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van Leeuwen LM, Fourie E, van den Brink G, Bekker V, van Houten MA. Diagnostic value of maternal, cord blood and neonatal biomarkers for early-onset sepsis: a systematic review and meta-analysis. Clin Microbiol Infect 2024:S1198-743X(24)00117-4. [PMID: 38467246 DOI: 10.1016/j.cmi.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 02/26/2024] [Accepted: 03/04/2024] [Indexed: 03/13/2024]
Abstract
BACKGROUND An accurate diagnosis of early-onset sepsis (EOS) is challenging because of subtle symptoms and the lack of a good diagnostic tool, resulting in considerable antibiotic overtreatment. A biomarker, discriminating between infected and non-infected newborns at an early stage of the disease, could improve EOS prediction. Numerous biomarkers have been tested, but have never been compared directly. OBJECTIVES We aimed to provide a comprehensive overview of early biomarkers and their diagnostic value in maternal samples, umbilical cord blood, and neonatal serum. DATA SOURCES PubMed-Medline, EMBASE, The Cochrane Library, and Web of Science were searched up to 1 March 2023, without restrictions on publication date, population, or language. STUDY ELIGIBILITY CRITERIA Articles describing the diagnostic value of at least one biomarker in the detection of EOS in neonates, independent of gestational age, were included. ASSESSMENT OF RISK OF BIAS The QUADAS-2 tool was used to assess study quality. METHODS OF DATA SYNTHESIS Three independent researchers assessed the articles using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Meta-analysis was performed with all manuscripts describing diagnostic accuracy using a random-effects model. RESULTS Of 2296 identified articles, 171 reports were included in the systematic review and 69 in the meta-analysis. Literature showed mixed and inconsistent evidence for most biomarkers and sample types, because of a lack of a uniform EOS case definition, small sample sizes, and large heterogeneity between studies. Interesting markers were procalcitonin (pooled sensitivity 79%, 95% CI 71-84%; specificity 91%, 95% CI 83-96%, n = 11) and interleukin (IL)-6 (pooled sensitivity 83%, 95% CI 71-90%; specificity 87%, 95% CI 78-93%, n = 8) in umbilical cord blood and presepsin (pooled sensitivity 82%, 95% CI 62-93%; specificity 86%, 95% CI 73-93%, n = 3) and serum amyloid A (pooled sensitivity 92%, 95% CI 75-98%; specificity 96%, 95% CI 78-99%, n = 4) in neonatal serum. Studies on the combination of biomarkers were scarce. CONCLUSIONS A biomarker stand-alone test is currently not reliable for direct antibiotic stewardship in newborns, although several biomarkers show promising initial results. Further research into biomarker combinations could lead to an improved EOS diagnosis, reduce antibiotic overtreatment, and prevent associated health-related problems.
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Affiliation(s)
- Lisanne M van Leeuwen
- Department of Paediatrics and of Vaccine, Infection and Immunology, Spaarne Gasthuis Hospital, Haarlem, the Netherlands; Willem-Alexander Children's Hospital, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands
| | - Elandri Fourie
- Department of Paediatrics and of Vaccine, Infection and Immunology, Spaarne Gasthuis Hospital, Haarlem, the Netherlands
| | - Gerrie van den Brink
- Department of Paediatrics and of Vaccine, Infection and Immunology, Spaarne Gasthuis Hospital, Haarlem, the Netherlands
| | - Vincent Bekker
- Willem-Alexander Children's Hospital, Department of Pediatrics, Division of Neonatology, Leiden University Medical Center, the Netherlands
| | - Marlies A van Houten
- Department of Paediatrics and of Vaccine, Infection and Immunology, Spaarne Gasthuis Hospital, Haarlem, the Netherlands.
