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1. Diagnostic accuracy of SARS-CoV-2 rapid antigen self-tests in asymptomatic individuals in the omicron period: a cross-sectional study

Author

Venekamp, Roderick P., primary, Schuit, Ewoud, additional, Hooft, Lotty, additional, Veldhuijzen, Irene K., additional, van den Bijllaardt, Wouter, additional, Pas, Suzan D., additional, Zwart, Vivian F., additional, Lodder, Esther B., additional, Hellwich, Marloes, additional, Koppelman, Marco, additional, Molenkamp, Richard, additional, Wijers, Constantijn J.H., additional, Vroom, Irene H., additional, Smeets, Leonard C., additional, Nagel-Imming, Carla R.S., additional, Han, Wanda G.H., additional, van den Hof, Susan, additional, Kluytmans, Jan A.J.W., additional, van de Wijgert, Janneke H.H.M., additional, and Moons, Karel G.M., additional

Published
2023
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2. Diagnostic accuracy of SARS-CoV-2 rapid antigen self-tests in asymptomatic individuals in the omicron period:a cross-sectional study

Author

Venekamp, Roderick P., Schuit, Ewoud, Hooft, Lotty, Veldhuijzen, Irene K., van den Bijllaardt, Wouter, Pas, Suzan D., Zwart, Vivian F., Lodder, Esther B., Hellwich, Marloes, Koppelman, Marco, Molenkamp, Richard, Wijers, Constantijn J.H., Vroom, Irene H., Smeets, Leonard C., Nagel-Imming, Carla R.S., Han, Wanda G.H., van den Hof, Susan, Kluytmans, Jan A.J.W., van de Wijgert, Janneke H.H.M., Moons, Karel G.M., Venekamp, Roderick P., Schuit, Ewoud, Hooft, Lotty, Veldhuijzen, Irene K., van den Bijllaardt, Wouter, Pas, Suzan D., Zwart, Vivian F., Lodder, Esther B., Hellwich, Marloes, Koppelman, Marco, Molenkamp, Richard, Wijers, Constantijn J.H., Vroom, Irene H., Smeets, Leonard C., Nagel-Imming, Carla R.S., Han, Wanda G.H., van den Hof, Susan, Kluytmans, Jan A.J.W., van de Wijgert, Janneke H.H.M., and Moons, Karel G.M.

Abstract

Objectives: To assess the performances of three commonly used antigen rapid diagnostic tests used as self-tests in asymptomatic individuals in the Omicron period. Methods: We performed a cross-sectional diagnostic test accuracy study in the Omicron period in three public health service COVID-19 test sites in the Netherlands, including 3600 asymptomatic individuals aged ≥ 16 years presenting for SARS-CoV-2 testing for any reason except confirmatory testing after a positive self-test. Participants were sampled for RT-PCR (reference test) and received one self-test (either Acon Flowflex [Flowflex], MP Biomedicals (MPBio), or Siemens-Healthineers CLINITEST [CLINITEST]) to perform unsupervised at home. Diagnostic accuracies of each self-test were calculated. Results: Overall sensitivities were 27.5% (95% CI, 21.3–34.3%) for Flowflex, 20.9% (13.9–29.4%) for MPBio, and 25.6% (19.1–33.1%) for CLINITEST. After applying a viral load cut-off (≥5.2 log10 SARS-CoV-2 E-gene copies/mL), sensitivities increased to 48.3% (37.6–59.2%), 37.8% (22.5–55.2%), and 40.0% (29.5–51.2%), respectively. Specificities were >99% for all tests in most analyses. Discussion: The sensitivities of three commonly used SARS-CoV-2 antigen rapid diagnostic tests when used as self-tests in asymptomatic individuals in the Omicron period were very low. Antigen rapid diagnostic test self-testing in asymptomatic individuals may only detect a minority of infections at that point in time. Repeated self-testing in case of a negative self-test is advocated to improve the diagnostic yield, and individuals should be advised to re-test when symptoms develop.

