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Kinsella CM, Edridge AWD, van Zeggeren IE, Deijs M, van de Beek D, Brouwer MC, van der Hoek L. Bacterial ribosomal RNA detection in cerebrospinal fluid using a viromics approach. Fluids Barriers CNS 2022; 19:102. [PMID: 36550487 PMCID: PMC9773461 DOI: 10.1186/s12987-022-00400-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND In patients with central nervous system (CNS) infections identification of the causative pathogen is important for treatment. Metagenomic next-generation sequencing techniques are increasingly being applied to identify causes of CNS infections, as they can detect any pathogen nucleic acid sequences present. Viromic techniques that enrich samples for virus particles prior to sequencing may simultaneously enrich ribosomes from bacterial pathogens, which are similar in size to small viruses. METHODS We studied the performance of a viromic library preparation technique (VIDISCA) combined with low-depth IonTorrent sequencing (median ~ 25,000 reads per sample) for detection of ribosomal RNA from common pathogens, analyzing 89 cerebrospinal fluid samples from patients with culture proven bacterial meningitis. RESULTS Sensitivity and specificity to Streptococcus pneumoniae (n = 24) before and after optimizing threshold parameters were 79% and 52%, then 88% and 90%. Corresponding values for Neisseria meningitidis (n = 22) were 73% and 93%, then 67% and 100%, Listeria monocytogenes (n = 24) 21% and 100%, then 27% and 100%, and Haemophilus influenzae (n = 18) 56% and 100%, then 71% and 100%. A higher total sequencing depth, no antibiotic treatment prior to lumbar puncture, increased disease severity, and higher c-reactive protein levels were associated with pathogen detection. CONCLUSION We provide proof of principle that a viromic approach can be used to correctly identify bacterial ribosomal RNA in patients with bacterial meningitis. Further work should focus on increasing assay sensitivity, especially for problematic species (e.g. L. monocytogenes), as well as profiling additional pathogens. The technique is most suited to research settings and examination of idiopathic cases, rather than an acute clinical setting.
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Affiliation(s)
- Cormac M. Kinsella
- grid.7177.60000000084992262Amsterdam UMC, Laboratory of Experimental Virology, Department of Medical Microbiology and Infection Prevention, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ,Amsterdam Institute for Infection and Immunity, Postbus 22660, 1100 DD Amsterdam, The Netherlands
| | - Arthur W. D. Edridge
- grid.7177.60000000084992262Amsterdam UMC, Laboratory of Experimental Virology, Department of Medical Microbiology and Infection Prevention, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ,Amsterdam Institute for Infection and Immunity, Postbus 22660, 1100 DD Amsterdam, The Netherlands
| | - Ingeborg E. van Zeggeren
- grid.7177.60000000084992262Amsterdam UMC, Department of Neurology, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ,grid.484519.5Amsterdam Neuroscience, Neuroinfection and Inflammation, Amsterdam, The Netherlands
| | - Martin Deijs
- grid.7177.60000000084992262Amsterdam UMC, Laboratory of Experimental Virology, Department of Medical Microbiology and Infection Prevention, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ,Amsterdam Institute for Infection and Immunity, Postbus 22660, 1100 DD Amsterdam, The Netherlands
| | - Diederik van de Beek
- grid.7177.60000000084992262Amsterdam UMC, Department of Neurology, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ,grid.484519.5Amsterdam Neuroscience, Neuroinfection and Inflammation, Amsterdam, The Netherlands
| | - Matthijs C. Brouwer
- grid.7177.60000000084992262Amsterdam UMC, Department of Neurology, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ,grid.484519.5Amsterdam Neuroscience, Neuroinfection and Inflammation, Amsterdam, The Netherlands
| | - Lia van der Hoek
- grid.7177.60000000084992262Amsterdam UMC, Laboratory of Experimental Virology, Department of Medical Microbiology and Infection Prevention, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands ,Amsterdam Institute for Infection and Immunity, Postbus 22660, 1100 DD Amsterdam, The Netherlands
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Principi N, Esposito S. Bacterial meningitis: new treatment options to reduce the risk of brain damage. Expert Opin Pharmacother 2019; 21:97-105. [PMID: 31675255 DOI: 10.1080/14656566.2019.1685497] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Introduction: Bacterial meningitis (BM) is a medical emergency and its etiology varies according to the age group and geographic area. Studies have shown that brain damage, sequelae and neuropsychological deficits depend not only on the direct deleterious action of the pathogens, but also on the host defenses themselves.Areas covered: Corticosteroids (CS) were the first drugs used with the intent to limit the exaggerated host response. However, as steroid addition to antibiotics is frequently unsatisfactory, other measures have been suggested. In this study, the most important adjuvant therapies that are potentially useful to limit the neuropsychological damage of BM are discussed.Expert opinion: The pathophysiological mechanisms leading to the development of brain damage are not completely defined. Moreover, the efficacy of adjuvant therapies can vary according to the aetiologic cause of BM, and differences in immune system function of the host can play a relevant role in the expression of inflammation and related problems. It is likely that none of the measures with demonstrated efficacy in animal models can be translated into clinical practice in the next few years, suggesting that to reduce the total burden of BM, the increased use of vaccines seems to be the best solution.
