37 results on '"Leavis, Helen L"'
Search Results
2. YajC, a predicted membrane protein, promotes Enterococcus faecium biofilm Formation in vitro and in a rat endocarditis model
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Top, Janetta, primary, Zhang, Xinglin, additional, Hendrickx, Antoni P A, additional, Boeren, Sjef, additional, van Schaik, Willem, additional, Huebner, Johannes, additional, Willems, Rob J L, additional, Leavis, Helen L, additional, and Paganelli, Fernanda L, additional
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- 2024
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3. Neurological phenotype of adenosine deaminase 2 deficient patients: a cohort study.
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Verschoof, Merelijne A., van Meenen, Laura C. C., Andriessen, M. Valérie E., Brinkman, Daniëlle M. C., Kamphuis, Sylvia, Kuijpers, Taco W., Leavis, Helen L., Legger, G. Elizabeth, Mulders‐Manders, Catharina M., de Pagter, Anne P. J., Rutgers, Abraham, van Well, Gijs T. J., Coutinho, Jonathan M., Hak, A. Elisabeth, van Montfrans, Joris M., and Klouwer, Femke C. C.
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ADENOSINE deaminase ,TRANSIENT ischemic attack ,ISCHEMIC stroke ,HEMORRHAGIC stroke ,TUMOR necrosis factors ,STROKE - Abstract
Background and purpose: Patients with adenosine deaminase 2 (ADA2) deficiency can present with various neurological manifestations due to vasculopathies and autoinflammation. These include ischaemic and hemorrhagic stroke, but less clearly defined neurological symptoms have also been reported. Methods: In this cohort study, patients with confirmed ADA2 deficiency from seven university hospitals in the Netherlands were included. The frequency and recurrence rates of neurological manifestations before and after initiation of tumor necrosis factor α (TNF‐α) inhibiting therapy were analyzed. Results: Twenty‐nine patients were included with a median age at presentation of 5 years (interquartile range 1–17). Neurological manifestations occurred in 19/29 (66%) patients and were the presenting symptom in 9/29 (31%) patients. Transient ischaemic attack (TIA)/ischaemic stroke occurred in 12/29 (41%) patients and was the presenting symptom in 8/29 (28%) patients. In total, 25 TIAs/ischaemic strokes occurred in 12 patients, one after initiation of TNF‐α inhibiting therapy and one whilst switching between TNF‐α inhibitors. None was large‐vessel occlusion stroke. Two hemorrhagic strokes occurred: one aneurysmatic subarachnoid hemorrhage and one spontaneous intracerebral hemorrhage. Most neurological symptoms, including cranial nerve deficits, vertigo, ataxia and seizures, were caused by TIAs/ischaemic strokes and seldom recurred after initiation of TNF‐α inhibiting therapy. Conclusions: Neurological manifestations, especially TIA/ischaemic stroke, are common in patients with ADA2 deficiency and frequently are the presenting symptom. Because it is a treatable cause of young stroke, for which antiplatelet and anticoagulant therapy are considered contraindicated, awareness amongst neurologists and pediatricians is important. Screening for ADA2 deficiency in young patients with small‐vessel ischaemic stroke without an identified cause should be considered. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Leflunomide/hydroxychloroquine combination therapy targets type I IFN-associated proteins in patients with Sjögren’s syndrome that show potential to predict and monitor clinical response
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Hamkour, Safae, primary, van der Heijden, Eefje HM, additional, Lopes, Ana P, additional, Blokland, Sofie L M, additional, Bekker, Cornelis P J, additional, Van Helden-Meeuwsen, Cornelia G, additional, Versnel, Marjan A, additional, Kruize, Aike A, additional, Radstake, Timothy RDJ, additional, Leavis, Helen L, additional, Hillen, Maarten R, additional, and van Roon, Joel AG, additional
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- 2023
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5. CCR9/CXCR5 Co-Expressing CD4 T Cells Are Increased in Primary Sjögren’s Syndrome and Are Enriched in PD-1/ICOS-Expressing Effector T Cells
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Hinrichs, Anneline C., primary, Kruize, Aike A., additional, Lafeber, Floris P. J. G., additional, Leavis, Helen L., additional, and van Roon, Joel A. G., additional
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- 2023
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6. Effect of Antiplatelet Therapy on Survival and Organ Support-Free Days in Critically Ill Patients With COVID-19
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Bradbury, Charlotte A., Lawler, Patrick R., Stanworth, Simon J., McVerry, Bryan J., McQuilten, Zoe, Higgins, Alisa M., Mouncey, Paul R., Al-Beidh, Farah, Rowan, Kathryn M., Berry, Lindsay R., Lorenzi, Elizabeth, Zarychanski, Ryan, Arabi, Yaseen M., Annane, Djillali, Beane, Abi, Van Bentum-Puijk, Wilma, Bhimani, Zahra, Bihari, Shailesh, Bonten, Marc J. M., Brunkhorst, Frank M., Buzgau, Adrian, Buxton, Meredith, Carrier, Marc, Cheng, Allen C., Cove, Matthew, Detry, Michelle A., Estcourt, Lise J., Fitzgerald, Mark, Girard, Timothy D., Goligher, Ewan C., Goossens, Herman, Haniffa, Rashan, Hills, Thomas, Huang, David T., Horvat, Christopher M., Hunt, Beverley J., Ichihara, Nao, Lamontagne, Francois, Leavis, Helen L., Linstrum, Kelsey M., Litton, Edward, Marshall, John C., McAuley, Daniel F., McGlothlin, Anna, McGuinness, Shay P., Middeldorp, Saskia, Montgomery, Stephanie K., Morpeth, Susan C., Murthy, Srinivas, Neal, Matthew D., Nichol, Alistair D., Parke, Rachael L., Parker, Jane C., Reyes, Luis, Saito, Hiroki, Santos, Marlene S., Saunders, Christina T., Serpa-Neto, Ary, Seymour, Christopher W., Shankar-Hari, Manu, Singh, Vanessa, Tolppa, Timo, Turgeon, Alexis F., Turner, Anne M., van de Veerdonk, Frank L., Green, Cameron, Lewis, Roger J., Angus, Derek C., McArthur, Colin J., Berry, Scott, Derde, Lennie P. G., Webb, Steve A., Gordon, Anthony C., Depuydt, Pieter, De Waele, Jan, De Bus, Liesbet, Fierens, Jan, Vermassen, Joris, REMAP-CAP Investigators, University of Bristol [Bristol], University Health Network, University of Toronto, University of Oxford, University of Pittsburgh (PITT), Pennsylvania Commonwealth System of Higher Education (PCSHE), Monash