisms of neuronal death. The contribution of these pathways to human disease is unknown. Using proteomic techniques, neuronal death pathways could be described in CSF samples. This information could lead to the design of novel therapies to minimize brain damage and lower mortality. This minireview will summarize the known pathogenesis of meningitis, and current gaps in knowledge, that could be filled by proteomic analysis.
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O'Neill LAJ, Bryant CE, Doyle SL. Therapeutic targeting of Toll-like receptors for infectious and inflammatory diseases and cancer. Pharmacol Rev 2009; 61:177-97. [PMID: 19474110 DOI: 10.1124/pr.109.001073] [Citation(s) in RCA: 333] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Since first being described in the fruit fly Drosophila melanogaster, Toll-like receptors (TLRs) have proven to be of great interest to immunologists and investigators interested in the molecular basis to inflammation. They recognize pathogen-derived factors and also products of inflamed tissue, and trigger signaling pathways that lead to activation of transcription factors such as nuclear factor-kappaB and the interferon regulatory factors. These in turn lead to induction of immune and inflammatory genes, including such important cytokines as tumor necrosis factor-alpha and type I interferon. Much evidence points to a role for TLRs in immune and inflammatory diseases and increasingly in cancer. Examples include clear roles for TLR4 in sepsis, rheumatoid arthritis, ischemia/reperfusion injury, and allergy. TLR2 has been implicated in similar pathologic conditions and also in systemic lupus erythematosus (SLE) and tumor metastasis. TLR7 has also been shown to be important in SLE. TLR5 has been shown to be radioprotective. Recent advances in our understanding of signaling pathways activated by TLRs, structural insights into TLRs bound to their ligands and antagonists, and approaches to inhibit TLRs (including antibodies, peptides, and small molecules) are providing possiblemeans by which to interfere with TLRs clinically. Here we review these recent advances and speculate about whether manipulating TLRs is likely to be successful in fighting off different diseases.
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Affiliation(s)
- Luke A J O'Neill
- School of Biochemistry and Immunology, Trinity College Dublin, Ireland.
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Filippidis A, Fountas KN. Nasal lymphatics as a novel invasion and dissemination route of bacterial meningitis. Med Hypotheses 2009; 72:694-7. [PMID: 19243893 DOI: 10.1016/j.mehy.2008.10.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 10/19/2008] [Accepted: 10/21/2008] [Indexed: 10/21/2022]
Abstract
Bacterial meningitis constitutes an infectious disease with high morbidity and mortality, characterized by complex pathophysiology. Neisseria meningitis, Streptococcus pneumoniae, Haemophilus influenzae type b and other pathogens are capable of invading the CNS and infecting the meninges due to the incorporation of virulence factors. The pathophysiologic theories concerning the route of infection in bacterial meningitis consider a general cascade of events involving nasopharyngeal or middle ear colonization, pathogen bloodstream dissemination, blood-brain and blood-cerebrospinal fluid barriers crossing, and finally entrance of the implicated pathogen into the subarachnoid space, survival and subsequent infection. However, these theories cannot adequately explain the high percentage of negative blood cultures especially in cases of neonatal meningitis. Also, they cannot address with certainty the pathogens' entry site in to the cerebrospinal fluid, since the presence of barriers could act against bacterial infection of the meninges. In addition, experimental models of S. pneumoniae meningitis indicate that the route of infection may be independent of bacteraemia. The documented direct communication between the nasal lymphatics and the subarachnoid space could provide a hypothesis explaining the pathophysiologic mechanisms of meningeal infection and overcoming all the limitations of the current theories. It could also explain the presence of negative blood cultures while meningeal inflammation is present. Furthermore, it could also interpret the occasional fulminating evolution of bacterial meningitis since intense host defenses and central nervous system barriers could be bypassed. In our current communication we examine the role of the nasal lymphatic pathway in the development of meningitis. It is apparent that better understanding of the infection and dissemination route for bacterial meningitis can provide the opportunity for a more effective treatment.
