Neisseria meningitidis: biology, microbiology, and epidemiology

Cost-effectiveness analysis of vaccination strategies against meningococcal disease for children under nine years of age in China

Meningococcal vaccination strategies in China are intricate, including multiple vaccines targeting different serogroups. The current National Immunization Program (NIP) includes two polysaccharide vaccines for serogroups A and C (MPV-A and MPV-AC), covering limited serogroups and requiring adaptation. This study aims to evaluate the cost-effectiveness of replacing the current strategy with alternative strategies utilizing non-NIP vaccines to inform policy decisions. From a societal perspective, a decision tree-Markov model was constructed to simulate the economic and health consequences of meningococcal disease in a 2019 birth cohort with four vaccination strategies. Epidemiology, vaccine efficacy, cost, and other parameters were derived from previous studies. We conducted sensitivity analyses to assess the robustness of the findings and explored prices for non-NIP vaccines that enable cost-effective strategies. Compared to the current strategy, alternative strategies using quadrivalent polysaccharide vaccine (MPV-4), bivalent conjugate vaccine (MCV-AC), and quadrivalent conjugate vaccine (MCV-4) could avoid 91, 286, and 455 more meningococcal cases. The ICERs were estimated at approximately $250 thousand/QALY, $450 thousand/QALY, and $1.5 million/QALY, all exceeding the threshold of three times GDP per capita. The alternative strategies were not cost-effective. However, if vaccine prices were reduced to $3.9 for MPV-4, $9.9 for MCV-AC, and $12 for MCV-4, the corresponding strategy would be cost-effective. The current meningococcal vaccination strategy in China could effectively prevent the disease at a low cost, but with limited serogroup coverage. Strategies using MPV-4, MCV-AC, or MCV-4 could increase health benefits at a substantial cost, and might become cost-effective if vaccine prices decrease.

Intake of compound probiotics accelerates the construction of immune function and gut microbiome in Holstein calves

Acquired immunity is an important way to construct the intestinal immune barrier in mammals, which is almost dependent on suckling. To develop a new strategy for accelerating the construction of gut microbiome, newborn Holstein calves were continuously fed with 40 mL of compound probiotics (containing Lactobacillus plantarum T-14, Enterococcus faecium T-11, Saccharomyces cerevisiae T-209, and Bacillus licheniformis T-231) per day for 60 days. Through diarrhea rate monitoring, immune index testing, antioxidant capacity detection, and metagenome sequencing, the changes in diarrhea incidence, average daily gain, immune index, and gut microbiome of newborn calves within 60 days were investigated. Results indicated that feeding the compound probiotics reduced the average diarrhea rate of calves by 42.90%, increased the average daily gain by 43.40%, raised the antioxidant indexes of catalase, superoxide dismutase, total antioxidant capacity, and Glutathione peroxidase by 22.81%, 6.49%, 8.33%, and 13.67%, respectively, and increased the immune indexes of IgA, IgG, and IgM by 10.44%, 4.85%, and 6.12%, respectively. Moreover, metagenome sequencing data showed that feeding the compound probiotics increased the abundance of beneficial strains (e.g., Lactococcus lactis and Bacillus massionigeriensis) and decreased the abundance of some harmful strains (e.g., Escherichia sp. MOD1-EC5189 and Mycobacterium brisbane) in the gut microbiome of calves, thus contributing to accelerating the construction of healthy gut microbiome in newborn Holstein calves.

IMPORTANCE

The unstable gut microbiome and incomplete intestinal function of newborn calves are important factors for the high incidence of early diarrhea. This study presents an effective strategy to improve the overall immunity and gut microbiome in calves and provides new insights into the application of compound probiotics in mammals.

Analyzing the dynamics of meningococcal vaccinations initiatives by local government units in Poland (2017-2021) - Scope, challenges and recommendations

INTRODUCTION

Meningococcal vaccinations are recommended by Polish public health authorities but lack coverage under health insurance, prompting Local Government Units (LGUs) to implement local health policy programs. This study examines the effectiveness and impact of LGU-driven meningococcal vaccination initiatives in Poland between 2017 and 2021.

MATERIAL AND METHODS

A retrospective analysis utilized data from reports on local public health interventions submitted annually to the Ministry of Health in Poland. The study focused on the number of meningococcal vaccination programs, their scope, the vaccinated population, and associated program costs. Additionally, nationwide data on meningococcal disease incidence and vaccine uptake were analyzed.

RESULTS

Within LGUs programs, 48,617 individuals received meningococcal vaccinations, constituting approximately 10% of all vaccinations in Poland during the study period. Notably, cities with poviat rights spearheaded programs covering 54% of the total participants. The total cost incurred by these initiatives amounted to EUR 2,553,661.

CONCLUSIONS

While LGUs activities positively contributed to increased meningococcal vaccination rates, the overall engagement of local governments remains limited. The findings underscore the importance of expanding local government involvement in meningococcal vaccination programs to address public health needs effectively. Improved collaboration and increased funding may enhance the reach and impact of these initiatives.