University [Melbourne], Imperial College London, University of Manitoba [Winnipeg], Université de Versailles Saint-Quentin-en-Yvelines - UFR Sciences de la santé Simone Veil (UVSQ Santé), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), University Medical Center [Utrecht], St. Michael's Hospital, 215522, CS-2016-16-011, RP-2015-06-18, National Institutes of Health, NIH, U.S. Department of Defense, DOD, National Institute of General Medical Sciences, NIGMS, National Institute of Neurological Disorders and Stroke, NINDS, Gordon and Betty Moore Foundation, GBMF, Medtronic, Baxter International, Medical Center, University of Pittsburgh, CancerCare Manitoba Foundation, CCMF, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NICHD, Wellcome Trust, WT, Health Research Board, HRB: CTN 2014-012, Horizon 2020 Framework Programme, H2020: 101003589, LAM Therapeutics, Canadian Institutes of Health Research, IRSC: 158584, Medical Research Council, MRC, National Institute for Health and Care Research, NIHR, European Commission, EC, National Heart and Lung Institute, NHLI, Queen's University Belfast, QUB: US8962032, National Health and Medical Research Council, NHMRC: APP1101719, National Medical Research Council, NMRC, Health Research Council of New Zealand, HRC: 16/631, Ministère des Affaires Sociales et de la Santé: PHRC-20-0147, Innovate UK, Horizon 2020, Pharmaceuticals Bayer, Swedish Orphan Biovitrum, NIHR Imperial Biomedical Research Centre, BRC, Minderoo Foundation, Funding/Support: This study was funded by the following: the Platform for European Preparedness Against (Re-)Emerging Epidemics (PREPARE) consortium of the European Union, FP7-HEALTH-2013-INNOVATION-1 (grant 602525), the Rapid European COVID-19 Emergency Research Response (RECOVER) consortium of the European Union’s Horizon 2020 Research and Innovation Programme (grant 101003589), the Australian National Health and Medical Research Council (grant APP1101719), the Health Research Council of New Zealand (grant 16/631), the Canadian Institute of Health Research Strategy for Patient-Oriented Research Innovative Clinical Trials Program (grant 158584), the NIHR and the NIHR Imperial Biomedical Research Centre, the Health Research Board of Ireland (grant CTN 2014-012), the University of Pittsburgh Medical Center (UPMC) Learning While Doing Program, the Translational Breast Cancer Research Consortium, the French Ministry of Health (grant PHRC-20-0147), the Minderoo Foundation, and the Wellcome Trust Innovations Project (grant 215522). Dr Shankar-Hari is funded by an NIHR clinician scientist fellowship (grant CS-2016-16-011) and Dr Gordon is funded by an NIHR research professorship (grant RP-2015-06-18)., The REMAP-CAP platform is supported by the Australian and New Zealand Intensive Care Society Clinical Trials Group, the Canadian Critical Care Clinical Trials Group, the Irish Critical Care Clinical Trials Network, the UK Critical Care Research Group and the International Forum of Acute Care Trialists., REMAP-CAP was supported in the Netherlands by the Research Collaboration Critical Care the Netherlands, reported receipt of personal fees from Lilly, BMS-Pfizer, Bayer, Amgen, Novartis, Janssen, Portola, Ablynx, and Grifols. Dr Lawler reported receipt of personal fees from Novartis, CorEvitas, and Brigham and Women’s Hospital and royalties from McGraw-Hill Publishing. Dr McVerry reported receipt of grants from the National Heart, Lung, and Blood Institute and Bayer Pharmaceuticals and personal fees from Boehringer Ingelheim. Dr L. Berry reported being an employee of Berry Consultants, Berry Consultants receives payments for the statistical analysis and design of REMAP-CAP. Dr Lorenzi reported being an employee of Berry Consultants, Berry Consultants receives payments for the statistical analysis and design of REMAP-CAP. Dr Zarychanski reported receipt of grants from the Canadian Institutes of Health Research, LifeArc, Research Manitoba, the CancerCare Manitoba Foundation, Peter Munk Cardiac Centre, and the Thistledown Foundation and research operating support as the Lyonel G. Israels Research Chair in Hematology. Dr Bonten reported membership in international study steering committees, advisory boards, and independent data safety and monitoring committees funded by Janssen Vaccines, Merck Sharp & Dohme, AstraZeneca, Pfizer, and Sanofi Pasteur (all reimbursements to UMC Utrecht). Dr Brunkhorst reported receipt of grants from Jena University Hospital. Dr Buxton reported receipt of a gift from the Breast Cancer Research Foundation and contracts with Amgen and Eisai. Dr Carrier reported receipt of grants from BMS-Pfizer and personal fees from Bayer, Sanofi, Servier, Leo Phama, and BMS-Pfizer to his institution. Dr Cove reported receipt of grants from the National Medical Research Council and personal fees from Baxter and Medtronic. Dr Estcourt reported receipt of grants from the UK National Institute for Health Research (NIHR) and the European Union Horizon 2020 Research and Innovation Programme. Dr Haniffa reported receipt of grants from the UK Research and Innovation/Medical Research Council African Critical Care Registry Network. Dr Horvat reported receipt of grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Neurological Disorders and Stroke. Dr Ichihara reported being affiliated with the Department of Healthcare Quality Assessment, University of Tokyo, which is a social collaboration supported by the National Clinical Database, Johnson & Johnson, and Nipro Corporation. Dr Marshall reported receipt of personal fees from AM Pharma and Critical Care Medicine. Dr McAuley reported receipt of personal fees from Bayer, GlaxoSmithKline, Boehringer Ingelheim, Novartis, Lilly, Vir Biotechnology, Faron Pharmaceutical, and SOBI and grants from the NIHR, the Wellcome Trust, Innovate UK, the UK Medical Research Council, and the Northern Ireland Health and Social Care Research and Development Division, in addition, Dr McAuley had a Queen’s University Belfast patent for novel treatment for inflammatory disease (US8962032), was co-director of research at the Intensive Care Society until June 2021, and was director of the Efficacy and Mechanisms Evaluation Program for the UK Medical Research Council/NIHR. Dr Middeldorp reported receipt of personal fees from Daiichi Sankyo, Bayer, Pfizer, Boehringer