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Abstract
SUMMARY Streptococcus pneumoniae is a colonizer of human nasopharynx, but it is also an important pathogen responsible for high morbidity, high mortality, numerous disabilities, and high health costs throughout the world. Major diseases caused by S. pneumoniae are otitis media, pneumonia, sepsis, and meningitis. Despite the availability of antibiotics and vaccines, pneumococcal infections still have high mortality rates, especially in risk groups. For this reason, there is an exceptionally extensive research effort worldwide to better understand the diseases caused by the pneumococcus, with the aim of developing improved therapeutics and vaccines. Animal experimentation is an essential tool to study the pathogenesis of infectious diseases and test novel drugs and vaccines. This article reviews both historical and innovative laboratory pneumococcal animal models that have vastly added to knowledge of (i) mechanisms of infection, pathogenesis, and immunity; (ii) efficacies of antimicrobials; and (iii) screening of vaccine candidates. A comprehensive description of the techniques applied to induce disease is provided, the advantages and limitations of mouse, rat, and rabbit models used to mimic pneumonia, sepsis, and meningitis are discussed, and a section on otitis media models is also included. The choice of appropriate animal models for in vivo studies is a key element for improved understanding of pneumococcal disease.
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Abstract
Central nervous system (CNS) infections continue to be an important cause of morbidity and mortality. Microbial invasion and traversal of the blood-brain barrier is a prerequisite for CNS infections. Pathogens can cross the blood-brain barrier transcellularly, paracellularly and/or in infected phagocytes (the so-called Trojan-horse mechanism). Consequently, pathogens can cause blood-brain barrier dysfunction, including increased permeability, pleocytosis and encephalopathy. A more complete understanding of the microbial-host interactions that are involved in microbial traversal of the blood-brain barrier and the associated barrier dysfunction should help to develop new strategies to prevent CNS infections.
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Kim KS. Microbial translocation of the blood–brain barrier. Int J Parasitol 2006; 36:607-14. [PMID: 16542662 DOI: 10.1016/j.ijpara.2006.01.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 01/19/2006] [Accepted: 01/30/2006] [Indexed: 11/23/2022]
Abstract
A major contributing factor to high mortality and morbidity associated with CNS infection is the incomplete understanding of the pathogenesis of this disease. Relatively small numbers of pathogens account for most cases of CNS infections in humans, but it is unclear how such pathogens cross the blood-brain barrier (BBB) and cause infections. The development of the in vitro BBB model using human brain microvascular endothelial cells has facilitated our understanding of the microbial translocation of the BBB, a key step for the acquisition of CNS infections. Recent studies have revealed that microbial translocation of the BBB involves host cell actin cytoskeletal rearrangements, most likely as the result of specific microbial-host interactions. A better understanding of microbial-host interactions that are involved in microbial translocation of the BBB should help in developing new strategies to prevent CNS infections. This review summarises our current understanding of the pathogenic mechanisms involved in translocation of the BBB by meningitis-causing bacteria, fungi and parasites.
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Affiliation(s)
- Kwang Sik Kim
- Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Park 256, Baltimore, MD 21287, USA.
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Paterson GK, Mitchell TJ. The role of Streptococcus pneumoniae sortase A in colonisation and pathogenesis. Microbes Infect 2006; 8:145-53. [PMID: 16182588 DOI: 10.1016/j.micinf.2005.06.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 06/01/2005] [Accepted: 06/06/2005] [Indexed: 10/25/2022]
Abstract
Sortase enzymes are found throughout Gram-positive bacteria and are responsible for the covalent attachment of specific proteins to the cell wall. Through the anchoring of these cell wall proteins, sortase enzymes are important in the ability of several Gram-positive pathogens to cause disease. Previously, deletion of srtA from Streptococcus pneumoniae (the pneumococcus) was shown to disturb the localisation of surface proteins, and decrease bacterial adherence to human pharyngeal cells in vitro. Here we present data demonstrating, for the first time, a role for srtA as a pneumococcal fitness factor in experimental models of pneumonia and bacteraemia. In addition, srtA contributed to nasopharyngeal colonisation in vivo. Furthermore, we find that the contribution of srtA varied between two pneumococcal strains. We show that the known role of srtA in adherence in vitro is dependent on capsule expression, the role of SrtA in adherence to human cells only being apparent in the absence of the pneumococcal capsule. The srtA gene was detected by PCR in all 82 clinical isolates examined and sequencing of the gene from 20 strains showed srtA to be highly conserved. The ubiquitous distribution of srtA was in contrast to the other known pneumococcal sortase genes, srtB, C and D, which were found in only 14 of the 82 tested strains (17%).
