Severe Meningococcal Meningitis Revealing a Novel Form of Properdin Deficiency in a Previously Healthy 13-year-old Child

A 13-year-old boy was admitted with severe meningococcal meningitis. Immunologic workup revealed a properdin deficiency, and genetic sequencing of CFP identified a novel, private and predicted pathogenic variant in exon 8. The patient received broad immunizations and penicillin prophylaxis. Children with invasive meningococcal disease should be tested for complement deficiency.

Invasive meningococcal disease in older adults: current perspectives and call for action

PURPOSE

Invasive meningococcal disease (IMD) is a devastating condition. While most attention is directed towards disease in children and adolescents, IMD poses an important cause of morbidity and mortality in adults ≥60 years. While immunization is a critical component of healthy ageing strategies, meningococcal immunization is not routinely offered to older adults. The aim of this review was to summarize clinical and epidemiological aspects of IMD and available immunization strategies, with a particular focus on disease in older individuals, to emphasize the importance of this rather neglected area.

METHODS

An expert working group was established to evaluate clinical and epidemiological data to raise awareness of IMD in older individuals, and develop suggestions to improve the existing burden.

RESULTS

Routine child and adolescent meningococcal immunization has substantially reduced IMD in these targeted populations. Consequently, prevalence and proportion of IMD among those ≥60 years, mostly unvaccinated, is increasing in developed countries (accounting for up to 25% of cases). IMD-related mortality is highest in this age-group, with substantial sequelae in survivors. IMD due to serogroups W and Y is more prevalent among older adults, often with atypical clinical features (pneumonia, gastrointestinal presentations) which may delay timely treatment.

CONCLUSIONS

IMD in older adults remains overlooked and greater awareness is required at clinical and societal levels. We encourage clinicians and immunization policy makers to reconsider IMD, with a call for action to remedy existing inequity in older adult access to protective meningococcal immunization.

Characterizing Neisseria meningitidis in Southern Vietnam between 2012 and 2021: A predominance of the chloramphenicol-resistant ST-1576 lineage

Objectives

Our goal was to describe Invasive Meningococcal Disease (IMD) in Southern Vietnam over the last 10 years. We characterized 109 Neisseria meningitidis strains in Southern Vietnam isolated between 1980s to 2021, that were collected from IMD (n = 44), sexually transmitted infections (n = 2), and healthy carriage (n = 63).

Methods

IMD were confirmed by bacterial culture and/or real-time polymerase chain reaction at the national reference laboratory in Pasteur Institute of Ho Chi Minh City (PIHCM). Antimicrobial resistance was determined on 31 IMD and two sexually transmitted infection isolates with E-test for chloramphenicol (CHL), penicillin (PEN), ciprofloxacin (CIP), ceftriaxone (CRO), and rifampicin (RIF). Sequencing was performed for analyzing of multilocus-sequence-typing (MLST), porA, fetA, and antibiotic resistance genes, including gyrA, penA, and rpoB.

Results

The incidence rate during this period was 0.02 per 100,000 persons/year. Serogroup B accounted for over 90% of cases (50/54). ST-1576 were mainly responsible for IMD, 27/42 MLST profiles, and associated with CHL resistance. Resistance was prevalent among IMD isolates. Thirteen were resistant to CHL (minimum inhibitory concentration [MIC] ≥16 mg/l), 12 were intermediate to PEN (MIC between 0.19 and 0.5 mg/l), and five were CIP-resistant (MIC between 0.19 and 0.5 mg/l). Particularly, one was non-susceptible to CRO (MIC at 0.125 mg/l), belonging to ST-5571 lineage. The resistance was due to carrying resistant alleles of penA and gyrA genes, and catP gene. Notably, seven isolates were resistant/non-susceptible to two or more antibiotics.

Conclusion

Our results suggest the persistence of the circulating ST-1576 in Southern Vietnam, with a spread of antimicrobial resistance across the community.

Detection of CTX-M-15 ESBL in XDR Haemophilus parainfluenzae from a urethral swab

OBJECTIVES

Haemophilus parainfluenzae is an opportunistic pathogen causing respiratory tract infection and sexually transmitted diseases. The emergence of multidrug resistance in this species is particularly worrisome, especially since the recent description of CTX-M-15 ESBL-producing isolates in Spain. The aim of this study was to characterize a CTX-M-15-producing H. parainfluenzae clinical isolate, HP01, obtained from a urethral swab.

METHODS

MICs were determined with gradient strips for this isolate. Hydrolysis assays were performed with the β LACTA test. Genomic DNA from HP01 was subjected to Illumina and Oxford Nanopore sequencing to investigate the genetic environment of blaCTX-M-15. Phylogenetic analysis was performed with available H. parainfluenzae genomes from the NCBI database, including CTX-M-15 producers.

RESULTS

HP01, an XDR isolate, was resistant to penicillin, third-generation cephalosporins, fluoroquinolones, macrolides, cyclines and co-trimoxazole and susceptible only to carbapenems and rifampicin. HP01 carried blaTEM-1, blaCTX-M-15, tet(M), catS and mef(E)/mel and harboured amino acid substitutions in PBP3, PBP5, GyrA, ParC and FolA implicated in resistance. Genomic analysis revealed that blaCTX-M-15 was carried by a Tn3-like transposon inserted into a novel integrative and conjugative element (ICE), ICEHpaSLS, present on the chromosome and belonging to the ICEHin1056 family described in Haemophilus influenzae. The tet(M)-MEGA element was also detected on the chromosome. No plasmid was found. The phylogenetic analysis showed that four H. parainfluenzae producing CTX-M-15 clustered in the same clade.

CONCLUSIONS

Here we report the description of an XDR H. parainfluenzae producing blaCTX-M-15 isolated from a urethral swab. The blaCTX-M-15 gene was inserted into an ICE structure similar to those recently described in CTX-M-15 producers in Spain. The emergence of XDR H. parainfluenzae producing blaCTX-M-15 is a matter of great concern. Careful surveillance is required to prevent its spread.

Meningococcal disease in the Middle East: A report from the Global Meningococcal Initiative

This review details recent findings from the Global Meningococcal Initiative's (GMI) recent meeting on the surveillance and control strategies for invasive meningococcal disease in the Middle East. The nature of case reporting and notification varies across the region, with many countries using bacterial meningitis as an IMD case definition in lieu of meningitis and septicaemia. This may overlook a significant burden associated with IMD leading to underreporting or misreporting of the disease. Based on these current definitions, IMD reported incidence remains low across the region, with historical outbreaks mainly occurring due to the Hajj and Umrah mass gatherings. The use of case confirmation techniques also varies in Middle Eastern countries. While typical microbiological techniques, such as culture and Gram staining, are widely used for characterisation, polymerase chain reaction (PCR) testing is utilised in a small number of countries. PCR testing may be inaccessible for several reasons including sample transportation, cost, or a lack of laboratory expertise. These barriers, not exclusive to PCR use, may impact surveillance systems more broadly. Another concern throughout the region is potentially widespread ciprofloxacin resistance since its use for chemoprophylaxis remains high in many countries.

Vaccine-preventable Pediatric Acute Bacterial Meningitis in France: A Time Series Analysis of a 19-Year Prospective National Surveillance Network

BACKGROUND

In France, vaccination has been implemented against Hi serotype b (Hib), pneumococcus with pneumococcal conjugate vaccines (PCV), and Neisseria meningitidis serogroup C (MenC). These interventions with different coverage and uptake have disrupted the epidemiology of vaccine-preventable acute bacterial meningitis (ABM).

METHODS

We analyzed data from a French prospective surveillance network of ABM in children ≤15 years old enrolled by 259 pediatric wards (estimated national coverage: 61%). From 2001 to 2020, the effect of vaccine implementation was estimated with segmented linear regression.