Ingelheim, Portola/Alexion, AbbVie, BMS-Pfizer, Sanofi, and Viatris, all paid to his institution, and grants from Daiichi Sankyo, Bayer, Pfizer, and Boehringer Ingelheim. Dr Neal reported equity in Haima Therapeutics, receipt of personal fees from Janssen Pharma and Haemonetics, and receipt of grants from Instrumentation Laboratory, the National Institutes of Health, and the Department of Defense. Dr Nichol reported receipt of personal fees from AM Pharma, paid to his university, and grants from Baxter. Dr Parke reported receipt of grants from Fisher and Paykel Healthcare NZ. Dr Serpa-Neto reported receipt of personal fees from Drager and Endpoint Health. Dr Seymour reported receipt of grants from the Gordon and Betty Moore Foundation and the National Institutes of Health/National Institute of General Medical Sciences. Dr Lewis reported being senior medical scientist at Berry Consultants, Berry Consultants receives payments for the statistical analysis and design of REMAP-CAP. Dr S. Berry reported being an employee with an ownership role at Berry Consultants, Berry Consultants receives payments for the statistical analysis and design of REMAP-CAP. Dr Derde reported being a coordinating committee member for the European Clinical Research Alliance on Infectious Diseases, a member of the Dutch Intensivists Task Force on Acute Infectious Threats, a member of the International Scientific Advisory Board for Sepsis Canada, and a member of the Dutch Academy of Sciences’ Pandemic Preparedness Plan committee. Dr Gordon reported receipt of personal fees from 30 Respiratory, paid to his institution. No other disclosures were reported., European Project: 101003589, H2020-SC1-PHE-CORONAVIRUS-2020,RECOVER(2020), European Project: 602525,EC:FP7:HEALTH,FP7-HEALTH-2013-INNOVATION-1,PREPARE(2014), Investigators, REMAP-CAP Writing Committee for the REMAP-CAP, Vascular Medicine, ACS - Pulmonary hypertension & thrombosis, ARD - Amsterdam Reproduction and Development, and Intensive Care Medicine
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Adult ,Male ,Platelet Aggregation Inhibitors/adverse effects ,Critical Illness ,[SDV]Life Sciences [q-bio] ,Vascular damage Radboud Institute for Health Sciences [Radboudumc 16] ,lnfectious Diseases and Global Health Radboud Institute for Molecular Life Sciences [Radboudumc 4] ,Hemorrhage ,Aspirin/adverse effects ,Hemorrhage/chemically induced ,INFECTION ,Humans ,COAGULOPATHY ,Aspirin ,Anticoagulants ,COVID-19 ,Bayes Theorem ,Venous Thromboembolism ,General Medicine ,Middle Aged ,Respiration, Artificial ,COVID-19 Drug Treatment ,Critical Illness/mortality ,lnfectious Diseases and Global Health Radboud Institute for Health Sciences [Radboudumc 4] ,Purinergic P2Y Receptor Antagonists/adverse effects ,Purinergic P2Y Receptor Antagonists ,COVID-19/complications ,Female ,Human medicine ,Anticoagulants/adverse effects ,Platelet Aggregation Inhibitors ,Venous Thromboembolism/drug therapy - Abstract
Contains fulltext : 248713.pdf (Publisher’s version ) (Closed access) IMPORTANCE: The efficacy of antiplatelet therapy in critically ill patients with COVID-19 is uncertain. OBJECTIVE: To determine whether antiplatelet therapy improves outcomes for critically ill adults with COVID-19. DESIGN, SETTING, AND PARTICIPANTS: In an ongoing adaptive platform trial (REMAP-CAP) testing multiple interventions within multiple therapeutic domains, 1557 critically ill adult patients with COVID-19 were enrolled between October 30, 2020, and June 23, 2021, from 105 sites in 8 countries and followed up for 90 days (final follow-up date: July 26, 2021). INTERVENTIONS: Patients were randomized to receive either open-label aspirin (n = 565), a P2Y12 inhibitor (n = 455), or no antiplatelet therapy (control; n = 529). Interventions were continued in the hospital for a maximum of 14 days and were in addition to anticoagulation thromboprophylaxis. MAIN OUTCOMES AND MEASURES: The primary end point was organ support-free days (days alive and free of intensive care unit-based respiratory or cardiovascular organ support) within 21 days, ranging from -1 for any death in hospital (censored at 90 days) to 22 for survivors with no organ support. There were 13 secondary outcomes, including survival to discharge and major bleeding to 14 days. The primary analysis was a bayesian cumulative logistic model. An odds ratio (OR) greater than 1 represented improved survival, more organ support-free days, or both. Efficacy was defined as greater than 99% posterior probability of an OR greater than 1. Futility was defined as greater than 95% posterior probability of an OR less than 1.2 vs control. Intervention equivalence was defined as greater than 90% probability that the OR (compared with each other) was between 1/1.2 and 1.2 for 2 noncontrol interventions. RESULTS: The aspirin and P2Y12 inhibitor groups met the predefined criteria for equivalence at an adaptive analysis and were statistically pooled for further analysis. Enrollment was discontinued after the prespecified criterion for futility was met for the pooled antiplatelet group compared with control. Among the 1557 critically ill patients randomized, 8 patients withdrew consent and 1549 completed the trial (median age, 57 years; 521 [33.6%] female). The median for organ support-free days was 7 (IQR, -1 to 16) in both the antiplatelet and control groups (median-adjusted OR, 1.02 [95% credible interval {CrI}, 0.86-1.23]; 95.7% posterior probability of futility). The proportions of patients surviving to hospital discharge were 71.5% (723/1011) and 67.9% (354/521) in the antiplatelet and control groups, respectively (median-adjusted OR, 1.27 [95% CrI, 0.99-1.62]; adjusted absolute difference, 5% [95% CrI, -0.2% to 9.5%]; 97% posterior probability of efficacy). Among survivors, the median for organ support-free days was 14 in both groups. Major bleeding occurred in 2.1% and 0.4% of patients in the antiplatelet and control groups (adjusted OR, 2.97 [95% CrI, 1.23-8.28]; adjusted absolute risk increase, 0.8% [95% CrI, 0.1%-2.7%]; 99.4% probability of harm). CONCLUSIONS AND RELEVANCE: Among critically ill patients with COVID-19, treatment with an antiplatelet agent, compared with no antiplatelet agent, had a low likelihood of providing improvement in the number of organ support-free days within 21 days. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02735707.