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Affiliation(s)
- Nicola Principi
- Emeritus of Pediatrics, Università degli Studi di Milano, Milan, Italy
| | - Susanna Esposito
- Pietro Barilla Children's Hospital, Department of Medicine and Surgery, University of Parma, Parma, Italy
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Kim JY, Seo SM, Lee HK, Kim HW, Choi YK. Comparison of the virulence of Streptococcus pneumoniae in ICR mouse stocks of three different origins. Lab Anim Res 2019; 35:5. [PMID: 31463224 PMCID: PMC6707427 DOI: 10.1186/s42826-019-0002-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/11/2019] [Indexed: 01/13/2023] Open
Abstract
Streptococcus pneumoniae causes many people to suffer from pneumonia, septicemia, and other diseases worldwide. To identify the difference in susceptibility of and treatment efficacy against S. pneumoniae in three ICR mouse stocks (Korl:ICR, A:ICR, and B:ICR) with different origins, mice were infected with 2 × 106, 2 × 107, and 2 × 108 CFU of S. pneumoniae D39 intratracheally. The survival of mice was observed until three weeks after the infection. The three stocks of mice showed no significant survival rate difference at 2 × 106 and 2 × 107 CFU. However, the lung and spleen weight in the A:ICR stock was significantly different from that in the other two stocks, whereas the liver weight in B:ICR stock was significantly lower than that in the other two stocks. Interestingly, no significant CFU difference in the organs was observed between the ICR stocks. The level of interferon gamma inducible protein 10 in Korl:ICR was significantly lower than that in the other two stocks. The level of granulocyte colony stimulating factor in B:ICR was significantly lower than in the other two stocks. However, tumor-necrosis factor-alpha and interleukin-6 levels showed no significant difference between the ICR stocks. In the vancomycin efficacy test after the S. pneumoniae infection, both the single-dose and double-dose vancomycin-treated groups showed a significantly better survival rate than the control group. There was no significant survival difference between the three stocks. These data showed that Korl:ICR, A:ICR, and B:ICR have no susceptibility difference to the S. pneumoniae D39 serotype 2.
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Affiliation(s)
- Jun-Young Kim
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029 Republic of Korea
| | - Sun-Min Seo
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029 Republic of Korea
| | - Han-Kyul Lee
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029 Republic of Korea
| | - Han-Woong Kim
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029 Republic of Korea
| | - Yang-Kyu Choi
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029 Republic of Korea
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4
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Zhang P, Zhang N, Liu L, Zheng K, Zhu L, Zhu J, Cao L, Jiang Y, Liu G, He Q. Polymorphisms of toll-like receptors 2 and 9 and severity and prognosis of bacterial meningitis in Chinese children. Sci Rep 2017; 7:42796. [PMID: 28202935 PMCID: PMC5311876 DOI: 10.1038/srep42796] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 01/13/2017] [Indexed: 02/07/2023] Open
Abstract
Toll-like receptors (TLRs) play a crucial role in innate immunity, protecting the host from bacterial pathogens. We investigated whether bacterial meningitis (BM) in children was associated with gene polymorphisms in TLR2 (rs3804099), TLR3 (rs3775291 and rs3775290) and TLR9 (rs352139 and rs352140). Blood samples were taken from 218 child patients with confirmed BM and 330 healthy adult controls (HC) and polymorphisms of these genes were analyzed by PCR-based sequencing. For TLR2 rs3804099, frequencies of the minor allele C were markedly higher in patients with severe BM (defined as CSF glucose concentration ≤ 1.5 mmol/L and seizures) than those without (43.5% and 40.1% vs. 30.1% and 29.1%, p = 0.008 and p = 0.016, respectively). For TLR9 rs352139, patients who carried genotype AA and minor allele A developed seizures less often than those without (OR = 0.289, p = 0.003 and OR = 0.568, p = 0.004, respectively). However, for TLR9 rs352140, patients who carried genotype TT and minor allele T developed seizures more often than those without (OR = 3.385, p = 0.004 and OR = 1.767, p = 0.004, respectively). Our finding suggested that genetic variations in TLR2 and TLR9 are associated with severity and prognosis of bacterial meningitis in Chinese children. However, the results should be interpreted with caution since the number of subjects included was limited.
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Affiliation(s)
- Pingping Zhang
- Department of Infectious Diseases, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China
| | - Nan Zhang
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing 100069, China
| | - Linlin Liu
- Department of Infectious Diseases, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China
| | - Kai Zheng
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing 100069, China
| | - Liang Zhu
- Department of Infectious Diseases, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China
| | - Junping Zhu
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing 100069, China
| | - Lina Cao
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing 100069, China
| | - Yiyuan Jiang
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing 100069, China
| | - Gang Liu
- Department of Infectious Diseases, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China
| | - Qiushui He
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing 100069, China.,Department of Medical Microbiology and Immunology, University of Turku, Turku 20520, Finland
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Too LK, Mitchell AJ, McGregor IS, Hunt NH. Antibody-induced neutrophil depletion prior to the onset of pneumococcal meningitis influences long-term neurological complications in mice. Brain Behav Immun 2016; 56:68-83. [PMID: 26965652 DOI: 10.1016/j.bbi.2016.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 01/23/2016] [Accepted: 01/30/2016] [Indexed: 10/22/2022] Open
Abstract
During pneumococcal meningitis, clearance of bacteria by recruited neutrophils is crucial for host protection. However, these innate immune mechanisms are often insufficient and treatment with antibiotics is necessary to prevent death. Despite this antibiotic treatment, approximately half of all survivors suffer lifelong neurological problems. There is growing evidence indicating the harmful effects of neutrophils on CNS integrity. Therefore, the present study investigated the roles of neutrophils in the acute inflammatory response and the resulting long-term neuropsychological effects in murine pneumococcal meningitis. Long-term behavioural and cognitive functions in mice were measured using an automated IntelliCage system. Neutrophil depletion with antibody 1A8 as adjunctive therapy was shown to remarkably impair survival in meningitic C57BL/6J mice despite antibiotic (ceftriaxone) treatment. This was accompanied by increased bacterial load in the cerebrospinal fluid (CSF) and an increase in IL-1β, but decrease in TNF, within the CSF at 20h after bacterial inoculation. In the longer term, the surviving neutrophil-depleted post-meningitic (PM) mice displayed reduced diurnal hypolocomotion compared to PM mice treated with an isotype antibody. However, they showed nocturnal hyperactivity, and greater learning impairment in a patrolling task that is believed to depend upon an intact hippocampus. The data thus demonstrate two important mechanisms: 1. Neutrophil extravasation into the CNS during pneumococcal meningitis influences the pro-inflammatory response and is central to control of the bacterial load, an increase in which may lead to death. 2. Neutrophil-mediated changes in the acute inflammatory response modulate the neuropsychological sequelae in mice that survive pneumococcal meningitis.