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2
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Nusman CM, Snoek L, van Leeuwen LM, Dierikx TH, van der Weijden BM, Achten NB, Bijlsma MW, Visser DH, van Houten MA, Bekker V, de Meij TGJ, van Rossem E, Felderhof M, Plötz FB. Group B Streptococcus Early-Onset Disease: New Preventive and Diagnostic Tools to Decrease the Burden of Antibiotic Use. Antibiotics (Basel) 2023; 12:antibiotics12030489. [PMID: 36978356 PMCID: PMC10044457 DOI: 10.3390/antibiotics12030489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/18/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
The difficulty in recognizing early-onset neonatal sepsis (EONS) in a timely manner due to non-specific symptoms and the limitations of diagnostic tests, combined with the risk of serious consequences if EONS is not treated in a timely manner, has resulted in a low threshold for starting empirical antibiotic treatment. New guideline strategies, such as the neonatal sepsis calculator, have been proven to reduce the antibiotic burden related to EONS, but lack sensitivity for detecting EONS. In this review, the potential of novel, targeted preventive and diagnostic methods for EONS is discussed from three different perspectives: maternal, umbilical cord and newborn perspectives. Promising strategies from the maternal perspective include Group B Streptococcus (GBS) prevention, exploring the virulence factors of GBS, maternal immunization and antepartum biomarkers. The diagnostic methods obtained from the umbilical cord are preliminary but promising. Finally, promising fields from the newborn perspective include biomarkers, new microbiological techniques and clinical prediction and monitoring strategies. Consensus on the definition of EONS and the standardization of research on novel diagnostic biomarkers are crucial for future implementation and to reduce current antibiotic overexposure in newborns.
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Affiliation(s)
- Charlotte M. Nusman
- Department of Paediatrics, Emma Children’s Hospital, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Linde Snoek
- Department of Neurology, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Lisanne M. van Leeuwen
- Department of Paediatrics and Department of Vaccin, Infection and Immunology, Spaarne Hospital, Boerhaavelaan 22, 2035 RC Haarlem, The Netherlands
- Department of Paediatrics, Willem Alexander Children Hospital, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Thomas H. Dierikx
- Department of Pediatric Gastroenterology, Emma Children’s Hospital, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism Research Institute, Meibergdreef 69-71, 1105 BK Amsterdam, The Netherlands
| | - Bo M. van der Weijden
- Department of Paediatrics, Emma Children’s Hospital, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Department of Paediatrics, Tergooi Hospital, Rijksstraatweg 1, 1261 AN Blaricum, The Netherlands
| | - Niek B. Achten
- Department of Paediatrics, Erasmus University Medical Centre, Sophia Children’s Hospital, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Merijn W. Bijlsma
- Department of Paediatrics, Emma Children’s Hospital, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Douwe H. Visser
- Department of Neonatology, Emma Children’s Hospital, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Marlies A. van Houten
- Department of Paediatrics and Department of Vaccin, Infection and Immunology, Spaarne Hospital, Boerhaavelaan 22, 2035 RC Haarlem, The Netherlands
| | - Vincent Bekker
- Division of Neonatology, Department of Pediatrics, Willem Alexander Children’s Hospital, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Tim G. J. de Meij
- Department of Pediatric Gastroenterology, Emma Children’s Hospital, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism Research Institute, Meibergdreef 69-71, 1105 BK Amsterdam, The Netherlands
