Epidemiology of invasive meningococcal disease in the Netherlands, 1960–2012: an analysis of national surveillance data

Otitis in Patients With Community-Acquired Bacterial Meningitis: A Nationwide Prospective Cohort Study

BACKGROUND

Otitis is commonly associated with community-acquired bacterial meningitis, but the role of ear surgery as treatment is debated. In this study, we investigated the impact of otitis and ear surgery on outcome of adults with community-acquired bacterial meningitis.

METHODS

We analyzed episodes of adults with community-acquired bacterial meningitis from a nationwide prospective cohort study in the Netherlands, between March 2006 and July 2021.

RESULTS

A total of 2548 episodes of community-acquired bacterial meningitis were evaluated. Otitis was present in 696 episodes (27%). In these patients the primary causative pathogen was Streptococcus pneumoniae (615 of 696 [88%]), followed by Streptococcus pyogenes (5%) and Haemophilus influenzae (4%). In 519 of 632 otitis episodes (82%) an ear-nose-throat specialist was consulted, and surgery was performed in 287 of 519 (55%). The types of surgery performed were myringotomy with ventilation tube insertion in 110 of 287 episodes (38%), mastoidectomy in 103 of 287 (36%), and myringotomy alone in 74 of 287 (26%). Unfavorable outcome occurred in 210 of 696 episodes (30%) and in 65 of 696 episodes was fatal (9%). Otitis was associated with a favorable outcome in a multivariable analysis (odds ratio 0.74; 95% confidence interval [CI] .59-.92; P = .008). There was no association between outcome and ear surgery.

CONCLUSIONS

Otitis is a common focus of infection in community-acquired bacterial meningitis in adults, with S. pneumoniae being the most common causative pathogen. Presence of otitis is associated with a favorable outcome. Ear surgery's impact on the outcome of otogenic meningitis patients remains uncertain.

Recurrent bacterial meningitis in children in the Netherlands: a nationwide surveillance study

OBJECTIVES

This study aimed to estimate the recurrence rate of culture-positive bacterial meningitis in children in the Netherlands.

DESIGN

Nationwide surveillance study, using the database of the Netherlands Reference Laboratory for Bacterial Meningitis to identify patients with culture-positive bacterial meningitis during childhood.

SETTING

The study was based in the Netherlands.

PARTICIPANTS

A total of 9731 children with a first bacterial meningitis episode between 1 July 1987 and 30 June 2019 were identified.

PRIMARY AND SECONDARY OUTCOME MEASURES

Recurrence was defined as a subsequent episode >28 days, or caused by a different pathogen. Annual incidence and incidence rate ratios (IRRs) comparing the periods 1988-2003 and 2004-2019 were calculated. Predictors of recurrent meningitis were assessed using Cox proportional hazards regression.

RESULTS

Sixty-three (0.6%) of the 9731 children with a first bacterial meningitis episode contracted recurrent meningitis. Neisseria meningitidis was the leading pathogen for first meningitis episodes (52%) and Streptococcus pneumoniae for recurrent episodes (52%). The median annual incidence of first episodes per 100 000 children decreased from 11.81 (IQR 11.26-17.60) in 1988-2003 to 2.60 (IQR 2.37-4.07) in 2004-2019 (IRR 0.25, 95% CI 0.23 to 0.26). The incidence of recurrences did not change: 0.06 (IQR 0.02-0.11) in 1988-2003 to 0.03 (IQR 0.00-0.06) in 2004-2019 (IRR 0.65, 95% CI 0.39 to 1.1). Age above 5 years (OR 3.6 (95% CI 1.5 to 8.3)) and a first episode due to Escherichia coli (OR 25.7 (95% CI 7.2 to 92.0)) were associated with higher risks of recurrence.

CONCLUSION

The recurrence rate of childhood bacterial meningitis in the Netherlands was 0.6%. While the incidence rate of first episodes decreased substantially, this was not the case for recurrent episodes. Older age and a first episode due to E. coli were associated with higher recurrence risks.

Epidemiology, clinical features and outcome of adults with meningococcal meningitis: a 15-year prospective nationwide cohort study

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) between January 2006 and July 2021. Incidences were calculated per epidemiological year (July-June).

Findings

We identified 442 episodes of adult meningococcal meningitis. The median patient age was 32 years (IQR 18-55) and 226 episodes (51%) occurred in female patients. The annual incidence per 100,000 adults fluctuated, from 0.33 in 2006-2007 to 0.05 in 2020-2021, with a temporal increase up to 0.30 from 2016 to 2018, driven by an outbreak of serogroup W (MenW). Of 442 episodes, 274 episodes (62%) in 273 patients were included in the clinical cohort study. The overall case fatality rate was 4% (10 of 274) and 16% (43 of 274) had an unfavourable outcome (Glasgow Outcome Scale score 1-4). Compared to other serogroups, MenW was associated with higher rates of unfavourable outcome (6 of 16 [38%] vs. 37 of 251 [15%], P = 0.03) and death (4 of 16 [25%] vs. 6 of 251 [2%], P = 0.001).

Interpretation

The overall incidence of adult meningococcal meningitis in the Netherlands is low and outcome is generally favourable. An increase of MenW meningitis occurred from 2016 to 2018, which was associated with more unfavourable outcome and death.

Funding

Netherlands Organisation for Health Research and Development, European Research Council, National Institute of Public Health and Environmental protection.

Meningococcal Antibiotic Resistance: Molecular Characterization of Isolates from Patients with Invasive Meningococcal Disease (IMD) in Greece

For effective case management and chemoprophylaxis of Invasive Meningococcal Disease (IMD), prompt antibiotic treatment is required. N. meningitidis is usually susceptible to antibiotics, but reduced susceptibility to penicillin, ciprofloxacin, and rifampicin is increasing worldwide, jeopardizing patients' outcome. We assessed, phenotypically and genotypically, the antimicrobial resistance patterns of 192 strains isolated from IMD cases from all over Greece during 2010-2021. Antimicrobial susceptibility to penicillin, rifampicin, and ciprofloxacin was determined using the E-test. All isolates were genotyped by Multilocus Sequence Typing (MLST). penA, rpoB, and gyrA genes were amplified by PCR and sequenced. Of the 192 isolates, 37% (72/192) were penicillin-susceptible/had increased exposure, and 11% (21/192) were penicillin-resistant. Among those, 40 penA alleles were identified; penA1, penA27, and penA3 were highly associated with susceptibility to penicillin; penA14, penA25, and penA22 related to reduced susceptibility to penicillin, while penA9, penA910, and penA295 had resistance to penicillin. Two ciprofloxacin-resistant isolates harbored the gyrA346 allele, while one rifampicin-resistant isolate harbored the rpoB5 allele. Resistance to ciprofloxacin and rifampicin remains rare. As Greece is one of the countries with high antimicrobial resistance, continued monitoring of antibiotic resistance is important to ensure timely detection of emerging resistance for treatment and prevention guidelines.

Penicillin-Susceptible Streptococcus pneumoniae Meningitis in Adults: Does the Ceftriaxone Dosing Matter?

The recommended empiric ceftriaxone dosing regimen for acute bacterial meningitis in adults is 2 g every 12 h. After penicillin-susceptible Streptococcus pneumoniae is isolated as a causative microorganism, the ceftriaxone dose may be continued or reduced to a single dose of 2 g every 24 h, per institutional preference. There is no clear guidance that indicates the superiority of one regimen over the other. The objective of this study was to evaluate the susceptibility of S. pneumoniae in the cerebral spinal fluid (CSF) of patients with meningitis and the relationship between ceftriaxone dose and clinical outcomes. We identified 52 patients with S. pneumoniae meningitis with positive CSF cultures who were treated at the University Hospital, Bern, Switzerland, over a 19-year period. We collected clinical and microbiological data for evaluation. Broth microdilution and Etest methods were performed to test penicillin and ceftriaxone susceptibility. All isolates were susceptible to ceftriaxone. Ceftriaxone was empirically used in 50 patients, with a starting dosing regimen of 2 g every 24 h in 15 patients and 2 g every 12 h in 35 patients. In 32 patients started on a twice-daily regimen (91%), doses were reduced to once daily after a median of 1.5 (95% CI 1-2) days. The overall in-hospital mortality was 15.4% (n = 8), and 45.7% of patients reported at least one sequela of meningitis at the last follow-up (median 375, 95% CI 189-1585 days). We found no statistical difference in outcome between the 2 g every 24 h and the 2 g every 12 h ceftriaxone dosing regimens. A ceftriaxone total daily dose of 2 g may be associated with similar outcomes to a 4 g total daily dose, provided that the causative organism is highly susceptible to ceftriaxone. The persistence of neurological and infection sequelae at the last follow-up underscores the need for optimal treatment of these complex infections.