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Affiliation(s)
- Lay Khoon Too
- Molecular Immunopathology Unit, Bosch Institute and School of Medical Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | | | - Iain S McGregor
- School of Psychology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Nicholas H Hunt
- Molecular Immunopathology Unit, Bosch Institute and School of Medical Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.
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Doran KS, Fulde M, Gratz N, Kim BJ, Nau R, Prasadarao N, Schubert-Unkmeir A, Tuomanen EI, Valentin-Weigand P. Host-pathogen interactions in bacterial meningitis. Acta Neuropathol 2016; 131:185-209. [PMID: 26744349 PMCID: PMC4713723 DOI: 10.1007/s00401-015-1531-z] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/21/2015] [Accepted: 12/22/2015] [Indexed: 12/26/2022]
Abstract
Bacterial meningitis is a devastating disease occurring worldwide with up to half of the survivors left with permanent neurological sequelae. Due to intrinsic properties of the meningeal pathogens and the host responses they induce, infection can cause relatively specific lesions and clinical syndromes that result from interference with the function of the affected nervous system tissue. Pathogenesis is based on complex host–pathogen interactions, some of which are specific for certain bacteria, whereas others are shared among different pathogens. In this review, we summarize the recent progress made in understanding the molecular and cellular events involved in these interactions. We focus on selected major pathogens, Streptococcus pneumonia, S. agalactiae (Group B Streptococcus), Neisseria meningitidis, and Escherichia coli K1, and also include a neglected zoonotic pathogen, Streptococcus suis. These neuroinvasive pathogens represent common themes of host–pathogen interactions, such as colonization and invasion of mucosal barriers, survival in the blood stream, entry into the central nervous system by translocation of the blood–brain and blood–cerebrospinal fluid barrier, and induction of meningeal inflammation, affecting pia mater, the arachnoid and subarachnoid spaces.
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7
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Jordan I, Calzada Y, Monfort L, Vila-Pérez D, Felipe A, Ortiz J, Cambra FJ, Muñoz-Almagro C. Clinical, biochemical and microbiological factors associated with the prognosis of pneumococcal meningitis in children. Enferm Infecc Microbiol Clin 2016; 34:101-7. [DOI: 10.1016/j.eimc.2015.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/28/2015] [Accepted: 03/02/2015] [Indexed: 10/23/2022]
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8
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Liechti FD, Grandgirard D, Leib SL. Bacterial meningitis: insights into pathogenesis and evaluation of new treatment options: a perspective from experimental studies. Future Microbiol 2015; 10:1195-213. [PMID: 26119836 DOI: 10.2217/fmb.15.43] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacterial meningitis is associated with high mortality and morbidity rates. Bacterial components induce an overshooting inflammatory reaction, eventually leading to brain damage. Pathological correlates of neurofunctional deficits include cortical necrosis, damage of the inner ear and hippocampal apoptosis. The hippocampal dentate gyrus is important for memory acquisition and harbors a neuronal stem cell niche, thus being potentially well equipped for regeneration. Adjuvant therapies aimed at decreasing the inflammatory reaction, for example, dexamethasone, and those protecting the brain from injury have been evaluated in animal models of the disease. They include nonbacteriolytic antibiotics (e.g., daptomycin), metalloproteinase inhibitors and modulators of the immunological response, for example, granulocyte colony-stimulating factor. Increasing research interest has recently been focused on interventions aimed at supporting regenerative processes.
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Affiliation(s)
- Fabian D Liechti
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstr. 51, CH-3010 Bern, Switzerland
| | - Denis Grandgirard
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstr. 51, CH-3010 Bern, Switzerland
| | - Stephen L Leib
- Neuroinfection Laboratory, Institute for Infectious Diseases, University of Bern, Friedbühlstr. 51, CH-3010 Bern, Switzerland.,Biology Division, Spiez Laboratory, Swiss Federal Office for Civil Protection, Austrasse, CH-3700 Spiez, Switzerland
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9
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Adjuvant granulocyte colony-stimulating factor therapy results in improved spatial learning and stimulates hippocampal neurogenesis in a mouse model of pneumococcal meningitis. J Neuropathol Exp Neurol 2015; 74:85-94. [PMID: 25470346 DOI: 10.1097/nen.0000000000000152] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Despite the development of new antibiotic agents, mortality of pneumococcal meningitis remains high. In addition, meningitis results in severe long-term morbidity, most prominently cognitive deficits. Granulocyte colony-stimulating factor (G-CSF) stimulates proliferation and differentiation of hematopoietic progenitor cells and increases the number of circulating neutrophil granulocytes. This study investigated the effect of adjuvant G-CSF treatment on cognitive function after pneumococcal meningitis. C57BL/6 mice were infected by subarachnoid injection of Streptococcus pneumoniae serotype 3 and treated with ceftriaxone and G-CSF subcutaneously or ceftriaxone alone for 5 days. Clinical scores, motor performance, and mortality during bacterial meningitis were unaffected by adjuvant G-CSF treatment. No effect of G-CSF treatment on production of proinflammatory cytokines or activation of microglia or astrocytes was observed. The G-CSF treatment did, however, result in hippocampal neurogenesis and improved spatial learning performance 6 weeks after meningitis. These results suggest that G-CSF might offer a new adjuvant therapeutic approach in bacterial meningitis to reduce long-term cognitive deficits.
