Merijn W Bijlsma

University of Amsterdam | UVA · Department of Neurology

Background: We describe the epidemiology, clinical features and outcome of adult meningococcal meningitis in the Netherlands over a 15-year period. Methods: We studied adults (age ≥ 16 years) who were listed by the Netherlands Reference Laboratory for Bacterial Meningitis and/or included in the prospective nationwide cohort study (MeninGene) bet...

Background: Neonatal bacterial infections have long been recognised as an important cause of acute morbidity and mortality, but long-term neurodevelopmental consequences have not been comprehensively described and discussed. Objectives: We aimed to summarise evidence on the pathogenesis, diagnosis, and epidemiology of long-term sequelae after ne...

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, suc...

Objectives We aimed to derive and validate a risk score to differentiate patients with bacterial meningitis from those with viral meningitis or encephalitis, among patients presenting with CSF leukocytosis and a negative Gram stain. Methods We included adults with bacterial and viral meningitis or encephalitis, presenting with CSF leukocytes >10 p...

Background As SARS-CoV-2 will likely continue to circulate, low-impact methods become more relevant to monitor antibody-mediated immunity. Saliva sampling could provide a non-invasive method with reduced impact on children. Studies reporting on the differences between systemic and mucosal humoral immunity to SARS-CoV-2 are inconsistent in adults an...

Background Approximately 90% of the children with chronic abdominal pain are diagnosed as having functional abdominal pain disorder (FAPD). The Dutch guideline “functional abdominal pain” provides a stepwise approach to treat FAPD. The aim of this survey was twofold first, to determine adherence to the Dutch guideline, and second to determine curre...

Group B Streptococcus (GBS), or Streptococcus agalactiae, is a pathogen that causes preterm births, stillbirths, and acute invasive neonatal disease burden and mortality. Here, we investigate bacterial genetic signatures associated with disease onset time and meningeal tissue infection in acute invasive neonatal GBS disease. We carry out a genome-w...

Background Few studies have reported the long-term consequences of bacterial meningitis during infancy, and studies that have been done usually do not include a comparison cohort. We aimed to assess short-term and long-term risk of mortality, neurodevelopmental impairment (NDI), and health-care use and household income in cohorts of children with a...

Background Group B streptococcus (GBS) colonisation during pregnancy can lead to invasive GBS disease (iGBS) in infants, including meningitis or sepsis, with a high mortality risk. Other outcomes include stillbirths, maternal infections, and prematurity. There are data gaps, notably regarding neurodevelopmental impairment (NDI), especially after iG...

Background: The early-onset sepsis calculator (EOSC) reduces unnecessary antibiotic treatment in newborns. However, its performance in identifying cases with early-onset disease (EOD) is unclear. We compared the sensitivity of the EOSC to the current Dutch and National Institute for Health and Care Excellence (NICE) guidelines when applied to a co...

Background Higher incidences of invasive GBS disease (iGBS) have been described in male, compared to female, infants, however data on sex differences in mortality and long-term outcomes after iGBS are lacking. We therefore assessed whether a child´s sex influences the effect of iGBS on mortality and risk of neurodevelopmental impairments (NDI). Me...

Background: Preterm birth and neonatal infections are both associated with mortality and long-term neurodevelopmental impairments (NDI). We examined whether the effect of invasive group B streptococcus disease (iGBS) on mortality and long-term NDI differs for preterm and term infants, and whether co-occurrence of iGBS and prematurity leads to wors...

COVID-19 patients produce circulating and mucosal antibodies. In adults, specific saliva antibodies have been detected. Nonetheless, seroprevalence is routinely investigated, while little attention has been paid to mucosal antibodies. We therefore assessed SARS-CoV-2-specific antibody prevalence in serum and saliva in children in the Netherlands. W...

Background The epidemiology and treatment of pneumococcal meningitis has changed with the implementation of conjugate vaccines and the introduction of adjunctive dexamethasone therapy. Methods We analysed episodes of community-acquired pneumococcal meningitis in adults (≥16 years) in the Netherlands, identified by the National Reference Laboratory...

Background Colonization and transmission precede invasive group B streptococcal (GBS) disease. Data on GBS colonization prevalence, detection methods and risk factors for carriage are relevant for vaccine development and to understand GBS pathogenesis. Objectives To evaluate GBS colonization prevalence after the first week of life in the healthy n...

Background Group B Streptococcus (GBS) disease is a leading cause of neonatal death, but its long-term effects have not been studied after early childhood. The aim of this study was to assess long-term mortality, neurodevelopmental impairments (NDIs), and economic outcomes after infant invasive GBS (iGBS) disease up to adolescence in Denmark and th...