Penicillin and Cefotaxime Resistance of Quinolone-Resistant Neisseria meningitidis Clonal Complex 4821, Shanghai, China, 1965-2020

Clonal complex 4821 (CC4821) Neisseria meningitidis, usually resistant to quinolones but susceptible to penicillin and third-generation cephalosporins, is increasing worldwide. To characterize the penicillin-nonsusceptible (PenNS) meningococci, we analyzed 491 meningococci and 724 commensal Neisseria isolates in Shanghai, China, during 1965-2020. The PenNS proportion increased from 0.3% in 1965-1985 to 7.0% in 2005-2014 and to 33.3% in 2015-2020. Of the 26 PenNS meningococci, 11 (42.3%) belonged to the CC4821 cluster; all possessed mutations in penicillin-binding protein 2, mostly from commensal Neisseria. Genetic analyses and transformation identified potential donors of 6 penA alleles. Three PenNS meningococci were resistant to cefotaxime, 2 within the CC4821 cluster. With 96% of the PenNS meningococci beyond the coverage of scheduled vaccination and the cefotaxime-resistant isolates all from toddlers, quinolone-resistant CC4821 has acquired penicillin and cefotaxime resistance closely related to the internationally disseminated ceftriaxone-resistant gonococcal FC428 clone, posing a greater threat especially to young children.

Short-term and long-term risk of mortality and neurodevelopmental impairments after bacterial meningitis during infancy in children in Denmark and the Netherlands: a nationwide matched cohort study

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 and without a history of bacterial meningitis during infancy in Denmark and the Netherlands.

Methods

In this nationwide cohort study, infants with a history of bacterial meningitis before age 1 year were identified through the Danish Medical Birth Registry and Danish National Patient Registry using International Classification of Diseases (ICD)-10 codes and through the Netherlands Reference Laboratory for Bacterial Meningitis. Infants were matched (1:10) by sex and birth month and year to a comparison cohort of the general population without a history of bacterial meningitis. We analysed mortality using Cox proportional hazards regression. In Denmark, diagnoses of NDIs were based on ICD-10 codes; in the Netherlands, special educational needs were used as a functional NDI outcome. Risk ratios (RRs) of NDIs were estimated using modified Poisson regression. We also analysed long-term health-care use in Denmark and household income in both countries. All regression analyses were adjusted for sex and year of birth, and stratified by pathogen whenever sample size allowed.

Findings

We included 2216 children with a history of bacterial meningitis (570 [25·7%] in Denmark between Jan 1, 1997, and Dec 31, 2018, and 1646 [74·3%] in the Netherlands between Jan 1, 1995, and Dec 31, 2018), matched to 22 127 comparison cohort members. Median age at diagnosis was 2·8 months (IQR 0·4–7·1) in Denmark and 4·3 months (0·7–7·4) in the Netherlands. Mortality risks within 3 months after disease onset were 3·9% (95% CI 2·6–5·8%) in Denmark and 5·9% (4·7–7·0) in the Netherlands, compared with 0·0% (p<0·0001) and 0·1% (p<0·0001) in the comparison cohorts. Survivors had an increased risk of moderate or severe NDIs at age 10 years (RR 5·0 [95% CI 3·5–7·1] in Denmark and 4·9 [4·0–6·2] in the Netherlands) compared to children in the comparison cohort, particularly after pneumococcal and group B streptococcal meningitis. In Denmark, a history of bacterial meningitis was associated with increased health-care use in the 10 years following diagnosis (rate ratio 4·5 [95% CI 3·9–5·2] for outpatient visits and 4·1 [3·6–4·7] for hospital admissions).

Interpretation

Our study shows increased risk of mortality in the short and long term, a five times increase in risk of NDIs, and increased health-care use after bacterial meningitis during infancy. Together with context-specific incidence data, our results can advance pathogen-specific estimation of the meningitis burden and inform service provision at the individual and population level.

Funding

Bill & Melinda Gates Foundation, the Stichting Remmert Adriaan Laan Fonds, and the Netherlands Organisation for Health Research and Development.

Population genomics of Group B Streptococcus reveals the genetics of neonatal disease onset and meningeal invasion

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-wide association study (GWAS) of 1,338 GBS isolates from newborns with acute invasive disease; the isolates had been collected annually, for 30 years, through a national bacterial surveillance program in the Netherlands. After controlling for the population structure, we identify genetic variation within noncoding and coding regions, particularly the capsule biosynthesis locus, statistically associated with neonatal GBS disease onset time and meningeal invasion. Our findings highlight the impact of integrating microbial population genomics and clinical pathogen surveillance, and demonstrate the effect of GBS genetics on disease pathogenesis in neonates and infants.

Antimicrobial Susceptibility Survey of Invasive Neisseria meningitidis, United States 2012-2016

BACKGROUND

Historically, antimicrobial resistance has been rare in US invasive meningococcal disease cases.

METHODS

Meningococcal isolates (n = 695) were collected through population-based surveillance, 2012-2016, and national surveillance, 2015-2016. Antimicrobial susceptibility was assessed by broth microdilution. Resistance mechanisms were characterized using whole-genome sequencing.

RESULTS

All isolates were susceptible to 6 antibiotics (cefotaxime, ceftriaxone, meropenem, rifampin, minocycline, and azithromycin). Approximately 25% were penicillin or ampicillin intermediate; among these, 79% contained mosaic penA gene mutations. Less than 1% of isolates were penicillin, ampicillin, ciprofloxacin, or levofloxacin resistant.

CONCLUSIONS

Penicillin- and ampicillin-intermediate isolates were common, but resistance to clinically relevant antibiotics remained rare.

Pathogen- and Type-Specific Changes in Invasive Bacterial Disease Epidemiology during the First Year of the COVID-19 Pandemic in The Netherlands

COVID-19 control measures have resulted in a decline in invasive bacterial disease caused by Neisseria meningitidis (IMD), Streptococcus pneumoniae (IPD), and Haemophilus influenzae (Hi-D). These species comprise different serogroups and serotypes that impact transmissibility and virulence. We evaluated type- and pathogen-specific changes in invasive bacterial disease epidemiology in the Netherlands during the first year of the SARS-CoV-2 pandemic. Cases were based on nationwide surveillance for five bacterial species with either respiratory (IMD, IPD, Hi-D) or non-respiratory (controls) transmission routes and were compared from the pre-COVID period (April 2015−March 2020) to the first COVID-19 year (April 2020−March 2021). IMD, IPD, and Hi-D cases decreased by 78%, 67%, and 35%, respectively, in the first COVID-19 year compared to the pre-COVID period, although effects differed per age group. Serogroup B-IMD declined by 61%, while serogroup W and Y-IMD decreased >90%. IPD caused by serotypes 7F, 15A, 12F, 33F, and 8 showed the most pronounced decline (≥76%). In contrast to an overall decrease in Hi-D cases, vaccine-preventable serotype b (Hib) increased by 51%. COVID-19 control measures had pathogen- and type-specific effects related to invasive infections. Continued surveillance is critical to monitor potential rebound effects once restriction measures are lifted and transmission is resumed.

Community-acquired bacterial meningitis in patients of 80 years and older

Background

Advanced age is a risk factor for unfavorable outcome in community‐acquired bacterial meningitis, but clinical characteristics and outcome in meningitis patients of 80 years or older have not been defined.

Methods

We compared clinical characteristics and outcome of community‐acquired bacterial meningitis patients aged 80 years or older and adults under 80 years old within a prospective nationwide cohort study.

Results

Out of 2140 episodes identified between March 2006 and July 2018, 149 occurred in patients aged 80 years or older (7%). Common predisposing factors other than age were diabetes mellitus (25 of 148 [17%]), otitis or sinusitis (30 of 136 [22%]), and pneumonia (23 of 141 [16%]). The triad of fever, neck stiffness and altered consciousness was present in 60 of 139 (43%). The most common causative pathogen was Streptococcus pneumoniae (99 of 149 [66%]). Atypical causative pathogens, such as Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli, occurred more often compared to younger patients (49 of 149 [33%] vs 362 of 1991 [18%]; p < 0.001). Patients of 80 years and older had high case fatality rate (75 of 149 [50%]), but 45 of 149 (30%) had a favorable outcome. Characteristics associated with an unfavorable outcome were absence of otitis or sinusitis, presence of aphasia, mono‐ or hemiparesis, a lower score on the Glasgow Coma Scale, a higher heart rate, a higher blood C‐reactive protein concentration and CSF leukocytes <100 per mm³.

Conclusions

Bacterial meningitis in patients of 80 years of older is associated with high rates of unfavorable outcome and death. Atypical causative pathogens such as L. monocytogenes, S. aureus, and E. coli occur commonly and should be considered when starting empirical antimicrobial therapy in this age group.

Equity in vaccination policies to overcome social deprivation as a risk factor for invasive meningococcal disease

INTRODUCTION

Social deprivation is associated with poorer healthcare access. Vaccination is among the most effective public health interventions and achieving equity in vaccination access is vitally important. However, vaccines are often reimbursed by public funds only when recommended in national immunization programs (NIPs), which can increase inequity between high and low socioeconomic groups. Invasive meningococcal disease (IMD) is a serious vaccination-preventable disease. This review focuses on vaccination strategies against IMD designed to reduce inequity.

AREAS COVERED

We reviewed meningococcal epidemiology and current vaccination recommendations worldwide. We also reviewed studies demonstrating an association between social deprivation and risk of meningococcal disease, as well as studies demonstrating an impact of social deprivation on uptake of meningococcal vaccines. We discuss factors influencing inclusion of meningococcal vaccines in NIPs.