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Abstract
OBJECTIVE To examine the pathways of bacterial invasion and subsequent spreading in the inner ear during pneumococcal meningitis. STUDY DESIGN A well-established adult rat model of Streptococcus pneumoniae meningitis was used. METHODS Thirty rats were inoculated intrathecally with S. pneumoniae serotype 1, 3 or 9 V and received no additional treatment. The rats were sacrificed when reaching terminal illness or on Day 7 and then prepared for serial sectioning and PAS-Alcian blue staining for light microscopy. RESULTS During the first few days after inoculation, bacteria invade the inner ear through the cochlear aqueduct, into the scala tympani of the cochlea (perilymphatic space). From here, bacteria spreads apically toward the helicotrema and subsequently basally through the scala vestibuli, toward the vestibule and the vestibular system. When the bacteria after 5 to 6 days had reached scala vestibuli of the basal turn of the cochlea, hematogenous spreading occurred to the spiral ligament and into the cochlear endolymph, subsequently to the vestibular endolymph. We found no evidence of alternative routes for bacterial invasion in the inner ear. Several internal barriers to bacterial spreading were found within the inner ear. Bacterial elimination was evidenced by engulfment by macrophages within the inner ear. CONCLUSION From the meninges, pneumococci invade the inner ear through the cochlear aqueduct during the first days of infection, whereas hematogenous invasion via the spiral ligament capillary bed occur at later stages. Although internal barriers exist within the inner ear, the spreading of bacteria occurs via the natural pathways of the fluid compartments. Bacterial elimination occurs by local macrophage engulfment.
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Martinot M, Oswald L, Parisi E, Etienne E, Argy N, Grawey I, De Briel D, Zadeh MM, Federici L, Blaison G, Koebel C, Jaulhac B, Hansmann Y, Christmann D. Immunoglobulin deficiency in patients with Streptococcus pneumoniae or Haemophilus influenzae invasive infections. Int J Infect Dis 2014; 19:79-84. [DOI: 10.1016/j.ijid.2013.10.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/30/2013] [Accepted: 10/31/2013] [Indexed: 10/25/2022] Open
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Møller MN, Brandt C, Østergaard C, Caye-Thomasen P. Endolymphatic sac involvement in bacterial meningitis. Eur Arch Otorhinolaryngol 2014; 272:843-851. [DOI: 10.1007/s00405-014-2884-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/03/2014] [Indexed: 11/24/2022]
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McIntosh EDG. Treatment and prevention strategies to combat pediatric pneumococcal meningitis. Expert Rev Anti Infect Ther 2014; 3:739-50. [PMID: 16207165 DOI: 10.1586/14787210.3.5.739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pneumococcal meningitis is a severe, life-threatening infection of the nervous system affecting infants, children and adults alike. The incidence of pneumococcal meningitis in infants and children less than 2 years of age in Europe is approximately 10 out of 100,000 per year, rising to approximately 148 out of 100,000 per year in Gambian infants. The use of highly sensitive tests such as PCR may increase the likelihood of detecting the infection by 20% or more. Epidemics of serotype 1 pneumococcal meningitis in northern Ghana, have had many of the characteristics of meningococcal meningitis epidemics. Neurologic sequelae may occur in 28-63% of cases, and serotype 3 is associated with a 2.54 relative risk of death. The pathogenic process can be divided into invasion, inflammatory pathways, bacterial toxicity and damage; pneumolysin being particularly associated with apoptosis. In the future, neuroprotection may be achieved, targeting this process at all these levels. Therapeutic guidelines have been published by the Infectious Diseases Society of America. Standard empiric therapy, in those aged greater than or equal to 1 month, is a third-generation cephalosporin plus vancomycin. There is insufficient evidence relating to the use or otherwise of corticosteroids in pneumococcal meningitis to make a firm recommendation. The advent of a pneumococcal conjugate vaccine is the most powerful tool available for the prevention of pneumococcal meningitis in all parts of the world.
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Inngjerdingen KT, Langerud BK, Rasmussen H, Olsen TK, Austarheim I, Grønhaug TE, Aaberge IS, Diallo D, Paulsen BS, Michaelsen TE. Pectic Polysaccharides Isolated from Malian Medicinal Plants Protect againstStreptococcus pneumoniaein a Mouse Pneumococcal Infection Model. Scand J Immunol 2013; 77:372-88. [DOI: 10.1111/sji.12047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 03/09/2013] [Indexed: 01/19/2023]
Affiliation(s)
- K. T. Inngjerdingen
- Department of Pharmaceutical Chemistry; School of Pharmacy; University of Oslo; Oslo; Norway
| | - B. K. Langerud
- Department of Bacteriology and Immunology; Division of Infectious Disease Control; Norwegian Institute of Public Health; Oslo; Norway
| | - H. Rasmussen
- Department of Laboratory Animal Services; Division of Public Relations and Institute Resources; Norwegian Institute of Public Health; Oslo; Norway
| | - T. K. Olsen
- Department of Laboratory Animal Services; Division of Public Relations and Institute Resources; Norwegian Institute of Public Health; Oslo; Norway
| | - I. Austarheim
- Department of Pharmaceutical Chemistry; School of Pharmacy; University of Oslo; Oslo; Norway
| | - T. E. Grønhaug
- Department of Pharmaceutical Chemistry; School of Pharmacy; University of Oslo; Oslo; Norway
| | - I. S. Aaberge
- Department of Bacteriology and Immunology; Division of Infectious Disease Control; Norwegian Institute of Public Health; Oslo; Norway
| | | | - B. S. Paulsen
- Department of Pharmaceutical Chemistry; School of Pharmacy; University of Oslo; Oslo; Norway
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Abstract
Pneumococcal meningitis continues to be associated with high rates of mortality and long-term neurological sequelae. The most common route of infection starts by nasopharyngeal colonization by Streptococcus pneumoniae, which must avoid mucosal entrapment and evade the host immune system after local activation. During invasive disease, pneumococcal epithelial adhesion is followed by bloodstream invasion and activation of the complement and coagulation systems. The release of inflammatory mediators facilitates pneumococcal crossing of the blood-brain barrier into the brain, where the bacteria multiply freely and trigger activation of circulating antigen-presenting cells and resident microglial cells. The resulting massive inflammation leads to further neutrophil recruitment and inflammation, resulting in the well-known features of bacterial meningitis, including cerebrospinal fluid pleocytosis, cochlear damage, cerebral edema, hydrocephalus, and cerebrovascular complications. Experimental animal models continue to further our understanding of the pathophysiology of pneumococcal meningitis and provide the platform for the development of new adjuvant treatments and antimicrobial therapy. This review discusses the most recent views on the pathophysiology of pneumococcal meningitis, as well as potential targets for (adjunctive) therapy.