RESULTS

We analyzed 7,186 cases, mainly due to meningococcus (35.0%), pneumococcus (29.8%), and Hi (3.7%). MenC ABM incidence decreased (-0.12%/month, 95% CI: -0.17 to -0.07, P < 0.001) with no change for the overall meningococcal ABM when comparing the pre-MenC vaccination and the post-MenC vaccination trends. Despite a decreasing MenB ABM incidence without a vaccination program (-0.43%/month, 95% CI: -0.53 to -0.34, P < 0.001), 68.3% of meningococcal ABM involved MenB. No change in pneumococcal ABM incidence was observed after the PCV7 recommendation. By contrast, this incidence significantly decreased after the switch to PCV13 (-0.9%/month, 95% CI: -1.6 to -0.2%, P = 0.01). After May 2014, a rebound occurred (0.5%/month, 95% CI: 0.3-0.8%, P < 0.001), with 89.5% of non-PCV13 vaccine serotypes. Hib ABM incidence increased after June 2017.

CONCLUSIONS

PCV7 and MenC vaccine introduction in France, with slow vaccine uptake and low coverage, had no to little impact as compared to the switch from PCV7 to PCV13, which occurred when coverage was optimal. Our data suggest that MenB and next-generation PCVs could prevent a large part of the ABM incidence in France.

Not Only Meningitis but Also Epiglottitis: An Emerging Clinical Presentation of Invasive Meningococcal Disease

The rebound of invasive meningococcal disease cases in France since the fall of 2022 was accompanied by an increase in adult epiglottitis. These cases were provoked mainly by isolates of serogroup W belonging to the clonal complex 11 of Neisseria meningitidis. Awareness and surveillance should be reinforced.

Biofilm formation by non-typeable Haemophilus influenzae confers resistance to complement-mediated clearance

Biofilm formation is suggested to be associated with phenotype changes compared to planktonic form. We screened 1092 Haemophilus influenzae isolates for their genetic relationships and then selected 29 isolates from different genotypes and phenotypes and tested their ability to form biofilm. Our data showed a higher capacity of non-typeable isolates and particularly isolates from respiratory and genital infections to form biofilm compared to typeable isolates. This ability to form biofilm was also correlated with reduced deposition of the complement component C3b on biofilm-involved bacteria. These data suggest that the biofilm formation contributes to the virulence of non-typeable H. influenzae.

The rapid rebound of invasive meningococcal disease in France at the end of 2022

BACKGROUND

Invasive meningococcal disease (IMD) cases declined upon the implementation of non-pharmaceutical measures to control the COVID-19 pandemic. A rebound in IMD cases was feared upon easing these measures.

METHODS

We conducted a retrospective descriptive study using the French National Reference Center Database for meningococci between 2015 and 2022. We scored serogroups, sex, age groups, and clonal complexes of the corresponding isolates.

FINDINGS

Our data clearly show a decline in the number of IMD cases for all serogroups and age groups until 2021. This decline was mainly due to a decrease in IMD cases provoked by the hyperinvasive ST-11 clonal complex. However, since the fall of 2021, there has been an increase in IMD cases, which accelerated in the second half of 2022. This rebound concerned all age groups, in particular 16-24 years. The increase in cases due to serogroups B, W, and Y were mainly due to the expansion of isolates of the ST-7460, the clonal complex ST-9316 and the clonal complex ST-23, respectively.

INTERPRETATION

IMD epidemiology changes constantly and profound epidemiological changes have been recently observed. The surveillance of IMD needs to be enhanced using molecular tools. Additionally, vaccination strategies need to be updated to acknowledge recent epidemiological changes of these vaccine-preventable serogroups.

Range of Clinical Manifestations Caused by Invasive Meningococcal Disease Due to Serogroup W: A Systematic Review

INTRODUCTION

Invasive meningococcal disease (IMD) due to serogroup W meningococci (MenW) is consistently reported with atypical clinical manifestations, including gastrointestinal symptoms, bacteremic pneumonia, and septic arthritis. We undertook a systematic review of the literature for a comprehensive assessment of the clinical presentation of IMD caused by MenW.

METHODS

PubMed and Embase databases were searched from inception to June 2022 using a combination of MeSH terms and free text for articles that reported symptoms and signs of MenW IMD, and associated manifestations.

RESULTS

The most commonly reported symptoms identified included: fever (range 36-100% of cases), nausea and/or vomiting (range 38-47%), vomiting (range 14-68%), cough (range 7-57%), sore throat (range 13-34%), headache (range 7-50%), diarrhea (range 8-47%), altered consciousness/mental status (range 7-38%), stiff neck (range 7-54%), and nausea (range 7-20%). Sepsis (range 15-83% of cases) was the most commonly reported manifestation followed by meningitis (range 5-72%), sepsis and meningitis (range 6-74%), bacteremic pneumonia (range 4-24%), arthritis (range 1-15%), and other manifestations (e.g., pharyngitis/epiglottitis/supraglottitis/tonsillitis/conjunctivitis; range 1-24%). The case fatality rates ranged from 8-40%, and among the survivors 4-14% had long-term sequelae.

CONCLUSIONS

Clinicians need to be aware of the nonspecific symptoms and signs of IMD, as well as of the atypical manifestations in regions where MenW is known to circulate to ensure timely diagnoses and treatment.

Trends in invasive bacterial diseases during the first 2 years of the COVID-19 pandemic: analyses of prospective surveillance data from 30 countries and territories in the IRIS Consortium

BACKGROUND

The Invasive Respiratory Infection Surveillance (IRIS) Consortium was established to assess the impact of the COVID-19 pandemic on invasive diseases caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, and Streptococcus agalactiae. We aimed to analyse the incidence and distribution of these diseases during the first 2 years of the COVID-19 pandemic compared to the 2 years preceding the pandemic.

METHODS

For this prospective analysis, laboratories in 30 countries and territories representing five continents submitted surveillance data from Jan 1, 2018, to Jan 2, 2022, to private projects within databases in PubMLST. The impact of COVID-19 containment measures on the overall number of cases was analysed, and changes in disease distributions by patient age and serotype or group were examined. Interrupted time-series analyses were done to quantify the impact of pandemic response measures and their relaxation on disease rates, and autoregressive integrated moving average models were used to estimate effect sizes and forecast counterfactual trends by hemisphere.

FINDINGS

Overall, 116 841 cases were analysed: 76 481 in 2018-19, before the pandemic, and 40 360 in 2020-21, during the pandemic. During the pandemic there was a significant reduction in the risk of disease caused by S pneumoniae (risk ratio 0·47; 95% CI 0·40-0·55), H influenzae (0·51; 0·40-0·66) and N meningitidis (0·26; 0·21-0·31), while no significant changes were observed for S agalactiae (1·02; 0·75-1·40), which is not transmitted via the respiratory route. No major changes in the distribution of cases were observed when stratified by patient age or serotype or group. An estimated 36 289 (95% prediction interval 17 145-55 434) cases of invasive bacterial disease were averted during the first 2 years of the pandemic among IRIS-participating countries and territories.

INTERPRETATION

COVID-19 containment measures were associated with a sustained decrease in the incidence of invasive disease caused by S pneumoniae, H influenzae, and N meningitidis during the first 2 years of the pandemic, but cases began to increase in some countries towards the end of 2021 as pandemic restrictions were lifted. These IRIS data provide a better understanding of microbial transmission, will inform vaccine development and implementation, and can contribute to health-care service planning and provision of policies.