EXPERT OPINION

Incorporating meningococcal vaccines in NIPs is necessary to reduce inequity, but insufficient alone. Inclusion provides clear guidance to healthcare professionals and helps to ensure that vaccines are offered universally to all target groups. Beyond NIPs, cost of vaccination should be reimbursed especially for disadvantaged individuals. These approaches should help to achieve optimal protection against IMD, by increasing access and immunization rates, eventually reducing social inequities, and helping to protect those at greatest risk.

BACTERIAL MENINGITIS PRESENTING WITH A NORMAL CEREBROSPINAL FLUID LEUKOCYTE COUNT

OBJECTIVES

We describe clinical characteristics and outcome of adults with bacterial meningitis presenting with a normal CSF leukocyte count.

METHODS

We studied community-acquired bacterial meningitis with a normal CSF leukocyte count (≤ 5 per mm³) in adults from a prospective nationwide cohort study.

RESULTS

From 2006 through 2020, 39 of 2,357 (2%) episodes presented with a normal CSF leukocyte count. Immunocompromising conditions were present in 19 of 39 patients (49%), compared to 690 of 2303 (30%) in patients with elevated leukocytes (P=0.02). The triad of fever, neck stiffness, and altered consciousness was present in 6 of 34 patients (18%). CSF protein was abnormal in 25 of 37 patients (68%). We identified 3 clinical subgroups: those with severe pneumococcal meningitis (20 patients [51%]), with mainly sepsis (8 [21%]), and a miscellaneous group (11 [28%]). All patients with severe pneumococcal meningitis presented with high CSF protein levels and 18 of 19 (95%) had bacteria in the CSF Gram stain. Outcome was unfavorable in 23 of 39 (59%) patients and 12 (31%) died.

CONCLUSION

Patients with bacterial meningitis may present with normal CSF leukocyte counts. In these patients, CSF protein levels and Gram staining are important diagnostic parameters.

Sex Differences in Long-term Outcomes After Group B Streptococcal Infections During Infancy in Denmark and the Netherlands: National Cohort Studies of Neurodevelopmental Impairments and Mortality

BACKGROUND

Male infants have a higher incidence of invasive group B Streptococcus disease (iGBS) compared with female infants; however, data on sex differences in mortality and long-term outcomes after iGBS are lacking. We assessed whether a child's sex influences the effects of iGBS on mortality and risk of neurodevelopmental impairments (NDIs).

METHODS

We used Danish and Dutch registry data to conduct a nationwide cohort study of infants with a history of iGBS. A comparison cohort, children without a history of iGBS, was randomly selected and matched on relevant factors. Effect modification by sex was assessed on additive and multiplicative scales.

RESULTS

Our analyses included data from children with a history of iGBS in Denmark (period 1997 -2017; n = 1432) and the Netherlands (2000 -2017; n = 697) and from 21 172 children without iGBS. There was no clear evidence of between-sex heterogeneity in iGBS-associated mortality. Boys had a higher risk of NDI, with evidence for effect modification on additive scale at the age of 5 years for any NDI (relative excess risk due to interaction = 1.28; 95% confidence interval [CI], -0.53 to 3.09 in Denmark and 1.14; 95% CI, -5.13 to 7.41 in the Netherlands). A similar pattern was observed for moderate/severe NDI at age 5 years in Denmark and age 10 years in the Netherlands.

CONCLUSION

Boys are at higher risk of NDI ; our results suggest this is disproportionally increased in those who develop iGBS. Future studies should investigate mechanisms of this effect modification by sex.

Detection of Neisseria meningitidis in saliva and oropharyngeal samples from college students

Carriage of Neisseria meningitidis is an accepted endpoint in monitoring meningococcal vaccines effects. We have assessed N. meningitidis and vaccine-type genogroup carriage prevalence in college students at the time of MenACWY vaccine introduction in the Netherlands, and evaluated the feasibility of saliva sampling for the surveillance of carriage. For this, paired saliva and oropharyngeal samples collected from 299 students were cultured for meningococcus. The DNA extracted from all bacterial growth was subjected to qPCRs quantifying meningococcal and genogroup-specific genes presence. Samples negative by culture yet positive for qPCR were cultured again for meningococcus. Altogether 74 (25%) of students were identified as meningococcal carrier by any method. Sixty-one students (20%) were identified as carriers with qPCR. The difference between number of qPCR-positive oropharyngeal (n = 59) and saliva (n = 52) samples was not significant (McNemar’s test, p = 0.07). Meningococci were cultured from 72 students (24%), with a significantly higher (p < 0.001) number of oropharyngeal (n = 70) compared with saliva (n = 54) samples. The prevalence of genogroups A, B, C, W, and Y was none, 9%, 1%, 1% and 6%, respectively, and 8% of students carried MenACWY vaccine-type genogroup meningococci. Saliva is easy to collect and when combined with qPCR detection can be considered for meningococcal carriage studies.

Community-acquired bacterial meningitis

Progress has been made in the prevention and treatment of community-acquired bacterial meningitis during the past three decades but the burden of the disease remains high globally. Conjugate vaccines against the three most common causative pathogens (Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae) have reduced the incidence of disease, but with the replacement by non-vaccine pneumococcal serotypes and the emergence of bacterial strains with reduced susceptibility to antimicrobial treatment, meningitis continues to pose a major health challenge worldwide. In patients presenting with bacterial meningitis, typical clinical characteristics (such as the classic triad of neck stiffness, fever, and an altered mental status) might be absent and cerebrospinal fluid examination for biochemistry, microscopy, culture, and PCR to identify bacterial DNA are essential for the diagnosis. Multiplex PCR point-of-care panels in cerebrospinal fluid show promise in accelerating the diagnosis, but diagnostic accuracy studies to justify routine implementation are scarce and randomised, controlled studies are absent. Early administration of antimicrobial treatment (within 1 hour of presentation) improves outcomes and needs to be adjusted according to local emergence of drug resistance. Adjunctive dexamethasone treatment has proven efficacy beyond the neonatal age but only in patients from high-income countries. Further progress can be expected from implementing preventive measures, especially the development of new vaccines, implementation of hospital protocols aimed at early treatment, and new treatments targeting checkpoints of the inflammatory cascade.

Every Country, Every Woman, Every Child; Group B Streptococcal Disease Worldwide Prematurity modifies the risk of long-term neurodevelopmental impairments after invasive Group B Streptococcus infections during infancy in Denmark and the Netherlands

Background

Preterm birth and neonatal infections are both associated with mortality and long-term neurodevelopmental impairments (NDIs). 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 worse outcome.

Methods

Nationwide cohort studies of children with a history of iGBS were conducted using Danish and Dutch medical databases. Comparison cohorts of children without iGBS were matched on birth year/month, sex, and gestational age. Effects of iGBS on all-cause mortality and NDI were analyzed using Cox proportional hazards and logistic regression. Effect modification by prematurity was evaluated on additive and multiplicative scales.

Results

We identified 487 preterm and 1642 term children with a history of iGBS and 21 172 matched comparators. Dutch preterm children exposed to iGBS had the highest mortality rate by 3 months of age (671/1000 [95% CI, 412–929/1000] person-years). Approximately 30% of this mortality rate could be due to the common effect of iGBS and prematurity. Preterm children with iGBS had the highest NDI risk (8.8% in Denmark, 9.0% in the Netherlands). Of this NDI risk 36% (Denmark) and 60% (the Netherlands) might be due to the combined effect of iGBS and prematurity.

Conclusions

Prematurity is associated with iGBS development. Our study shows that it also negatively impacts outcomes of children who survive iGBS. Preterm infants would benefit from additional approaches to prevent maternal GBS colonization, as this decreases risk of both preterm birth and iGBS.

Changing Epidemiology of Bacterial Meningitis Since Introduction of Conjugate Vaccines: 3 Decades of National Meningitis Surveillance in The Netherlands

BACKGROUND

The epidemiology of acute bacterial meningitis has changed substantially since the introduction of conjugate vaccines.

METHODS

We analyzed nationwide surveillance data of all cerebrospinal fluid isolates received by the Netherlands Reference Laboratory for Bacterial Meningitis in the Netherlands. We assessed the impact of conjugate vaccines on incidence (defined as episodes per 100 000 population per year) and for different age groups using incidence rate ratios (IRRs), comparing incidence before and after conjugate vaccine introduction.

RESULTS

We analyzed 17 393 episodes, of which 5960 episodes (34%) occurred in preschool children (aged 3 months to 4 years). Overall, bacterial meningitis incidence decreased from 6.37 to 1.58 between 1989-1993 and 2014-2019 (IRR, 0.25 [95% confidence interval {CI}, .23-.26]; P < .001). This decrease was most pronounced in preschool and school-aged children (5-15 years); IRR, 0.10 [95% CI, .09-.12] and 0.08 [95% CI, .06-.10]; both P < .001. The incidence was highest in young infants (<90 days) due to a high incidence of group B Streptococcus and Escherichia coli meningitis (42.48 and 19.49, respectively). Conjugate vaccines effectively reduced the incidence of Haemophilus influenzae type b, Neisseria meningitidis serogroup C, and 10 pneumococcal serotypes (IRRs, .02-.04; P < .001). At the end of the observed period, Streptococcus pneumoniae caused the majority of meningitis cases (829/1616 [51%]), mostly in older adults (aged 45-64 years) and elderly adults (aged ≥65 years; incidence of 1.06 and 1.54, respectively).

