Publications by authors named "Mark van der Linden"

Microbiology reference laboratories perform a crucial role within public health systems. This role was especially evident during the COVID-19 pandemic. In this Viewpoint, we emphasise the importance of microbiology reference laboratories and highlight the types of digital data and expertise they provide, which benefit national and international public health.

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  • The text discusses the impact of pneumococcal conjugate vaccines (PCVs), specifically PCV10 and PCV13, on invasive pneumococcal disease (IPD) globally, highlighting how these vaccines have reduced the prevalence of disease caused by vaccine-type serotypes after extensive use.
  • It describes the methodology of data collection from various surveillance sites, which aimed to evaluate IPD cases that occurred five years after the vaccines were implemented, focusing on different age groups for analysis.
  • Findings indicate significant differences in serotype distribution between PCV10 and PCV13 sites; notably, certain serotypes, such as 19A and serotype 3, were prevalent in specific age groups, signaling ongoing challenges in controlling
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Background: Pneumococcal conjugate vaccines (PCVs) that are ten-valent (PCV10) and 13-valent (PCV13) became available in 2010. We evaluated their global impact on invasive pneumococcal disease (IPD) incidence in all ages.

Methods: Serotype-specific IPD cases and population denominators were obtained directly from surveillance sites using PCV10 or PCV13 in their national immunisation programmes and with a primary series uptake of at least 50%.

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is an important cause of community-acquired pneumonia (CAP) in Japan. Here, we report the serotype distribution and antimicrobial susceptibility of cultured pneumococcal isolates from Japanese adults aged ≥18 years with CAP. This was a prospective, population-based, active surveillance study conducted in Goto City, Japan from December 2015 to November 2020.

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As a potential side effect of the severe acute respiratory syndrome coronavirus type 2 pandemic, invasive group A (iGAS) infections in Europe have increased dramatically in both children and adults in the end of 2022. This epidemiological and molecular study describes the distributions of streptococcal genes encoding the M antigen ( types) and superantigens in patients with invasive and non-invasive GAS infections. From December 2022 to December 2023, a total of 163 GAS isolates were collected from sterile and non-sterile sites of patients at five hospitals in Germany including two tertiary care centers.

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Streptococcus suis, a zoonotic bacterial pathogen circulated through swine, can cause severe infections in humans. Because human S. suis infections are not notifiable in most countries, incidence is underestimated.

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Purpose: In late 2022, a surge of severe S. pyogenes infections was reported in several European countries. This study assessed hospitalizations and disease severity of community-acquired bacterial infections with S.

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  • * In Q1 2023, there was a significant increase in invasive bacterial infections with S. pyogenes up by 142% and H. influenzae by 90%, especially among adults over 55 and children under 5 years old.
  • * The rise in infections may relate to increased viral circulation and greater vulnerability due to relaxed COVID-19 restrictions, highlighting the need for ongoing surveillance and public health measures, including vaccination.
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  • Next-generation pneumococcal conjugate vaccines (PCVs) have been approved, prompting an evaluation of their effects on invasive pneumococcal disease (IPD) trends in adults in Germany.
  • A Bayesian hierarchical logistic regression analysis showed that serotypes from the 13-valent PCV caused 60% of IPD cases in 2006, but this dropped to 30% by 2018, indicating a decline in these strains.
  • In 2018, over half of the IPD cases were from serotypes included in the newer 15-valent and 20-valent PCVs, highlighting their potential to further decrease IPD rates.
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The identification of the novel pneumococcal serotype 7D by Neufeld quellung reaction requires significant expertise. To circumvent this, we developed a simple serotype-specific PCR method to discriminate serotype 7D from the closely related serotypes 7C, 7B and 40. The established PCR was validated with the strain collection of the German National Reference Center for Streptococci (GNRCS).

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  • The IRIS Consortium investigated the impact of the COVID-19 pandemic on invasive diseases caused by specific bacteria over a four-year period, comparing data from before and during the pandemic.
  • Laboratories from 30 countries provided surveillance data, revealing a significant decrease in cases of Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis during the pandemic, while Streptococcus agalactiae cases remained unchanged.
  • An estimated 36,289 cases of invasive bacterial disease were prevented due to COVID-19 containment measures during the first two years of the pandemic.
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Purpose: Vaccination against Streptococcus pneumoniae is recommended in transplant recipients to reduce the morbidity and mortality from invasive pneumococcal disease. Previous studies indicate that transplant recipients can produce specific antibodies after vaccination with the 13-valent pneumococcal conjugate vaccine Prevenar 13 (PCV13) or the pneumococcal polysaccharide vaccine Pneumovax 23 (PPSV23). National guidelines recommend sequential vaccination with PCV13 followed by PPSV23 in kidney transplant patients.