Published
2023

3. Diagnostic accuracy of SARS-CoV-2 rapid antigen self-tests in asymptomatic individuals in the Omicron period: a cross-sectional study

Author

HAG Onderzoek, Child Health, Infection & Immunity, JC onderzoeksprogramma Infectieziekten, Epi Methoden Team 4, JC onderzoeksprogramma Methodologie, Epidemiology & Health Economics, Medische Microbiologie, Epi Infectieziekten Team 1b, Epi Methoden, Cancer, Venekamp, Roderick P, Schuit, Ewoud, Hooft, Lotty, Veldhuijzen, Irene K, van den Bijllaardt, Wouter, Pas, Suzan D, Zwart, Vivian F, Lodder, Esther B, Hellwich, Marloes, Koppelman, Marco, Molenkamp, Richard, Wijers, Constantijn Jh, Vroom, Irene H, Smeets, Leonard C, Nagel-Imming, Carla R S, Han, Wanda G H, van den Hof, Susan, Kluytmans, Jan AJW, van de Wijgert, Janneke H M, Moons, Karel G M, HAG Onderzoek, Child Health, Infection & Immunity, JC onderzoeksprogramma Infectieziekten, Epi Methoden Team 4, JC onderzoeksprogramma Methodologie, Epidemiology & Health Economics, Medische Microbiologie, Epi Infectieziekten Team 1b, Epi Methoden, Cancer, Venekamp, Roderick P, Schuit, Ewoud, Hooft, Lotty, Veldhuijzen, Irene K, van den Bijllaardt, Wouter, Pas, Suzan D, Zwart, Vivian F, Lodder, Esther B, Hellwich, Marloes, Koppelman, Marco, Molenkamp, Richard, Wijers, Constantijn Jh, Vroom, Irene H, Smeets, Leonard C, Nagel-Imming, Carla R S, Han, Wanda G H, van den Hof, Susan, Kluytmans, Jan AJW, van de Wijgert, Janneke H M, and Moons, Karel G M

Published
2023

4. Diagnostic accuracy of covid-19 rapid antigen tests with unsupervised self-sampling in people with symptoms in the omicron period: cross sectional study

Author

Schuit, Ewoud, primary, Venekamp, Roderick P, additional, Hooft, Lotty, additional, Veldhuijzen, Irene K, additional, van den Bijllaardt, Wouter, additional, Pas, Suzan D, additional, Zwart, Vivian F, additional, Lodder, Esther B, additional, Hellwich, Marloes, additional, Koppelman, Marco, additional, Molenkamp, Richard, additional, Wijers, Constantijn J H, additional, Vroom, Irene H, additional, Smeets, Leonard C, additional, Nagel-Imming, Carla R S, additional, Han, Wanda G H, additional, van den Hof, Susan, additional, Kluytmans, Jan A J W, additional, van de Wijgert, Janneke H H M, additional, and Moons, Karel G M, additional

Published
2022
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5. Diagnostic accuracy of SARS-CoV-2 rapid antigen self-tests in asymptomatic individuals in the Omicron period: cross sectional study

Author

Venekamp, Roderick P, primary, Schuit, Ewoud, additional, Hooft, Lotty, additional, Veldhuijzen, Irene K, additional, Bijllaardt, Wouter, additional, Pas, Suzan D, additional, Zwart, Vivian F, additional, Lodder, Esther B, additional, Hellwich, Marloes, additional, Koppelman, Marco, additional, Molenkamp, Richard, additional, Wijers, Constantijn, additional, Vroom, Irene H, additional, Smeets, Leonard C, additional, Nagel-Imming, Carla RS, additional, Han, Wanda GH, additional, van den Hof, Susan, additional, Kluytmans, Jan AJ, additional, van de Wijgert, Janneke HHM, additional, and Moons, Karel GM, additional