CONCLUSIONS

Conjugate vaccines reduced the burden of bacterial meningitis, especially in children. The efforts for new measures to prevent bacterial meningitis should be focused on neonates and elderly, as the residual rate of disease is still high in these age groups.

Meningococcal W135 Disease Vaccination Intent, the Netherlands, 2018-2019

To control the rise in Neisseria meningitidis strain W infections, during 2018–2019, the Netherlands launched a catch-up meningococcal conjugate (MenACWY) vaccination campaign for teenagers (13–18 years of age). Applying a mental models approach, we surveyed teenagers and their parents about their knowledge and beliefs about meningococcal disease, the MenACWY vaccination, vaccinations in general, and their MenACWY vaccination intentions. Using random forest analysis, we studied predictions of vaccination intentions by knowledge and beliefs. Survey response rate was 52.8% among teenagers and 59.4% among parents. MenACWY vaccination intentions were best predicted by knowledge and beliefs about vaccinations in general, surpassing knowledge and beliefs about meningococcal disease and the MenACWY vaccination. For teenagers, their parents’ intention that the teenager be vaccinated was a strong predictor of the teenagers’ own vaccination intention. To optimize vaccination uptake during future outbreaks, we recommend that communications emphasize the effectiveness and safety of vaccines and continue to focus on parents.

Acquisition of ciprofloxacin resistance among an expanding clade of β-lactamase positive, serogroup Y Neisseria meningitidis in the United States

BACKGROUND

Penicillin and ciprofloxacin are important for invasive meningococcal disease (IMD) management and prevention. IMD cases caused by penicillin- and ciprofloxacin-resistant Neisseria meningitidis containing a ROB-1 β-lactamase gene (blaROB-1) and a mutated DNA gyrase gene (gyrA), have been recently reported in the USA.

METHODS

We examined 2097 meningococcal genomes collected through US population-based surveillance from January 2011-February 2020 to identify IMD cases caused by strains with blaROB-1 or gyrA-mediated resistance. Antimicrobial resistance was confirmed phenotypically. The US isolate genomes were compared to non-US isolate genomes containing blaROB-1. Interspecies transfer of ciprofloxacin resistance was assessed by comparing gyrA among Neisseria species.

RESULTS

Eleven penicillin- and ciprofloxacin-resistant isolates were identified after December 2018; all were serogroup Y, sequence type 3587, clonal complex (CC) 23, and contained blaROB-1 and a T91I-containing gyrA allele. An additional 22 penicillin-resistant, blaROB-1-containing US isolates with wild-type gyrA were identified from 2013-2020. All 33 blaROB-1-containing isolates formed a single clade, along with 12 blaROB-1-containing isolates from six other countries. Two-thirds of blaROB-1-containing US isolates were from Hispanic individuals. Twelve additional ciprofloxacin-resistant isolates with gyrA T91 mutations were identified. Ciprofloxacin-resistant isolates belonged to six CCs and contained 10 unique gyrA alleles; seven were similar or identical to alleles from N. lactamica or N. gonorrhoeae.

CONCLUSIONS

Recent IMD cases caused by a dual resistant serogroup Y suggest changing antimicrobial resistance patterns in the USA. The emerging dual-resistance is due to acquisition of ciprofloxacin resistance by β-lactamase-containing N. meningitidis. Routine antimicrobial resistance surveillance will effectively monitor resistance changes and spread.

Mortality, neurodevelopmental impairments, and economic outcomes after invasive group B streptococcal disease in early infancy in Denmark and the Netherlands: a national matched cohort study

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 the Netherlands.

Methods

For this cohort study, children with iGBS disease were identified in Denmark and the Netherlands using national medical and administrative databases and culture results that confirmed their diagnoses. Exposed children were defined as having a history of iGBS disease (sepsis, meningitis, or pneumonia) by the age of 89 days. For each exposed child, ten unexposed children were randomly selected and matched by sex, year and month of birth, and gestational age. Mortality data were analysed with the use of Cox proportional hazards models. NDI data up to adolescence were captured from discharge diagnoses in the National Patient Registry (Denmark) and special educational support records (the Netherlands). Health care use and household income were also compared between the exposed and unexposed cohorts.

Findings

2258 children—1561 in Denmark (born from Jan 1, 1997 to Dec 31, 2017) and 697 in the Netherlands (born from Jan 1, 2000 to Dec 31, 2017)—were identified to have iGBS disease and followed up for a median of 14 years (IQR 7–18) in Denmark and 9 years (6–11) in the Netherlands. 366 children had meningitis, 1763 had sepsis, and 129 had pneumonia (in Denmark only). These children were matched with 22 462 children with no history of iGBS disease. iGBS meningitis was associated with an increased mortality at age 5 years (adjusted hazard ratio 4·08 [95% CI 1·78–9·35] for Denmark and 6·73 [3·76–12·06] for the Netherlands). Any iGBS disease was associated with an increased risk of NDI at 10 years of age, both in Denmark (risk ratio 1·77 [95% CI 1·44–2·18]) and the Netherlands (2·28 [1·64–3·17]). A history of iGBS disease was associated with more frequent outpatient clinic visits (incidence rate ratio 1·93 [95% CI 1·79–2·09], p<0·0001) and hospital admissions (1·33 [1·27–1·38], p<0·0001) in children 5 years or younger. No differences in household income were observed between the exposed and unexposed cohorts.

Interpretation

iGBS disease, especially meningitis, was associated with increased mortality and a higher risk of NDIs in later childhood. This previously unquantified burden underlines the case for a maternal GBS vaccine, and the need to track and provide care for affected survivors of iGBS disease.

Funding

The Bill & Melinda Gates Foundation.

Translations

For the Dutch and Danish translations of the abstract see Supplementary Materials section.

Longitudinal study of meningococcal carriage rates in university entrants living in a dormitory in South Korea

University students, especially those living in dormitories, are known to have a high risk of invasive meningococcal disease. We performed a longitudinal study to investigate the change in Neisseria meningitidis carriage rates and identify the risk factors for carriage acquisition in university students in South Korea. We recruited university entrants who were admitted to a student dormitory. Pharyngeal swabs were taken from participants at baseline, 1 month, and 3 months, and the subjects completed a questionnaire. Culture and real-time polymerase chain reaction (PCR) for species-specific ctrA and sodC genes were performed. The cultured isolates or PCR-positive samples were further evaluated for epidemiologic characterization using serogrouping, PorA typing, FetA typing, and multilocus sequence typing (MLST). At the first visit, we enrolled 332 participants who were predominantly male (64.2%) with a median age of 19 years. Meningococcal carriage rates increased from 2.7% (95% confidence interval [CI] 0.9–4.4%) at baseline to 6.3% (95% CI 3.4–9.0%) at 1 month and 11.8% (95% CI 7.8–15.6%) at 3 months. Nongroupable isolates accounted for 50.0% of all isolates, with serogroup B being the next most prevalent (24.1%). In the study population, male sex (OR 2.613, 95% CI 1.145–5.961, p = 0.022) and frequent pub or club visits (OR 3.701, 95% CI 1.536–8.919, p = 0.004) were significantly associated with meningococcal carriage. Based on serotype and MLST analyses, six carriers transmitted meningococci to other study participants. N. meningitidis carriage rates among new university entrants who lived in a dormitory significantly increased within the first 3 months of dormitory stay, probably owing to the transmission of identical genotype among students. Based on the risk of meningococcal disease, meningococcal vaccination should be considered for students before dormitory admission.

The Clinical Picture and Severity of Invasive Meningococcal Disease Serogroup W Compared With Other Serogroups in the Netherlands, 2015-2018

Background

An increase in invasive meningococcal disease (IMD) serogroup W (IMD-W) cases caused by sequence type-11 clonal complex (cc11) was observed from October 2015 in the Netherlands. We compared the clinical picture and disease outcome of IMD-W cases with other serogroups, adjusting for host characteristics.

Methods

We included IMD cases reported from January 2015 to June 2018 in the Netherlands and assessed clinical manifestation and symptoms at disease onset and calculated case fatality rates (CFRs). We used logistic regression to compare clinical manifestations and mortality of IMD-W with IMD caused by meningococci serogroup B, Y, or C, adjusting for age, gender, and comorbidities.

Results

A total of 565 IMD cases were reported, of which 204 were IMD-W, 270 IMD-B, 63 IMD-Y, and 26 IMD-C. Most IMD-W isolates belonged to cc11 (93%; 175/188). Compared with other serogroups, IMD-W patients were diagnosed more often with septicemia (46%) or pneumonia (12%) and less often with meningitis (17%, P < .001). IMD-W cases presented more often with respiratory symptoms (45%, P < .001); 16% of IMD-W patients presented with diarrhea without IMD-specific symptoms (P = .061). The CFR for IMD-W was 16% (32/199, P < .001). The differences between IMD-W and other serogroups remained after adjusting for age, gender, and comorbidities.