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Genome-wide identification of Streptococcus pneumoniae genes essential for bacterial replication during experimental meningitis. Infect Immun 2010; 79:288-97. [PMID: 21041497 DOI: 10.1128/iai.00631-10] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Meningitis is the most serious of invasive infections caused by the Gram-positive bacterium Streptococcus pneumoniae. Vaccines protect only against a limited number of serotypes, and evolving bacterial resistance to antimicrobials impedes treatment. Further insight into the molecular pathogenesis of invasive pneumococcal disease is required in order to enable the development of new or adjunctive treatments and/or pneumococcal vaccines that are efficient across serotypes. We applied genomic array footprinting (GAF) in the search for S. pneumoniae genes that are essential during experimental meningitis. A total of 6,000 independent TIGR4 marinerT7 transposon mutants distributed over four libraries were injected intracisternally into rabbits, and cerebrospinal fluid (CSF) was collected after 3, 9, and 15 h. Microarray analysis of mutant-specific probes from CSF samples and inocula identified 82 and 11 genes mutants of which had become attenuated or enriched, respectively, during infection. The results point to essential roles for capsular polysaccharides, nutrient uptake, and amino acid biosynthesis in bacterial replication during experimental meningitis. The GAF phenotype of a subset of identified targets was followed up by detailed studies of directed mutants in competitive and noncompetitive infection models of experimental rat meningitis. It appeared that adenylosuccinate synthetase, flavodoxin, and LivJ, the substrate binding protein of a branched-chain amino acid ABC transporter, are relevant as targets for future therapy and prevention of pneumococcal meningitis, since their mutants were attenuated in both models of infection as well as in competitive growth in human cerebrospinal fluid in vitro.
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Abstract
The clinical outcome of central nervous system infection is determined by the characteristics of the pathogen and the brain's response to the invading bacteria. How infection leads to brain injury remains unresolved. An impediment to progress is the complexity of pathophysiologic processes. Some of the mechanisms involved have been identified in experimental models, providing insights into the molecular basis of brain injury and regeneration, and hinting at targets for therapy. Adjuvant therapies have been proposed. Interventions that protect the brain are evaluated for their potential to preserve neuro-integrative functions in long-term survivors of bacterial meningitis. This article summarizes current studies evaluating pharmacologic interventions in experimental models of bacterial meningitis and discusses how the knowledge gathered could translate into more effective therapies.
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Worsøe L, Brandt CT, Lund SP, Østergaard C, Thomsen J, Cayé-Thomasen P. Systemic steroid reduces long-term hearing loss in experimental pneumococcal meningitis. Laryngoscope 2010; 120:1872-9. [DOI: 10.1002/lary.21007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Intratympanic Steroid Prevents Long-Term Spiral Ganglion Neuron Loss in Experimental Meningitis. Otol Neurotol 2010; 31:394-403. [DOI: 10.1097/mao.0b013e3181d2796c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Østergaard C, Benfield T. Macrophage migration inhibitory factor in cerebrospinal fluid from patients with central nervous system infection. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:R101. [PMID: 19558639 PMCID: PMC2717473 DOI: 10.1186/cc7933] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/22/2009] [Accepted: 06/26/2009] [Indexed: 12/29/2022]
Abstract
Introduction Macrophage migration inhibitory factor (MIF) plays an essential pathophysiological role in septic shock, but its role in central nervous system infection (CNS) remains to be defined. Methods We investigated cerebrospinal fluid (CSF) levels of MIF in 171 patients who were clinically suspected of having meningitis on admission. Of these, 31 were found to have purulent meningitis of known aetiology, 20 purulent meningitis of unknown aetiology, 59 lymphocytic meningitis and 11 encephalitis, whereas 50 were suspected of having but had no evidence of CNS infection. Results CSF MIF levels were significantly higher in patients with purulent meningitis of known aetiology (median [interquartile range]: 8,639 [3,344 to 20,600] ng/l) than in patients with purulent meningitis of unknown aetiology (2,209 [1,516 to 6,550] ng/l; Mann-Whitney test, P = 0.003), patients with lymphocytic meningitis (1,912 [1,302 to 4,105] ng/l; P < 0.001) and patients suspected of having but without evidence of CNS infection (1,472 [672 to 3,447] ng/l; P < 0.001). Also, patients with encephalitis (6,937 [3,961 to 8,353] ng/l) had higher CSF MIF than did patients without CNS infection (P < 0.01). Among patients with purulent meningitis, CSF MIF levels were significantly higher in patients infected with pneumococci than in those with meningococcal infection (11,569 [8,615 to 21,935] ng/l versus 5,006 [1,717 to 10,905] ng/l; P = 0.02), in patients who required versus those not requiring assisted ventilation (10,493 [5,961 to 22,725] ng/l versus 3,240 [1,563 to 9,302] ng/l; P = 0.003), and in patients with versus those without impaired consciousness (8,614 [3,344 to 20,935] ng/l versus 2,625 [1,561 to 7,530] ng/l; P = 0.02). CSF MIF levels correlated significantly with meningeal inflammation (P < 0.05) but not with systemic inflammatory response (P > 0.05) in patients with purulent meningitis of known aetiology, those with lymphocytic meningitis and those with encephalitis. Conclusions MIF was significantly increased in the CSF of patients with purulent meningitis and encephalitis, and was to some degree associated with severity of the infection. Our findings indicate that MIF may play an important role in CNS infection.