FUNDING

Wellcome Trust, NIHR Oxford Biomedical Research Centre, Spanish Ministry of Science and Innovation, Korea Disease Control and Prevention Agency, Torsten Söderberg Foundation, Stockholm County Council, Swedish Research Council, German Federal Ministry of Health, Robert Koch Institute, Pfizer, Merck, and the Greek National Public Health Organization.

Characteristics of Meningococcal Invasive Disease in Neonates and Virulence of the Corresponding Isolates

BACKGROUND

The highest incidence of invasive meningococcal disease (IMD) is observed in infants. However, its prevalence in neonates (≤28 days of age) and the characteristics of the corresponding isolates are less described. This report aimed to analyze meningococcal isolates from neonates.

METHODS

We first screened the database of the national reference center for meningococci in France for confirmed neonatal IMD cases between 1999 and 2019. We then performed whole-genome sequencing on all cultured isolates, and we evaluated their virulence in a mouse model.

RESULTS

Fifty-three neonatal cases of IMD (mainly bacteremia) were identified (50 culture-confirmed cases and 3 PCR-confirmed cases) of a total of 10,149 cases (0.5%) but represented 11% of cases among infants of under 1 year of age. Nine cases (17%) occurred among neonates of 3 days of age and younger (early onset). The neonate isolates were often of serogroup B (73.6%) and belonged to the clonal complex CC41/44 (29.4%) with at least 68.5% of coverage by vaccines against serogroup B isolates. The neonatal isolates were able to infect mice although to variable levels.

CONCLUSION

IMD in neonates is not rare and can be of early or late onsets suggesting that anti-meningococcal vaccination can target women planning to have a baby.

Recent Evolution of Susceptibility to Beta-Lactams in Neisseria meningitidis

Beta-lactams are the main antibiotics for the treatment of invasive meningococcal disease. However, reduced susceptibility to penicillin G is increasingly reported in Neisseria meningitidis and reduced susceptibility to third-generation cephalosporines (3GC) and the rare acquisition of ROB-1 beta-lactamase were also described. Modifications of penicillin-binding protein 2 (PBP2) encoded by the penA gene are the main described mechanism for the reduced susceptibility to penicillin and to other beta-lactams. penA modifications were analyzed using the sequences of all penA genes from cultured isolates between 2017-2021 in France (n = 1255). Data showed an increasing trend of reduced susceptibility to penicillin from 36% in 2017 to 58% in 2021. Reduced susceptibility to 3GC remained limited at 2.4%. We identified 74 different penA alleles and penA1 was the most frequent wild-type allele and represented 29% of all alleles while penA9 was the most frequently altered allele and represented 17% of all alleles. Reduced susceptibility to 3GC was associated with the penA327 allele. The amino acid sequences of wild-type and altered PBP2 were modeled. The critical amino acid substitutions were shown to change access to the active S310 residue and hence hinder the binding of beta-lactams to the active site of PBP2.

Changing patterns of invasive meningococcal disease and future immunization strategies

Invasive meningococcal disease (IMD) is a life-threatening disease caused by Neisseria meningitidis and has high mortality rates. Survivors often exhibit long-term sequelae and reduced life expectancy. Disease incidence is highest in infants and toddlers, with a resurgence of cases in adolescents and older adults (>50 years of age). Substantial heterogeneity exists in the recommendations of meningococcal vaccines included in National Immunization Programs (NIPs) across countries. Recommendations are usually based on infant/toddler immunization, with some countries recommending immunization only for toddlers. While existing recommendations have led to a reduced incidence of IMD in children <5 years of age, there has been an increase in cases among adolescents and older adults. Currently, older adults are not included in the recommendations. The higher healthcare burden and the economic costs associated with IMD in these age groups suggest that it is time to consider including adolescents and older adults in NIPs to protect against IMD caused by the five most prevalent serogroups. Currently, the lack of equity of access to vaccines in the immunization programs is a glaring gap in the betterment of public health, and a broader meningococcal strategy is recommended to provide optimal protection for all age groups.

Meningococcal disease in North America: Updates from the Global Meningococcal Initiative

This review summarizes the recent Global Meningococcal Initiative (GMI) regional meeting, which explored meningococcal disease in North America. Invasive meningococcal disease (IMD) cases are documented through both passive and active surveillance networks. IMD appears to be decreasing in many areas, such as the Dominican Republic (2016: 18 cases; 2021: 2 cases) and Panama (2008: 1 case/100,000; 2021: <0.1 cases/100,000); however, there is notable regional and temporal variation. Outbreaks persist in at-risk subpopulations, such as people experiencing homelessness in the US and migrants in Mexico. The recent emergence of β-lactamase-positive and ciprofloxacin-resistant meningococci in the US is a major concern. While vaccination practices vary across North America, vaccine uptake remains relatively high. Monovalent and multivalent conjugate vaccines (which many countries in North America primarily use) can provide herd protection. However, there is no evidence that group B vaccines reduce meningococcal carriage. The coronavirus pandemic illustrates that following public health crises, enhanced surveillance of disease epidemiology and catch-up vaccine schedules is key. Whole genome sequencing is a key epidemiological tool for identifying IMD strain emergence and the evaluation of vaccine strain coverage. The Global Roadmap on Defeating Meningitis by 2030 remains a focus of the GMI.

Haemophilus influenzae drug resistance in France from 2017 to 2021: consideration for treatment of otitis media

OBJECTIVES

Haemophilus influenzae is a prevalent agent of respiratory infections, including acute otitis media (AOM), that lead to high antibiotic prescription and may contribute to the development of bacterial resistance to antibiotics. The objective of this work was to describe and analyse antibiotic resistance of H. influenzae from 2017 to 2021 in France.

METHODS

We characterized H. influenzae isolates transmitted to the French national reference centre for H. influenzae between 2017 and 2021. We included all the 608 non-invasive respiratory isolates. Resistance rates to the main antibiotics were described. The relationship between resistance rate, age, and sex of patients and germ serotype was investigated.

RESULTS

Isolates were mainly from alveolar lavage (29.3%), expectoration (22.9%), or sputum (15%). Resistance to amoxicillin (61.4%), amoxicillin/clavulanic acid (47.4%), and cefotaxime (39.3%) was high and correlated with the presence of β-lactamase and/or modifications of the ftsI gene encoding penicillin-binding protein 3. Resistance to sulfamethoxazole/trimethoprim (33.2%) was more moderate. There were no significant differences according to serotype, age, or gender.

CONCLUSIONS

The benefit/risk balance of first choice use of amoxicillin and even of amoxicillin/clavulanic acid in AOM is questionable in view of the significant resistance to H. influenzae. The use of sulfamethoxazole/trimethoprim could be an alternative but may still need further evaluation.

Immunogenicity and safety of the meningococcal B recombinant (4CMenB) vaccine in allogeneic hematopoietic cell transplantation recipients

OBJECTIVES

Despite a high risk of invasive meningococcal (Men) disease, there is no published data on any MenB vaccine after hematopoietic cell transplantation (HCT). We investigated the immunogenicity and safety of the 4CMenB recombinant vaccine (Bexsero®) in adult HCT recipients.

METHODS

Patients were eligible from 6 months post-HCT to receive 2 4CMenB doses at 2 months interval. Sera were collected at baseline, 1 month after the second dose, and 12 months after enrollment. The serum bactericidal activity (SBA) using human complement (hSBA) was assessed against fHbp, NadA, PorAP1.4 and NHBA antigens. The vaccine response was defined by one criteria for one vaccine antigen: (1) In patients with a hSBA titer < 4 at baseline: a titer > 4; (2) In patients with a hSBA titer > 4 at baseline: at least a x4 increase.