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Affiliation(s)
- Gavin K Paterson
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK
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Kerr AR, Paterson GK, Riboldi-Tunnicliffe A, Mitchell TJ. Innate immune defense against pneumococcal pneumonia requires pulmonary complement component C3. Infect Immun 2005; 73:4245-52. [PMID: 15972516 PMCID: PMC1168602 DOI: 10.1128/iai.73.7.4245-4252.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Complement is known to be involved in protection against systemic infection with Streptococcus pneumoniae. However, less is known about effects of complement within the lungs during pneumococcal pneumonia. By intranasally infecting transgenic mice unable to express complement C3, we investigated the role of complement in pulmonary defenses against S. pneumoniae. It was demonstrated that within the lungs, there is a requirement for C3 during the initial hours of infection. It was found that within 1 h of infection, bacterial loads decreased within lung airways of control mice as C3 protein increased. The lack of C3 resulted in the inability to control growth of wild-type or attenuated pneumococci within the lungs and bloodstream, resulting in an overwhelming inflammatory response and shorter survival times. Our results show that during the initial hours of infection with S. pneumoniae, C3 is protective within the lungs and subsequently plays an important role systemically.
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Affiliation(s)
- Alison R Kerr
- Division of Infection and Immunity, IBLS, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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Wong SM, Akerley BJ. Environmental and genetic regulation of the phosphorylcholine epitope of Haemophilus influenzae lipooligosaccharide. Mol Microbiol 2005; 55:724-38. [PMID: 15660999 DOI: 10.1111/j.1365-2958.2004.04439.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In response to environmental signals in the host, bacterial pathogens express factors required during infection and repress those that interfere with specific stages of this process. Signalling pathways controlling virulence factors of the human respiratory pathogen, Haemophilus influenzae, are predominantly unknown. The lipooligosaccharide (LOS) outer core represents a prototypical virulence trait of H. influenzae that enhances virulence but also provides targets for innate and adaptive immunity. We report regulation of the display of the virulence-associated phosphorylcholine (PC) epitope on the LOS in response to environmental conditions. PC display is optimal under microaerobic conditions and markedly decreased under conditions of high culture aeration. Gene expression analysis using a DNA microarray was performed to begin to define the metabolic state of the cell under these conditions and to identify genes potentially involved in PC epitope modulation. Global gene expression profiling detected changes in redox responsive genes and in genes of carbohydrate metabolism. The effects on carbohydrate metabolism led us to examine the role of the putative H. influenzae homologue of csrA, a regulator of glycolysis and gluconeogenesis in Escherichia coli. A mutant containing an in-frame deletion of the H. influenzae csrA gene showed increased PC epitope levels under aerobic conditions. Furthermore, deletion of csrA elevated mRNA expression of galU, an essential virulence gene that is critical in generating sugar precursors needed for polysaccharide formation and LOS outer core synthesis. Growth conditions predicted to alter the redox state of the culture modulated the PC epitope and galU expression as well. The results are consistent with a multifactorial mechanism of control of LOS-PC epitope display involving csrA and environmental signals that coordinately regulate biosynthetic and metabolic genes controlling the LOS structure.
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Affiliation(s)
- Sandy M Wong
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Pettigrew MM, Fennie KP. Genomic subtraction followed by dot blot screening of Streptococcus pneumoniae clinical and carriage isolates identifies genetic differences associated with strains that cause otitis media. Infect Immun 2005; 73:2805-11. [PMID: 15845484 PMCID: PMC1087362 DOI: 10.1128/iai.73.5.2805-2811.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus pneumoniae strains are the leading cause of bacterial otitis media, yet little is known about specific bacterial factors important for this disease. We utilized a molecular epidemiological approach involving genomic subtraction of the S. pneumoniae serogroup 19 middle ear strain 5093 against the laboratory strain R6. Resulting subtraction PCR (sPCR) products were used to screen a panel of 93 middle ear, 90 blood, 35 carriage, and 58 cerebrospinal fluid isolates from young children to identify genes found more frequently among middle ear isolates. Probe P41, similar to a hypothetical protein of Brucella melitensis, occurred among 41% of middle ear isolates and was found 2.8 (95% confidence interval [CI], 1.32 to 6.5), 3.3 (95% CI, 1.9 to 5.7), and 1.8 (95% CI, 1.1 to 3.0) times more frequently among middle ear strains than carriage, blood, or meningitis strains, respectively. sPCR fragment H10, similar to an unknown Streptococcus agalactiae protein, was present in 31% of middle ear isolates and occurred 3.6 (95% CI, 1.2 to 11.2), 2.8 (95% CI, 1.5 to 5.4), and 2.6 (95% CI, 1.2 to 5.5) times more often among middle ear isolates than carriage, blood, or meningitis strains, respectively. These studies have identified two genes of potential importance in otitis media virulence. Further studies are warranted to outline the precise role of these genes in otitis media pathogenesis.
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Affiliation(s)
- Melinda M Pettigrew
- Yale University School of Medicine, Department of Epidemiology and Public Health, 60 College Street, P. O. Box 208034, New Haven, CT 06520-8034, USA.