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- 2022
7. Clinical Symptoms, Laboratory Parameters and Long-Term Follow-up in a National DADA2 Cohort
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Andriessen, Marie Valérie E., Legger, G. Elizabeth, Bredius, Robbert G.M., van Gijn, Marielle E., Hak, A. Elisabeth, Muller, Petra C.E.Hissink, Kamphuis, Sylvia, Klouwer, Femke C.C., Kuijpers, Taco W., Leavis, Helen L., Nierkens, Stefan, Rutgers, Abraham, van der Veken, Lars T., van Well, Gijs T.J., Mulders-Manders, Catharina M., van Montfrans, Joris M., and Pediatrics
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Deficiency of adenosine deaminase-2 (DADA2) is an autosomal recessive autoinflammatory disease with an extremely variable disease presentation. This paper provides a comprehensive overview of the Dutch DADA2 cohort. We performed a retrospective cohort study in 29 ADA2-deficient patients from 23 families with a median age at inclusion of 26 years. All patients had biallelic pathogenic variants in the ADA2 gene. The most common clinical findings included cutaneous involvement (79.3%), (hepato)splenomegaly (70.8%) and recurrent infections (58.6%). Stroke was observed in 41.4% of the patients. The main laboratory abnormalities were hypogammaglobulinemia and various cytopenias. Patients presented most often with a mixed phenotype involving vasculopathy, immunodeficiency and hematologic manifestations (62.1%). In this cohort, malignancies were reported in eight patients (27.6%), of whom five presented with a hematologic malignancy and two with a basal cell carcinoma. Four patients developed hemophagocytic lymphohistiocytosis (HLH) or an HLH-like episode, of whom three passed away during or shortly after the occurrence of HLH. TNF-inhibitors (TNFi) were effective in treating vasculopathy-associated symptoms and preventing stroke, but were hardly effective in the treatment of hematologic manifestations. Three patients underwent hematopoietic cell transplantation and two of them are doing well with complete resolution of DADA2-related symptoms. The overall mortality in this cohort was 17.2%. In conclusion, this cohort describes the clinical, genetic and laboratory findings of 29 Dutch DADA2 patients. We describe the occurrence of HLH as a life-threatening disease complication and report a relatively high incidence of malignancies and mortality.
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- 2023
8. Roux-Y Gastric Bypass and Sleeve Gastrectomy directly change gut microbiota composition independent of surgery type
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Paganelli, Fernanda L., Luyer, Misha, Hazelbag, C. Marijn, Uh, Hae-Won, Rogers, Malbert R. C., Adriaans, Danielle, Berbers, Roos-Marijn, Hendrickx, Antoni P. A., Viveen, Marco C., Groot, James A., Bonten, Marc J. M., Fluit, Ad C., Willems, Rob J. L., and Leavis, Helen L.
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- 2019
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9. In patients with primary Sjögren’s syndrome innate-like MAIT cells display upregulated IL-7R, IFN-γ, and IL-21 expression and have increased proportions of CCR9 and CXCR5-expressing cells
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Hinrichs, Anneline C., primary, Kruize, Aike A., additional, Leavis, Helen L., additional, and van Roon, Joel A. G., additional
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- 2022
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10. Air pollution from livestock farms and the oropharyngeal microbiome of COPD patients and controls
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van Kersen, Warner, primary, Bossers, Alex, additional, de Steenhuijsen Piters, Wouter A.A., additional, de Rooij, Myrna M.T., additional, Bonten, Marc, additional, Fluit, Ad C., additional, Heederik, Dick, additional, Paganelli, Fernanda L., additional, Rogers, Malbert, additional, Viveen, Marco, additional, Bogaert, Debby, additional, Leavis, Helen L., additional, and Smit, Lidwien A.M., additional
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- 2022
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11. Heterozygous Variants in the DNA-binding Domain of c-Myb May Affect Normal B/T Cell Development
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Smits, Bas M., primary, Hartley, Taila, additional, Dünnebach, Ester, additional, Bartels, Marije, additional, Boycott, Kim M., additional, Kernohan, Kirstin D., additional, Dyment, David A., additional, Giltay, Jacques C., additional, Haddad, Elie, additional, Jarinova, Olga, additional, van Montfrans, Joris, additional, van Royen-Kerkhof, Annet, additional, van der Veken, Lars T., additional, de Witte, Moniek, additional, Nierkens, Stefan, additional, Pham-Huy, Anne, additional, and Leavis, Helen L., additional
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- 2022
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12. CCL5 Release by CCR9+ CD8 T Cells: A Potential Contributor to Immunopathology of Primary Sjögren’s Syndrome
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Hinrichs, Anneline C., primary, Blokland, Sofie L. M., additional, Kruize, Aike A., additional, Lafeber, Floris P. J., additional, Leavis, Helen L., additional, and van Roon, Joel A. G., additional
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- 2022
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13. Clinical features and immune-related protein patterns of anti-MDA5 positive clinically amyopathic dermatomyositis Dutch patients
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Hensgens, Marjolein P M, primary, Delemarre, Eveline M, additional, Drylewicz, Julia, additional, Voortman, Mareye, additional, Krol, Roline M, additional, Dalm, Virgil A S H, additional, Miedema, Jelle R, additional, Wiertz, Ivo, additional, Grutters, Jan, additional, Limper, Maarten, additional, Nierkens, Stefan, additional, and Leavis, Helen L, additional
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- 2022
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14. Repetitive Immune-Mediated Noninfectious Endocarditis Necessitating 5 Mitral Valve Replacements
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Muller, Steven A., primary, Leavis, Helen L., additional, Taha, Karim, additional, Koenderman, Leo, additional, Chamuleau, Steven A.J., additional, Suyker, Willem J.L., additional, and Cramer, Maarten J., additional
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- 2021
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15. Interleukin-6 Receptor Antagonists in Critically Ill Patients with Covid-19 – Preliminary report
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Gordon, Anthony C., Mouncey, Paul R., Al-Beidh, Farah, Rowan, Kathryn M., Nichol, Alistair D., Arabi, Yaseen M., Annane, Djillali, Beane, Abi, van Bentum-Puijk, Wilma, Berry, Lindsay R., Bhimani, Zahra, Bonten, Marc J.M., Bradbury, Charlotte A., Brunkhorst, Frank M., Buzgau, Adrian, Cheng, Allen C., Detry, Michelle A., Duffy, Eamon J., Estcourt, Lise J., Fitzgerald, Mark, Goossens, Herman, Haniffa, Rashan, Higgins, Alisa M., Hills, Thomas E., Horvat, Christopher M., Lamontagne, Francois, Lawler, Patrick R., Leavis, Helen L., Linstrum, Kelsey M., Litton, Edward, Lorenzi, Elizabeth, Marshall, John C., Mayr, Florian B., McAuley, Danny, McGlothlin, Anna, McGuinness, Shay P, McVerry, Bryan J., Montgomery, Stephanie K., Morpeth, Susan C., Murthy, Srinivas, Orr, Katrina, Parke, Rachael L., Parker, Jane C., Patanwala, Asad E., Pettilä, Ville, Rademaker, Emma, Santos, Marlene S., Saunders, Christina T., Seymour, Christopher W., Shankar-Hari, Manu, Sligl, Wendy I., Turgeon, Alexis F., Turner, Anne M., van de Veerdonk, Frank L., Zarychanski, Ryan, Green, Cameron, Lewis, Roger J., Angus, Derek C., McArthur, Colin J., Berry, Scott, Webb, Steve A., and Derde, Lennie P.G.