Published
2022
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6. Detection of intrathecal antibodies to diagnose enterovirus infections of the central nervous system

Author

Sooksawasdi Na Ayudhya, Syriam, primary, Sips, Gregorius J., additional, Bogers, Susanne, additional, Leijten, Lonneke M.E., additional, Laksono, Brigitta M., additional, Smeets, Leonard C., additional, Bruning, Andrea, additional, Benschop, Kimberley, additional, Wolthers, Katja, additional, van Riel, Debby, additional, and GeurtsvanKessel, Corine H., additional

Published
2022
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7. Detection of intrathecal antibodies to diagnose enterovirus infections of the central nervous system

Author

Ayudhya, Syriam Sooksawasdi Na, Sips, Gregorius J., Bogers, Susanne, Leijten, Lonneke M. E., Laksono, Brigitta M., Smeets, Leonard C., Bruning, Andrea, Benschop, Kimberley, Wolthers, Katja, van Riel, Debby, GeurtsvanKessel, Corine H., Ayudhya, Syriam Sooksawasdi Na, Sips, Gregorius J., Bogers, Susanne, Leijten, Lonneke M. E., Laksono, Brigitta M., Smeets, Leonard C., Bruning, Andrea, Benschop, Kimberley, Wolthers, Katja, van Riel, Debby, and GeurtsvanKessel, Corine H.

Abstract

Background Enterovirus-D68 (EV-D68) predominantly causes respiratory disease. However, EV-D68 infections also have been associated with central nervous system (CNS) complications, most specifically acute flaccid myelitis (AFM). Diagnosing EV-D68-associated CNS disease is challenging since viral RNA is rarely detected in cerebrospinal fluid (CSF). Objective In order to determine an EV antibody index (AI), we evaluated the value of a commercially available quantitative ELISA to detect EV-specific antibodies in paired CSF and blood. Study design Nine paired CSF and blood samples were obtained from patients with EV-D68-associated AFM or from patients with a confirmed EV-associated CNS disease. EV-specific antibodies were detected using a quantitative ELISA. A Reiber diagram analysis was performed, by which the AI was calculated. Subsequently, EV ELISA results were compared with an EV-D68 virus neutralization test. Results ELISA detected EV-specific antibodies in 1 out of the 3 patients with EV-D68-associated AFM and in 3 out of the 6 patients with confirmed EV-associated CNS disease. In these patients, the AI was indicative for intrathecal antibody production against enterovirus. Assay comparison showed that EV-D68 neutralizing antibody detection increased the sensitivity of EV-D68 antibody detection. Conclusions A quantitative EV IgG ELISA in combination with Reiber diagram analysis and AI-calculation can be used as a diagnostic tool for EV-associated CNS disease, including EV-D68. An EV-D68 specific ELISA will improve the sensitivity of the tool. With the growing awareness that the detection of non-polio enteroviruses needs to be improved, diagnostic laboratories should consider implementation of EV serology.

Published
2022

8. Diagnostic accuracy of covid-19 rapid antigen tests with unsupervised self-sampling in people with symptoms in the omicron period: cross sectional study