| | - Ellen van Rossem
- Department of Paediatrics, Flevo Hospital, Hospitaalweg 1, 1315 RA Almere, The Netherlands
| | - Mariet Felderhof
- Department of Paediatrics, Flevo Hospital, Hospitaalweg 1, 1315 RA Almere, The Netherlands
| | - Frans B. Plötz
- Department of Paediatrics, Emma Children’s Hospital, Amsterdam University Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Department of Paediatrics, Tergooi Hospital, Rijksstraatweg 1, 1261 AN Blaricum, The Netherlands
- Correspondence: ; Tel.: +31-88-753-3664
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3
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van Leeuwen LM, Boot M, Kuijl C, Picavet DI, van Stempvoort G, van der Pol SM, de Vries HE, van der Wel NN, van der Kuip M, van Furth AM, van der Sar AM, Bitter W. Mycobacteria employ two different mechanisms to cross the blood-brain barrier. Cell Microbiol 2018; 20:e12858. [PMID: 29749044 PMCID: PMC6175424 DOI: 10.1111/cmi.12858] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Revised: 03/27/2018] [Accepted: 04/23/2018] [Indexed: 12/16/2022]
Abstract
Central nervous system (CNS) infection by Mycobacterium tuberculosis is one of the most devastating complications of tuberculosis, in particular in early childhood. In order to induce CNS infection, M. tuberculosis needs to cross specialised barriers protecting the brain. How M. tuberculosis crosses the blood-brain barrier (BBB) and enters the CNS is not well understood. Here, we use transparent zebrafish larvae and the closely related pathogen Mycobacterium marinum to answer this question. We show that in the early stages of development, mycobacteria rapidly infect brain tissue, either as free mycobacteria or within circulating macrophages. After the formation of a functionally intact BBB, the infiltration of brain tissue by infected macrophages is delayed, but not blocked, suggesting that crossing the BBB via phagocytic cells is one of the mechanisms used by mycobacteria to invade the CNS. Interestingly, depletion of phagocytic cells did not prevent M. marinum from infecting the brain tissue, indicating that free mycobacteria can independently cause brain infection. Detailed analysis showed that mycobacteria are able to cause vasculitis by extracellular outgrowth in the smaller blood vessels and by infecting endothelial cells. Importantly, we could show that this second mechanism is an active process that depends on an intact ESX-1 secretion system, which extends the role of ESX-1 secretion beyond the macrophage infection cycle.
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Affiliation(s)
- Lisanne M. van Leeuwen
- Medical Microbiology and Infection ControlVU Medical CenterAmsterdamThe Netherlands
- Paediatric Infectious Diseases and ImmunologyVU Medical CenterAmsterdamThe Netherlands
| | - Maikel Boot
- Medical Microbiology and Infection ControlVU Medical CenterAmsterdamThe Netherlands
| | - Coen Kuijl
- Medical Microbiology and Infection ControlVU Medical CenterAmsterdamThe Netherlands
| | - Daisy I. Picavet
- Cell Biology and Histology, Electron Microscopy Centre AmsterdamAcademic Medical CentreAmsterdamThe Netherlands
| | - Gunny van Stempvoort
- Medical Microbiology and Infection ControlVU Medical CenterAmsterdamThe Netherlands
| | - Susanne M.A. van der Pol
- Molecular Cell Biology and Immunology, Amsterdam NeuroscienceVU Medical CenterAmsterdamThe Netherlands
| | - Helga E. de Vries
- Molecular Cell Biology and Immunology, Amsterdam NeuroscienceVU Medical CenterAmsterdamThe Netherlands
| | - Nicole N. van der Wel
- Cell Biology and Histology, Electron Microscopy Centre AmsterdamAcademic Medical CentreAmsterdamThe Netherlands
| | - Martijn van der Kuip
- Paediatric Infectious Diseases and ImmunologyVU Medical CenterAmsterdamThe Netherlands
| | | | | | - Wilbert Bitter