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medicine.medical_specialty ,Coronavirus disease 2019 (COVID-19) ,business.industry ,COVID-19 ,Odds ratio ,Intensive care unit ,law.invention ,Coronavirus ,Sarilumab ,chemistry.chemical_compound ,Tocilizumab ,chemistry ,Interquartile range ,law ,Intensive care ,Internal medicine ,Interleukin-6 receptor ,Medicine ,business - Abstract
BackgroundThe efficacy of interleukin-6 receptor antagonists in critically ill patients with coronavirus disease 2019 (Covid-19) is unclear.MethodsWe evaluated tocilizumab and sarilumab in an ongoing international, multifactorial, adaptive platform trial. Adult patients with Covid-19, within 24 hours of commencing organ support in an intensive care unit, were randomized to receive either tocilizumab (8mg/kg) or sarilumab (400mg) or standard care (control). The primary outcome was an ordinal scale combining in-hospital mortality (assigned −1) and days free of organ support to day 21. The trial uses a Bayesian statistical model with pre-defined triggers to declare superiority, efficacy, equivalence or futility.ResultsTocilizumab and sarilumab both met the pre-defined triggers for efficacy. At the time of full analysis 353 patients had been assigned to tocilizumab, 48 to sarilumab and 402 to control. Median organ support-free days were 10 (interquartile range [IQR] −1, 16), 11 (IQR 0, 16) and 0 (IQR −1, 15) for tocilizumab, sarilumab and control, respectively. Relative to control, median adjusted odds ratios were 1.64 (95% credible intervals [CrI] 1.25, 2.14) for tocilizumab and 1.76 (95%CrI 1.17, 2.91) for sarilumab, yielding >99.9% and 99.5% posterior probabilities of superiority compared with control. Hospital mortality was 28.0% (98/350) for tocilizumab, 22.2% (10/45) for sarilumab and 35.8% (142/397) for control. All secondary outcomes and analyses supported efficacy of these IL-6 receptor antagonists.ConclusionsIn critically ill patients with Covid-19 receiving organ support in intensive care, treatment with the IL-6 receptor antagonists, tocilizumab and sarilumab, improved outcome, including survival. (ClinicalTrials.govnumber:NCT02735707)
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- 2021
16. Severe thrombotic microangiopathy after autologous stem cell transplantation in systemic sclerosis: a case report
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Sharif, Maryam O., primary, Leavis, Helen L., additional, van Paassen, Pieter, additional, van Rhenen, Anna, additional, Timmermans, Sjoerd A. M. E. G., additional, Ton, Evelien, additional, Laar, Jacob M. van, additional, and Spierings, Julia, additional
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- 2021
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17. Broad Virus Detection and Variant Discovery in Fecal Samples of Hematopoietic Transplant Recipients Using Targeted Sequence Capture Metagenomics
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Jansen, Suze A., primary, Nijhuis, Wouter, additional, Leavis, Helen L., additional, Riezebos-Brilman, Annelies, additional, Lindemans, Caroline A., additional, and Schuurman, Rob, additional
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- 2020
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18. Epidemic and nonepidemic multidrug-resistant Enterococcus faecium
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Leavis, Helen L., Willems, Rob J.L., Top, Janetta, Spalburg, Emile, Mascini, Ellen M., Fluit, Ad C., Hoepelman, Andy, de Neeling, Albert J., and Bonten, Mark J.M.
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Drug resistance -- Physiological aspects ,Drug resistance -- Genetic aspects ,Enterococcal infections -- Genetic aspects ,Enterococcal infections -- Development and progression ,Enterococcal infections -- Care and treatment - Abstract
The epidemiology of vancomycin-resistant Enterococcus faecium (VREF) in Europe is characterized by a large community reservoir. In contrast, nosocomial outbreaks and infections (without a community reservoir) characterize VREF in the [...]
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- 2003
19. Implementation of Early Next-Generation Sequencing for Inborn Errors of Immunity: A Prospective Observational Cohort Study of Diagnostic Yield and Clinical Implications in Dutch Genome Diagnostic Centers.
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Elsink, Kim, Huibers, Manon M. H., Hollink, Iris H. I. M., Simons, Annet, Zonneveld-Huijssoon, Evelien, van der Veken, Lars T., Leavis, Helen L., Henriet, Stefanie S. V., van Deuren, Marcel, van de Veerdonk, Frank L., Potjewijd, Judith, Berghuis, Dagmar, Dalm, Virgil A. S. H., Vermont, Clementien L., van de Ven, Annick A. J. M., Lambeck, Annechien J. A., Abbott, Kristin M., van Hagen, P. Martin, de Bree, Godelieve J., and Kuijpers, Taco W.