Public Health Impact and Cost-Effectiveness Analysis of 4-Component Meningococcal Serotype B Vaccination for Infants in France

BACKGROUND AND OBJECTIVES

In France, meningococcal serogroup B (MenB) is the most common serogroup causing invasive meningococcal disease (IMD) in infants and young children. Our objective was to illustrate the impact of model choices on health outcomes and the cost-effectiveness of infant vaccination with the multicomponent meningococcal serogroup B vaccine (4CMenB) versus no vaccine in France.

METHODS

A previously published dynamic transmission-based cost-effectiveness model was adapted for the French context using updated, French-specific demographic, epidemiological, and cost data. IMD incidence and long-term sequelae were derived through analysis of French healthcare and surveillance databases. A collective perspective over a 100-year time horizon was adopted, with a discount rate of 2.5%, reduced to 1.5% after the first 30 years. Deterministic and probabilistic sensitivity and scenario analyses were performed.

RESULTS

In the base case analysis, infant vaccination with 4CMenB avoided 3101 MenB IMD cases in infants aged < 1 year (- 54%) and 6845 cases in all age groups (- 21%). The estimated incremental cost-effectiveness ratio was €316,272/quality-adjusted life-year (QALY) but was highly sensitive to the types of sequelae included, MenB incidence, vaccine effectiveness parameters, and consideration of life-expectancy in IMD survivors (range: €65,272/QALY to €493,218/QALY).

CONCLUSIONS

Using economic models compliant with French methodology guidelines, 4CMenB does not seem cost-effective; however, results are sensitive to model choices and 4CMenB immunization is an effective strategy to prevent MenB IMD cases and to improve quality of life and economic burden associated with MenB IMD treatment, especially with regard to long-term sequelae.

Nurses' preferences regarding MenACWY conjugate vaccines attributes: a discrete choice experiment in Spain

OBJECTIVES

Immunisation against preventable diseases as meningitis is crucial from a public health perspective to face challenges posed by these infections. Nurses hold a great responsibility for these programs, which highlights the importance of understanding their preferences and needs to improve the success of campaigns. This study aimed to investigate nurses' preferences regarding Meningococcus A, C, W, and Y (MenACWY) conjugate vaccines commercialised in Spain.

STUDY DESIGN

A national-level discrete choice experiment (DCE) was conducted.

METHODS

A literature review and a focus group informed the DCE design. Six attributes were included: pharmaceutical form, coadministration evidence, shelf-life, package contents, single-doses per package, and package volume. Conditional logit models quantified preferences and relative importance (RI).

RESULTS

Thirty experienced primary care nurses participated in this study. Evidence of coadministration with other vaccines was the most important attribute (RI = 43.78%), followed by package size (RI = 22.17%), pharmaceutical form (RI = 19.07%), and package content (RI = 11.80%). There was a preference for evidence of coadministration with routine vaccines (odds ratio [OR] = 2.579, 95% confidence interval [95%CI] = 2.210-3.002), smaller volumes (OR = 1.494, 95%CI = 1.264-1.767), liquid formulations (OR = 1.283, 95%CI = 1.108-1.486) and package contents including only vial/s (OR = 1.283, 95%CI = 1.108-1.486). No statistical evidence was found for the remaining attributes.

CONCLUSIONS

Evidence of coadministration with routine vaccines, easy-to-store packages, and fully liquid formulations were drivers of nurses' preferences regarding MenACWY conjugate vaccines. These findings provide valuable insights for decision-makers to optimize current campaigns.

Diverse proinflammatory response in pharyngeal epithelial cells upon interaction with Neisseria meningitidis carriage and invasive isolates

BACKGROUND

Invasive meningococcal disease (IMD), including sepsis and meningitis, can develop when Neisseria meningitidis bacteria breach the barrier and gain access to the circulation. While IMD is a rare outcome of bacterial exposure, colonization of the oropharynx is present in approximately 10% of the human population. This asymptomatic carriage can be long or short term, and it is unknown which determining factors regulate bacterial colonization. Despite descriptions of many bacterial virulence factors and recent advances in detailed genetic identification and characterization of bacteria, the factors mediating invasion and disease vs. asymptomatic carriage following bacterial colonization remain unknown. The pharyngeal epithelia play a role in the innate immune defense against pathogens, and the aim of this study was to investigate the proinflammatory response of pharyngeal epithelial cells following meningococcal exposure to describe the potential inflammatory mediation performed during the initial host‒pathogen interaction. Clinically relevant isolates of serogroups B, C, W and Y, derived from patients with meningococcal disease as well as asymptomatic carriers, were included in the study.

RESULTS

The most potent cellular response with proinflammatory secretion of TNF, IL-6, CXCL8, CCL2, IL-1β and IL-18 was found in response to invasive serogroup B isolates. This potent response pattern was also mirrored by increased bacterial adhesion to cells as well as induced cell death. It was, however, only with serogroup B isolates where the most potent cellular response was toward the IMD isolates. In contrast, the most potent cellular response using serogroup Y isolates was directed toward the carriage isolates rather than the IMD isolates. In addition, by comparing isolates from outbreaks in Sweden (epidemiologically linked and highly genetically similar), we found the most potent proinflammatory response in cells exposed to carriage isolates rather than the IMD isolates.

CONCLUSION

Although certain expected correlations between host‒pathogen interactions and cellular proinflammatory responses were found using IMD serogroup B isolates, our data indicate that carriage isolates invoke stronger proinflammatory activation of the epithelial lining than IMD isolates.