RESULTS

40 patients were included at a median of 2.14 (0.57-13.03) years post-transplant. At baseline, most patients (32/40 80%) had hSBA titers < 4 for all vaccine antigens. After 2 vaccine doses, the proportion of patients with a titer > 4 was significantly increased for fHbp (23/40 57.5%), NadA (25/40 62.5%), and PorA (31/40 77.5%) but not for NHBA for which only 6/40 (15%) patients responded. 36/40 (90%) patients were responders to > 1 antigen. However, 9 months later, only 23/37 (62.2%) patients were still seroprotected. No severe adverse event was observed.

CONCLUSION

The response rate of 90% for >1 vaccine antigen and our safety data supports the 4CMenB vaccination of HCT recipients from 6 months after transplant with 2 doses.

CLINICAL TRIALS REGISTRATION

Clinicaltrials.gov, NCT03509051.

Impact of mandatory vaccination against serogroup C meningococci in targeted and non-targeted populations in France

Since January 2018, mandatory vaccination against meningococci serogroup C has been implemented in France for children <2 years with a recommended catch-up vaccination until the age of 24 years. We aimed to analyse the impact of mandatory vaccination on populations not targeted by it (2–24 years old). We used the database of the national reference centre for meningococci to collect the number of invasive meningococcal disease (IMD) cases before (2016–2017) and after (2018–2019) the mandatory vaccination. The cultured isolates were sequenced and submitted for genomic comparison. The total number of cases was 1706, including 376 cases of IMD serogroup C. Mandatory vaccination correlated with a significant decrease among the <2 years old and a decreasing trend among the 2–14 years old group but not among 15–25 years of age. This observation may be explained by the vaccine coverage that is still low among adolescents and young adults. Moreover, the genomic analysis revealed the co-circulation of two major genotypes belonging to the clonal complex ST-11 whose distribution differed across the age groups in accord with cyclic variations of genotypes. It is important to increase specific knowledge on meningococcal epidemiology and vaccination to involve them in establishing the vaccination strategy.

Changes in Invasive Neisseria meningitidis and Haemophilus influenzae Infections in France during the COVID-19 Pandemic

BackgroundSince the appearance of COVID-19 in January 2020, invasive bacterial infections have decreased significantly worldwide. However, alterations in age and sex distributions, clinical forms, phenotypes, and genotypes of isolates have not been analyzed. Our goal is to present and discuss these data considering the current COVID-19 pandemic situation. Methods: The data of the national reference center for meningococci and Haemophilus influenzae in France were mined to examine the above aspects of invasive bacterial infection before (2018−2019) and after (2020−2021) the COVID-19 pandemic. Detailed epidemiological, clinical, and microbiological data were collected, and whole genome sequencing was carried out on meningococcal isolates (n = 1466). Results: In addition to the overall decline in the number of cases, various changes in age, sex, and phenotypes of isolates were also noted. As for N. meningitidis, more cases were observed in adults, as well as more invasive pneumopathies. Furthermore, fewer hyperinvasive meningococcal genotypes have circulated since COVID-19 emerged. The situation has been different for H. influenzae, as the number of invasive cases among adults decreased due to a reduction in non-typeable isolates. In contrast, cases due to serotypeable isolates, particularly serotypes a and b, increased in children <5 years-old. Conclusions: It is possible that measures implemented to stop COVID-19 may have reduced the circulation of N. meningitidis and H. influenzae isolates, but to a variable extent. This may be due to differences in circulation between these two species according to age groups. Vaccination schedules against these two species may have also influenced the evolution of these invasive bacterial infections since the emergence of the COVID-19 pandemic.

Phylogenetic Structure and Comparative Genomics of Multi-National Invasive Haemophilus influenzae Serotype a Isolates

Recent reports have indicated a rise of invasive disease caused by Haemophilus influenzae serotype a (Hia) in North America and some European countries. The whole-genome sequences for a total of 410 invasive Hia isolates were obtained from 12 countries spanning the years of 1998 to 2019 and underwent phylogenetic and comparative genomic analysis in order to characterize the major strains causing disease and the genetic variation present among factors contributing to virulence and antimicrobial resistance. Among 410 isolate sequences received, 408 passed our quality control and underwent genomic analysis. Phylogenetic analysis revealed that the Hia isolates formed four genetically distinct clades: clade 1 (n = 336), clade 2 (n = 13), clade 3 (n = 3) and clade 4 (n = 56). A low diversity subclade 1.1 was found in clade 1 and contained almost exclusively North American isolates. The predominant sequence types in the Hia collection were ST-56 (n = 125), ST-23 (n = 98) and ST-576 (n = 51), which belonged to clade 1, and ST-62 (n = 54), which belonged to clade 4. Clades 1 and 4 contained predominantly North American isolates, and clades 2 and 3 predominantly contained European isolates. Evidence of the presence of capsule duplication was detected in clade 1 and 2 isolates. Seven of the virulence genes involved in endotoxin biosynthesis were absent from all Hia isolates. In general, the presence of known factors contributing to β-lactam antibiotic resistance was low among Hia isolates. Further tests for virulence and antibiotic susceptibility would be required to determine the impact of these variations among the isolates.

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.

Care pathways in invasive meningococcal disease: a retrospective analysis of the French national public health insurance database

Invasive meningococcal disease (IMD) carries a high burden in terms of mortality, long-term complications, and cost, which can be significantly reduced by vaccination. The objectives of this case–control study were to document the care pathways of patients with IMD before, during, and after hospitalization and to assess in-hospital complications and long-term sequelae. Cases consisted of all people hospitalized for IMD in France between 2012 and 2017. Controls were matched by age, gender, and district of residence. Data were extracted from the French national public health insurance database on demographics, hospitalizations, mortality and potential sequelae of IMD. Overall, 3,532 cases and 10,590 controls were assessed and followed up for 2.8 years (median). During hospitalization, 1,577 cases (44.6%) stayed in an intensive care unit, 1,238 (35.1%) required mechanical ventilation, and 43 (1.2%) underwent amputation; 293 cases (8.3%) died in hospital and a further 163 (4.6%) died following discharge; 823 cases (25.4% of survivors) presented ≥1 sequela and 298 (9.2%) presented multiple sequelae. The most frequently documented sequelae were epilepsy (N = 205; 5.8%), anxiety (N = 196; 5.5%), and severe neurological disorders (N = 193; 5.5%). All individual sequelae were significantly more frequent (p < .0001) in cases than controls. Hearing/visual impairment and communication problems were conditions that presented the highest risk for cases compared to controls (risk ratios >20 in all cases). In conclusion, this study highlights the importance of providing optimal medical care for patients with IMD, of minimizing the delay before hospitalization, and of effective prevention through comprehensive vaccination programs.

Benefits of providing optimal medical care for IMD patients.

Importance of minimising the delay before hospitalization.

IMD remains challenging to diagnose, and vaccination is the most efficient way to prevent the disease and its complications.

Evolution of strain coverage by the multicomponent meningococcal serogroup B vaccine (4CMenB) in France

The 4CMenB, a protein-based vaccine, was licensed in Europe in 2013 against invasive meningococcal disease caused by serogroup B and is currently implemented in several countries although according to different national strategies. Isolate coverage estimation is required as vaccine-targeted antigens may vary among isolates over time. Several phenotypic and genotypic methods have been developed to predict strain coverage by scoring the expression and cross-reactivity of vaccine antigens using the Meningococcal Antigen Typing system (MATS), by the genetic correlation of alleles encoding these antigens and MATS expression data (gMATS) and by the Meningococcal Deduced Vaccine Antigen Reactivity (MenDeVAR). We applied these approaches on meningococcal B isolates in France and compared two epidemiological years, 2013-2014 and 2018-2019. A strong correlation was observed between MATS data that were generated for the year 2013-2014 and the gMATS data extracted from whole genome sequencing. gMATS and MenDeVAR were next used to compare the two years. Using gMATS, the overall coverage was 77.2% (lower limit (LL)-upper limit (UL) 66.7-87.7) and 70.7% (LL-UL 61.5-80.0) for the two years, respectively. The reduction in coverage between the two years is mainly driven by the reduction of alleles exactly matching the vaccine antigens. A high number of unpredictable isolates was observed using the MenDeVAR and was due to lack of MATS information for new or rare alleles in particular for the year 2018-2019. Our data underline the need of continuous surveillance of strain coverage and the importance of generating phenotypic MATS data to update the genetic approaches of prediction.

