Pediatric Bacterial Meningitis Surveillance in Niger: Increased Importance of Neisseria meningitidis Serogroup C, and a Decrease in Streptococcus pneumoniae Following 13-Valent Pneumococcal Conjugate Vaccine Introduction

Molecular Epidemiology of Streptococcus pneumoniae Serotype 1: A Systematic Review of Circulating Clones and Clonal Clusters

Streptococcus pneumoniae serotype 1 is one of the most prevalent serotypes commonly associated with invasive pneumococcal disease cases and outbreaks worldwide. Several sequence types of this serotype have been identified globally, including those exhibiting both high virulence potential and antimicrobial resistance profiles. This systematic review presents the global distribution of clones of pneumococcal serotype 1, describing their circulating patterns in various regions in the world. A database search was conducted in Google Scholar, PubMed, Scopus, ScienceDirect, and Web of Science using keywords related to Streptococcus pneumoniae serotype 1. The inclusion criteria entailed peer-reviewed studies published in English describing the utilization of at least one molecular genotyping tool to identify S. pneumoniae serotype 1 clones based on their sequence types. Data extracted were managed and analyzed using Microsoft Excel 365 (Version 2108). Forty-three studies were finally included in the systematic review. A total of 103 MLST serotype 1 sequence types were identified in 48 countries. These clones were widely reported to be associated with invasive pneumococcal diseases. Globally, ST217 and ST306 clonal complexes (CC217 and CC306) were the predominant lineages of serotype 1 sequence types, exhibiting distinct continental distribution patterns. CC217, characterized by ST217, ST303, ST612, ST618, and ST3081, was predominant in Africa and Asia. ST306 clonal complex, which is grouped into ST306, ST304, and ST227 were mostly found in Europe, Oceania, North America, and some countries in South America. ST615 was predominant in Chile, Peru, and Argentina. The hypervirulence nature of serotype 1, coupled with its complex genetic diversity, poses a significant public health threat. Our findings emphasize the need for enhanced surveillance and targeted interventions to mitigate the spread of these hypervirulent clones, ultimately informing evidence-based strategies for disease prevention and control.

Advances in the pathogenesis and treatment of pneumococcal meningitis

Streptococcus pneumoniae is a common pathogen associated with community-acquired bacterial meningitis, characterized by high morbidity and mortality rates. While vaccination reduces the incidence of meningitis, many survivors experience severe brain damage and corresponding sequelae. The pathogenesis of pneumococcal meningitis has not been fully elucidated. Currently, meningitis requires bacterial disruption of the blood - brain barrier, a process that involves the interaction of bacterial surface components with host cells and various inflammatory responses. This review delineates the global prevalence, pathogenesis, and treatment strategies of pneumococcal meningitis. The objective is to enhance the thorough comprehension of the clinical manifestations and biological mechanisms of the disease, thereby enabling more efficient prevention, diagnosis, and therapeutic interventions.

Estimating the Global and Regional Burden of Streptococcus pneumoniae Meningitis in Children: Protocol for a Systematic Review and Meta-Analysis

BACKGROUND

Streptococcus pneumoniae (Spn) has been a leading cause of bacterial meningitis in children. The most recent estimation of the global burden of Spn meningitis indicates a positive trajectory in eliminating Spn through the implementation of pneumococcal conjugate vaccines. However, continuous monitoring and assessment of the disease burden are necessary due to the evidence of serotype replacement, antibiotic resistance, and the impact of the recent COVID-19 pandemic.

OBJECTIVE

The aim of this systematic review is to provide an updated and focused assessment of the global and regional burden of Spn meningitis in children, which can guide policies and strategies to reduce the disease burden.

METHODS

Population-based studies published from January 1, 2000, to January 1, 2022, were preliminarily searched from the electronic databases PubMed, Embase, Global Health (CABI), and CINAHL Plus without any language restrictions. Studies were included if they reported the incidence, prevalence, mortality, or case-fatality ratio (CFR) for Spn meningitis in children aged 0-4 years; meningitis was confirmed by cerebrospinal fluid culture; the study period was a minimum of 1 year; the number of reported cases was at least 10; and the study had no methodological ambiguities. The article screening process follows the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Characteristics including study period, setting, World Health Organization region, income level, vaccination information, and participant data (age, number of cases, deaths, sequelae, and risk factors) will be extracted from the included studies. Search results will be updated and incorporated into our review prior to finalizing the extraction of data. Generalized linear mixed models meta-analysis will be performed to estimate the pooled incidence and CFR. We will further assess the risk of bias and heterogeneity, and will perform subgroup and sensitivity analyses to provide a meaningful interpretation of the current burden and literature for pneumococcal meningitis.