Understanding bacterial pathogenicity: a closer look at the journey of harmful microbes

Bacteria are the most prevalent form of microorganisms and are classified into two categories based on their mode of existence: intracellular and extracellular. While most bacteria are beneficial to human health, others are pathogenic and can cause mild to severe infections. These bacteria use various mechanisms to evade host immunity and cause diseases in humans. The susceptibility of a host to bacterial infection depends on the effectiveness of the immune system, overall health, and genetic factors. Malnutrition, chronic illnesses, and age-related vulnerabilities are the additional confounders to disease severity phenotypes. The impact of bacterial pathogens on public health includes the transmission of these pathogens from healthcare facilities, which contributes to increased morbidity and mortality. To identify the most significant threats to public health, it is crucial to understand the global burden of common bacterial pathogens and their pathogenicity. This knowledge is required to improve immunization rates, improve the effectiveness of vaccines, and consider the impact of antimicrobial resistance when assessing the situation. Many bacteria have developed antimicrobial resistance, which has significant implications for infectious diseases and favors the survival of resilient microorganisms. This review emphasizes the significance of understanding the bacterial pathogens that cause this health threat on a global scale.

Host-microbe interactions at the blood-brain barrier through the lens of induced pluripotent stem cell-derived brain-like endothelial cells

Microbe-induced meningoencephalitis/meningitis is a life-threatening infection of the central nervous system (CNS) that occurs when pathogens are able to cross the blood-brain barrier (BBB) and gain access to the CNS. The BBB consists of highly specialized brain endothelial cells that exhibit specific properties to allow tight regulation of CNS homeostasis and prevent pathogen crossing. However, during meningoencephalitis/meningitis, the BBB fails to protect the CNS. Modeling the BBB remains a challenge due to the specialized characteristics of these cells. In this review, we cover the induced pluripotent stem cell-derived, brain-like endothelial cell model during host-pathogen interaction, highlighting the strengths and recent work on various pathogens known to interact with the BBB. As stem cell technologies are becoming more prominent, the stem cell-derived, brain-like endothelial cell model has been able to reveal new insights in vitro, which remain challenging with other in vitro cell-based models consisting of primary human brain endothelial cells and immortalized human brain endothelial cell lines.

Do Not Waste Time─Ensure Success in Your Cross-Linking Mass Spectrometry Experiments before You Begin

Cross-linking mass spectrometry (XL-MS) has become a very useful tool for studying protein complexes and interactions in living systems. It enables the investigation of many large and dynamic assemblies in their native state, providing an unbiased view of their protein interactions and restraints for integrative modeling. More researchers are turning toward trying XL-MS to probe their complexes of interest, especially in their native environments. However, due to the presence of other potentially higher abundant proteins, sufficient cross-links on a system of interest may not be reached to achieve satisfactory structural and interaction information. There are currently no rules for predicting whether XL-MS experiments are likely to work or not; in other words, if a protein complex of interest will lead to useful XL-MS data. Here, we show that a simple iBAQ (intensity-based absolute quantification) analysis performed from trypsin digest data can provide a good understanding of whether proteins of interest are abundant enough to achieve successful cross-linking data. Comparing our findings to large-scale data on diverse systems from several other groups, we show that proteins of interest should be at least in the top 20% abundance range to expect more than one cross-link found per protein. We foresee that this guideline is a good starting point for researchers who would like to use XL-MS to study their protein of interest and help ensure a successful cross-linking experiment from the beginning. Data are available via ProteomeXchange with identifier PXD045792.

Improved Activities of Daily Living With Adjunctive Intravenous Steroids in Bacterial Meningitis: A Nationwide, Population-Based Medical Database Study

The benefit of using adjunctive intravenous steroids (IVS) to reduce the neurological sequelae in bacterial meningitis remains inconclusive. This study evaluated the effect of IVS on improving the subsequent Activities of Daily Living (ADL) in bacterial meningitis by analyzing data from a large nationwide administrative medical database in Japan. Data from 1,132 hospitals, covered by the administrative Diagnosis Procedure Combination (DPC) payment system from 2016 to 2022, were evaluated. The ADL levels at admission and discharge were measured using the Barthel Index (BI). Out of the cumulative 47,366,222 patients hospitalized, 8,736 were diagnosed with acute bacterial meningitis and had BI data available. The BI at discharge, adjusted for sex, age, and BI at admission, was significantly better among those treated with IVS (p<0.0001). Exploratory subgroup analyses suggested that this benefit is expected across a broad spectrum of bacterial species. In summary, the use of IVS for improving the subsequent ADL level in bacterial meningitis was suggested.

The important lessons lurking in the history of meningococcal epidemiology

INTRODUCTION

The epidemiology of invasive meningococcal disease (IMD), a rare but potentially fatal illness, is typically described as unpredictable and subject to sporadic outbreaks.

AREAS COVERED

Meningococcal epidemiology and vaccine use during the last ~ 200 years are examined within the context of meningococcal characterization and classification to guide future IMD prevention efforts.