Implementation of a prospective study for enhancing surveillance of invasive bacterial infections in North Africa

OBJECTIVES

We implemented a project named MENINGSTOP in three countries of North Africa (Algeria, Morocco and Tunisia). The main objective was to use real-time PCR to detect, identify and type the three main agents (Neisseria meningitidis, Streptococcus pneumoniae and Haemophilus influenzae) responsible for invasive bacterial infections (IBI).

METHODS

The protocol of WHO and US CDC for real-time PCR was used to detect and type the three bacterial agents in clinical samples. We also designated two quality exercises using an external interlaboratory study and cross-testing of 10% of randomly selected samples.

RESULTS

Among the 752 samples tested, 18% were positive for one of the three agents. N. meningitidis was the most frequent globally reaching 9% of all samples (7% to 17% range) followed by S. pneumoniae 8% of all samples (6% to 15%). Group B meningococci was the most frequent (74% of all positive samples for meningococci and ranging from 50% to 90%). Quality assurance showed >85% correlation scores.

CONCLUSIONS

Real-time PCR can help improving epidemiological surveillance. Data confirm the prevalence of meningococci B. Our project adds a reliable tool to enhance surveillance and to help decision making in vaccination strategies against IBI.

Surveillance and control of meningococcal disease in the COVID-19 era: A Global Meningococcal Initiative review

This review article incorporates information from the 4th Global Meningococcal Initiative summit meeting. Since the introduction of stringent COVID-19 infection control and lockdown measures globally in 2020, there has been an impact on IMD prevalence, surveillance, and vaccination compliance. Incidence rates and associated mortality fell across various regions during 2020. A reduction in vaccine uptake during 2020 remains a concern globally. In addition, several Neisseria meningitidis clonal complexes, particularly CC4821 and CC11, continue to exhibit resistance to antibiotics, with resistance to ciprofloxacin or beta-lactams mainly linked to modifications of gyrA or penA alleles, respectively. Beta-lactamase acquisition was also reported through horizontal gene transfer (bla_ROB-1) involving other bacterial species. Despite the challenges over the past year, progress has also been made on meningococcal vaccine development, with several pentavalent (serogroups ABCWY and ACWYX) vaccines currently being studied in late-stage clinical trial programmes.

Looking beyond meningococcal B with the 4CMenB vaccine: the Neisseria effect

Infections with Neisseria meningitidis and Neisseria gonorrhoeae have different clinical manifestations, but the bacteria share up to 80-90% genome sequence identity. The recombinant meningococcal serogroup B (MenB) vaccine 4CMenB consists of four antigenic components that can be present in non-B meningococcal and gonococcal strains. This comprehensive review summarizes scientific evidence on the genotypic and phenotypic similarities between vaccine antigens and their homologs expressed by non-B meningococcal and gonococcal strains. It also includes immune responses of 4CMenB-vaccinated individuals and effectiveness and impact of 4CMenB against these strains. Varying degrees of strain coverage were estimated depending on the non-B meningococcal serogroup and antigenic repertoire. 4CMenB elicits immune responses against non-B meningococcal serogroups and N. gonorrhoeae. Real-world evidence showed risk reductions of 69% for meningococcal serogroup W clonal complex 11 disease and 40% for gonorrhea after 4CMenB immunization. In conclusion, functional antibody activity and real-world evidence indicate that 4CMenB has the potential to provide some protection beyond MenB disease.

Effect of change in vaccine schedule on pertussis epidemiology in France: a modelling and serological study

BACKGROUND

In April-May, 2013, France modified its pertussis vaccination schedule, which uses the acellular pertussis vaccine, from three primary doses at 2, 3, and 4 months of age and a first booster at 16-18 months of age (former schedule) to two primary doses at 2 and 4 months of age and a first booster at 11 months of age (new schedule). We aimed to assess the subsequent effect of the vaccine schedule change on pertussis epidemiology in France.

METHODS

In this modelling study, using data collected between Jan 1, 2012, and Dec 31, 2019, from French national surveillance sources, we analysed the PCR test results of nasopharyngeal swabs collected from symptomatic outpatients aged 2-20 years with suspected pertussis. We developed a negative binomial regression model for the number of confirmed pertussis cases by year and age to assess the relative risks of pertussis depending on vaccine schedule. The linear predictor included the year, the age group, the population size, and a proxy of waning immunity. We tested different models in which waning immunity could vary with vaccine schedule and type of primary vaccine. The models were fitted to the 2012-18 data via Bayesian Markov chain Monte Carlo sampling, and the 2019 data were left out for external model validation. We also compared the anti-pertussis toxin (PT) antibody concentrations in leftover sera from children not tested for pertussis or recent respiratory tract infection aged 2-5 years born before and after the vaccine schedule change.

FINDINGS

We collected data on 7493 confirmed cases of pertussis. The model that best fitted the 2012-18 epidemiological data supported a faster waning of immunity following vaccination with the new vaccine schedule. 3 years after vaccination, the risk of developing pertussis was 1·7 (95% CI 1·4-2·0) times higher for children vaccinated according to the new schedule than those vaccinated according to the former schedule. The model correctly predicted the age distribution of cases in 2019. Geometric mean concentrations (GMC) of anti-PT IgG were 50% lower in children aged 2 years vaccinated with the new schedule (GMC=5·85 IU/mL [95% CI 4·08-8·39]) than in children of the same age vaccinated with the former schedule (GMC=11·62 IU/mL [95% CI 9·05-14·92]; p=0·0016), and 43% lower in children aged 3 years vaccinated with the new schedule (GMC=3·88 IU/mL [95% CI 2·82-5·34]) than those with the former schedule (GMC=6·80 IU/mL [95% CI 4·77-9·70]; p=0·026).

INTERPRETATION

A shorter-lived protection induced by the new vaccine schedule recommended in France since 2013 is associated with an increase of pertussis cases in children aged 2-5 years. If similar findings are observed in other countries and clinical trials, these findings should be considered in future pertussis vaccination policies.

FUNDING

INCEPTION, Labex-IBEID, Institut Pasteur, and Santé Publique France.

Evolving strategies for meningococcal vaccination in Europe: Overview and key determinants for current and future considerations

Invasive meningococcal disease (IMD) is a life-threatening, unpredictable condition. Vaccines are available against 5 of the 6 meningococcal serogroups (Men) accounting for nearly all IMD cases worldwide; conjugate monovalent MenC, quadrivalent MenACWY, and protein-based MenB vaccines are commonly used. We provide a comprehensive overview of the evolution of meningococcal vaccination strategies employed in national immunization programmes (NIPs) and their impact on IMD incidence in Europe. A more in-depth description is given for several countries: the United Kingdom (UK), the Netherlands, Greece, Italy, and Ireland. We searched European health authorities' websites and PubMed. Various vaccines and immunization schedules are used in 21 NIPs. Most countries implement MenC vaccination in infants, MenACWY in adolescents, and a growing number, MenB in infants. Only Malta has introduced MenACWY vaccination in infants, and several countries reimburse immunization of toddlers. The UK, Italy, Ireland, Malta, Andorra, and San Marino recommend MenB vaccination in infants and MenACWY vaccination in adolescents, targeting the most prevalent serogroups in the most impacted age groups. Main factors determining new vaccination strategies are fluctuating IMD epidemiology, ease of vaccine implementation, ability to induce herd protection, favorable benefit-risk balance, and acceptable cost-effectiveness. Since 1999, when the UK introduced MenC vaccination, the reduction in IMD incidence has been gradually enhanced as other countries adopted routine meningococcal vaccinations. Meningococcal vaccination strategies in each country are continually adapted to regional epidemiology and national healthcare priorities. Future strategies may include broader coverage vaccines when available (e.g., MenABCWY, MenACWY), depending on prevailing epidemiology.