RESULTS

Our preliminary search in December 2021 yielded 9295 articles. Out of 275 studies that were assessed with our eligibility criteria, 117 articles were included. Data extraction and analysis are expected to be complete by January 2025. We plan to publish the results from the full study, including an updated search in 2024, by March 2025.

CONCLUSIONS

Given that the major burden of Spn meningitis affects children under the age of 5 years, this systematic review will provide a thorough understanding of the global burden of Spn meningitis in this vulnerable population over a span of 2 decades. Insights into incidence trends, geospatial distribution, risk factors, and sequelae will be valuable for stakeholders, policy makers, and the academic community. This information will aid in the ongoing monitoring of the disease and in enhancing targeted vaccine programs to further mitigate the impact of the disease on children worldwide.

TRIAL REGISTRATION

PROSPERO CRD42021293110; https://tinyurl.com/kc3j5k4m.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/50678.

Epidemiology and Clinical Outcomes of Bacterial Meningitis in Children and Adults in Low- and Middle-Income Countries

Purpose of Review

Despite the availability of effective vaccines against the three primary pathogens (Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis) that cause bacterial meningitis, this condition remains a significant cause of morbidity, neurologic sequelae, and mortality among children and adults living in low-income and middle-income countries.

Recent Findings

Bacterial meningitis represents a significant public health challenge for national and global health systems. Since vaccine-preventable meningitis remains highly prevalent in low-income and middle-income countries, the World Health Organization (WHO) recently developed a global roadmap to defeating meningitis by 2030 and ameliorating its associated neurological sequelae.

Summary

There is a need for a global approach to surveillance and prevention of bacterial meningitis. Increasing vaccination coverage with conjugate vaccines against pneumococcus and meningococcus with optimal immunization schedules are high-value healthcare interventions. Additionally, overcoming diagnostic challenges and the early institution of empirical antibiotic therapy and, when feasible, adjunctive steroid therapy constitutes the pillars of reducing the disease burden of bacterial meningitis in resource-limited settings.

Clinical and Bacteriological Analysis of Pediatric Pneumococcal Meningitis after 13-Valent Pneumococcal Conjugate Vaccine Introduction in Japan

Streptococcus pneumoniae is one of the leading causes of meningitis in children. In Japan, since the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), the number of pneumococcal meningitis due to non-PCV13 serotypes in children has increased. To clarify the clinical outcomes, serotype distributions, and antimicrobial susceptibility of isolated S. pneumoniae strains from pediatric pneumococcal meningitis, we clinically and bacteriologically analyzed 34 cases of pediatric pneumococcal meningitis that were reported after the PCV13 introduction era in Japan. The median age at diagnosis was 1 year (range: 3 months–13 years). Ten (29.4%) patients had underlying diseases. Twenty-nine (85.3%) patients had received at least one dose of any pneumococcal vaccine. Of the 34 patients with pneumococcal meningitis, 6 had sequelae, and 4 died. Nine (26.5%) strains were resistant to penicillin; five (15%) strains to meropenem, with an MIC of 0.5 μg/mL. All strains were susceptible to vancomycin and linezolid. Daptomycin’s MIC₅₀ was 0.064 μg/mL and MIC₉₀ was 0.094 μg/mL. Among the tested strains, only four were PCV13 serotypes. Penicillin-resistant S. pneumoniae was isolated from 30.0% of the patients with sequelae and death. Particularly, the proportion of serotype 10A in the sequelae and deceased cases was significantly higher than that in the complete recovery cases. We should carefully monitor the serotype and drug susceptibility of S. pneumoniae strains isolated from patients with meningitis after the PCV13 era and reconsider the treatment strategy to prepare against further drug-resistant pneumococcal strains.

IMPORTANCE We analyzed 34 cases of pediatric pneumococcal meningitis that were reported after the 13-valent pneumococcal conjugate vaccine (PCV13) introduction era in Japan. Our study revealed that pneumococcal meningitis in children was mainly caused by non-PCV13 serotypes; all cases with sequelae and death were caused by non-PCV13 serotypes. Moreover, all serotypes of penicillin resistant Streptococcus pneumoniae strains (26.5%; 9/34) were non-PCV13 serotypes. We also analyzed antimicrobial susceptibilities of glycopeptides, linezolid (LZD), and daptomycin (DAP) of isolated S. pneumoniae strains. All tested strains were susceptible to vancomycin, teicoplanin, LZD, and DAP. Especially. DAP demonstrated the best outcome among the tested antibiotics, with MIC₉₀ of 0.094 μg/mL. Pneumococcal meningitis in children continues to persist and is difficult to control with the current conjugate vaccines. Therefore, it is important to monitor the serotype and antimicrobial susceptibility of S. pneumoniae strains isolated from patients with meningitis and accordingly reconsider the treatment strategy.