- Medical Microbiology and Infection ControlVU Medical CenterAmsterdamThe Netherlands
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Phan TH, van Leeuwen LM, Kuijl C, Ummels R, van Stempvoort G, Rubio-Canalejas A, Piersma SR, Jiménez CR, van der Sar AM, Houben ENG, Bitter W. EspH is a hypervirulence factor for Mycobacterium marinum and essential for the secretion of the ESX-1 substrates EspE and EspF. PLoS Pathog 2018; 14:e1007247. [PMID: 30102741 PMCID: PMC6107294 DOI: 10.1371/journal.ppat.1007247] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/23/2018] [Accepted: 07/26/2018] [Indexed: 12/31/2022] Open
Abstract
The pathogen Mycobacterium tuberculosis employs a range of ESX-1 substrates to manipulate the host and build a successful infection. Although the importance of ESX-1 secretion in virulence is well established, the characterization of its individual components and the role of individual substrates is far from complete. Here, we describe the functional characterization of the Mycobacterium marinum accessory ESX-1 proteins EccA1, EspG1 and EspH, i.e. proteins that are neither substrates nor structural components. Proteomic analysis revealed that EspG1 is crucial for ESX-1 secretion, since all detectable ESX-1 substrates were absent from the cell surface and culture supernatant in an espG1 mutant. Deletion of eccA1 resulted in minor secretion defects, but interestingly, the severity of these secretion defects was dependent on the culture conditions. Finally, espH deletion showed a partial secretion defect; whereas several ESX-1 substrates were secreted in normal amounts, secretion of EsxA and EsxB was diminished and secretion of EspE and EspF was fully blocked. Interaction studies showed that EspH binds EspE and therefore could function as a specific chaperone for this substrate. Despite the observed differences in secretion, hemolytic activity was lost in all M. marinum mutants, implying that hemolytic activity is not strictly correlated with EsxA secretion. Surprisingly, while EspH is essential for successful infection of phagocytic host cells, deletion of espH resulted in a significantly increased virulence phenotype in zebrafish larvae, linked to poor granuloma formation and extracellular outgrowth. Together, these data show that different sets of ESX-1 substrates play different roles at various steps of the infection cycle of M. marinum. M. tuberculosis is a facultative intracellular pathogen that has an intimate relationship with host macrophages. Proteins secreted by the ESX-1 secretion system play an important role in this interaction, for instance by orchestrating the escape from the phagosome into the cytosol of the macrophage. However, the exact role of the ESX-1 substrates is unknown, due to their complicated interdependency for secretion. Here, we study the function of ESX-1 accessory proteins EccA1, EspG1 and EspH in ESX-1 secretion in Mycobacterium marium, the causative agent of fish tuberculosis. We found that these proteins affect the secretion of different substrate classes, which offers an approach to study the roles of these substrate groups. An espG1 deletion broadly aborts ESX-1 secretion and thus resulted in severe attenuation in a zebrafish model for tuberculosis, whereas EccA1 is only crucial under specific growth conditions. The most surprising results were obtained for EspH. This protein seems to function as a molecular chaperone for EspE and is as such involved in the secretion of a small subset of ESX-1 substrates. Disruption of espH showed a dual character: whereas this gene is essential for the successful infection of macrophages, deletion of espH resulted in significantly increased virulence in zebrafish larvae. These data convincingly show that different subsets of ESX-1 substrates play different roles at various steps in the mycobacterial infection cycle.