Global epidemiology and changing clinical presentations of invasive meningococcal disease: a narrative review

Neisseria meningitidis (the meningococcus) causes significant morbidity and mortality worldwide through an epidemic or sporadic invasive infections. The epidemiology of N. meningitidis is changing and unpredictable. Certain emerging meningococcal genotypes seem to be associated with increasing unusual clinical presentations. Indeed, early symptoms may vary and are frequently non-specific. However, atypical clinical forms including abdominal presentations, septic arthritis, and bacteremic pneumonia may lead to misdiagnosis and some are usually associated with higher case fatality rates due to delayed optimal management. Improving awareness of clinicians and public health specialists about these unusual but potentially severe presentations should help establish prompt diagnoses and provide appropriate management of cases. In this review, we described unusual panels of clinical presentations of invasive meningococcal disease linked to the recent changes in meningococcal epidemiology.

Haemophilus influenzae type b (Hib) seroprevalence in France: impact of vaccination schedules

Background

Haemophilus influenzae serotype b (Hib) conjugate vaccine was introduced in France in 1992 as a 3 + 1 scheme at 2, 3, and 4 months (primary vaccination) with a booster at the age of 16–18 months. The vaccination was simplified in 2013 to a 2 + 1 scheme at 2 and 4 months (primary immunization) and a booster at the age of 11 months. The coverage was 95.4% in France at 24 months in 2017. During the period 2017–2019 the number of Hib invasive infections increased with several cases of vaccine failure.

Methods

The numbers and proportions of Hib invasive isolates during the period 2017–2019 were compared and vaccine failure cases were explored. A seroprevalence study was performed by measuring anti-polyribosyl-ribitol phosphate (PRP) IgG concentrations by ELISA among children < 5 years of age at the time of sampling covering the periods of the 3 + 1 or 2 + 1 schemes of Hib vaccination. A collection of residual 232 sera was tested (group 3 + 1 n = 130) and (group 2 + 1, n = 102) was used.

Results

Anti-PRP IgG concentrations were significantly higher in toddlers of 2 years (median 2.9 μg/ml) in the 3 + 1 group while these concentrations showed a median of 0.58 μg/ml among children in 2 + 1 group. The proportion of children of 2 years of age who achieved 1 μg/ml threshold (56%) was higher in the 3 + 1 group than that observed in the 2 + 1 group (25%). All the detected cases of vaccine failure received the 2 + 1 scheme and anti-PRP IgG levels were less than 1 μg/ml at the admission. However, these levels increased significantly 1 month after the admission suggesting a secondary immune response to the Hib infection.

Conclusions

The simplification of the vaccination to a 2 + 1 scheme seems to reduce the level of anti PRP IgG. Hib antibodies wane rapidly after the 11 months booster and may not be enough to ensure long term protection. Surveillance of cases and monitoring of titres need to be continued to inform future vaccination policy.

Correlates of protection for meningococcal surface protein vaccines: lessons from the past

INTRODUCTION

Recombinant surface protein meningococcal serogroup B (MenB) vaccines are available but with different antigen compositions, leading to differences between vaccines in their immunogenicity and likely breadth of coverage. The serology and breadth of coverage assessment for MenB vaccines are multifaceted areas, and a comprehensive understanding of these complexities is required to appropriately compare licensed vaccines and those under development.

AREAS COVERED

In the first of two companion papers that comprehensively review the serology and breadth of coverage assessment for MenB vaccines, the history of early meningococcal vaccines is considered in this narrative review to identify transferable lessons applicable to the currently licensed MenB vaccines and those under development, as well as their serology.

EXPERT OPINION

Understanding correlates of protection and the breadth of coverage assessment for meningococcal surface protein vaccines is significantly more complex than that for capsular polysaccharide vaccines. Determination and understanding of the breadth of coverage of surface protein vaccines are clinically important and unique to each vaccine formulation. It is essential to estimate the proportion of MenB cases that are preventable by a specific vaccine to assess its overall potential impact and to compare the benefits and limitations of different vaccines in preventing invasive meningococcal disease.

Pediatric Infectious Disease Group (GPIP) position paper on the immune debt of the COVID-19 pandemic in childhood, how can we fill the immunity gap?

Since the beginning of the COVID-19 pandemic, reduced incidence of many viral and bacterial infections has been reported in children: bronchiolitis, varicella, measles, pertussis, pneumococcal and meningococcal invasive diseases. The purpose of this opinion paper is to discuss various situations that could lead to larger epidemics when the non-pharmaceutical interventions (NPI) imposed by the SARS-CoV-2 epidemic will no longer be necessary. While NPIs limited the transmission of SARS-CoV-2, they also reduced the spread of other pathogens during and after lockdown periods, despite the re-opening of schools since June 2020 in France. This positive collateral effect in the short term is welcome as it prevents additional overload of the healthcare system. The lack of immune stimulation due to the reduced circulation of microbial agents and to the related reduced vaccine uptake induced an "immunity debt" which could have negative consequences when the pandemic is under control and NPIs are lifted. The longer these periods of "viral or bacterial low-exposure" are, the greater the likelihood of future epidemics. This is due to a growing proportion of "susceptible" people and a declined herd immunity in the population. The observed delay in vaccination program without effective catch-up and the decrease in viral and bacterial exposures lead to a rebound risk of vaccine-preventable diseases. With a vaccination schedule that does not include vaccines against rotavirus, varicella, and serogroup B and ACYW Neisseria meningitidis, France could become more vulnerable to some of these rebound effects.

Molecular diagnostic assays for the detection of common bacterial meningitis pathogens: A narrative review

Bacterial meningitis is a major global cause of morbidity and mortality. Rapid identification of the aetiological agent of meningitis is essential for clinical and public health management and disease prevention given the wide range of pathogens that cause the clinical syndrome and the availability of vaccines that protect against some, but not all, of these. Since microbiological culture is complex, slow, and often impacted by prior antimicrobial treatment of the patient, molecular diagnostic assays have been developed for bacterial detection. Distinguishing between meningitis caused by Neisseria meningitidis (meningococcus), Streptococcus pneumoniae (pneumococcus), Haemophilus influenzae, and Streptococcus agalactiae and identifying their polysaccharide capsules is especially important. Here, we review methods used in the identification of these bacteria, providing an up-to-date account of available assays, allowing clinicians and diagnostic laboratories to make informed decisions about which assays to use.