EXPERT OPINION

Historical and contemporary data highlight the dynamic nature of meningococcal epidemiology, with continued emergence of hyperinvasive clones and affected regions. Recent shifts include global increases in serogroup W disease, meningococcal antimicrobial resistance (AMR), and meningococcal urethritis; additionally, unvaccinated populations have experienced disease resurgences following lifting of COVID-19 restrictions. Despite these changes, a close analysis of meningococcal epidemiology indicates consistent dominance of serogroups A, B, C, W, and Y and elevated IMD rates among infants and young children, adolescents/young adults, and older adults. Demonstrably effective vaccines against all 5 major disease-causing serogroups are available, and their prophylactic use represents a powerful weapon against IMD, including AMR. The World Health Organization's goal of defeating meningitis by the year 2030 demands broad protection against IMD, which in turn indicates an urgent need to expand meningococcal vaccination programs across major disease-causing serogroups and age-related risk groups.

Benefits of Combining Molecular Biology and Controlled Human Infection Model Methodologies in Advancing Vaccine Development

Infectious diseases continue to account for a significant portion of global deaths despite the use of vaccines for several centuries. Immunization programs around the world are a testament to the great success of multiple vaccines, yet there are still diseases without vaccines and others that require safer more effective ones. Addressing uncontrolled and emerging disease threats is restrained by the limitations and bottlenecks encountered with traditional vaccine development paradigms. Recent advances in modern molecular biology technologies have enhanced the interrogation of host pathogen interaction and deciphered complex pathways, thereby uncovering the myriad interplay of biological events that generate immune protection against foreign agents. Consequent to insights into the immune system, modern biology has been instrumental in the development and production of next generation 21st century vaccines. As these biological tools, commonly and collectively referred to as 'omics, became readily available, there has been a renewed consideration of Controlled Human Infection Models (CHIMs). Successful and reproducible CHIMs can complement modern molecular biology for the study of infectious diseases and development of effective vaccines in a regulated process that mitigates risk, cost, and time, with capacity to discern immune correlates of protection.

Bioinformatics Analysis of Global Diversity in Meningococcal Vaccine Antigens over the Past 10 Years: Vaccine Efficacy Prognosis

Neisseria meningitidis (N. meningitidis) serogroup B (MenB) is the leading cause of invasive meningococcal disease worldwide. The pathogen has a wide range of virulence factors, which are potential vaccine components. Studying the genetic variability of antigens within a population, especially their long-term persistence, is necessary to develop new vaccines and predict the effectiveness of existing ones. The multicomponent 4CMenB vaccine (Bexsero), used since 2014, contains three major genome-derived recombinant proteins: factor H-binding protein (fHbp), Neisserial Heparin-Binding Antigen (NHBA) and Neisserial adhesin A (NadA). Here, we assessed the prevalence and sequence variations of these vaccine antigens in a panel of 5667 meningococcal isolates collected worldwide over the past 10 years and deposited in the PubMLST database. Using multiple amino acid sequence alignments and Random Forest Classifier machine learning methods, we estimated the potential strain coverage of fHbp and NHBA vaccine variants (51 and about 25%, respectively); the NadA antigen sequence was found in only 18% of MenB genomes analyzed, but cross-reactive variants were present in less than 1% of isolates. Based on our findings, we proposed various strategies to improve the 4CMenB vaccine and broaden the coverage of N. meningitidis strains.

Antimicrobial Resistance in Papua New Guinea: A Narrative Scoping Review

Antimicrobial-resistant bacterial infections are a known threat to the public health of low-income countries and are undercharacterized in Papua New Guinea. A scoping literature review of scientific peer-reviewed publications on antimicrobial resistance in Papua New Guinea was conducted, and their results were summarized. Many of the available data on resistant bacteria in Papua New Guinea have come from Port Moresby and Goroka and have been focused on Staphylococcus aureus, as well as important pediatric pathogens such as Streptococcus pneumoniae and Haemophilus influenzae. Progressive resistance to the commonly used antibiotics penicillin and chloramphenicol among most clinically important bacterial pathogens has prompted healthcare workers to adopt expensive broad-spectrum antibiotics. There is already evidence of resistance to newly adopted antibiotics among several Gram-negative organisms. Drivers of antimicrobial resistance in Papua New Guinea include a high burden of infectious diseases, inappropriate antibiotic prescription practices, poor regulation of antibiotics, incomplete adherence, substandard drug quality, and overcrowding of healthcare facilities. There is a lack of information on antimicrobial resistance among priority pathogens and from several important regions of Papua New Guinea.

Neisseria meningitidis accumulate in large organs during meningococcal sepsis

Background

Neisseria meningitidis (Nm) is the cause of epidemic meningitis and fulminant meningococcal septicemia. The clinical presentations and outcome of meningococcal septic shock is closely related to the circulating levels of lipopolysaccharides (LPS) and of Neisseria meningitidis DNA (Nm DNA). We have previously explored the distribution of Nm DNA in tissues from large organs of patients dying of meningococcal septic shock and in a porcine meningococcal septic shock model.

Objective

1) To explore the feasibility of measuring LPS levels in tissues from the large organs in patients with meningococcal septic shock and in a porcine meningococcal septic shock model. 2) To evaluate the extent of contamination of non-specific LPS during the preparation of tissue samples.