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Affiliation(s)
- Christian Østergaard
- Department of Clinical Microbiology, Copenhagen University Hospital Herlev, Herlev Ringvej, DK-2730 Herlev, Denmark.
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Cayé-Thomasen P, Worsøe L, Brandt CT, Miyazaki H, Ostergaard C, Frimodt-Møller N, Thomsen J. Routes, dynamics, and correlates of cochlear inflammation in terminal and recovering experimental meningitis. Laryngoscope 2009; 119:1560-70. [PMID: 19504554 DOI: 10.1002/lary.20260] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES/HYPOTHESIS To examine the routes, dynamics and correlates of cochlear inflammation in meningitis to provide information on the pathogenesis of the associated hearing loss and indications for rational pharmacotherapeutical intervention. STUDY DESIGN A well-established rat model of Streptococcus pneumoniae meningitis was employed. METHODS Eight rats were inoculated intrathecally and not treated, whereas 26 were inoculated and treated with ceftriaxone. Six rats were sham-inoculated, making a total of 40 rats. The rats were sacrificed when reaching terminal illness or after 7 days, followed by light microscopy. Routes of cochlear inflammatory infiltration were examined. The volume fraction of inflammatory infiltration was estimated and correlated to bacterial and leukocyte counts in cerebrospinal fluid (CSF) and blood. RESULTS The perilymphatic space was infiltrated with inflammatory cells via cochlear aqueduct, whereas the endolymphatic space was infiltrated from the spiral ligament. Rosenthal's canal was infiltrated through osseous spiral lamina canaliculi. In the untreated group, the degree of inflammation correlated with time of death, whereas antibiotic treatment reversed this development. Perilymphatic inflammation correlated significantly with the CSF leukocyte count, whereas endolymphatic inflammation correlated with spiral ligament inflammation. CONCLUSIONS Meningogenic inflammation of the rat cochlea occurs via the cochlear aqueduct and the spiral ligament capillary bed. The spiral ganglion is infiltrated through the osseous spiral lamina. The degree of inflammation correlates positively with time of death in untreated meningitis, whereas antibiotic treatment leads to subsiding infiltration during recovery.
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Affiliation(s)
- Per Cayé-Thomasen
- Department of Otorhinolaryngology, Head and Neck Surgery, Copenhagen University Hospital Gentofte, Denmark.
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Brandt C, Holm D, Liptrot M, Østergaard C, Lundgren J, Frimodt‐Møller N, Skovsted I, Rowland I. Impact of Bacteremia on the Pathogenesis of Experimental Pneumococcal Meningitis. J Infect Dis 2008; 197:235-44. [DOI: 10.1086/524874] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Brandt CT, Simonsen H, Liptrot M, Søgaard LV, Lundgren JD, Ostergaard C, Frimodt-Møller N, Rowland IJ. In vivo study of experimental pneumococcal meningitis using magnetic resonance imaging. BMC Med Imaging 2008; 8:1. [PMID: 18194516 PMCID: PMC2253532 DOI: 10.1186/1471-2342-8-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 01/14/2008] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Magnetic Resonance Imaging (MRI) methods were evaluated as a tool for the study of experimental meningitis. The identification and characterisation of pathophysiological parameters that vary during the course of the disease could be used as markers for future studies of new treatment strategies. METHODS Rats infected intracisternally with S. pneumoniae (n = 29) or saline (n = 13) were randomized for imaging at 6, 12, 24, 30, 36, 42 or 48 hours after infection. T1W, T2W, quantitative diffusion, and post contrast T1W images were acquired at 4.7 T. Dynamic MRI (dMRI) was used to evaluate blood-brain-barrier (BBB) permeability and to obtain a measure of cerebral and muscle perfusion. Clinical- and motor scores, bacterial counts in CSF and blood, and WBC counts in CSF were measured. RESULTS MR images and dMRI revealed the development of a highly significant increase in BBB permeability (P < 0.002) and ventricle size (P < 0.0001) among infected rats. Clinical disease severity was closely related to ventricle expansion (P = 0.024). Changes in brain water distribution, assessed by ADC, and categorization of brain 'perfusion' by cortex DeltaSI(bolus) were subject to increased inter-rat variation as the disease progressed, but without overall differences compared to uninfected rats (P > 0.05). Areas of well-'perfused' muscle decreased with the progression of infection indicative of septicaemia (P = 0.05). CONCLUSION The evolution of bacterial meningitis was successfully followed in-vivo with MRI. Increasing BBB-breakdown and ventricle size was observed in rats with meningitis whereas changes in brain water distribution were heterogeneous. MRI will be a valuable technique for future studies aiming at evaluating or optimizing adjunctive treatments.
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Affiliation(s)
- Christian T Brandt
- National Center for Antimicrobials and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
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Pedersen M, Brandt CT, Knudsen GM, Ostergaard C, Skinhøj P, Skovsted IC, Frimodt-Møller N, Møller K. The effect of S. pneumoniae bacteremia on cerebral blood flow autoregulation in rats. J Cereb Blood Flow Metab 2008; 28:126-34. [PMID: 17565362 DOI: 10.1038/sj.jcbfm.9600514] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the present study, we studied the effect of bacteremia on cerebral blood flow (CBF) autoregulation in a rat model of pneumococcal bacteremia and meningitis. Anesthetized rats were divided into five groups (A to E) and inoculated with pneumococci intravenously and normal saline intracisternally (group A, N=10); saline intravenously and pneumococci intracisternally (group B, N=10); pneumococci intravenously and pneumococci intracisternally (group C, N=5); saline intravenously, antipneumococcal antibody intravenously (to prevent bacteremia), and pneumococci intracisternally (group D, N=10); or saline intravenously and saline intracisternally (group E, N=10), respectively. Positive cultures occurred in the blood for all rats in groups A, B, and C, and in the cerebrospinal fluid for all rats in groups D and E. Twenty-four hours after inoculation, CBF was measured with laser-Doppler ultrasound during incremental reductions in cerebral perfusion pressure (CPP) by controlled hemorrhage. Autoregulation was preserved in all rats without meningitis (groups A and E) and was lost in 24 of 25 meningitis rats (groups B, C, and D) (P<0.01). In group A, the lower limit was higher than that of group E (P<0.05). The slope of the CBF/CPP regression line differed between the meningitis groups (P<0.001), being steeper for group B than groups C and D, with no difference between these two groups. The results suggest that pneumococcal bacteremia in rats triggers cerebral vasodilation, which right shifts the lower limit of, but does not entirely abolish, CBF autoregulation in the absence of meningitis, and which may further aggravate the vasoparalysis induced by concomitant pneumococcal meningitis.