Conclusions

The atypical presentation and severe outcome among IMD-W cases could not be explained by age, gender, and comorbidities. Almost all our IMD-W cases were caused by cc11. More research is needed to identify the bacterial factors involved in clinical presentation and severity of IMD-W cc11.

Antibiotic susceptibility and molecular analysis of invasive Neisseria meningitidis recovered in the Republic of Ireland, 1996 to 2016

This study examined the antimicrobial susceptibility of invasive meningococcal disease (IMD)-associated Neisseria meningitidis recovered in the Republic of Ireland between 1996 and 2016. In total, 1359 isolates representing over one-third of all laboratory-confirmed cases of IMD diagnosed each epidemiological year (EY; July 1-June 30) were analysed. All isolates were susceptible to ciprofloxacin, rifampicin and cefotaxime and 74% and 87% were susceptible to sulphonamide and penicillin, respectively. The proportion of isolates exhibiting reduced susceptibility to penicillin increased significantly during the study with no evidence of major clonal expansion or horizontal spread of a specific penA allele. Greater diversity observed among recently recovered meningococci and specifically among isolates exhibiting reduced penicillin susceptibility contributed to the overall increase in penA allele diversity throughout. The emergence and dissemination of strains with phenotypic and genotypic reduced susceptibility to penicillin increase the need for continued surveillance of antimicrobial susceptibility of meningococci in the Republic of Ireland especially in view of the recommendation of penicillin G as empiric treatment of choice for pre-hospital management.

IgA and FcαRI: Versatile Players in Homeostasis, Infection, and Autoimmunity

Mucosal surfaces constitute the frontiers of the body and are the biggest barriers of our body for the outside world. Immunoglobulin A (IgA) is the most abundant antibody class present at these sites. It passively contributes to mucosal homeostasis via immune exclusion maintaining a tight balance between tolerating commensals and providing protection against pathogens. Once pathogens have succeeded in invading the epithelial barriers, IgA has an active role in host-pathogen defense by activating myeloid cells through divers receptors, including its Fc receptor, FcαRI (CD89). To evade elimination, several pathogens secrete proteins that interfere with either IgA neutralization or FcαRI-mediated immune responses, emphasizing the importance of IgA-FcαRI interactions in preventing infection. Depending on the IgA form, either anti- or pro-inflammatory responses can be induced. Moreover, the presence of excessive IgA immune complexes can result in continuous FcαRI-mediated activation of myeloid cells, potentially leading to severe tissue damage. On the one hand, enhancing pathogen-specific mucosal and systemic IgA by vaccination may increase protective immunity against infectious diseases. On the other hand, interfering with the IgA-FcαRI axis by monovalent targeting or blocking FcαRI may resolve IgA-induced inflammation and tissue damage. This review describes the multifaceted role of FcαRI as immune regulator between anti- and pro-inflammatory responses of IgA, and addresses potential novel therapeutic strategies that target FcαRI in disease.

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Systematic literature review of the impact and effectiveness of monovalent meningococcal C conjugated vaccines when used in routine immunization programs

BACKGROUND

Monovalent meningococcal C conjugate vaccine (MCCV) was introduced into the routine immunization program in many countries in Europe and worldwide following the emergence of meningococcal serogroup C (MenC) in the late 1990s. This systematic literature review summarizes the immediate and long-term impact and effectiveness of the different MCCV vaccination schedules and strategies employed.

METHODS

We conducted a systematic literature search for peer-reviewed, scientific publications in the databases of MEDLINE (via PubMed), LILACS, and SCIELO. We included studies from countries where MCCV have been introduced in routine vaccination programs and studies providing the impact and effectiveness of MCCV published between 1st January 2001 and 31st October 2017.

RESULTS

Forty studies were included in the review; 30 studies reporting impact and 17 reporting effectiveness covering 9 countries (UK, Spain, Italy, Canada, Brazil, Australia, Belgium, Germany and the Netherlands). Following MCCV introduction, significant and immediate reduction of MenC incidence was consistently observed in vaccine eligible ages in all countries with high vaccine uptake. The reduction in non-vaccine eligible ages (especially population > 65 years) through herd protection was generally observed 3-4 years following introduction. Vaccine effectiveness (VE) was mostly assessed through screening methods and ranged from 38 to 100%. The VE was generally highest during the first year after vaccination and waned over time. The VE was better maintained in countries employing catch-up campaigns in older children and adolescents, compared to routine infant only schedules.

CONCLUSIONS

MCCV were highly effective, showing a substantial and sustained decrease in MenC invasive meningococcal disease. The epidemiology of meningococcal disease is in constant transition, and some vaccination programs now include adolescents and higher valent vaccines due to the recent increase in cases caused by serogroups not covered by MCCV. Continuous monitoring of meningococcal disease is essential to understand disease evolution in the setting of different vaccination programs.

Broad vaccine protection against Neisseria meningitidis using factor H binding protein

Neisseria meningitidis, the causative agent of invasive meningococcal disease (IMD), is classified into different serogroups defined by their polysaccharide capsules. Meningococcal serogroups A, B, C, W, and Y are responsible for most IMD cases, with serogroup B (MenB) causing a substantial percentage of IMD cases in many regions. Vaccines using capsular polysaccharides conjugated to carrier proteins have been successfully developed for serogroups A, C, W, and Y. However, because the MenB capsular polysaccharide is poorly immunogenic, MenB vaccine development has focused on alternative antigens. The 2 currently available MenB vaccines (MenB-4C and MenB-FHbp) both include factor H binding protein (FHbp), a surface-exposed protein harboured by nearly all meningococcal isolates that is important for survival of the bacteria in human blood. MenB-4C contains a nonlipidated FHbp from subfamily B in addition to other antigens, including Neisserial Heparin Binding Antigen, Neisserial adhesin A, and outer membrane vesicles, whereas MenB-FHbp contains a lipidated FHbp from each subfamily (A and B). FHbp is highly immunogenic and a main target of bactericidal activity of antibodies elicited by both licensed MenB vaccines. FHbp is also an important vaccine component, in contrast to some other meningococcal antigens that may have limited cross-protection across strains, as FHbp-specific antibodies can provide broad cross-protection within each subfamily. Limited cross-protection between subfamilies necessitates the inclusion of FHbp variants from both subfamilies to achieve broad FHbp-based vaccine coverage. Additionally, immune responses to the lipidated form of FHbp have a superior cross-reactive profile to those elicited by the nonlipidated form. Taken together, the inclusion of lipidated FHbp variants from both FHbp subfamilies is expected to provide broad protection against the diverse disease-causing meningococcal strains expressing a wide range of FHbp sequence variants. This review describes the development of vaccines for MenB disease prevention, with a focus on the FHbp antigen.

Genetic Variation in Neisseria meningitidis Does Not Influence Disease Severity in Meningococcal Meningitis

Neisseria meningitidis causes sepsis and meningitis in humans. It has been suggested that pathogen genetic variation determines variance in disease severity. Here we report results of a genome-wide association study of 486 N. meningitidis genomes from meningococcal meningitis patients and their association with disease severity. Of 369 meningococcal meningitis patients for whom clinical data was available, 44 (12%) had unfavorable outcome and 24 (7%) died. To increase power, thrombocyte count was used as proxy marker for disease severity. Bacterial genetic variants were called as k-mers, SNPs, insertions and deletions and clusters of orthologous genes (COGs). Population-level meningococcal genetic variation did not explain variance in disease severity (unfavorable outcome or thrombocyte count) in this cohort (h² = 0.0%; 95% confidence interval: 0.0–0.9). Genetic variants in the bacterial uppS gene represented the top signal associated with thrombocyte count (p-value = 9.96e-07) but this did not reach statistical significance. We did not find an association between previously published variants in lpxL1, fHbp, and tps genes and unfavorable outcome or thrombocyte count. A power analysis based on simulated phenotypes based on real genetic data from 880 N. meningitidis genomes showed that we would be able to detect a continuous phenotype with h² > = 0.5 with the population size available in this study. This rules out a major contribution of pathogen genetic variation to disease severity in meningococcal meningitis, and shows that much larger sample sizes are required to find specific low-effect genetic variants modulating disease outcome in meningococcal meningitis.

Different Long-Term Duration of Seroprotection against Neisseria meningitidis in Adolescents and Middle-Aged Adults after a Single Meningococcal ACWY Conjugate Vaccination in The Netherlands

Neisseria meningitidis is often asymptomatically carried in the nasopharynx but may cause invasive meningococcal disease, leading to morbidity and mortality. Meningococcal conjugate vaccinations induce functional protective antibodies against capsular antigens, but seroprotection wanes over time. We measured functional antibody titers five years after administration of a single dose of the meningococcal ACWY-polysaccharide-specific tetanus toxoid-conjugated (MenACWY-TT) vaccine in adolescents and middle-aged adults in the Netherlands, using the serum bactericidal antibody with baby rabbit complement (rSBA) assay. Protection was defined as rSBA titer ≥8. The meningococcal ACWY-specific serum IgG concentrations were measured with a multiplex immunoassay. Duration of protection was estimated by a bi-exponential decay model. Sufficient protection for MenC, MenW, and MenY was achieved in 94–96% of the adolescents five years postvaccination, but, in middle-aged adults, only in 32% for MenC, 65% for MenW and 71% for MenY. Median duration of protection for MenCWY was 4, 14, and 21 years, respectively, in middle-aged adults, while, in adolescents, it was 32, 98, and 33 years. Our findings suggest that adolescents, primed in early childhood with MenC conjugate vaccination, remain sufficiently protected after a single dose of MenACWY-TT vaccine. Middle-aged adults without priming vaccination show fast waning of antibodies, particularly MenC, for which protection is lost after four years.