Background Neonatal invasive Group B Streptococcus (GBS) infection causes considerable disease burden in the Netherlands. Intrapartum antibiotic prophylaxis (IAP) prevents early-onset disease (EOD), but has no effect on late-onset disease (LOD). A potential maternal GBS vaccine could prevent both EOD and LOD by conferring immunity in neonates. Obj...

Objectives To provide a comprehensive assessment of case stratification by the Neonatal Early-Onset Sepsis (EOS) Calculator, a novel tool for reducing unnecessary antibiotic treatment. Study design A systematic review with individual patient data meta-analysis was conducted, extending PROSPERO record CRD42018116188. Cochrane, PubMed/MEDLINE, EMBAS...

Background Streptococcus agalactiae (group B streptococcus) causes invasive disease in all age groups. In the Netherlands, the incidence of group B streptococcal sepsis in early infancy is increasing because of a specific genetic subtype, clonal complex (CC) 17-A1. We assessed the molecular epidemiology, incidence, and mortality of group B streptoc...

Background The epidemiology of acute bacterial meningitis has changed substantially since the introduction of conjugate vaccines. Methods We analysed nationwide surveillance data of all cerebrospinal fluid isolates received from 1988 to 2019 in the Netherlands. We assessed the impact of conjugate vaccines on incidence (defined as episodes per 100,...

Background Group B streptococcus (GBS) is a leading cause of sepsis, pneumonia and meningitis in infants, with long term neurodevelopmental sequelae. GBS may be associated with poor pregnancy outcomes, including spontaneous abortion, stillbirth and preterm birth. Intrapartum antibiotic prophylaxis (IAP) is currently the only way to prevent early-on...

We studied population genomics of 486 Neisseria meningitidis isolates causing meningitis in the Netherlands during the period 1979–2003 and 2006–2013 using whole-genome sequencing to evaluate the impact of a hyperendemic period of serogroup B invasive disease. The majority of serogroup B isolates belonged to ST-41/44 (41 %) and ST-32 complex (16 %)...

Group B streptococcus (GBS) is the leading cause of neonatal invasive disease worldwide. In the Netherlands incidence of the disease increased despite implementation of preventive guidelines. We describe a genomic analysis of 1345 GBS isolates from neonatal (age 0–89 days) invasive infections in the Netherlands reported between 1987 and 2016. Most...

Introduction: Streptococcus agalactiae (group B streptococci; GBS) is an uncommon cause of bacterial meningitis in adults. Methods: We reviewed literature published between 1975 and 2018. Studies were included if they reported age, sex and outcome of patients above 16 years of age with cerebrospinal fluid culture (CSF) positive for GBS. Results...

Objectives: Diagnostic prediction models have been developed to assess the likelihood of bacterial meningitis (BM) in patients presented with suspected central nervous system (CNS) infection. External validation in patients suspected of meningitis is essential to determine the diagnostic accuracy of these models. Methods: We prospectively includ...

Objective: Pneumonia is considered a focus of infection in patients presenting with community-acquired bacterial meningitis but the impact on disease course is unclear. The aim was to study presenting characteristics, clinical course and outcome of meningitis patients with co-existing pneumonia on admission. Methods: We evaluated adult patients...

Background Group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis worldwide. We aimed to estimate the current burden of neonatal invasive GBS disease in the Netherlands, as a first step in providing an evidence base for policy makers on the potential benefits of a future maternal GBS vaccine. Methods Surveillance of neo...

Ranking of vaccine-preventable diseases by estimated disease burden (expressed in DALYs) at population and individual level. Adapted from: Van Lier A, De Gier B, McDonald SA, Mangen MJJ, Van Wijhe M, Sanders EAM, Kretzschmar ME, Van Vliet H, De Melker HE. Disease burden of varicella versus other vaccine-preventable diseases before introduction of v...

Neonatal GBS sepsis model import file for BCoDE toolkit version 1.4. (XLS)

Neonatal GBS meningitis model import file for BCoDE toolkit version 1.4. (XLS)

Objectives: To evaluate the Full Outline of Unresponsiveness (FOUR) score as a predictor of outcome in adult patients with bacterial meningitis. Methods: We selected 427 patients from a nationwide, prospective cohort on community-acquired bacterial meningitis included from August 2011 to November 2016. Data on patient history, symptoms and signs...

Group B Streptococcus (GBS) is a major cause of neonatal invasive disease worldwide. In the Netherlands, the incidence of the disease increased, despite the introduction of prevention guidelines in 1999. This was accompanied by changes in pathogen genotype distribution, with a significant increase in the prevalence of isolates belonging to clonal c...

Objectives: Streptococcus agalactiae (group B streptococcus, GBS) is an uncommon cause of bacterial meningitis in adults. We describe clinical characteristics, serotype distribution and outcome of adult GBS meningitis. Patients and methods: Patients aged 16 years or older with GBS cultured in cerebrospinal fluid included in two prospective natio...