Use of a new multiplex quantitative polymerase chain reaction based assay for simultaneous detection of Neisseria meningitidis, Escherichia coli K1 , Streptococcus agalactiae, and Streptococcus pneumoniae

Background and Objectives

Neisseria meningitidis, Escherichia coli K₁, Streptococcus agalactiae, and Streptococcus pneumoniae cause 90% of bacterial meningitis. Almost all infected people die or have irreversible neurological complications. Therefore, it is essential to have a diagnostic kit with the ability to quickly detect these fatal infections.

Materials and Methods

The project involved 212 patients from whom cerebrospinal fluid samples were obtained. After total genome extraction and performing multiplex quantitative polymerase chain reaction (qPCR), the presence or absence of each infectious factor was determined by comparing with standard strains.

Results

The specificity, sensitivity, positive predictive value, and negative predictive value calculated were 100%, 92.9%, 50%, and 100%, respectively. So, due to the high specificity and sensitivity of the designed primers, they can be used instead of bacterial culture that takes at least 24 to 48 hours.

Conclusion

The remarkable benefit of this method is associated with the speed (up to 3 hours) at which the procedure could be completed. It is also worth noting that this method can reduce the personnel unintentional errors which may occur in the laboratory. On the other hand, as this method simultaneously identifies four common factors that cause bacterial meningitis, it could be used as an auxiliary method diagnostic technique in laboratories particularly in cases of emergency medicine.

Invasive Haemophilus influenzae Infections after 3 Decades of Hib Protein Conjugate Vaccine Use

Haemophilus influenzae serotype b (Hib) was previously the most common cause of bacterial meningitis and an important etiologic agent of pneumonia in children aged <5 years. Its major virulence factor is the polyribosyl ribitol phosphate (PRP) polysaccharide capsule. In the 1980s, PRP-protein conjugate Hib vaccines were developed and are now included in almost all national immunization programs, achieving a sustained decline in invasive Hib infections. However, invasive Hib disease has not yet been eliminated in countries with low vaccine coverage, and sporadic outbreaks of Hib infection still occur occasionally in countries with high vaccine coverage. Over the past 2 decades, other capsulated serotypes have been recognized increasingly as causing invasive infections. H. influenzae serotype a (Hia) is now a major cause of invasive infection in Indigenous communities of North America, prompting a possible requirement for an Hia conjugate vaccine. H. influenzae serotypes e and f are now more common than serotype b in Europe. Significant year-to-year increases in nontypeable H. influenzae invasive infections have occurred in many regions of the world. Invasive H. influenzae infections are now seen predominantly in patients at the extremes of life and those with underlying comorbidities. This review provides a comprehensive and critical overview of the current global epidemiology of invasive H. influenzae infections in different geographic regions of the world. It discusses those now at risk of invasive Hib disease, describes the emergence of other severe invasive H. influenzae infections, and emphasizes the importance of long-term, comprehensive, clinical and microbiologic surveillance to monitor a vaccine's impact.

Progress in the Application of Nanoparticles and Graphene as Drug Carriers and on the Diagnosis of Brain Infections

The blood–brain barrier (BBB) is the protective sheath around the brain that protects the sensitive microenvironments of the brain. However, certain pathogens, viruses, and bacteria disrupt the endothelial barrier and cause infection and hence inflammation in meninges. Macromolecular therapeutics are unable to cross the tight junctions, thereby limiting their bioavailability in the brain. Recently, nanotechnology has brought a revolution in the field of drug delivery in brain infections. The nanostructures have high targeting accuracy and specificity to the receptors in the case of active targeting, which have made them the ideal cargoes to permeate across the BBB. In addition, nanomaterials with biomimetic functions have been introduced to efficiently cross the BBB to be engulfed by the pathogens. This review focuses on the nanotechnology-based drug delivery approaches for exploration in brain infections, including meningitis. Viruses, bacteria, fungi, or, rarely, protozoa or parasites may be the cause of brain infections. Moreover, inflammation of the meninges, called meningitis, is presently diagnosed using laboratory and imaging tests. Despite attempts to improve diagnostic instruments for brain infections and meningitis, due to its complicated and multidimensional nature and lack of successful diagnosis, meningitis appears almost untreatable. Potential for overcoming the difficulties and limitations related to conventional diagnostics has been shown by nanoparticles (NPs). Nanomedicine now offers new methods and perspectives to improve our knowledge of meningitis and can potentially give meningitis patients new hope. Here, we review traditional diagnosis tools and key nanoparticles (Au-NPs, graphene, carbon nanotubes (CNTs), QDs, etc.) for early diagnosis of brain infections and meningitis.