Expanding the role of bacterial vaccines into life-course vaccination strategies and prevention of antimicrobial-resistant infections

A crisis in bacterial infections looms as ageing populations, increasing rates of bacteraemia and healthcare-associated infections converge with increasing antimicrobial resistance and a paucity of new antimicrobial classes. New initiatives are needed to develop bacterial vaccines for older adults in whom immune senescence plays a critical role. Novel vaccines require an expanded repertoire to prevent mucosal diseases such as pneumonia, skin and soft tissue infections and urinary tract infections that are major causes of morbidity and mortality in the elderly, and key drivers of antimicrobial resistance. This review considers the challenges inherent to the prevention of bacterial diseases, particularly mucosal infections caused by major priority bacterial pathogens against which current vaccines are sub-optimal. It has become clear that prevention of many lung, urinary tract and skin infections requires more than circulating antibodies. Induction of Th1/Th17 cellular responses with tissue-resident memory (Trm) cells homing to mucosal tissues may be a pre-requisite for success.

Diversification in immunogenicity genes caused by selective pressures in invasive meningococci

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 %). Comparing the time periods, before and after the decline of serogroup B invasive disease, there was a decrease of ST-41/44 complex sequences (P=0.002). We observed the expansion of a sub-lineage within ST-41/44 complex sequences being associated with isolation from the 1979-2003 time period (P=0.014). Isolates belonging to this sub-lineage expansion within ST-41/44 complex were marked by four antigen allele variants. Presence of these allele variants was associated with isolation from the 1979-2003 time period after correction for multiple testing (Wald test, P=0.0043 for FetA 1-5; P=0.0035 for FHbp 14; P=0.012 for PorA 7-2.4 and P=0.0031 for NHBA two peptide allele). These sequences were associated with 4CMenB vaccine coverage (Fisher's exact test, P<0.001). Outside of the sub-lineage expansion, isolates with markedly lower levels of predicted vaccine coverage clustered in phylogenetic groups showing a trend towards isolation in the 2006-2013 time period (P=0.08). In conclusion, we show the emergence and decline of a sub-lineage expansion within ST-41/44 complex isolates concurrent with a hyperendemic period in meningococcal meningitis. The expansion was marked by specific antigen peptide allele combinations. We observed preliminary evidence for decreasing 4CMenB vaccine coverage in the post-hyperendemic period.

Increasing incidence of group B streptococcus neonatal infections in the Netherlands is associated with clonal expansion of CC17 and CC23

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 isolates clustered into one of five major lineages: CC17 (39%), CC19 (25%), CC23 (18%), CC10 (9%) and CC1 (7%). There was a significant rise in the number of infections due to isolates from CC17 and CC23. Phylogenetic clustering analysis revealed that this was caused by expansion of specific sub-lineages, designated CC17-A1, CC17-A2 and CC23-A1. Dating of phylogenetic trees estimated that these clones diverged in the 1960s/1970s, representing historical rather than recently emerged clones. For CC17-A1 the expansion correlated with acquisition of a new phage, carrying gene encoding a putative cell-surface protein. Representatives of CC17-A1, CC17-A2 and CC23-A1 clones were identified in datasets from other countries demonstrating their global distribution.

Epidemiology of Community-Onset Severe Bacterial Infections in Children and Its Evolution: A Population-Based Study in France

OBJECTIVES

To describe the epidemiology of community-onset severe bacterial infections in children and its recent evolution.

DESIGN

Prospective, observational, population-based study from 2009 to 2014.

SETTING

An administrative area accounting for 13% of the French pediatric population.

PATIENTS

All children 1 month to 16 years old who died before admission or were admitted to a PICU for a community-onset severe bacterial infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The incidence and mortality rate of community-onset severe bacterial infections were compared with data from a reference population-based study conducted between 2000 and 2006, that is, before national recommendations for antimeningococcal C and antipneumococcal generalized vaccinations. Among the 261 children included (median age 25 mo), 28 (10.7%) died. The main diagnoses were meningitis (n = 85; 32%) and purpura fulminans (n = 59; 22%). The most common isolated bacteria were Neisseria meningitidis (n = 75; 29%), including 47 (63%) cases of serogroup B and 15 (20%) serogroup C, Streptococcus pneumoniae (n = 49, 19%), and Staphylococcus aureus (n = 15; 6%). The incidence of community-onset severe bacterial infections was three per 100,000 person-years (95% CI, 2.6-3.3) and had decreased by 53% from the reference period. Mortality rate was 0.3 per 100,000 person-years (95% CI, 0.2-0.4) and had decreased by 73% from the reference period. The incidence of community-onset severe bacterial infections caused by N. meningitidis and S. pneumoniae was 0.8 and 0.5 per 100,000 person-years and had decreased by 70% and 67% from the reference period. The incidence of community-onset severe bacterial infections-related to Staphylococcus aureus was 0.16 per 100,000 person-years and had increased by 220% from the reference period.

CONCLUSIONS

The incidence and mortality rate of community-onset severe bacterial infections, except for S. aureus infection, have decreased in France. N. meningitidis and S. pneumoniae continue to account for many infections, which indicates the need for better vaccination coverage and spectrum.

Transmissibility and pathogenicity of the emerging meningococcal serogroup W sequence type-11 complex South American strain: a mathematical modeling study

BACKGROUND

The recent emergence of strains belonging to the meningococcal serogroup W (MenW) sequence type-11 clonal complex and descending from the South American sub-lineage (MenW:cc11/SA) has caused significant shifts in the epidemiology of meningococcal disease worldwide. Although MenW:cc11/SA is deemed highly transmissible and invasive, its epidemiological characteristics have not yet been quantified.

METHODS

We designed a mathematical model of MenW transmission, carriage, and infection to analyze the recent epidemiology of invasive disease caused by MenW:cc11/SA strains and by other MenW strains in England and in France. We confronted that model with age-stratified incidence data to estimate the transmissibility and the invasiveness of MenW:cc11/SA in England, using the data in France as a validation cohort.

RESULTS

During the epidemiological years 2010/2011-2014/2015 in England, the transmissibility of MenW:cc11/SA relative to that of other MenW strains was estimated at 1.20 (95% confidence interval, 1.15 to 1.26). The relative invasiveness of MenW:cc11/SA was also found to exceed unity and to increase with age, with estimates ranging from 4.0 (1.6 to 9.7) in children aged 0-4 years to 20 (6 to 34) in adults aged ≥ 25 years. In France, the model calibrated in England correctly reproduced the early increase of MenW:cc11/SA disease during 2012/2013-2016/2017. Most recent surveillance data, however, indicated a decline in MenW:cc11/SA disease. In both countries, our results suggested that the transmission of MenW:cc11/SA carriage possibly started several months before the first reported case of MenW:cc11/SA disease.

DISCUSSION

Our results confirm earlier suggestions about the transmission and the pathogenic potential of MenW:cc11/SA. The main limitation of our study was the lack of age-specific MenW carriage data to confront our model predictions with. Furthermore, the lesser model fit to the most recent data in France suggests that the predictive accuracy of our model might be limited to 5-6 years.

CONCLUSIONS

Our study provides the first estimates of the transmissibility and of the invasiveness of MenW:cc11/SA. Such estimates may be useful to anticipate changes in the epidemiology of MenW and to adapt vaccination strategies. Our results also point to silent, prolonged transmission of MenW:cc11/SA carriage, with potentially important implications for epidemic preparedness.

Meningococcal carriage in Norwegian teenagers: strain characterisation and assessment of risk factors

Teenagers have a higher risk of invasive meningococcal disease (IMD) than the general population. This cross-sectional study aimed to characterise strains of Neisseria meningitidis circulating among Norwegian teenagers and to assess risk factors for meningococcal carriage. Oropharyngeal swabs were collected from secondary-school students in southeastern Norway in 2018-2019. Meningococcal isolates were characterised using whole genome sequencing. Risk factors for meningococcal carriage were assessed from questionnaire data. Samples were obtained from 2296 12-24-year-olds (majority 13-19-year-olds). N. meningitidis was identified in 167 (7.3%) individuals. The highest carriage rate was found among 18-year-olds (16.4%). Most carriage isolates were capsule null (40.1%) or genogroup Y (33.5%). Clonal complexes cc23 (35.9%) and cc198 (32.3%) dominated and 38.9% of carriage strains were similar to invasive strains currently causing IMD in Norway. Use of Swedish snus (smokeless tobacco) (OR 1.56, 95% CI 1.07-2.27), kissing >two persons/month (OR 2.76, 95% CI 1.49-5.10) and partying >10 times/3months (OR 3.50, 95% CI 1.45-8.48) were associated with carriage, while age, cigarette smoking, sharing of drinking bottles and meningococcal vaccination were not. The high meningococcal carriage rate among 18-year-olds is probably due to risk-related behaviour. Use of Swedish snus is possibly a new risk factor for meningococcal carriage. Almost 40% of circulating carriage strains have invasive potential.