Objectives: Listeria monocytogenes can cause sepsis and meningitis. We report national surveillance data on L. monocytogenes meningitis in the Netherlands, describing incidence changes, genetic epidemiology and fatality rate. Methods: We analyzed data from the Netherlands Reference Laboratory of Bacterial Meningitis for cases of Listeria monocyt...

Objectives: Current information on rates and dynamics of meningococcal carriage is essential for public health policy. This study aimed to determine meningococcal carriage prevalence, its risk factors and duration in the Netherlands, where meningococcal C vaccine coverage is >90%. Several methods to identify serogroups of meningococcal carriage is...

Purpose of review: Bacterial meningitis is a medical emergency and is associated with a high disease burden. We reviewed recent progress in the management of patients with community-acquired bacterial meningitis. Recent findings: The worldwide burden of disease of bacterial meningitis remains high, despite the decreasing incidence following intr...

Objectives: To investigate sex-based differences in clinical features, causative pathogens, outcome and treatment of adult community-acquired meningitis. Methods: From January 2006 to July 2014, adults with community-acquired bacterial meningitis were prospectively evaluated in a nationwide cohort study in the Netherlands. Sex was analysed along...

Objectives: To perform an external validation study of risk scores, identified through a systematic review, predicting outcome in community-acquired bacterial meningitis. Methods: MEDLINE and EMBASE were searched for articles published between January 1960 and August 2014. Performance was evaluated in 2,108 episodes of adult community-acquired b...

Objectives: To study the impact of an evidence-based guideline on the management of community-acquired bacterial meningitis. The guideline stresses the importance of cranial imaging before LP in selected patients based on clinical criteria and early treatment with amoxicillin and a third generation cephalosporin for adults with suspected community...

Background: We studied causative pathogens, clinical characteristics, and outcome of adult community-acquired bacterial meningitis after the introduction of adjunctive dexamethasone treatment and nationwide implementation of paediatric conjugate vaccines. Methods: In this cohort study, we prospectively assessed adults (age >16 years) with commun...

Group B streptococcus is the most common cause of neonatal infections. We studied the clinical and molecular epidemiology of invasive group B streptococcus infection in children younger than 3 months in the Netherlands over 25 years. We assessed the effect of the Dutch guidelines, introduced in 1999, for prevention of group B streptococcus, consist...

Background Epidemiological data for invasive meningococcal disease is essential for public health policy and vaccine development. We analysed national surveillance data from the Netherlands for PorA coverage of two PorA-based meningococcal serogroup B vaccines to describe the epidemiology of invasive meningococcal disease. Methods We examined nati...

Background: Vaccination with meningococcal serogroup C (MenC) conjugate (MCC) polysaccharide vaccines led to a substantial decline in MenC disease in the vaccinated and the unvaccinated population. The decline in the unvaccinated population can be explained by herd protection by reduced colonization of meningococci expressing the MenC capsule. The...

To elucidate why pediatricians fail to diagnose childhood hypertension, with special emphasis on the use of blood pressure (BP) reference data. We hypothesized that pediatricians frequently omit BP measurements and do not routinely relate BP measurements to reference data. We conducted a multicenter survey on BP measurement among 197 participants....

Background: We aimed to derive and validate a risk score that identifies adults with cerebrospinal fluid (CSF) pleocytosis and a negative CSF Gram stain at low risk for an urgent treatable cause. Methods: Patients with CSF pleocytosis and a negative CSF Gram stain were stratified into a prospective derivation (n = 193) and a retrospective valida...

Background: We analyzed clinical characteristics, treatment, genetic diversity, and outcome of 92 adults with Listeria monocytogenes meningitis included in 2 prospective nationwide cohort studies. Methods: Episodes of community-acquired listerial meningitis confirmed by cerebrospinal fluid culture were included from 1998 to 2002 and 2006 to 2012...

To investigate the diagnostic significance of a normal urine sediment in the work-up for fever of unknown origin in neutropenia. Urinary tract infection was defined as ≥105 urinary pathogens in the absence of another focus. Pyuria was found in only 1/23 neutropenic episodes compared to 21/31 in controls (P < 0.0001). Pediatr Blood Cancer 2011;56:86...

Requests to place an unborn child under formal supervision was made in the course of two pregnancies. The first woman was 27 years old, she had a history of schizophrenia, forensic psychiatric care, and a personality disorder with impulsive aggressive behaviour. The second patient was 36 years old. She had a bipolar disorder due to which her firstb...

The fact that tuberculosis can be treated with the DOTS strategy (Directly Observed Treatment, Short-course) is not enough to control the disease. Patients have to find their way to tuberculosis treatment first. To better understand the route to tuberculosis treatment in rural Nepal we interviewed twenty-six patients under treatment. In semi-struct...