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Method for inducing experimental pneumococcal meningitis in outbred mice. BMC Microbiol 2004; 4:36. [PMID: 15385055 PMCID: PMC524167 DOI: 10.1186/1471-2180-4-36] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2004] [Accepted: 09/22/2004] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Streptococcus pneumoniae is the leading cause of bacterial meningitis. Pneumococcal meningitis is associated with the highest mortality among bacterial meningitis and it may also lead to neurological sequelae despite the use of antibiotic therapy. Experimental animal models of pneumococcal meningitis are important to study the pathogenesis of meningitis, the host immune response induced after infection, and the efficacy of novel drugs and vaccines. RESULTS In the present work, we describe in detail a simple, reproducible and efficient method to induce pneumococcal meningitis in outbred mice by using the intracranial subarachnoidal route of infection. Bacteria were injected into the subarachnoid space through a soft point located 3.5 mm rostral from the bregma. The model was tested with several doses of pneumococci of three capsular serotypes (2, 3 and 4), and mice survival was recorded. Lethal doses killing 50 % of animals infected with type 2, 3 and 4 S. pneumoniae were 3.2 x 10, 2.9 x 10 and 1.9 x 10(2) colony forming units, respectively. Characterisation of the disease caused by the type 4 strain showed that in moribund mice systemic dissemination of pneumococci to blood and spleen occurred. Histological analysis of the brain of animals infected with type 4 S. pneumoniae proved the induction of meningitis closely resembling the disease in humans. CONCLUSIONS The proposed method for inducing pneumococcal meningitis in outbred mice is easy-to-perform, fast, cost-effective, and reproducible, irrespective of the serotype of pneumococci used.
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Drevets DA, Leenen PJM, Greenfield RA. Invasion of the central nervous system by intracellular bacteria. Clin Microbiol Rev 2004; 17:323-47. [PMID: 15084504 PMCID: PMC387409 DOI: 10.1128/cmr.17.2.323-347.2004] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Infection of the central nervous system (CNS) is a severe and frequently fatal event during the course of many diseases caused by microbes with predominantly intracellular life cycles. Examples of these include the facultative intracellular bacteria Listeria monocytogenes, Mycobacterium tuberculosis, and Brucella and Salmonella spp. and obligate intracellular microbes of the Rickettsiaceae family and Tropheryma whipplei. Unfortunately, the mechanisms used by intracellular bacterial pathogens to enter the CNS are less well known than those used by bacterial pathogens with an extracellular life cycle. The goal of this review is to elaborate on the means by which intracellular bacterial pathogens establish infection within the CNS. This review encompasses the clinical and pathological findings that pertain to the CNS infection in humans and includes experimental data from animal models that illuminate how these microbes enter the CNS. Recent experimental data showing that L. monocytogenes can invade the CNS by more than one mechanism make it a useful model for discussing the various routes for neuroinvasion used by intracellular bacterial pathogens.
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Affiliation(s)
- Douglas A Drevets
- Department of Medicine, Oklahoma University Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
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Kim KS. Pathogenesis of bacterial meningitis: from bacteraemia to neuronal injury. Nat Rev Neurosci 2003; 4:376-85. [PMID: 12728265 DOI: 10.1038/nrn1103] [Citation(s) in RCA: 301] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Kwang Sik Kim
- Pediatric Infectious Diseases, Johns Hopkins Hospital, 600 North Wolfe Street, Park 256, Baltimore, Maryland 21287, USA.
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Abstract
The mortality and morbidity associated with bacterial meningitis have remained significant despite advances in antimicrobial chemotherapy and supportive care. A major contributing factor to this high mortality and morbidity is our incomplete understanding of the pathogenesis of this disease and its associated neurological sequelae. Most cases of bacterial meningitis develop as a result of haematogenous spread, but it is unclear how circulating bacteria cross the blood-brain barrier. Experimental animal studies indicate that two forms of neuronal injury, such as necrotic cortical injury and apoptotic hippocampal injury, are predominant in bacterial meningitis, but the mechanisms by which these two forms of injury occur are unclear. Recent studies have identified several bacteria-host determinants for bacterial translocation of the blood-brain barrier, and several host inflammatory markers that are associated with neuronal injury in animal models of experimental bacterial meningitis. These determinants/markers may provide important targets for the prevention and treatment of bacterial meningitis. This review focuses on representative steps in the pathogenesis of bacterial meningitis that are likely to be key targets in coming years, and summarises the status of current knowledge for each target.