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Affiliation(s)
- Trang H. Phan
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Lisanne M. van Leeuwen
- Department of Medical Microbiology and Infection Control, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Coen Kuijl
- Department of Medical Microbiology and Infection Control, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Roy Ummels
- Department of Medical Microbiology and Infection Control, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Gunny van Stempvoort
- Department of Medical Microbiology and Infection Control, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Alba Rubio-Canalejas
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Sander R. Piersma
- Department of Medical Oncology, OncoProteomics Laboratory, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Connie R. Jiménez
- Department of Medical Oncology, OncoProteomics Laboratory, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Astrid M. van der Sar
- Department of Medical Microbiology and Infection Control, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Edith N. G. Houben
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Wilbert Bitter
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicines & Systems, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Medical Microbiology and Infection Control, Amsterdam University Medical Centers, Amsterdam, the Netherlands
- * E-mail:
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5
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van de Weerd R, Boot M, Maaskant J, Sparrius M, Verboom T, van Leeuwen LM, Burggraaf MJ, Paauw NJ, Dainese E, Manganelli R, Bitter W, Appelmelk BJ, Geurtsen J. Inorganic Phosphate Limitation Modulates Capsular Polysaccharide Composition in Mycobacteria. J Biol Chem 2016; 291:11787-99. [PMID: 27044743 DOI: 10.1074/jbc.m116.722454] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 12/19/2022] Open
Abstract
Mycobacterium tuberculosis is protected by an unusual and highly impermeable cell envelope that is critically important for the successful colonization of the host. The outermost surface of this cell envelope is formed by capsular polysaccharides that play an important role in modulating the initial interactions once the bacillus enters the body. Although the bioenzymatic steps involved in the production of the capsular polysaccharides are emerging, information regarding the ability of the bacterium to modulate the composition of the capsule is still unknown. Here, we study the mechanisms involved in regulation of mycobacterial capsule biosynthesis using a high throughput screen for gene products involved in capsular α-glucan production. Utilizing this approach we identified a group of mutants that all carried mutations in the ATP-binding cassette phosphate transport locus pst These mutants collectively exhibited a strong overproduction of capsular polysaccharides, including α-glucan and arabinomannan, suggestive of a role for inorganic phosphate (Pi) metabolism in modulating capsular polysaccharide production. These findings were corroborated by the observation that growth under low Pi conditions as well as chemical activation of the stringent response induces capsule production in a number of mycobacterial species. This induction is, in part, dependent on σ factor E. Finally, we show that Mycobacterium marinum, a model organism for M. tuberculosis, encounters Pi stress during infection, which shows the relevance of our findings in vivo.
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Affiliation(s)
- Robert van de Weerd
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands,
| | - Maikel Boot
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Janneke Maaskant
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Marion Sparrius
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Theo Verboom
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Lisanne M van Leeuwen
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Maroeska J Burggraaf
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Nanne J Paauw
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, P. O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Elisa Dainese
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy
| | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy
| | - Wilbert Bitter
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands, Department of Molecular Microbiology, VU University Amsterdam, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands, and
| | - Ben J Appelmelk
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands,
| | - Jeroen Geurtsen
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
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Abstract
Over the past decade the zebrafish (Danio rerio) has become an attractive new vertebrate model organism for studying mycobacterial pathogenesis. The combination of medium-throughput screening and real-time in vivo visualization has allowed new ways to dissect host pathogenic interaction in a vertebrate host. Furthermore, genetic screens on the host and bacterial sides have elucidated new mechanisms involved in the initiation of granuloma formation and the importance of a balanced immune response for control of mycobacterial pathogens. This article will highlight the unique features of the zebrafish-Mycobacterium marinum infection model and its added value for tuberculosis research.
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Affiliation(s)
- Lisanne M van Leeuwen
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Department of Medical Microbiology and Infection control, VU University Medical Center, 1081 BT Amsterdam, The Netherlands
| | - Astrid M van der Sar