Epidemiology of two decades of invasive meningococcal disease in the Republic of Ireland: an analysis of national surveillance data on laboratory-confirmed cases from 1996 to 2016

We examined the epidemiology of invasive meningococcal disease (IMD) in the Republic of Ireland (ROI) between epidemiological year (EY) 1996/1997 and EY2015/2016. Over the 20 EYs, 3707 cases were reported with annual incidence rates per 100 000 peaking at 11.6 in EY1999/2000, decreasing significantly to 1.5 in EY2015/2016. The highest disease burden was in infants and children <5, whereas adults aged ⩾65 years experienced the highest case fatality ratio (CFR) of 15.7% but over the study period the median annual CFR remained low (4.4%). Meningococcal serogroup B (menB) dominated (78%), followed by menC (17%), menW (1%) and menY (1%). The incidence of menC IMD declined significantly in all age groups after menC vaccine introduction in 2000. MenB incidence also declined over the 20 EYs with decreasing trends in all age groups under 65, including an almost 50% decrease in infants over the final four EYs. IMD incidence in the ROI has declined, partly attributable to menC vaccination success, coupled with a spontaneous decline in menB. However, recent gradual increases in non-menB IMD and the introduction of vaccines targeting menB demand continued detailed surveillance to accurately monitor trends and to assess vaccine impact.

Diversity of meningococci associated with invasive meningococcal disease in the Republic of Ireland over a 19 year period, 1996-2015

This study examined the capsular phenotype and genotype of invasive meningococcal disease (IMD)-associated Neisseria meningitidis recovered in the Republic of Ireland (RoI) between 1996 and 2015. This time period encompasses both pre- (when IMD was hyperendemic in the RoI) and post- meningococcal serogroup C conjugate (MCC) vaccine introduction. In total, 1327 isolates representing over one-third of all laboratory-confirmed cases of IMD diagnosed each epidemiological year (EY), were characterised. Serogroups B (menB) and C (menC) predominated throughout, although their relative abundance changed; with an initial increase in the proportion of menC in the late 1990s followed by their dramatic reduction post-MCC vaccine implementation and a concomitant dominance of menB, despite an overall decline in IMD incidence. While the increase in menC was associated with expansion of specific clonal-complexes (cc), cc11 and cc8; the dominance of menB was not. There was considerable variation in menB-associated cc with declines in cc41/44 and cc32, and increases in cc269 and cc461, contributing to a significant increase in the clonal diversity of menB isolates over the study. This increase in diversity was also displayed among the serosubtyping data, with significant declines in proportions of menB isolates expressing p1.4 and p1.15 antigens. These data highlight the changing diversity of IMD-associated meningococci since 1996 in the RoI and emphasise the need for on-going surveillance particularly in view of the recent introduction of a menB vaccine.

Epidemiology of community-acquired bacterial meningitis

PURPOSE OF REVIEW

The epidemiology of bacterial meningitis has been dynamic in the past 30 years following introduction of conjugated vaccines against Haemophilus influenzae type B, Streptococcus pneumoniae and Neisseria meningitidis. The purpose of this review is to describe recent developments in bacterial meningitis epidemiology.

RECENT FINDINGS

The incidence of bacterial meningitis in Western countries (Finland, Netherlands, and the United States) gradually declined by 3-4% per year to 0.7-0.9 per 100 000 per year in the past 10-20 years. In African countries (Burkina Faso and Malawi), incidence rates are still substantially higher at 10-40 per 100 000 persons per year. Introduction of pneumococcal conjugate vaccines have not consistently decreased overall pneumococcal meningitis incidence because of serotype replacement. Following the introduction of serogroup A and C meningococcal vaccines, the incidence of meningococcal meningitis because of these serogroups strongly decreased. Novel outbreaks in the African meningitis belt by serogroup C and increased incidence of serogroup W in the United Kingdom and the Netherlands were observed recently.

SUMMARY

Bacterial meningitis remains an important infectious disease, despite a gradual decline in incidence after large-scale vaccination campaigns. Further development of vaccines with broader coverage is important, as is continuous surveillance of bacterial meningitis cases.

Bigger and Better? Representativeness of the Influenza A Surveillance Using One Consolidated Clinical Microbiology Laboratory Data Set as Compared to the Belgian Sentinel Network of Laboratories

Infectious diseases remain a serious public health concern globally, while the need for reliable and representative surveillance systems remains as acute as ever. The public health surveillance of infectious diseases uses reported positive results from sentinel clinical laboratories or laboratory networks, to survey the presence of specific microbial agents known to constitute a threat to public health in a given population. This monitoring activity is commonly based on a representative fraction of the microbiology laboratories nationally reporting to a single central reference point. However, in recent years a number of clinical microbiology laboratories (CML) have undergone a process of consolidation involving a shift toward laboratory amalgamation and closer real-time informational linkage. This report aims to investigate whether such merging activities might have a potential impact on infectious diseases surveillance. Influenza data was used from Belgian public health surveillance 2014–2017, to evaluate whether national infection trends could be estimated equally as effectively from only just one centralized CML serving the wider Brussels area (LHUB-ULB). The overall comparison reveals that there is a close correlation and representativeness of the LHUB-ULB data to the national and international data for the same time periods, both on epidemiological and molecular grounds. Notably, the effectiveness of the LHUB-ULB surveillance remains partially subject to local regional variations. A subset of the Influenza samples had their whole genome sequenced so that the observed epidemiological trends could be correlated to molecular observations from the same period, as an added-value proposition. These results illustrate that the real-time integration of high-throughput whole genome sequencing platforms available in consolidated CMLs into the public health surveillance system is not only credible but also advantageous to use for future surveillance and prediction purposes. This can be most effective when implemented for automatic detection systems that might include multiple layers of information and timely implementation of control strategies.

Global estimate of Neisseria meningitidis serogroups proportion in invasive meningococcal disease: A systematic review and meta-analysis

Using the PRISMA guideline, 102 studies were included in this study. The highest and the lowest proportion of N. meningitidis serogroups in invasive meningococcal disease (IMD) was for NmB with 48.5% (95% CI: 45-52) and NmX with 0.7% (95% CI: 0.3-1.7). Among the WHO regional offices, serogroup NmW with 57.5% (95% CI: 35-77.5) in Eastern Mediterranean, and NmZ with 0.1% (95% CI: 0-0.9) in America had the highest and the lowest proportion of N. meningitidis serogroups in IMD. NmC with 9.7% (95% CI: 5.6-16.2) and NmB with 9.5% (95% CI: 0.2-3.8) had the highest proportion in 1-4 and <1 year age groups, respectively. Our analysis showed that NmB had the highest proportion of N. meningitidis serogroups in IMD worldwide. However, proportion of N. meningitidis serogroups in IMD varied noticeably across countries and age groups. Therefore, establishing appropriate control guidelines depending on the geographical regions and age groups is essential for prevention of IMD.

Invasive Meningococcal Disease: What We Should Know, Before It Comes Back

Background

Invasive meningococcal disease (IMD), sepsis and/or meningitis continues to be a public health problem, with mortality rates ranging from 5% to 16%. The aim of our study was to further knowledge about IMD with a large series of cases occurring over a long period of time, in a cohort with a high percentage of adult patients.

Methods

Observational cohort study of patients with IMD between 1977 hand 2013 at our hospital, comparing patients with only sepsis and those with meningitis and several degrees of sepsis. The impact of dexamethasone and prophylactic phenytoin was determined, and an analysis of cutaneous and neurological sequelae was performed.

Results

A total of 527 episodes of IMD were recorded, comprising 57 cases of sepsis (11%) and 470 of meningitis with or without sepsis (89%). The number of episodes of IMD decreased from 352 of 527 (67%) in the first to 20 of 527 (4%) in the last quarter (P < .001). Thirty-three patients died (6%): 8 with sepsis (14%) and 25 with meningitis (5%) (P = .02). Cutaneous and neurological sequelae were present in 3% and 5% of survivors of sepsis and meningitis, respectively. The use of dexamethasone was safe and resulted in less arthritis, and patients given prophylactic phenytoin avoided seizures.

Conclusions

The frequency of IMD has decreased sharply since 1977. Patients with sepsis only have the highest mortality and complication rates, dexamethasone use is safe and can prevent some arthritis episodes, and prophylactic phenytoin might be useful in a selected population. A rapid response and antibiotic therapy may help improve the prognosis.

Use of saliva to monitor meningococcal vaccine responses: proposing a threshold in saliva as surrogate of protection

Background

Mucosal antibodies against capsular polysaccharides offer protection against acquisition and carriage of encapsulated bacteria like Neisseria meningitidis serogroup C. Measurements of salivary antibodies as replacement for blood testing has important (cost-effective) advantages, particular in studies that assess the impact of large-scale vaccination or in populations in which blood sampling is difficult. This study aimed to estimate a threshold for meningococcal IgG salivary antibody levels to discriminate between unprotected and protected vaccinated individuals.