Patients and methods

Plasma, serum, and fresh frozen (FF) tissue samples from the large organs of three patients with lethal meningococcal septic shock and two patients with lethal pneumococcal disease. Samples from a porcine meningococcal septic shock model were included. Frozen tissue samples were thawed, homogenized, and prepared for quantification of LPS by Pyrochrome® Limulus Amoebocyte Lysate (LAL) assay.

Results

N. meningitidis DNA and LPS was detected in FF tissue samples from large organs in all patients with meningococcal septic shock. The lungs are the organs with the highest LPS and Nm DNA concentration followed by the heart in two of the three meningococcal shock patients. Nm DNA was not detected in any plasma or tissue sample from patients with lethal pneumococcal infection. LPS was detected at a low level in all FF tissues from the two patients with lethal pneumococcal disease. The experimental porcine meningococcal septic shock model indicates that also in porcinis the highest LPS and Nm DNA concentration are detected in lungs tissue samples. The quantification analysis showed that the highest concentration of both Nm DNA and LPS are in the organs and not in the circulation of patients with lethal meningococcal septic shock. This was also shown in the experimental porcine meningococcal septic shock model.

Conclusion

Our results suggest that LPS can be quantified in mammalian tissues by using the LAL assay.

Distributed genotyping and clustering of Neisseria strains reveal continual emergence of epidemic meningococcus over a century

Core genome multilocus sequence typing (cgMLST) is commonly used to classify bacterial strains into different types, for taxonomical and epidemiological applications. However, cgMLST schemes require central databases for the nomenclature of new alleles and sequence types, which must be synchronized worldwide and involve increasingly intensive calculation and storage demands. Here, we describe a distributed cgMLST (dcgMLST) scheme that does not require a central database of allelic sequences and apply it to study evolutionary patterns of epidemic and endemic strains of the genus Neisseria. We classify 69,994 worldwide Neisseria strains into multi-level clusters that assign species, lineages, and local disease outbreaks. We divide Neisseria meningitidis into 168 endemic lineages and three epidemic lineages responsible for at least 9 epidemics in the past century. According to our analyses, the epidemic and endemic lineages experienced very different population dynamics in the past 100 years. Epidemic lineages repetitively emerged from endemic lineages, disseminated worldwide, and apparently disappeared rapidly afterward. We propose a stepwise model for the evolutionary trajectory of epidemic lineages in Neisseria, and expect that the development of similar dcgMLST schemes will facilitate epidemiological studies of other bacterial pathogens.

Loop-Mediated Isothermal Amplification-Integrated CRISPR Methods for Infectious Disease Diagnosis at Point of Care

Infectious diseases continue to pose an imminent threat to global public health, leading to high numbers of deaths every year and disproportionately impacting developing countries where access to healthcare is limited. Biological, environmental, and social phenomena, including climate change, globalization, increased population density, and social inequity, contribute to the emergence of novel communicable diseases. Rapid and accurate diagnoses of infectious diseases are essential to preventing the transmission of infectious diseases. Although some commonly used diagnostic technologies provide highly sensitive and specific measurements, limitations including the requirement for complex equipment/infrastructure and refrigeration, the need for trained personnel, long sample processing times, and high cost remain unresolved. To ensure global access to affordable diagnostic methods, loop-mediated isothermal amplification (LAMP) integrated clustered regularly interspaced short palindromic repeat (CRISPR) based pathogen detection has emerged as a promising technology. Here, LAMP-integrated CRISPR-based nucleic acid detection methods are discussed in point-of-care (PoC) pathogen detection platforms, and current limitations and future directions are also identified.

A normative microbiome is not restored following kidney transplantation

Dialysis and kidney transplantation (Ktx) mitigate some of the physiological deficits in chronic kidney disease (CKD), but it remains to be determined if these mitigate microbial dysbiosis and the production of inflammatory microbial metabolites, which contribute significantly to the uraemic phenotype. We have investigated bacterial DNA signatures present in the circulation of CKD patients and those receiving a KTx. Our data are consistent with increasing dysbiosis as CKD progresses, with an accompanying increase in trimethylamine (TMA) producing pathobionts Pseudomonas and Bacillus. Notably, KTx patients displayed a significantly different microbiota compared with CKD5 patients, which surprisingly included further increase in TMA producing Bacillus and loss of salutogenic Lactobacilli. Only two genera (Viellonella and Saccharimonidales) showed significant differences in abundance following KTx that may reflect a reciprocal relationship between TMA producers and utilisers, which supersedes restoration of a normative microbiome. Our metadata analysis confirmed that TMA N-oxide (TMAO) along with one carbon metabolism had significant impact upon both inflammatory burden and the composition of the microbiome. This indicates that these metabolites are key to shaping the uraemic microbiome and might be exploited in the development of dietary intervention strategies to both mitigate the physiological deficits in CKD and enable the restoration of a more salutogenic microbiome.