Evaluation of pneumococcal meningitis clusters in Burkina Faso and implications for potential reactive vaccination

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From 2011 to 2017, Burkina Faso had 20 pneumococcal meningitis clusters of ≥ 5 cases per district/week.

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Clusters had a maximum weekly incidence of 7 cases and a maximum duration of 4 weeks.

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Most clusters occurred prior to 13-valent pneumococcal conjugate vaccine introduction.

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Clusters were caused by a mixture of serotypes, with serotype 1 being most common.

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Due to the limited cluster size and duration, there were no clear indications for reactive vaccination.

Background

To better understand how to prevent and respond to pneumococcal meningitis outbreaks in the meningitis belt, we retrospectively examined Burkina Faso’s case-based meningitis surveillance data for pneumococcal meningitis clusters and assessed potential usefulness of response strategies.

Methods

Demographic and clinical information, and cerebrospinal fluid laboratory results for meningitis cases were collected through nationwide surveillance. Pneumococcal cases were confirmed by culture, polymerase chain reaction (PCR), or latex agglutination; strains were serotyped using PCR. We reviewed data from 2011 to 2017 to identify and describe clusters of ≥ 5 confirmed pneumococcal meningitis cases per week in a single district. We assessed whether identified clusters met the 2016 WHO provisional pneumococcal meningitis outbreak definition: a district with a weekly incidence of >5 suspected meningitis cases/100,000 persons, >60% of confirmed meningitis cases caused by Streptococcus pneumoniae, and >10 confirmed pneumococcal meningitis cases.

Results

Twenty pneumococcal meningitis clusters were identified, with a maximum weekly incidence of 7 cases and a maximum duration of 4 weeks. Most identified clusters (15/20; 75%) occurred before nationwide introduction of 13-valent pneumococcal conjugate vaccine (PCV13) in October 2013. Most cases were due to serotype 1 (74%), 10% were due to PCV13 serotypes besides serotype 1, and 8 clusters had >1 serotype. While 6 identified clusters had a weekly incidence of >5 suspected cases/100,000 and all 20 clusters had >60% of confirmed meningitis cases due to S. pneumoniae, no cluster had >10 confirmed pneumococcal meningitis cases in a single week.

Conclusions

Following PCV13 introduction, pneumococcal meningitis clusters were rarely detected, and none met the WHO provisional pneumococcal outbreak definition. Due to the limited cluster size and duration, there were no clear instances where reactive vaccination could have been useful. More data are needed to inform potential response strategies.

Etiology of Pediatric Meningitis in West Africa Using Molecular Methods in the Era of Conjugate Vaccines against Pneumococcus, Meningococcus, and Haemophilus influenzae Type b

Despite the implementation of effective conjugate vaccines against the three main bacterial pathogens that cause meningitis, Streptococcus pneumoniae, Haemophilus influenzae type b (Hib), and Neisseria meningitidis serogroup A, the burden of meningitis in West Africa remains high. The relative importance of other bacterial, viral, and parasitic pathogens in central nervous system infections is poorly characterized. Cerebrospinal fluid (CSF) specimens were collected from children younger than 5 years with suspected meningitis, presenting at pediatric teaching hospitals across West Africa in five countries including Senegal, Ghana, Togo, Nigeria, and Niger. Cerebrospinal fluid specimens were initially tested using bacteriologic culture and a triplex real-time polymerase chain reaction (PCR) assay for N. meningitidis, S. pneumoniae, and H. influenzae used in routine meningitis surveillance. A custom TaqMan Array Card (TAC) assay was later used to detect 35 pathogens including 15 bacteria, 17 viruses, one fungus, and two protozoans. Among 711 CSF specimens tested, the pathogen positivity rates were 2% and 20% by the triplex real-time PCR (three pathogens) and TAC (35 pathogens), respectively. TAC detected 10 bacterial pathogens, eight viral pathogens, and Plasmodium. Overall, Escherichia coli was the most prevalent (4.8%), followed by S. pneumoniae (3.5%) and Plasmodium (3.5%). Multiple pathogens were detected in 4.4% of the specimens. Children with human immunodeficiency virus (HIV) and Plasmodium detected in CSF had high mortality. Among 220 neonates, 17% had at least one pathogen detected, dominated by gram-negative bacteria. The meningitis TAC enhanced the detection of pathogens in children with meningitis and may be useful for case-based meningitis surveillance.