Methods

MenA-, MenC-, MenW- and MenY-polysaccharide (PS) specific IgG levels in serum and saliva from participants in a meningococcal vaccination study were measured using the fluorescent-bead-based multiplex immunoassay. Functional antibody titers in serum against the four serogroups were measured with serum bactericidal assay using rabbit complement (rSBA). A threshold for salivary IgG was determined by analysis of ROC curves using a serum rSBA titer ≥128 as correlate of protection. The area under the curve (AUC) was calculated to quantify the accuracy of the salivary test and was considered adequate when ≥0.80. The optimal cut-off was considered adequate when salivary IgG cut-off levels provided specificity of ≥90%. True positive rate (sensitivity), positive predictive value, and negative predictive value were calculated to explore the possible use of salivary antibody levels as a surrogate of protection.

Results

The best ROC curve (AUC of 0.95) was obtained for MenC, with an estimated minimum threshold of MenC-PS specific salivary IgG ≥3.54 ng/mL as surrogate of protection. An adequate AUC (> 0.80) was also observed for MenW and MenY with an estimated minimal threshold of 2.00 and 1.82 ng/mL, respectively. When applying these thresholds, all (100%) samples collected 1 month and 1 year after the (booster) meningococcal vaccination, that were defined as protective in the saliva test for MenC, MenW and MenY, corresponded with concomitant serum rSBA titer ≥128 for the respective meningococcal serogroups.

Conclusion

The saliva test offers an alternative screening tool to monitor protective vaccine responses up to one year after meningococcal vaccination against MenC, MenW and MenY. Future (large) longitudinal vaccination studies evaluating also clinical protection against IMD or carriage acquisition are required to validate the currently proposed threshold in saliva.

Induction of salivary antibody levels in Dutch adolescents after immunization with monovalent meningococcal serogroup C or quadrivalent meningococcal serogroup A, C, W and Y conjugate vaccine

Background

Meningococcal infection starts with colonisation of the upper respiratory tract. Mucosal immunity is important for protection against acquisition and subsequent meningococcal carriage. In this study, we assessed salivary antibody levels against meningococcal serogroup A (MenA), W (MenW) and Y (MenY) after vaccination with a quadrivalent MenACWY conjugated vaccine. We also compared salivary meningococcal serogroup C (MenC) antibody levels after monovalent MenC and quadrivalent MenACWY conjugated vaccination.

Methods

Healthy participants, who had received MenC conjugate vaccine between 14 months and 3 years of age, received a (booster) MenC or MenACWY vaccination at age 10–15 years. MenA-, MenC-, MenW- and MenY-polysaccharide (PS) specific IgG and IgA levels in saliva and serum and PS specific secretory component levels in saliva were measured using the fluorescent-bead-based multiplex immunoassay.

Results

MenACYW vaccination increased salivary PS-specific IgA (2-fold) and IgG levels(>10-fold) for MenA, MenY, and MenW. After one year, salivary IgA levels had returned to baseline levels. Both vaccines induced an increase in salivary MenC-PS specific IgA (>3-fold) and IgG (>100-fold), with higher levels after MenC as compared to MenACWY vaccination. The antibody decay rate of MenC in saliva between one month and one year was similar for both vaccines. The overall correlation between serum and saliva IgA levels was low (R = 0.39, R = 0.58, R = 0.31, and R = 0.36 for MenA, MenC, MenW and MenY, respectively). Serogroup-PS specific IgG levels between serum and saliva correlated better (R ranged from 0.51 to 0.88).

Conclusions

Both primary (MenA, MenY, and MenW) and booster (MenC) parenteral meningococcal conjugate vaccination induced high salivary antibody levels. The strong correlation for MenC, MenW and MenY between saliva and serum IgG levels indicates that saliva might be used as a reliable tool to measure vaccine responses after both primary and booster meningococcal vaccination.

Distinct evolutionary patterns of Neisseria meningitidis serogroup B disease outbreaks at two universities in the USA

Neisseria meningitidis serogroup B (MnB) was responsible for two independent meningococcal disease outbreaks at universities in the USA during 2013. The first at University A in New Jersey included nine confirmed cases reported between March 2013 and March 2014. The second outbreak occurred at University B in California, with four confirmed cases during November 2013. The public health response to these outbreaks included the approval and deployment of a serogroup B meningococcal vaccine that was not yet licensed in the USA. This study investigated the use of whole-genome sequencing(WGS) to examine the genetic profile of the disease-causing outbreak isolates at each university. Comparative WGS revealed differences in evolutionary patterns between the two disease outbreaks. The University A outbreak isolates were very closely related, with differences primarily attributed to single nucleotide polymorphisms/insertion-deletion (SNP/indel) events. In contrast, the University B outbreak isolates segregated into two phylogenetic clades, differing in large part due to recombination events covering extensive regions (>30 kb) of the genome including virulence factors. This high-resolution comparison of two meningococcal disease outbreaks further demonstrates the genetic complexity of meningococcal bacteria as related to evolution and disease virulence.

Meningococcal serogroup C immunogenicity, antibody persistence and memory B-cells induced by the monovalent meningococcal serogroup C versus quadrivalent meningococcal serogroup ACWY conjugate booster vaccine: A randomized controlled trial

BACKGROUND

Adolescents are considered the key transmitters of meningococci in the population. Meningococcal serogroup C (MenC) antibody levels wane rapidly after MenC conjugate vaccination in young children, leaving adolescents with low antibody levels. In this study, we compared MenC immune responses after booster vaccination in adolescence with either tetanus toxoid conjugated MenC (MenC-TT) or MenACWY (MenACWY-TT) vaccine, and aimed to establish an optimal age for this booster.

METHODS

Healthy 10-, 12-, and 15-year-olds, who received a single dose of MenC-TT vaccine in early childhood, were randomized to receive MenC-TT or MenACWY-TT vaccine. MenC serum bactericidal antibody (rSBA) titers, MenC polysaccharide (PS) specific IgG, IgG1 and IgG2 and MenC-specific IgG and IgA memory B-cells were determined before, one month and one year after the booster. Non-inferiority was tested by comparing geometric mean titers (GMTs) between vaccinees at one year.

RESULTS

Of 501 participants, 464 (92.6%) were included in the 'according to protocol' cohort analysis. At one month, all participants developed high MenC rSBA titers (>24,000 in all groups) and MenC-PS-specific IgG levels. Non-inferiority was not demonstrated one year after the booster with higher MenC GMTs after the monovalent vaccine, but 462/464 (99.6%) participants maintained protective MenC rSBA titers. IgG levels mainly consisted of IgG1, but similar levels of increase were observed for IgG1 and IgG2. Both vaccines induced a clear increase in the number of circulating MenC-PS specific IgG and IgA memory B-cells. Between one month and one year, the highest antibody decay rate was observed in the 10-year-olds.

CONCLUSION

Both MenC-TT and MenACWY-TT vaccines induced robust protective MenC immune responses after the booster vaccination, although non-inferiority could not be demonstrated for the MenACWY-TT vaccine after one year. Our results underline the importance of optimal timing of a meningococcal booster vaccination to protect against MenC disease in the long-term.

Adolescent meningococcal serogroup A, W and Y immune responses following immunization with quadrivalent meningococcal A, C, W and Y conjugate vaccine: Optimal age for vaccination

BACKGROUND

Recently the incidence of meningococcal serogroup Y (MenY) and in particular serogroup W (MenW) invasive disease has risen in several European countries, including the Netherlands. Adolescents are a target group for primary prevention through vaccination to protect against disease and reduce carriage and induce herd protection in the population. The present study assessed MenA, MenW and MenY antibody levels in adolescents up to one year following primary vaccination with quadrivalent MenACWY-PS conjugated to tetanus toxoid (MenACWY-TT).

METHODS

In this phase IV, open-label study, healthy 10-, 12- and 15-year-olds received the MenACWY-TT vaccine. Blood samples were collected before, 1month and 1year after the vaccination. Functional antibody levels against MenA, MenW and MenY were measured with serum bactericidal assay using baby rabbit complement (rSBA). MenA-, MenW-, and MenY-PS specific IgG, IgG1 and IgG2 levels were measured using fluorescent-bead-based multiplex immunoassay.

RESULTS

The quadrivalent MenACWY-TT vaccine elicited robust antibody responses against MenA, MenW and MenY, and the majority (94%) of the participants maintained rSBA titers ≥128 one year after the vaccination against all three serogroups. After one year, higher MenW rSBA GMTs were observed in the 12- and 15-year-olds compared to the 10-year-olds, while rSBA GMTs against MenA and MenY were similar between age groups. Furthermore, those participant who showed SBA titer ≥8 at baseline, also had higher antibody levels one year after vaccination as compared to participants with rSBA titer <8 at baseline.

CONCLUSION

The MenACWY-TT vaccine induces robust protective primary immune responses up to one year after vaccination. Our results suggest that persistence of individual protection increases with the age at which a primary quadrivalent MenACWY-TT vaccination is administered. Our results indicate that 12 or 15years seems a more optimal age for a primary quadrivalent MenACWY-TT vaccination to protect against the rapid increase of MenW disease.