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - Wilbert Bitter
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands Department of Molecular Microbiology, VU University, 1081 HV Amsterdam, The Netherlands
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7
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van Leeuwen LM, van der Kuip M, Youssef SA, de Bruin A, Bitter W, van Furth AM, van der Sar AM. Modeling tuberculous meningitis in zebrafish using Mycobacterium marinum. Dis Model Mech 2014; 7:1111-22. [PMID: 24997190 PMCID: PMC4142731 DOI: 10.1242/dmm.015453] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Tuberculous meningitis (TBM) is one of the most severe extrapulmonary manifestations of tuberculosis, with a high morbidity and mortality. Characteristic pathological features of TBM are Rich foci, i.e. brain- and spinal-cord-specific granulomas formed after hematogenous spread of pulmonary tuberculosis. Little is known about the early pathogenesis of TBM and the role of Rich foci. We have adapted the zebrafish model of Mycobacterium marinum infection (zebrafish-M. marinum model) to study TBM. First, we analyzed whether TBM occurs in adult zebrafish and showed that intraperitoneal infection resulted in granuloma formation in the meninges in 20% of the cases, with occasional brain parenchyma involvement. In zebrafish embryos, bacterial infiltration and clustering of infected phagocytes was observed after infection at three different inoculation sites: parenchyma, hindbrain ventricle and caudal vein. Infection via the bloodstream resulted in the formation of early granulomas in brain tissue in 70% of the cases. In these zebrafish embryos, infiltrates were located in the proximity of blood vessels. Interestingly, no differences were observed when embryos were infected before or after early formation of the blood-brain barrier (BBB), indicating that bacteria are able to cross this barrier with relatively high efficiency. In agreement with this observation, infected zebrafish larvae also showed infiltration of the brain tissue. Upon infection of embryos with an M. marinum ESX-1 mutant, only small clusters and scattered isolated phagocytes with high bacterial loads were present in the brain tissue. In conclusion, our adapted zebrafish-M. marinum infection model for studying granuloma formation in the brain will allow for the detailed analysis of both bacterial and host factors involved in TBM. It will help solve longstanding questions on the role of Rich foci and potentially contribute to the development of better diagnostic tools and therapeutics.
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Affiliation(s)
- Lisanne M van Leeuwen
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands Department of Medical Microbiology and Infection Control, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
| | - Martijn van der Kuip
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Sameh A Youssef
- Department of Pathobiology, Utrecht University, Faculty of Veterinary Medicine, Yalelaan 1, 3508 TB, Utrecht, The Netherlands
| | - Alain de Bruin
- Department of Pathobiology, Utrecht University, Faculty of Veterinary Medicine, Yalelaan 1, 3508 TB, Utrecht, The Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
| | - A Marceline van Furth
- Department of Pediatric Infectious Diseases and Immunology, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Astrid M van der Sar
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
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8
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Stoop EJM, Mishra AK, Driessen NN, van Stempvoort G, Bouchier P, Verboom T, van Leeuwen LM, Sparrius M, Raadsen SA, van Zon M, van der Wel NN, Besra GS, Geurtsen J, Bitter W, Appelmelk BJ, van der Sar AM. Mannan core branching of lipo(arabino)mannan is required for mycobacterial virulence in the context of innate immunity. Cell Microbiol 2013; 15:2093-108. [PMID: 23902464 PMCID: PMC3963455 DOI: 10.1111/cmi.12175] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 07/03/2013] [Accepted: 07/17/2013] [Indexed: 11/28/2022]
Abstract
The causative agent of tuberculosis (TB), Mycobacterium tuberculosis, remains an important worldwide health threat. Although TB is one of the oldest infectious diseases of man, a detailed understanding of the mycobacterial mechanisms underlying pathogenesis remains elusive. Here, we studied the role of the α(1→2) mannosyltransferase MptC in mycobacterial virulence, using the Mycobacterium marinum zebrafish infection model. Like its M. tuberculosis orthologue, disruption of M. marinum mptC (mmar_3225) results in defective elongation of mannose caps of lipoarabinomannan (LAM) and absence of α(1→2)mannose branches on the lipomannan (LM) and LAM mannan core, as determined by biochemical analysis (NMR and GC-MS) and immunoblotting. We found that the M. marinum mptC mutant is strongly attenuated in embryonic zebrafish, which rely solely on innate immunity, whereas minor virulence defects were observed in adult zebrafish. Strikingly, complementation with the Mycobacterium smegmatis mptC orthologue, which restored mannan core branching but not cap elongation, was sufficient to fully complement the virulence defect of the mptC mutant in embryos. Altogether our data demonstrate that not LAM capping, but mannan core branching of LM/LAM plays an important role in mycobacterial pathogenesis in the context of innate immunity.
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Affiliation(s)
- Esther J M Stoop
- Department of Medical Microbiology and Infection Control, VU University Medical Center, van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
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