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NUCLEOTIDE sequencing ,CHILD patients ,COHORT analysis ,IMMUNOLOGIC diseases ,GENETIC testing ,GENETIC disorder diagnosis ,MOLECULAR diagnosis - Abstract
Objective: Inborn errors of immunity (IEI) are a heterogeneous group of disorders, affecting different components of the immune system. Over 450 IEI related genes have been identified, with new genes continually being recognized. This makes the early application of next-generation sequencing (NGS) as a diagnostic method in the evaluation of IEI a promising development. We aimed to provide an overview of the diagnostic yield and time to diagnosis in a cohort of patients suspected of IEI and evaluated by an NGS based IEI panel early in the diagnostic trajectory in a multicenter setting in the Netherlands. Study Design: We performed a prospective observational cohort study. We collected data of 165 patients with a clinical suspicion of IEI without prior NGS based panel evaluation that were referred for early NGS using a uniform IEI gene panel. The diagnostic yield was assessed in terms of definitive genetic diagnoses, inconclusive diagnoses and patients without abnormalities in the IEI gene panel. We also assessed time to diagnosis and clinical implications. Results: For children, the median time from first consultation to diagnosis was 119 days versus 124 days for adult patients (U=2323; p=0.644). The median turn-around time (TAT) of genetic testing was 56 days in pediatric patients and 60 days in adult patients (U=1892; p=0.191). A definitive molecular diagnosis was made in 25/65 (24.6%) of pediatric patients and 9/100 (9%) of adults. Most diagnosed disorders were identified in the categories of immune dysregulation (n=10/25; 40%), antibody deficiencies (n=5/25; 20%), and phagocyte diseases (n=5/25; 20%). Inconclusive outcomes were found in 76/165 (46.1%) patients. Within the patient group with a genetic diagnosis, a change in disease management occurred in 76% of patients. Conclusion: In this cohort, the highest yields of NGS based evaluation for IEI early in the diagnostic trajectory were found in pediatric patients, and in the disease categories immune dysregulation and phagocyte diseases. In cases where a definitive diagnosis was made, this led to important disease management implications in a large majority of patients. More research is needed to establish a uniform diagnostic pathway for cases with inconclusive diagnoses, including variants of unknown significance. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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- View/download PDF
20. Low IgA Associated With Oropharyngeal Microbiota Changes and Lung Disease in Primary Antibody Deficiency
- Author
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Berbers, Roos-Marijn, primary, Mohamed Hoesein, Firdaus A. A., additional, Ellerbroek, Pauline M., additional, van Montfrans, Joris M., additional, Dalm, Virgil A. S. H., additional, van Hagen, P. Martin, additional, Paganelli, Fernanda L., additional, Viveen, Marco C., additional, Rogers, Malbert R. C., additional, de Jong, Pim A., additional, Uh, Hae-Won, additional, Willems, Rob J. L., additional, and Leavis, Helen L., additional
- Published
- 2020
- Full Text
- View/download PDF
21. Behçet's Disease Under Microbiotic Surveillance? A Combined Analysis of Two Cohorts of Behçet's Disease Patients
- Author
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van der Houwen, Tim B., primary, van Laar, Jan A. M., additional, Kappen, Jasper H., additional, van Hagen, Petrus M., additional, de Zoete, Marcel R., additional, van Muijlwijk, Guus H., additional, Berbers, Roos-Marijn, additional, Fluit, Ad C., additional, Rogers, Malbert, additional, Groot, James, additional, Hazelbag, C. Marijn, additional, Consolandi, Clarissa, additional, Severgnini, Marco, additional, Peano, Clelia, additional, D'Elios, Mario M., additional, Emmi, Giacomo, additional, and Leavis, Helen L., additional
- Published
- 2020
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- View/download PDF
22. Targeted Sequence Capture Metagenomics (ViroCap) to Detect Viruses in Stool Samples of Hematopoietic Stem Cell Transplantation Patients
- Author
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Jansen, Suze A., primary, Nijhuis, Wouter, additional, Leavis, Helen L., additional, Riezebos-Brilman, Annelies, additional, Lindemans, Caroline A., additional, and Schuurman, Rob, additional
- Published
- 2020
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- View/download PDF
23. First Report of IgG4 Related Disease Primary Presenting as Vertebral Bone Marrow Lesions
- Author
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van den Elshout-den Uyl, Debby, primary, Spoto, Clothaire P. E., additional, de Boer, Mirthe, additional, Leiner, Tim, additional, Leavis, Helen L., additional, and Leguit, Roos J., additional
- Published
- 2019
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24. Group IIA-Secreted Phospholipase A 2 in Human Serum Kills Commensal but Not Clinical Enterococcus faecium Isolates
- Author
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Paganelli, Fernanda L., primary, Leavis, Helen L., additional, He, Samantha, additional, van Sorge, Nina M., additional, Payré, Christine, additional, Lambeau, Gérard, additional, Willems, Rob J. L., additional, and Rooijakkers, Suzan H. M., additional
- Published
- 2018
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25. Identification of a novel genomic island specific to hospital-acquired clonal complex 17 Enterococcus faecium isolates
- Author
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Heikens, Esther, van Schaik, Willem, Leavis, Helen L., Bonten, Marc J.M., and Willems, Rob J.L.
- Subjects
Carbohydrate metabolism -- Analysis ,Enterococcus -- Genetic aspects ,Enterococcus -- Physiological aspects ,Polymerase chain reaction -- Usage ,Biological sciences - Abstract
The [delta][rho]-Web model, PCR, and dot blotting methods are used to identify anomalous GeCs in the genome of Enterococcus faecium DO, a clonal complex 17 (CC17) E. faecium strains that might contribute towards increased fitness and enhanced survival of CC17 E. faecium. A genomic island identified in CC17 E. faecium tentatively encoding a metabolic pathway involved in carbohydrate transport and metabolism might provide a competitive advantage over the E. faecium microbiota.
- Published
- 2008
26. Acute influenza virus-associated encephalitis and encephalopathy in adults: a challenging diagnosis
- Author
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Meijer, Wouter J., primary, Linn, Francisca H. H., additional, Wensing, Anne M. J., additional, Leavis, Helen L., additional, van Riel, Debby, additional, GeurtsvanKessel, Corine H., additional, Wattjes, Mike P., additional, and Murk, Jean-Luc, additional
- Published
- 2016
- Full Text
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27. The Enterococcus faecium Enterococcal Biofilm Regulator, EbrB, Regulates the esp Operon and Is Implicated in Biofilm Formation and Intestinal Colonization
- Author
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Top, Janetta, primary, Paganelli, Fernanda L., additional, Zhang, Xinglin, additional, van Schaik, Willem, additional, Leavis, Helen L., additional, van Luit-Asbroek, Miranda, additional, van der Poll, Tom, additional, Leendertse, Masja, additional, Bonten, Marc J. M., additional, and Willems, Rob J. L., additional
- Published
- 2013
- Full Text
- View/download PDF
28. Enterococcus faecium Biofilm Formation: Identification of Major Autolysin AtlA Efm , Associated Acm Surface Localization, and AtlA Efm -Independent Extracellular DNA Release
- Author
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Paganelli, Fernanda L., primary, Willems, Rob J. L., additional, Jansen, Pamela, additional, Hendrickx, Antoni, additional, Zhang, Xinglin, additional, Bonten, Marc J. M., additional, and Leavis, Helen L., additional
- Published
- 2013
- Full Text
- View/download PDF
29. Insertion Sequence–Driven Diversification Creates a Globally Dispersed Emerging Multiresistant Subspecies of E. faecium
- Author
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Leavis, Helen L, primary, Willems, Rob J. L, additional, van Wamel, Willem J. B, additional, Schuren, Frank H, additional, Caspers, Martien P. M, additional, and Bonten, Marc J. M, additional
- Published
- 2007
- Full Text
- View/download PDF
30. High-Level Ciprofloxacin Resistance from Point Mutations in gyrA and parC Confined to Global Hospital-Adapted Clonal Lineage CC17 of Enterococcus faecium
- Author
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Leavis, Helen L., primary, Willems, Rob J. L., additional, Top, Janetta, additional, and Bonten, Marc J. M., additional
- Published
- 2006
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- View/download PDF
31. Epidemic and Nonepidemic Multidrug-ResistantEnterococcus faecium
- Author
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Leavis, Helen L., primary, Willems, Rob J.L., additional, Top, Janetta, additional, Spalburg, Emile, additional, Mascini, Ellen M., additional, Fluit, Ad C., additional, Hoepelman, Andy, additional, de Neeling, Albert J., additional, and Bonten, Marc J.M., additional
- Published
- 2003
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32. The Enterococcus faecium Enterococcal Biofilm Regulator, EbrB, Regulates the esp Operon and Is Implicated in Biofilm Formation and Intestinal Colonization
- Author
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Top, Janetta, Paganelli, Fernanda L., Zhang, Xinglin, van Schaik, Willem, Leavis, Helen L., van Luit-Asbroek, Miranda, van der Poll, Tom, Leendertse, Masja, Bonten, Marc J. M., and Willems, Rob J. L.