Author

Epi Methoden Team 4, JC onderzoeksprogramma Methodologie, HAG Onderzoek, Child Health, Infection & Immunity, JC onderzoeksprogramma Infectieziekten, Epidemiology & Health Economics, Medische Microbiologie, Epi Infectieziekten Team 1b, Epi Methoden, Cancer, Schuit, Ewoud, Venekamp, Roderick P., Hooft, Lotty, Veldhuijzen, Irene K., van den Bijllaardt, Wouter, Pas, Suzan D., Zwart, Vivian F., Lodder, Esther B., Hellwich, Marloes, Koppelman, Marco, Molenkamp, Richard, Wijers, Constantijn J.H., Vroom, Irene H., Smeets, Leonard C., Nagel-Imming, Carla R.S., Han, Wanda G.H., van den Hof, Susan, Kluytmans, Jan A.J.W., van de Wijgert, Janneke H.H.M., Moons, Karel G.M., Epi Methoden Team 4, JC onderzoeksprogramma Methodologie, HAG Onderzoek, Child Health, Infection & Immunity, JC onderzoeksprogramma Infectieziekten, Epidemiology & Health Economics, Medische Microbiologie, Epi Infectieziekten Team 1b, Epi Methoden, Cancer, Schuit, Ewoud, Venekamp, Roderick P., Hooft, Lotty, Veldhuijzen, Irene K., van den Bijllaardt, Wouter, Pas, Suzan D., Zwart, Vivian F., Lodder, Esther B., Hellwich, Marloes, Koppelman, Marco, Molenkamp, Richard, Wijers, Constantijn J.H., Vroom, Irene H., Smeets, Leonard C., Nagel-Imming, Carla R.S., Han, Wanda G.H., van den Hof, Susan, Kluytmans, Jan A.J.W., van de Wijgert, Janneke H.H.M., and Moons, Karel G.M.

Published
2022

9. Accuracy of COVID-19 self-tests with unsupervised nasal or nasal plus oropharyngeal self-sampling in symptomatic individuals in the Omicron period

Author

Schuit, Ewoud, primary, Venekamp, Roderick P, additional, Hooft, Lotty, additional, Veldhuijzen, Irene K, additional, van den Bijllaardt, Wouter, additional, Pas, Suzan D, additional, Zwart, Vivian F, additional, Lodder, Esther B, additional, Hellwich, Marloes, additional, Koppelman, Marco, additional, Molenkamp, Richard, additional, Wijers, Constantijn, additional, Vroom, Irene H, additional, Smeets, Leonard C, additional, Nagel-Imming, Carla RS, additional, Han, Wanda GH, additional, van den Hof, Susan, additional, Kluytmans, Jan AJW, additional, van de Wijgert, Janneke HM, additional, and Moons, Karel GM, additional

Published
2022
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10. comH, a novel gene essential for natural transformation of Helicobacter pylori

Author

Smeets, Leonard C., Bijlsma, Jetta J.E., Boomkens, Sacha Y., Vandenbroucke-Grauls, Christina M.J.E., and Kusters, Johannes G.

Subjects
Bacteriology -- Research, Helicobacter pylori -- Research, Plasmids -- Research, DNA -- Research, Chromosomes -- Research, Biological sciences
Abstract

Research has been conducted on Helicobacter pylori. The identification of the Helicobacter-specific competence gene essential for H. pylori transformation with chromosomal DNA fragments and with plasmids is described.

Published
2000

11. Melioidosis in travelers: An analysis of Dutch melioidosis registry data 1985–2018

Author

Birnie, Emma, primary, Savelkoel, Jelmer, additional, Reubsaet, Frans, additional, Roelofs, Joris J.T.H., additional, Soetekouw, Robin, additional, Kolkman, Saskia, additional, Cremers, Anne Lia, additional, Grobusch, Martin P., additional, Notermans, Daan W., additional, Wiersinga, W. Joost, additional, Rozemeijer, Wouter, additional, Rijkeboer, Annemieke, additional, Birnie, Emma, additional, Scholing, Maarten, additional, van Dijk, Karin, additional, Mascini, Ellen M., additional, van der Veen, Henk, additional, van den Bijllaardt, Wouter, additional, de Vries, Maaike, additional, Smeets, Leonard C., additional, Ott, Alewijn, additional, van Krimpen, Kees, additional, Herpers, Bjorn L., additional, Watttel-Louis, G. Hanke, additional, Waar, Karola, additional, Schwandt, Noortje L.Q., additional, Maat, Ianthe, additional, Dofferhoff, Anthonius S.M., additional, Vermeulen, Joost N., additional, van Westreenen, Mireille, additional, de Man, Peter, additional, Hofland, Regina W., additional, van Gorp, Joost, additional, Thijsen, Steven, additional, van der Velden, Lieven B., additional, and Verduin, Cornelis M., additional

Published
2019
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13. DNA uptake sequences in Helicobacter pylori

Author

Bart, Aldert, Smeets, Leonard C., and Kusters, Johannes G.