Continuing genomic evolution of the Neisseria meningitidis cc11.2 urethritis clade, NmUC: a narrative review

Neisseria meningitidis (Nm) is a bacterial pathogen responsible for invasive meningococcal disease. Though typically colonizing the nasopharynx, multiple outbreaks of meningococcal urethritis were first reported in 2015-2016; outbreaks originally presumed to be caused by Neisseria gonorrhoeae (Ng). Genomic analysis revealed that the Nm isolates causing these outbreaks were a distinct clade, and had integrated gonococcal DNA at multiple genomic sites, including the gonococcal denitrification apparatus aniA-norB, a partial gonococcal operon of five genes containing ispD, and the acetylglutamate kinase gene argB with the adjacent gonococcal locus NGO0843. The urethritis isolates had also deleted the group C capsule biosynthesis genes cssA/B/C and csc, resulting in loss of capsule. Collectively, these isolates form the N. meningitidis urethritis clade (NmUC). Genomic analysis of recent (2016-2022) NmUC isolates revealed that the genomic features have been maintained in the clade, implying that they are important for NmUC's status as a urogenital pathogen. Furthermore, the analysis revealed the emergence of a sub-clade, designated NmUC-B, phylogenetically separated from the earlier NmUC-A. This sub-clade has integrated additional gonococcal alleles into the genome, including alleles associated with antimicrobial resistance. NmUC continues to adapt to a urethral niche and evolve as a urogenital pathogen.

Neisseria lisongii sp. nov. and Neisseria yangbaofengii sp. nov., isolated from the respiratory tracts of marmots

Four Gram-stain-negative, oxidase-positive, non-motile, cocci-shaped bacteria strains (ZJ106T, ZJ104, ZJ785T and ZJ930) were isolated from marmot respiratory tracts. Phylogenetic analyses based on 16S rRNA genes, 53 ribosomal protein sequences and 441 core genes supported that all four strains belonged to the genus Neisseria with close relatives Neisseria weixii 10022T and Neisseria iguanae ATCC 51483T. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were below the species-level thresholds (95-96 % for ANI, and 70 % for dDDH). The major fatty acids of all four strains were C16 : 1  ω7c /C16 : 1  ω6c, C16 : 0 and C18 : 1  ω9c. Major polar lipids were composed of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. MK-8 was the major menaquinone. Based on Virulence Factor Database analysis, the four strains were found to contain NspA and PorB H-factor binding proteins that promote evasion of host immunity. Strains ZJ106T and ZJ104 contained structures similar to the capsule synthesis manipulator of Neisseria meningitidis. Based on phenotypic and phylogenetic evidence, we propose that strains ZJ106T and ZJ785T represent two novel species of the genus Neisseria, respectively, with the names Neisseria lisongii sp. nov. and Neisseria yangbaofengii sp. nov. The type strains are ZJ106T (=GDMCC 1.3111T=JCM 35323T) and ZJ785T (=GDMCC 1.1998T=KCTC 82336T).

Comparative Transcriptome Profiling of mRNA and lncRNA of Mouse Spleens Inoculated with the Group ACYW135 Meningococcal Polysaccharide Vaccine

The Group ACYW135 meningococcal polysaccharide vaccine (MPV-ACYW135) is a classical common vaccine used to prevent Neisseria meningitidis serogroups A, C, Y, and W135, but studies on the vaccine at the transcriptional level are still limited. In the present study, mRNAs and lncRNAs related to immunity were screened from the spleens of mice inoculated with MPV-ACYW135 and compared with the control group to identify differentially expressed mRNAs and lncRNAs in the immune response. The result revealed 34375 lncRNAs and 41321 mRNAs, including 405 differentially expressed (DE) lncRNAs and 52 DE mRNAs between the MPV group and the control group. Results of GO and KEGG enrichment analysis turned out that the main pathways related to the immunity of target genes of those DE mRNAs and DE lncRNAs were largely associated with positive regulation of T cell activation, CD8-positive immunoglobulin production in mucosal tissue, alpha-beta T cell proliferation, negative regulation of CD4-positive, and negative regulation of interleukin-17 production, suggesting that the antigens of MPV-ACYW135 capsular polysaccharide might activate T cell related immune reaction in the vaccine inoculation. In addition, it was noted that Bach2 (BTB and CNC homolog 2), the target gene of lncRNA MSTRG.17645, was involved in the regulation of immune response in MPV-ACYW135 vaccination. This study provided a preliminary catalog of both mRNAs and lncRNAs associated with the proliferation and differentiation of body immune cells, which was worthy of further research to enhance the understanding of the biological immune process regulated by MPV-ACYW135.

Characterization of cerebrospinal fluid (CSF) microbiota at the time of initial surgical intervention for children with hydrocephalus

OBJECTIVE

To characterize the microbiota of the cerebrospinal fluid (CSF) from children with hydrocephalus at the time of initial surgical intervention.

STUDY DESIGN

CSF was obtained at initial surgical intervention. One aliquot was stored in skim milk-tryptone-glucose-glycerol (STGG) medium and the second was unprocessed; both were then stored at -70°C. Bacterial growth for CSF samples stored in STGG were subsequently characterized using aerobic and anaerobic culture on blood agar and MALDI-TOF sequencing. All unprocessed CSF samples underwent 16S quantitative polymerase chain reaction (qPCR) sequencing, and a subset underwent standard clinical microbiological culture. CSF with culture growth (either after storage in STGG or standard clinical) were further analyzed using whole-genome amplification sequencing (WGAS).