- Subjects
ENTEROCOCCUS faecium ,BIOFILMS ,NOSOCOMIAL infections ,PATHOGENIC microorganisms ,COLONIZATION (Ecology) ,BACTERIAL operons ,MOBILE genetic elements - Abstract
Nowadays, Enterococcus faecium is one of the leading nosocomial pathogens worldwide. Strains causing clinical infections or hospital outbreaks are enriched in the enterococcal surface protein (Esp) encoding ICEEfm1 mobile genetic element. Previous studies showed that Esp is involved in biofilm formation, endocarditis and urinary tract infections. In this study, we characterized the role of the putative AraC type of regulator (locus tag EfmE1162_2351), which we renamed ebrB and which is, based on the currently available whole genome sequences, always located upstream of the esp gene, and studied its role in Esp surface exposure during growth. A markerless deletion mutant of ebrB resulted in reduced esp expression and complete abolishment of Esp surface exposure, while Esp cell-surface exposure was restored when this mutant was complemented with an intact copy of ebrB. This demonstrates a role for EbrB in esp expression. However, during growth, ebrB expression levels did not change over time, while an increase in esp expression at both RNA and protein level was observed during mid-log and late-log phase. These results indicate the existence of a secondary regulation system for esp, which might be an unknown quorum sensing system as the enhanced esp expression seems to be cell density dependent. Furthermore, we determined that esp is part of an operon of at least 3 genes putatively involved in biofilm formation. A semi-static biofilm model revealed reduced biofilm formation for the EbrB deficient mutant, while dynamics of biofilm formation using a flow cell system revealed delayed biofilm formation in the ebrB mutant. In a mouse intestinal colonization model the ebrB mutant was less able to colonize the gut compared to wild-type strain, especially in the small intestine. These data indicate that EbrB positively regulates the esp operon and is implicated in biofilm formation and intestinal colonization. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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- View/download PDF
33. High-Level Ciprofloxacin Resistance from Point Mutations in gyrAand parCConfined to Global Hospital-Adapted Clonal Lineage CC17 of Enterococcus faecium
- Author
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Leavis, Helen L., Willems, Rob J. L., Top, Janetta, and Bonten, Marc J. M.
- Abstract
ABSTRACTTo substantiate a common genetic background of ciprofloxacin-resistant Enterococcus faecium, 32 ciprofloxacin-resistant (Cipr) and 31 ciprofloxacin-susceptible (Cips) isolates from outbreaks, clinical infections, surveillances, and animals from 10 different countries were genotyped by multilocus sequence typing. Additionally, susceptibilities to ampicillin and vancomycin and the presence of espwere determined and the quinolone resistance-determining regions of parC, gyrA, parB, and gyrEwere sequenced. High-level Cipr(MIC = 64 µg/ml) due to point mutations in the quinolone resistance-determining region was unique to a distinct hospital-adapted genetic complex in E. faecium, previously designated CC17. Low-level Cipr(MIC = 4 µg/ml) in non-CC17 strains is not attributable to point mutations in any subunit of the topoisomerase genes, and the mechanism of resistance remains unclear. Acquisition of mutations in parCand gyrA, leading to high-level Cipr, is, in addition to ampicillin resistance and the presence of a putative pathogenicity island, another cumulative step in hospital adaptation of CC17.
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- 2006
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34. Group IIA-Secreted Phospholipase A2in Human Serum Kills Commensal but Not Clinical Enterococcus faeciumIsolates
- Author
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Paganelli, Fernanda L., Leavis, Helen L., He, Samantha, van Sorge, Nina M., Payré, Christine, Lambeau, Gérard, Willems, Rob J. L., and Rooijakkers, Suzan H. M.
- Abstract
Human innate immunity employs cellular and humoral mechanisms to facilitate rapid killing of invading bacteria. The direct killing of bacteria by human serum is attributed mainly to the activity of the complement system, which forms pores in Gram-negative bacteria.
- Published
- 2018
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- View/download PDF
35. Enterococcus faeciumBiofilm Formation: Identification of Major Autolysin AtlAEfm, Associated Acm Surface Localization, and AtlAEfm-Independent Extracellular DNA Release
- Author
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Paganelli, Fernanda L., Willems, Rob J. L., Jansen, Pamela, Hendrickx, Antoni, Zhang, Xinglin, Bonten, Marc J. M., and Leavis, Helen L.
- Abstract
ABSTRACTEnterococcus faeciumis an important multidrug-resistant nosocomial pathogen causing biofilm-mediated infections in patients with medical devices. Insight into E. faeciumbiofilm pathogenesis is pivotal for the development of new strategies to prevent and treat these infections. In several bacteria, a major autolysin is essential for extracellular DNA (eDNA) release in the biofilm matrix, contributing to biofilm attachment and stability. In this study, we identified and functionally characterized the major autolysin of E. faeciumE1162 by a bioinformatic genome screen followed by insertional gene disruption of six putative autolysin genes. Insertional inactivation of locus tag EfmE1162_2692 resulted in resistance to lysis, reduced eDNA release, deficient cell attachment, decreased biofilm, decreased cell wall hydrolysis, and significant chaining compared to that of the wild type. Therefore, locus tag EfmE1162_2692 was considered the major autolysin in E. faeciumand renamed atlAEfm. In addition, AtlAEfmwas implicated in cell surface exposure of Acm, a virulence factor in E. faecium, and thereby facilitates binding to collagen types I and IV. This is a novel feature of enterococcal autolysins not described previously. Furthermore, we identified (and localized) autolysin-independent DNA release in E. faeciumthat contributes to cell-cell interactions in the atlAEfmmutant and is important for cell separation. In conclusion, AtlAEfmis the major autolysin in E. faeciumand contributes to biofilm stability and Acm localization, making AtlAEfma promising target for treatment of E. faeciumbiofilm-mediated infections.IMPORTANCENosocomial infections caused by Enterococcus faeciumhave rapidly increased, and treatment options have become more limited. This is due not only to increasing resistance to antibiotics but also to biofilm-associated infections. DNA is released in biofilm matrix via cell lysis, caused by autolysin, and acts as a matrix stabilizer. In this study, we identified and characterized the major autolysin in E. faecium, which we designated AtlAEfm. atlAEfmdisruption resulted in resistance to lysis, reduced extracellular DNA (eDNA), deficient cell attachment, decreased biofilm, decreased cell wall hydrolysis, and chaining. Furthermore, AtlAEfmis associated with Acm cell surface localization, resulting in less binding to collagen types I and IV in the atlAEfmmutant. We also identified AtlAEfm-independent eDNA release that contributes to cell-cell interactions in the atlAEfmmutant. These findings indicate that AtlAEfmis important in biofilm and collagen binding in E. faecium, making AtlAEfma promising target for treatment of E. faeciuminfections.