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Affiliation(s)
- Michael Pedersen
- Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
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Pagliano P, Fusco U, Attanasio V, Rossi M, Pantosti A, Conte M, Faella FS. Pneumococcal meningitis in childhood: a longitudinal prospective study. ACTA ACUST UNITED AC 2007; 51:488-95. [PMID: 17877732 DOI: 10.1111/j.1574-695x.2007.00324.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
After implementation of programmes for active immunization against Haemophilus influenzae b, Streptococcus pneumoniae and Neisseria meningitidis became the most common agents of bacterial meningitis in childhood. Over a 9-year period, children showing clinical and laboratory findings of meningitis on the basis of their positive cultures of blood or cerebro-spinal fluid (CSF) for S. pneumoniae were enrolled. Predisposing conditions, clinical and laboratory findings, and microbiological and imaging studies were considered. Meningitis-related death or neurological sequelae defined an unfavourable outcome. Sixty-four patients met the inclusion criteria. Thirty-one (48%) children had predisposing conditions to pneumococcal meningitis. Fever and neck stiffness were the main symptoms; 14 patients (22%) reported seizures before admission. Twenty-one patients required treatment in the intensive care unit (ICU). Streptococcus pneumoniae strains were penicillin susceptible in 54 cases (84%). Forty-eight children (75%) showed complete recovery. Two patients (3%) died, and 14 (22%) had sequelae. Patients with a low CSF cell count, low neutrophils, early admission to ICU or infection by penicillin-nonsusceptible strains of S. pneumoniae had an unfavourable outcome more frequently. Low blood neutrophils, low CSF cell count, early admission to ICU and infection by penicillin-nonsusceptible strains are the main factors predicting an unfavourable outcome in children with pneumococcal meningitis.
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Affiliation(s)
- Pasquale Pagliano
- Department of Emergency, I Division of Infectious Diseases, D. Cotugno Hospital, Naples, Italy.
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Pedersen M, Brandt CT, Knudsen GM, Ostergaard C, Skinhøj P, Frimodt-Møller N, Møller K. Cerebral blood flow autoregulation in early experimental S. pneumoniae meningitis. J Appl Physiol (1985) 2007; 102:72-8. [PMID: 17008439 DOI: 10.1152/japplphysiol.00697.2006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied cerebral blood flow (CBF) autoregulation and intracranial pressure (ICP) during normo- and hyperventilation in a rat model of Streptococcus pneumoniae meningitis. Meningitis was induced by intracisternal injection of S. pneumoniae. Mean arterial blood pressure (MAP), ICP, cerebral perfusion pressure (CPP, defined as MAP − ICP), and laser-Doppler CBF were measured in anesthetized infected rats ( n = 30) and saline-inoculated controls ( n = 30). CPP was either incrementally reduced by controlled hemorrhage or increased by intravenous norepinephrine infusion. Twelve hours postinoculation, rats were studied solely during normocapnia, whereas rats studied after 24 h were exposed to either normocapnia or to acute hypocapnia. In infected rats compared with control rats, ICP was unchanged at 12 h but increased at 24 h postinoculation (not significant and P < 0.01, respectively); hypocapnia did not lower ICP compared with normocapnia. Twelve hours postinoculation, CBF autoregulation was lost in all infected rats but preserved in all control rats ( P < 0.01). Twenty-four hours after inoculation, 10% of infected rats had preserved CBF autoregulation during normocapnia compared with 80% of control rats ( P < 0.01). In contrast, 60% of the infected rats and 100% of the control rats showed an intact CBF autoregulation during hypocapnia ( P < 0.05 for the comparison of infected rats at normocapnia vs. hypocapnia). In conclusion, CBF autoregulation is lost both at 12 and at 24 h after intracisternal inoculation of S. pneumoniae in rats. Impairment of CBF autoregulation precedes the increase in ICP, and acute hypocapnia may restore autoregulation without changing the ICP.
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Affiliation(s)
- Michael Pedersen
- Department of Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
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Brandt CT, Cayé-Thomasen P, Lund SP, Worsøe L, Ostergaard C, Frimodt-Møller N, Espersen F, Thomsen J, Lundgren JD. Hearing loss and cochlear damage in experimental pneumococcal meningitis, with special reference to the role of neutrophil granulocytes. Neurobiol Dis 2006; 23:300-11. [PMID: 16798006 DOI: 10.1016/j.nbd.2006.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 03/03/2006] [Accepted: 03/10/2006] [Indexed: 11/21/2022] Open
Abstract
Hearing loss is a well-known sequelae from meningitis, affecting up to 25% of survivors. However, the principal components of the infectious and inflammatory reaction responsible for the sensorineural hearing loss remain to be identified. The present study aimed to investigate the impact of an augmented neutrophil response on the development of hearing loss and cochlear damage in a model of experimental pneumococcal meningitis in rats. Hearing loss and cochlear damage were assessed by distortion product oto-acoustic emissions (DPOAE), auditory brainstem response (ABR) and histopathology in rats treated with ceftriaxone 28 h after infection. Rats were treated with Granulocyte Colony Stimulating Factor (G-CSF) initiated prior to infection, 28 h after infection or with ceftriaxone only. Rats were followed for 7 days, and assessment of hearing was performed before infection and 24 h and day 8 after infection. Pretreatment with G-CSF increased hearing loss 24 h after infection and on day 8 compared to untreated rats (Mann-Whitney, P = 0.012 and P = 0.013 respectively). The increased sensorineural hearing loss at day 8 was associated with significantly decreased spiral ganglion cell counts (P = 0.0006), increased damage to the organ of Corti (P = 0.007), increased areas of inflammatory infiltrates (P = 0.02) and increased white blood cell (WBC) counts in cerebrospinal fluid on day 8 after infection (P = 0.0084). Initiation of G-CSF 28 h after infection did not significantly affect hearing loss or cochlear pathology compared to controls. In conclusion, the inflammatory host reaction contributes significantly to the development of hearing loss in experimental meningitis.