Risk factors for invasive meningococcal disease: a retrospective analysis of the French national public health insurance database

Vaccination of at-risk populations against Neisseria meningitidis is an important strategy to prevent invasive meningococcal disease (IMD). The objective of this study was to characterize preexisting risk factors in patients with IMD and to compare their relative importance. This case-control analysis was performed in the French national public health insurance database (SNDS). Cases consisted of all people hospitalized for IMD in France over a six-year period (2012–2017). Controls were matched by age, gender, and district of residence. Medical risk factors were identified from ICD-10 codes in the SNDS. Socioeconomic risk factors studied were low household income and social deprivation of the municipality of residence. Associations of these risk factors with hospitalization for IMD were quantified as odds ratios (ORs) between cases and controls with their 95% confidence intervals (95%CI). The medical risk factors showing the most robust associations were congenital immunodeficiency (OR: 39.1 [95%CI: 5.1–299], acquired immunodeficiency (10.3 [4.5–24.0]) and asplenia/hyposplenia (6.7 [3.7–14.7]). In addition, certain chronic medical conditions, such as autoimmune disorders (5.4 [2.5–11.8]), hemophilia (4.7 [1.8–12.2]) and severe chronic respiratory disorders (4.3 [3.1–6.2]) were also strongly associated, as was low household income (1.68 [1.49–1.80]). In conclusion, this study has documented potential risk factors associated with hospitalization for IMD in a large and comprehensive sample of individuals with IMD in France. Several of the risk factors identified may help identify groups who could benefit from targeted prevention measures (such as vaccination) in order to reduce the burden of IMD.

Multicomponent meningococcal serogroup B vaccination elicits cross-reactive immunity in infants against genetically diverse serogroup C, W and Y invasive disease isolates

BACKGROUND

The multicomponent meningococcal serogroup B vaccine (4CMenB) is currently indicated for active immunization against invasive meningococcal disease caused by Neisseria meningitidis serogroup B (MenB). However, genes encoding the 4CMenB antigens are also variably present and expressed in strains belonging to other meningococcal serogroups. In this study, we evaluated the ability of antibodies raised by 4CMenB immunisation to induce complement-mediated bactericidal killing of non-MenB strains.

METHODS

A total of 227 invasive non-MenB disease isolates were collected between 1 July 2007 and 30 June 2008 from England and Wales, France, and Germany; 41 isolates were collected during 2012 from Brazil. The isolates were subjected to genotypic analyses. A subset of 147 isolates (MenC, MenW and MenY) representative of the meningococcal genetic diversity of the total sample were tested in the human complement serum bactericidal antibody assay (hSBA) using sera from infants immunised with 4CMenB.

RESULTS

Serogroup and clonal complex repertoires of non-MenB isolates were different for each country. For the European panel, MenC, MenW and MenY isolates belonged mainly to ST-11, ST-22 and ST-23 complexes, respectively. For the Brazilian panel, most MenC and MenW isolates belonged to the ST-103 and ST-11 complexes, respectively, and most MenY isolates were not assigned to clonal complexes. Of the 147 non-MenB isolates, 109 were killed in hSBA, resulting in an overall coverage of 74%.

CONCLUSION

This is the first study in which 147 non-MenB serogroup isolates have been analysed in hSBA to evaluate the potential of a MenB vaccine to cover strains belonging to other serogroups. These data demonstrate that antibodies raised by 4CMenB are able to induce bactericidal killing of 109 non-MenB isolates, representative of non-MenB genetic and geographic diversity. These findings support previous evidence that 4CMenB immunisation can provide cross-protection against non-MenB strains in infants, which represents an added benefit of 4CMenB vaccination.

Evidence for Multi-Organ Infection During Experimental Meningococcal Sepsis due to ST-11 Isolates in Human Transferrin-Transgenic Mice

The description of invasive meningococcal disease that is provoked by Neisseria meningitidis (Nm) is frequently restricted to meningitis. However, a wide panel of clinical presentations can be encountered including severe forms with intense inflammatory reaction leading to multi-organ failure. Several human factors are involved in the development of invasive infections such as transferrin, factor H or CEACAM1. In this study, we used an experimental meningococcal infection in transgenic mice expressing the human transferrin to show multi-organ infection. Mice were infected by an intraperitoneal injection of bacterial suspension (1.5 × 10⁷ colony-forming unit/mouse) of a bioluminescent serogroup C strain belonging to the clonal complex ST-11. Dynamic imaging and histological analysis were performed. The results showed invasion of tissues by Nm with bacteria observed, outside blood vessels, in the kidneys, the heart and the brain as well as skin involvement. These data further support the systemic aspect of invasive meningococcal disease with involvement of several organs including skin as in humans. Thus, our model can be used to study severe forms of meningococcal invasive infections with multi-organ failure.

Targeted vaccination campaigns of teenagers after two clusters of B invasive meningococcal disease in Brittany, France, 2017

Background

In December 2016, three cases of serogroup B invasive meningococcal disease, including two children from the same middle school (11 to 15 years old pupils), occurred in the department (administrative district) Côtes-d’Armor (Brittany, France). They were infected by a rare strain (B:P1.7–2,4:F5–9:cc162), covered by the 4CMenB vaccine (Bexsero®). Four months later, two cases due to the same strain occurred in a high school in the same area (15 to 19 years old students). In accordance with French recommendations, vaccination was proposed to students of both schools and to all individuals aged 11–19 years living or studying in the hyperendemic area. We describe these vaccination campaigns, from the alert to the impact evaluation.

Methods

The target population included 8884 people: 579 in the middle school, 2007 in the high school and 6298 in the community. In both schools, vaccination sessions were organized directly on site. In the community, teenagers were vaccinated by general practitioners. The vaccination campaign took place from May to October 2017. An active pharmacovigilance follow-up was set up to document adverse effects of the vaccine.

Results

Considering the whole target population, the vaccination coverage was estimated at 43% for 1 dose and 34% for 2 doses. Higher vaccination coverage was observed in the schools (79% in the middle school and 42% in the high school for 2 doses) than in the community (27% for 2 doses). The reported adverse effects were consistent with the safety profile of the vaccine and no severe adverse effect was reported.

Conclusions

This vaccination campaign was the third one implemented with Bexsero® in France and constitutes a reproducible approach for future targeted vaccination campaigns. No additional cases of the same strain have occurred since the end of the campaigns in the area.

Impact of COVID-19 pandemic and the lockdown on invasive meningococcal disease

Objective

Few data are available on the association between SARS-CoV-2 and secondary bacterial infections. Such an association was described for flu and invasive meningococcal disease (IMD). We aimed exploring such a correlation between COVID-19 and IMD as well as the impact of the lockdown on IMD.

Results

We compared IMD cases received at the French National Reference Centre for meningococci and Haemophilus influenzae that are sent as part of the mandatory reporting of IMD. We compared these data during the period 01 January-15 May 2020 to those from the same period in 2018 and 2019. IMD cases that were associated with respiratory presentations significantly increased in 2020 compared to 2018 (P = 0.029) and 2019 (P = 0.002), involved elderly and were due to unusual isolates. However, IMD cases due to hyperinvasive isolates decreased during the lockdown. Enhancing IMD surveillance and anti-meningococcal vaccination in elderly should be addressed.

Geographically widespread invasive meningococcal disease caused by a ciprofloxacin resistant non-groupable strain of the ST-175 clonal complex

INTRODUCTION

Invasive meningococcal disease (IMD) caused by non-serogroupable (NG) strains mainly affects immunocompromised individuals. Reduced susceptibility to penicillin in meningococci is increasing in Europe but ciprofloxacin resistance remains rare. In 2019, three travel-related meningococcal disease cases caused by a ciprofloxacin-resistant NG strain were identified in England, leading Germany to report four additional IMD cases (2016 to 2019). We describe these and newly identified cases and characterise the strain responsible.

METHODS

Cases were identified as part of national surveillance and by analysing available genomes using PubMLST tools.