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is capable of randomly switching their genomic DNA methylation pattern between six distinct bacterial subpopulations (A-F) via recombination of a type 1 restriction-modification locus, . These pneumococcal subpopulations exhibit phenotypic changes which favor carriage or invasive disease. In particular, the allele has been associated with increased nasopharyngeal carriage and the downregulation of the gene.

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  • The study investigates the emergence of the β-hemolytic pathogen SDSE in humans, particularly in Germany, where there has been limited research into its pathogenicity.
  • It combines national surveillance data and a clinical study to analyze factors like infection type, resistance, patient demographics, and disease severity over a 12-year period.
  • Findings indicate a rising incidence of invasive SDSE infections, with specific types becoming more prevalent and suggesting a mutation-driven outbreak, while age and sex also influenced infection patterns and severity.
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Introduction: Two next-generation pneumococcal conjugate vaccines (PCVs), a 15- and a 20-valent PCV (PCV15 and PCV20), have recently been licensed for use in adults, and PCV15 has also been licensed in children. We developed a dynamic transmission model specific for Germany, with the aim to predict carriage prevalence and invasive pneumococcal disease (IPD) burden for serotypes included in these vaccines.

Methods: The model allows to follow serotype distributions longitudinally both in the absence and presence of PCV vaccinations.

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This study evaluated the HiberGene Group B Streptococcus test, a CE-IVD-approved molecular assay for rapid detection of [Group B Streptococcus (GBS)] in human clinical specimens. Performance of the assay in terms of specificity, sensitivity and genotype inclusivity was investigated using an extended specificity panel of 113 human and animal GBS isolates, and eight isolates from other streptococcal species, from the isolate collection of the German National Reference Center for Streptococci. Broth cultures were tested according to the manufacturer's protocol, including lysis, heat denaturation and isothermal amplification.

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  • Bacteria can develop resistance to antibiotics through various mechanisms, which can be monitored by laboratory tests.
  • This study identifies a specific resistance mechanism in Group A Streptococcus that uses a gene (thfT) to acquire nutrients from the host, allowing it to bypass the antibiotic sulfamethoxazole's effects.
  • Understanding these resistance mechanisms during infections is crucial to reduce ineffective antibiotic use and limit the spread of resistance among bacteria.
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Preventive strategies involving the use of pneumococcal conjugate vaccines (PCVs) are known to drastically reduce pneumococcal disease. However, PCV vaccination has been plagued with serotype replacement by non-PCV serotypes. In this study, we describe the prevalence and molecular characteristics of non-PCV13 serotypes (non-vaccine serotypes, NVTs) from pneumococcal carriage isolates obtained from children < 5 years old in Cape Coast, Ghana, after PCV introduction.

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is the leading cause of bacterial paediatric meningitis after the neonatal period worldwide, but the bacterial factors and pathophysiology that drive pneumococcal meningitis are not fully understood. In this work, we have identified differences in raffinose utilization by isolates of identical serotype and sequence type from the blood and cerebrospinal fluid (CSF) of a single pediatric patient with meningitis. The blood isolate displayed defective raffinose metabolism, reduced transcription of the raffinose utilization pathway genes, and an inability to grow when raffinose was the sole carbon source.

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Background: The incidence of invasive pneumococcal disease (IPD) decreased worldwide in 2020 and the first quarter of 2021, concurrent with nonpharmaceutical interventions (NPIs) intended to stymie transmission of SARS-CoV-2. In 2021, the stringency of these NPI strategies has varied. We investigated age- and serotype-specific variations in IPD case counts in Germany in 2020-2021.

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Epidemiological data on nasopharyngeal (NP) bacterial carriage in children in Germany are scarce. We prospectively characterized NP colonization to evaluate the impact of pneumococcal immunization. We longitudinally collected NP swabs from 2-month-old infants (visit 1; V1) at eight representative pediatric offices 10/2008-06/2009.

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Background: Invasive pneumococcal disease (IPD) in people ≥60 years old is on the rise in Germany. There has been a recommendation for pneumococcal vaccination in this age group since 1998.

Methods: We determined the vaccination status of people ≥60 years old with IPD in Germany.

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Multidrug-resistant emerge through the modification of core genome loci by interspecies homologous recombinations, and acquisition of gene cassettes. Both occurred in the otherwise contrasting histories of the antibiotic-resistant lineages PMEN3 and PMEN9. A single PMEN3 clade spread globally, evading vaccine-induced immunity through frequent serotype switching, whereas locally circulating PMEN9 clades independently gained resistance.

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We analyzed middle ear fluid (MEF) and nasopharyngeal swabs (NPS) from spontaneously ruptured acute otitis media (AOM) cases occurring in children under 5 years in Germany. The aim of the study was the assessment of disease burden and bacterial etiology in the era of routine pneumococcal vaccination. Furthermore, we aimed to compare isolates from MEF with isolates from NPS and to analyze the serotype distribution.

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