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Affiliation(s)
- C T Brandt
- National Center for Antimicrobials and Infection Control, Division of Microbiology, Statens Serum Institut, Copenhagen, Denmark.
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Abstract
PURPOSE OF REVIEW The mortality of bacterial meningitis can reach 30%, and up to 50% of survivors suffer from persisting neurological deficits as a consequence of the disease. The incidence of neurological sequelae of bacterial meningitis has not improved over the last decade. Adjunctive therapeutic options are limited, and ongoing research into the pathophysiology of brain damage in bacterial meningitis aims at providing the scientific basis for future development of more efficient adjunctive options. RECENT FINDINGS In a population with good access to health care, dexamethasone given before or at the time of initiation of antibiotic therapy acts beneficially in paediatric pneumococcal meningitis, but not in meningococcal meningitis. In experimental animal models, brain-derived neurotrophic factor protected against brain injury and improved hearing while melatonin, which has antioxidant properties among other effects, reduced neuronal death. Transgene technology can be used to provide new insights into the pathophysiology of the disease and to identify potential therapeutic targets. SUMMARY Although dexamethasone improves outcome of bacterial meningitis under defined circumstances, the morbidity of bacterial meningitis still remains unacceptably high. Experimental models may help to identify new therapeutic strategies to further improve the neurological outcome in young children suffering from bacterial meningitis.
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Brandt CT, Lundgren JD, Frimodt-Møller N, Christensen T, Benfield T, Espersen F, Hougaard DM, Ostergaard C. Blocking of leukocyte accumulation in the cerebrospinal fluid augments bacteremia and increases lethality in experimental pneumococcal meningitis. J Neuroimmunol 2005; 166:126-31. [PMID: 15982752 DOI: 10.1016/j.jneuroim.2005.05.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Accepted: 05/25/2005] [Indexed: 10/25/2022]
Abstract
The role of leukocyte accumulation in the cerebrospinal fluid (CSF) in the evolution of the pathophysiological changes that occur in bacterial meningitis is unclear. Here, we investigate how leukocyte recruitment to the CSF, modulated by the leukocyte blocker fucoidin, affects the extent of brain damage and outcome in pneumococcal meningitis in rats treated with ceftriaxone from 28 h after infection. Rats treated with fucoidin from time of infection had an excess risk of a fatal outcome compared to rats not receiving fucoidin (25/63 versus 5/34, p=0.012), whereas the risk of cortical damage in surviving animals was comparable (16/44 versus 9/29, p=0.8). Pre-treatment with fucoidin attenuated CSF pleocytosis 24 h after infection (median 400 versus 800x10(6) cells/l, p=0.01) without affecting CSF bacterial counts (2.3x10(5) versus 3.6x10(5) CFU/ml, p=0.54). A significant increase in blood bacterial counts was found among rats pre-treated with fucoidin (median 9.6x10(2) versus 5.2x10(2) CFU/ml, p=0.03). Furthermore, blood bacterial count was found to be an important predictor of fatal outcome as shown by multivariate logistical regression analysis (OR 4.43, 95% CI [1.16-17.0] p=0.03). In summary, blocking leukocyte entry to the central nervous system in experimental pneumococcal meningitis compromises the survival prognosis but does not affect the risk of brain damage or level of infection in this compartment. Conversely, poorer prognosis was associated with an increase in bacterial load in blood, suggesting that leukocyte blockage affects the host's ability to control systemic infection.
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Affiliation(s)
- Christian T Brandt
- National Center for Antimicrobials and Infection Control, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen S, Denmark.
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Noursadeghi M, Pepys MB, Gallimore R, Cohen J. Relationship of granulocyte colony stimulating factor with other acute phase reactants in man. Clin Exp Immunol 2005; 140:97-100. [PMID: 15762880 PMCID: PMC1809334 DOI: 10.1111/j.1365-2249.2005.02732.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The non-specific acute phase response in mice is associated with increased resistance to bacterial infection, which is critically mediated by granulocyte colony stimulating factor (G-CSF), but the behaviour of G-CSF in the human acute phase response is not known. Cardiothoracic surgery is a powerful acute phase stimulus and we show here that this procedure caused increased production of G-CSF, in addition to increases in the circulating concentrations of the proinflammatory cytokine interleukin (IL)-6 and the acute phase plasma proteins C-reactive protein (CRP) and serum amyloid A protein (SAA). Values of G-CSF correlated positively with IL-6 concentrations and circulating neutrophil counts, but not with CRP values. These results confirm that G-CSF is a physiological component of the acute phase response in humans that shares some of the same regulatory controls as IL-6, but its downstream effects are on neutrophils, not hepatic acute phase protein synthesis. Our observations are compatible with a protective role against bacterial infection for G-CSF in the human acute phase response, and support investigation of the prophylactic use of G-CSF in at-risk patients.
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Affiliation(s)
- M Noursadeghi
- Department of Infectious Diseases and Microbiology, Imperial College School of Medicine, Hammersmith Hospital, London, UK.
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