RESULTS

Of the cases identified in England in 2019, two geographically distinct cases developed conjunctivitis after returning from Mecca (Kingdom of Saudi Arabia) and a third linked case presented with IMD. Of the four cases from Germany, three occurred in asylum seekers - two familial and a further geographically distinct case. Further IMD cases were identified in Italy (n = 2; 2017-2018), Sweden (n = 1; 2016) and England (n = 1; 2015). A single ST-175 clonal complex (cc175) strain with genosubtype P1.22-11,15-25 was responsible. Decreased susceptibility to penicillin was widespread with three ciprofloxacin resistant subclusters. Constituent isolates were potentially covered by subcapsular vaccines.

CONCLUSION

This disease associated NG cc175 strain exhibits resistance to antibiotics commonly used to prevent IMD but is potentially covered by subcapsular (meningococcal B) vaccines.

Analysis of Haemophilus species in patients with respiratory tract infections in Yaoundé, Cameroon

OBJECTIVES

To identifyHaemophilus species and characterize antimicrobial susceptibility of isolates from patients with respiratory tract infections (RTIs) in Cameroon.

METHODS

Isolates (n = 95) were from patients with RTIs obtained from two Hospitals in Yaoundé, Cameroon. Isolates were identified by biochemical assay, PCR-based method, MALDI-TOF and whole genome sequencing. Antibiotic minimum inhibitory concentrations were determined by E-test.

RESULTS

H. influenzae was the most prevalent species varying from 76.8% to 84.2% according to different methods. The isolates were mainly nontypable (n = 70, 96%). Three isolates of H. influenzae were capsulated (b, e and f). The isolates were genetically diverse and 40 unique sequence types were identified including 11 new ones. Resistance to ampicillin was observed among 55.3% (52/94) and 9% (14/52) produced TEM-1 β-lactamase. PBP3 mutations occurred in 57.7% of ampicillin resistant isolates (30/52). Eleven isolates were chloramphenicol resistant with 80% producing chloramphenicol acetyltransferase (8/10). Four Haemophilus isolates were rifampicin resistant with two mutations in rpoB gene. Five isolates were ciprofloxacin resistant and harbored mutations in the quinolone resistance determining regions of gyrA and parC genes.

CONCLUSION

H. influenzae isolates are highly diverse and show high levels of antibiotic resistance. H. influenzae serotype b is still circulating in the post-vaccination era.

Meningococcal disease surveillance in the Asia-Pacific region (2020): The global meningococcal initiative

The degree of surveillance data and control strategies for invasive meningococcal disease (IMD) varies across the Asia-Pacific region. IMD cases are often reported throughout the region, but the disease is not notifiable in some countries, including Myanmar, Bangladesh and Malaysia. Although there remains a paucity of data from many countries, specific nations have introduced additional surveillance measures. The incidence of IMD is low and similar across the represented countries (<0.2 cases per 100,000 persons per year), with the predominant serogroups of Neisseria meningitidis being B, W and Y, although serogroups A and X are present in some areas. Resistance to ciprofloxacin is also of concern, with the close monitoring of antibiotic-resistant clonal complexes (e.g., cc4821) being a priority. Meningococcal vaccination is only included in a few National Immunization Programs, but is recommended for high-risk groups, including travellers (such as pilgrims) and people with complement deficiencies or human immunodeficiency virus (HIV). Both polysaccharide and conjugate vaccines form part of recommendations. However, cost and misconceptions remain limiting factors in vaccine uptake, despite conjugate vaccines preventing the acquisition of carriage.

First report of meningococcal ciprofloxacin resistance in Greece due to invasive isolates of the sequence type ST-3129

A local outbreak caused by Neisseria meningitidis occurred in the migration camp in the Greek island of Lesbos during January-February 2020 (4 of 5 cases). In total, 5 samples positive for N. meningitidis were further investigated for sero-/genogroup, PorA, and WGS analysis. MenB was found among 3 cases, while in two cases, MenY was identified. WGS analysis and antibiotic susceptibility testing on the 2 culture positive MenB samples showed the new ST-3129, ciprofloxacin-resistant clone was circulating among the immigrants in the aforementioned camp. This is the first report of ciprofloxacin resistance in Greece.

Strain coverage of Bexsero vaccine assessed by whole-genome sequencing over a cohort of invasive meningococci of serogroups B and W isolated in Switzerland

Invasive meningococcal disease (IMD), caused by Neisseria meningitidis (Nm) strains, is a life-threatening but vaccine-preventable condition. Bexsero is a four-component vaccine that offers broad protection against Nm of serogroup B (NmB), particularly common in Europe. In Switzerland, Bexsero has not yet been licensed and no information is available concerning the predicted vaccine coverage on isolates of circulating Nm. We performed genotyping of Bexsero antigen loci by whole-genome sequencing (WGS) on 104 NmB collected in Switzerland in the 2010-2015 period. We searched for antigen variants previously defined as predictors of strain coverage and estimated that 50% of IMD NmB strains were potentially covered by the vaccine. Clonal complexes (cc) 32, 41/44 and 269, considered the best covered lineages, were further sub-typed according to Bexsero Antigen Sequence Type (BAST) scheme. We also genotyped by WGS 40 Nm of serogroup W (NmW) collected in the country between 2010 and 2016. NmW cc22 isolates appeared to be covered by the vaccine, which was not the case for cc11 isolates, whose incidence has recently increased in Switzerland and all over Europe. Our work underlines the benefit of using WGS for surveillance of vaccine antigen variant distribution in local Nm population and taking proper measures to prevent the spread of NmB.

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.

Difference in virulence between Neisseria meningitidis serogroups W and Y in transgenic mice

BACKGROUND

Neisseria meningitidis serogroups W and Y are the most common serogroups causing invasive meningococcal disease in Sweden. The majority of cases are caused by the serogroup W UK 2013 strain of clonal complex (cc) 11, and subtype 1 of the serogroup Y, YI strain of cc23. In this study, virulence factors of several lineages within cc11 and cc23 were investigated in transgenic BALB/c mice expressing human transferrin. Transgenic mice were infected intraperitoneally with serogroup W and Y isolates. Levels of bacteria and the proinflammatory cytokine CXCL1 were determined in blood collected 3 h and 24 h post-infection. Apoptosis was investigated in immune cells from peritoneal washes of infected mice. Adhesion and induction of apoptosis in human epithelial cells were also scored.

RESULTS

The levels of bacteraemia, CXCL1, and apoptosis were higher in serogroup W infected mice than in serogroup Y infected mice. Serogroup W isolates also induced higher levels of apoptosis and adhesion in human epithelial cells. No significant differences were observed between different lineages within cc11 and cc23.

CONCLUSIONS

N. meningitidis Serogroup W displayed a higher virulence in vivo in transgenic mice, compared to serogroup Y. This was reflected by higher bacteremia, proinflammatory activity, and ability to induce apoptosis in mouse immune cells and human epithelial cells.

Recent changes of invasive meningococcal disease in France: arguments to revise the vaccination strategy in view of those of other countries

In France, the incidence of invasive meningococcal disease (IMD) is around 1/100,000, with the following trends over the 2011-2018 period: a leading role of group B in subjects <15 years, a decrease of group C among <1 year since 2017, an increase of group W in all age groups including subjects <1 year since 2014 and a positive correlation between group Y and age group. In Europe, vaccination progressed with conjugate ACWY vaccines and proteins-based B vaccines. Their benefit-risk-cost balance is however not so obvious for area at low incidence (<2/100,000), explaining tremendous variations between countries, from no recommendation to recommend all available vaccines. In France, the calendar still includes only C with a good adhesion in infants but a fiasco of the catch-up campaign in adolescents and young adults. In Europe, it is time to consider not only national epidemiology but also trends in the neighborhood. The increase of group W cases encourages switching C to ACWY vaccine both in infants and adolescents. It is also time to protect infants with B vaccine. Large pedagogy on the disease is required to increase the adhesion to the vaccination and to recognize and treat earlier the residual cases.