RESULTS

11/66 (17%) samples stored in STGG and 1/36 (3%) that underwent standard clinical microbiological culture demonstrated bacterial growth. Of the organisms present, 8 were common skin flora and 4 were potential pathogens; only 1 was also qPCR positive. WGAS findings and STGG culture findings were concordant for only 1 sample, identifying Staphylococcus epidermidis. No significant difference in time to second surgical intervention was observed between the STGG culture-positive and negative groups.

CONCLUSION(S)

Using high sensitivity methods, we detected the presence of bacteria in a subset of CSF samples at the time of first surgery. Therefore, the true presence of bacteria in CSF of children with hydrocephalus cannot be ruled out, though our findings may suggest these bacteria are contaminants or false positives of the detection methods. Regardless of origin, the detection of microbiota in the CSF of these children may not have any clinical significance.

Invasive Meningococcal Disease epidemiology and vaccination strategies in four Southern European countries: a review of the available data

INTRODUCTION

Invasive meningococcal disease (IMD) is a major health concern which can be prevented through vaccination. Conjugate vaccines against serogroups A, C, W and Y and two protein-based vaccines against serogroup B are currently available in the European Union.

AREAS COVERED

We present epidemiologic data for Italy, Portugal, Greece and Spain using publicly available reports from national reference laboratories and national or regional immunization programs (1999-2019), aiming to confirm risk groups, and describe time trends in overall incidence and serogroup distribution, as well as impact of immunization. Analysis of circulating MenB isolates in terms of the surface factor H binding protein (fHbp) using PubMLST is discussed as fHbp represents an important MenB vaccine antigen. Predictions of potential reactivity of the two available MenB vaccines (MenB-fHbp and 4CMenB) with circulating MenB isolates are also provided as assessed using the recently developed MenDeVAR tool.

EXPERT OPINION

Understanding dynamics of IMD and continued genomic surveillance are essential for evaluating vaccine effectiveness, but also prompting proactive immunization programs to prevent future outbreaks. Importantly, the successful design of further effective meningococcal vaccines to fight IMD relies on considering the unpredictable epidemiology of the disease and combining lessons learnt from capsule polysaccharide vaccines and protein-based vaccines.

Acquisition of Gonococcal AniA-NorB Pathway by the Neisseria meningitidis Urethritis Clade Confers Denitrifying and Microaerobic Respiration Advantages for Urogenital Adaptation

Neisseria meningitidis historically has been an infrequent and sporadic cause of urethritis and other urogenital infections. However, a nonencapsulated meningococcal clade belonging to the hyperinvasive clonal complex 11.2 lineage has recently emerged and caused clusters of urethritis cases in the United States and other countries. One of the genetic signatures of the emerging N. meningitidis urethritis clade (NmUC) is a chromosomal gene conversion event resulting in the acquisition of the Neisseria gonorrhoeae denitrification apparatus-the N. gonorrhoeae alleles encoding the nitrite reductase AniA, the nitric oxide (NO) reductase NorB, and the intergenic promoter region. The biological importance of the N. gonorrhoeae AniA-NorB for adaptation of the NmUC to a new environmental niche is investigated herein. We found that oxygen consumption, nitrite utilization, and NO production were significantly altered by the conversion event, resulting in different denitrifying aerobic and microaerobic growth of the clade. Further, transcription of aniA and norB in NmUC isolates differed from canonical N. meningitidis, and important polymorphisms within the intergenic region, which influenced aniA promoter activity of the NmUC, were identified. The contributions of three known meningococcal regulators (NsrR, FNR, and NarQP) in controlling the denitrification pathway and endogenous NO metabolism were distinct. Overall, transcription of aniA was dampened relative to canonical N. meningitidis, and this correlated with the lower NO accumulation in the clade. Denitrification and microaerobic respiration were bolstered, and protection against host-derived NO was likely enhanced. The acquisition of the N. gonorrhoeae denitrification pathway by the NmUC supports the clade's adaptation and survival in a microaerobic urogenital environment.

Delving into Agri-Food Waste Composition for Antibacterial Phytochemicals

The overuse of antibiotics in the healthcare, veterinary, and agricultural industries has led to the development of antimicrobial resistance (AMR), resulting in significant economic losses worldwide and a growing healthcare problem that urgently needs to be solved. Plants produce a variety of secondary metabolites, making them an area of interest in the search for new phytochemicals to cope with AMR. A great part of agri-food waste is of plant origin, constituting a promising source of valuable compounds with different bioactivities, including those against antimicrobial resistance. Many types of phytochemicals, such as carotenoids, tocopherols, glucosinolates, and phenolic compounds, are widely present in plant by-products, such as citrus peels, tomato waste, and wine pomace. Unveiling these and other bioactive compounds is therefore very relevant and could be an important and sustainable form of agri-food waste valorisation, adding profit for local economies and mitigating the negative impact of these wastes' decomposition on the environment. This review will focus on the potential of agri-food waste from a plant origin as a source of phytochemicals with antibacterial activity for global health benefits against AMR.