Subjects
DNA -- Physiological aspects, Bacterial transformation -- Genetic aspects, Helicobacter pylori -- Genetic aspects, Influenza viruses -- Research, Biological sciences
Abstract

This article comments on inconsistencies and erroneous assumptions reported in an earler research publication. Authors contend that the method used for demonstrating DNA uptake sequences in Helicobacter pylori and the claim that Gram-negative bacteria lack a sequence for homospecific DNA uptake are incorrect.

Published
2000

19. Functional characterization of the competence protein DprA/Smf in Escherichia coli.

Author

Smeets, Leonard C., Becker, Stephen C., Barcak, Gerard J., Vandenbroucke-Grauls, Christina M.J. E., Bitter, Wilbert, and Goosen, Nora

Subjects
*ESCHERICHIA coli, *HAEMOPHILUS influenzae, *PROTEIN synthesis, *MYCOBACTERIUM tuberculosis, *CHROMOSOME replication, *GENETIC transformation
Abstract

In several bacterial species that show natural transformation, dprA has been described as a competence gene. The DprA protein has been suggested to be involved in the protection of incoming DNA. However, members of the dprA gene family (also called smf) can be detected in virtually all bacterial species, which suggests that their gene products have a more general function. We examined the function of the DprA/Smf homologue of Escherichia coli. Escherichia coli dprA/smf is able to partially restore transformation in a Haemophilus influenzae dprA mutant, which shows that dprA/smf genes from competent and noncompetent species are interchangeable with respect to their involvement in natural transformation. From this, we conclude that natural transformation is probably an additional function of these genes. Subsequently, the dprA/smf gene was deleted in various recombination mutants of E. coli, and the resultant phenotype was tested. All the resultant E. coli dprA/smf mutants did not differ from their parent strains with respect to transformation, Hfr-conjugation, recombination and DNA repair. Therefore, a role of DprA/Smf in DNA recombination could not be established and the basic function of dprA/smf remains unclear. [ABSTRACT FROM AUTHOR]

Published
2006
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21. Molecular Patchwork: Chromosomal Recombination between Two Helicobacter pyloriStrains during Natural Colonization

Author

Smeets, Leonard C., Arents, Nicolaas L. A., van Zwet, Anton A., Vandenbroucke-Grauls, Christina M. J. E., Verboom, Theo, Bitter, Wilbert, and Kusters, Johannes G.

Abstract

ABSTRACTGenetic analysis of two Helicobacter pyloristrains isolated from a single gastric biopsy showed evidence of extensive horizontal gene transfer. Several large recombinations were identified in the rdxAgene, which is involved in metronidazole resistance.

Published
2003
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22. The dprAgene is required for natural transformation of Helicobacter pylori

Author

Smeets, Leonard C., Bijlsma, Jetta J.E., Kuipers, Ernst J., Vandenbroucke‐Grauls, Christina M.J.E., and Kusters, Johannes G.

Abstract

Genetic recombination in Helicobacter pyloriis believed to be involved in host adaptation of this gastric pathogen and uptake of DNA by natural transformation can result in changes in virulence factors as well as antigenic variation. To elucidate the mechanisms involved in natural transformation we tested two genes with homology to known competence genes (dprAand traG) for their role in this process. Insertion mutants in these genes were constructed in two different H. pyloristrains and their competence by natural transformation was compared to the wild‐type. Mutation of the traGhomolog did not reduce competence. Mutation of the dprAgene, however, severely impaired natural transformation both with plasmid and chromosomal DNA. Our data indicate that dprAand comB3are essential parts of a common pathway for chromosomal and plasmid transformation.

Published
2000
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