- Published
- 2013
- Full Text
- View/download PDF
36. Measurement of antinuclear antibodies and their fine specificities: time for a change in strategy?
- Author
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Otten HG, Brummelhuis WJ, Fritsch-Stork R, Leavis HL, Wisse BW, van Laar JM, and Derksen RHWM
- Subjects
- Antibody Specificity, Autoimmune Diseases blood, Autoimmune Diseases immunology, Biomarkers blood, Connective Tissue Diseases blood, Connective Tissue Diseases immunology, Cost-Benefit Analysis, Health Care Costs, Humans, Predictive Value of Tests, Reproducibility of Results, Antibodies, Antinuclear blood, Autoimmune Diseases diagnosis, Connective Tissue Diseases diagnosis, Reagent Kits, Diagnostic economics, Serologic Tests economics
- Abstract
Objectives: The current strategy for antinuclear antibody (ANA) analysis involves screening for presence with a subsequent detailed analysis of their specificity. The aim of this study is to compare the clinical and financial efficacy of this strategy between different commercial tests in a large cohort of unselected patients., Methods: In all consecutive 1030 patients associations were defined between results from different ANA test systems and the pre-test probability for connective tissue disease (CTDs). Test systems were used for screening (ANA-IIF vs. CTD screen) and definition of their fine specificity (profile 3 line blot vs. CTD single analytes)., Results: Positive ANA-IIF and/or CTD screen results were found in 304 sera. Further analysis for ANA-specificity by profile 3 line blot and CTD single analytes showed 86 discrepant results of which more than a third are clinically relevant, with the CTD single analyte assay performing better than the line blot in supporting or confirming the presence of a CTD. Autoantigens present in one test but absent in the other were of minor practical use. The ANA screening and identification strategies currently employed are not cost-effective as 83% of tests were performed in order to find specific autoantibodies in patients without the fitting clinical signs or symptoms. This causes many unexpected positive results and subsequent confusion with regard to interpretation., Conclusions: We advocate that some autoantigens should be excluded from the line blot and CTD assays and propose the use of a cost-effective and selective ANA specificity testing purely based on clinical guidance.
- Published
- 2017
37. Enterococcus faecium biofilm formation: identification of major autolysin AtlAEfm, associated Acm surface localization, and AtlAEfm-independent extracellular DNA Release.
- Author
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Paganelli FL, Willems RJ, Jansen P, Hendrickx A, Zhang X, Bonten MJ, and Leavis HL
- Subjects
- Bacterial Adhesion, Cell Wall chemistry, Cell Wall metabolism, Collagen metabolism, Computational Biology, Gene Knockout Techniques, Humans, Mutagenesis, Insertional, N-Acetylmuramoyl-L-alanine Amidase genetics, Virulence Factors analysis, Adhesins, Bacterial analysis, Biofilms growth & development, DNA, Bacterial metabolism, Enterococcus faecium chemistry, Enterococcus faecium physiology, N-Acetylmuramoyl-L-alanine Amidase metabolism
- Abstract
Enterococcus faecium is an important multidrug-resistant nosocomial pathogen causing biofilm-mediated infections in patients with medical devices. Insight into E. faecium biofilm pathogenesis is pivotal for the development of new strategies to prevent and treat these infections. In several bacteria, a major autolysin is essential for extracellular DNA (eDNA) release in the biofilm matrix, contributing to biofilm attachment and stability. In this study, we identified and functionally characterized the major autolysin of E. faecium E1162 by a bioinformatic genome screen followed by insertional gene disruption of six putative autolysin genes. Insertional inactivation of locus tag EfmE1162_2692 resulted in resistance to lysis, reduced eDNA release, deficient cell attachment, decreased biofilm, decreased cell wall hydrolysis, and significant chaining compared to that of the wild type. Therefore, locus tag EfmE1162_2692 was considered the major autolysin in E. faecium and renamed atlAEfm. In addition, AtlAEfm was implicated in cell surface exposure of Acm, a virulence factor in E. faecium, and thereby facilitates binding to collagen types I and IV. This is a novel feature of enterococcal autolysins not described previously. Furthermore, we identified (and localized) autolysin-independent DNA release in E. faecium that contributes to cell-cell interactions in the atlAEfm mutant and is important for cell separation. In conclusion, AtlAEfm is the major autolysin in E. faecium and contributes to biofilm stability and Acm localization, making AtlAEfm a promising target for treatment of E. faecium biofilm-mediated infections. IMPORTANCE Nosocomial infections caused by Enterococcus faecium have rapidly increased, and treatment options have become more limited. This is due not only to increasing resistance to antibiotics but also to biofilm-associated infections. DNA is released in biofilm matrix via cell lysis, caused by autolysin, and acts as a matrix stabilizer. In this study, we identified and characterized the major autolysin in E. faecium, which we designated AtlAEfm. atlAEfm disruption resulted in resistance to lysis, reduced extracellular DNA (eDNA), deficient cell attachment, decreased biofilm, decreased cell wall hydrolysis, and chaining. Furthermore, AtlAEfm is associated with Acm cell surface localization, resulting in less binding to collagen types I and IV in the atlAEfm mutant. We also identified AtlAEfm-independent eDNA release that contributes to cell-cell interactions in the atlAEfm mutant. These findings indicate that AtlAEfm is important in biofilm and collagen binding in E. faecium, making AtlAEfm a promising target for treatment of E. faecium infections.
- Published
- 2013
- Full Text
- View/download PDF
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