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Affiliation(s)
- Kwang Sik Kim
- Pediatric Infectious Diseases Division, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Park 256, Baltimore, MD 21287, USA.
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Verhaegen J, Vandecasteele SJ, Vandeven J, Verbiest N, Lagrou K, Peetermans WE. Antibiotic susceptibility and serotype distribution of 240 Streptococcus pneumoniae causing meningitis in Belgium 1997-2000. Acta Clin Belg 2003; 58:19-26. [PMID: 12723258 DOI: 10.1179/acb.2003.58.1.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Cerebrospinal fluid isolates of Streptococcus pneumoniae, collected during the years 1997-2000 at more than 100 Belgian laboratories were studied. The 10 most common serotypes-serogroups representing 76% of the isolates were 14, 6, 9, 19, 23, 18, 4, 10, 8 and 12 (in order of frequency). Thirty-six percent of strains were isolated in children < 5 years old. In this age group the number of serogroups was more limited and 81.4% are included in the 7-valent conjugate vaccine. Decreased susceptibility to penicillin was observed in 13.9% of 237 strains (MIC > 0.06 mg/L), with only 2.1% resistant strains (MIC > 1 mg/L). Twelve strains showed reduced susceptibility to cefotaxime (MIC > 0.5 mg/L). Only three of the 237 strains were intermediately susceptible to meropenem. All strains were susceptible to vancomycin and moxifloxacin. In Belgium, high doses of third generation cephalosporins remain effective for the treatment of pneumococcal meningitis. The new fluoroquinolones seem the most promising agents for the treatment of pneumococcal meningitis in the future.
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Affiliation(s)
- J Verhaegen
- Afd. Microbiologie, Universitaire Ziekenhuizen Leuven, Herestraat 49, B-3000 Leuven, België.
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Meli DN, Christen S, Leib SL, Täuber MG. Current concepts in the pathogenesis of meningitis caused by Streptococcus pneumoniae. Curr Opin Infect Dis 2002; 15:253-7. [PMID: 12015459 DOI: 10.1097/00001432-200206000-00007] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In spite of improved antimicrobial therapy, bacterial meningitis still results in brain damage leading to significant long-term neurological sequelae in a substantial number of survivors, as confirmed by several recent studies. Meningitis caused by Streptococcus pneumoniae is associated with a particularly severe outcome. Experimental studies over the past few years have increased our understanding of the molecular mechanisms underlying the events that ultimately lead to brain damage during meningitis. Necrotic damage to the cerebral cortex is at least partly mediated by ischemia and oxygen radicals and therefore offers a promising target for adjunctive therapeutic intervention. Neuronal apoptosis in the hippocampus may represent the major pathological process responsible for cognitive impairment and learning disabilities in survivors. However, the mechanisms involved in causing this damage remain largely unknown. Anti-inflammatory treatment with corticosteroids aggravates hippocampal damage, thus underlining the potential shortcomings of current adjuvant strategies. In contrast, the combined inhibition of matrix metalloproteinase and tumour necrosis factor-alpha converting enzyme protected both the cortex and hippocampus in experimental meningitis, and may represent a promising new approach to adjunctive therapy. It is the hope that a more refined molecular understanding of the pathogenesis of brain damage during bacterial meningitis will lead to new adjunctive therapies.
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Affiliation(s)
- Damian N Meli
- Institute for Infectious Diseases, University of Berne, Berne, Switzerland
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Nassif X, Bourdoulous S, Eugène E, Couraud PO. How do extracellular pathogens cross the blood-brain barrier? Trends Microbiol 2002; 10:227-32. [PMID: 11973156 DOI: 10.1016/s0966-842x(02)02349-1] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Bacterial invasion of the meninges can occur as a consequence of bloodstream invasion by some bacterial pathogens. Bacteria enter the central nervous system following a direct interaction with the luminal side of the cerebral endothelium, which constitutes the blood-brain barrier. To breach the barriers protecting the brain, extracellular pathogens must cross a monolayer of tight junction-expressing endothelial or epithelial cells. The limited number of pathogens capable of crossing these tight barriers and invading the meninges suggests that they display very specific attributes. For Neisseria meningitidis, type IV pili have been identified as being essential for meningeal invasion and it is believed other, as-yet-unidentified factors are also involved.
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Affiliation(s)
- Xavier Nassif
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, Université Paris V, 156 Rue de Vaugirard, 75015 Paris, France.
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Affiliation(s)
- Barry M Gray
- Division of Medical Education, Medical College of South Carolina, Spartanburg, Spartanburg, South Carolina, USA
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