Serogroup B Meningococcal Sepsis and Meningitis Associated With Meningococcal Acute Otitis Media, and Paranasal Sinusitis in an Infant: A Case Report

Meningococcal disease (MD) is a potentially lethal condition. Typically, following infection, MD manifests with high fever, with signs and symptoms of severe septicemia with or without purpura, and in more than half of cases with meningitis. Acute otitis media (AOM) caused by Neisseria meningitidis has scarcely been reported, mostly without severe MD, and there are no reports of meningococcal paranasal sinusitis (PS). We present the case of a previously healthy 11-month-old infant who started with fever and cough and further developed intense irritability and right spontaneous purulent otorrhea, with subsequent increased fever and seizures. Blood, cerebrospinal, and middle ear fluid cultures were positive for N. meningitidis serogroup B, and a CT scan showed both maxillary and ethmoidal sinusitis. Intravenous ceftriaxone was administered for eight days, and three months following discharge, no sequelae were identified. This is the first report of a patient with MD associated with sepsis, meningitis, AOM, and PS.

Living with HIV and Getting Vaccinated: A Narrative Review

After 40 years of its appearance, human immunodeficiency virus (HIV) infection remains a leading public health challenge worldwide. Since the introduction of antiretroviral treatment (ART), HIV infection has become a chronic condition, and people living with HIV could have life expectancies close to those of the general population. People with HIV often have an increased risk of infection or experience more severe morbidity following exposure to vaccine-preventable diseases. Nowadays, several vaccines are available against bacteria and viruses. However, national and international vaccination guidelines for people with HIV are heterogeneous, and not every vaccine is included. For these reasons, we aimed to perform a narrative review about the vaccinations available for adults living with HIV, reporting the most updated studies performed for each vaccine among this population. We performed a comprehensive literature search through electronic databases (Pubmed-MEDLINE and Embase) and search engines (Google Scholar). We included English peer-reviewed publications (articles and reviews) on HIV and vaccination. Despite widespread use and guideline recommendations, few vaccine trials have been conducted in people with HIV. In addition, not all vaccines are recommended for people with HIV, especially for those with low CD4 cells count. Clinicians should carefully collect the history of vaccinations and patients' acceptance and preferences and regularly check the presence of antibodies for vaccine-preventable pathogens.

Meningococcal disease within the Gulf Cooperation Council Countries

This review reports on the recent epidemiology of invasive meningococcal disease (IMD) within the Gulf Cooperation Council (GCC) Countries (focusing from 2012 onwards), the existing immunization strategies and the potential for IMD resurgence. MenACWY vaccination is now established in infant or adolescent immunization programs in Saudi Arabia, Bahrain, Kuwait, and the United Arab Emirates. At present, GCC Countries do not include MenB immunization. National health surveillance reports indicate a total of 156 IMD cases reported across the GCC Countries between 2012 and 2021; between 30% and 80% of cases were reported in individuals aged ≥15 years. Lack of serogroup data hinders the assessment of vaccine impact and decision-making on additional vaccine introductions (e.g. MenB immunization). Hajj/Umrah pilgrimage and the increasing number of large-scale commercial and social events held in the GCC Countries pose a potential risk for future IMD outbreaks. Immunization policies for such events could be strengthened.

Genetic, Functional, and Immunogenic Analyses of the O-Linked Protein Glycosylation System in Neisseria meningitidis Serogroup A ST-7 Isolates

Neisseria meningitidis exhibits a general O-linked protein glycosylation system in which pili and other extracytoplasmic proteins are glycosylated. To investigate glycan antigenicity in humans and the significance of high glycan diversity on immune escape mechanisms, we exploited serogroup A meningococcal strains and serum samples obtained from laboratory-confirmed Ethiopian patients with meningococcal disease. The 37 meningococcal isolates were sequenced, and their protein glycosylation (pgl) genotypes and protein glycosylation phenotypes were investigated in detail. An insertion sequence (IS1655) element in pglH reduced glycan variability in the majority of isolates, while phase variation strengthened glycan variability and microheterogeneity. Homologous recombination events within the pgl genes were identified in eight of the 37 isolates, and the phenotypic consequences ranged from none detected to altered glycoforms in two of the isolates in which the whole pgl locus was exchanged. Immunoblotting of sera against a complete panel of glycan-expressing mutant strains demonstrated that most of these patient sera had IgG antibodies against various neisserial protein glycan antigens. Furthermore, using a bactericidal assay comparing a wild-type meningococcal A strain and a glycosylation-null variant strain, we showed that these protein glycan antigens interfere with bactericidal killing by antibodies in patient sera. Altogether, we were largely able to link pgl genotype with glycosylation phenotype. Our study reveals that protein glycans seem to contribute to the ability of N. meningitidis to resist the bactericidal activity of human serum, possibly by masking protein epitopes important for bactericidal killing and thus protection against meningococcal disease. IMPORTANCE Bacterial meningitis is a serious global health problem, and one of the major causative organisms is Neisseria meningitidis. Extensive variability in protein glycan structure and antigenicity is due to phase variation of protein glycosylation genes and polymorphic gene content and function. The exact role(s) of glycosylation in Neisseria remains to be determined, but increasing evidence, supported by this study, suggests that glycan variability can be a strategy to escape the human immune system. The complexity of the O-linked protein glycosylation system requires further studies to fully comprehend how these bacteria utilize variation in pgl genes to produce such high glycoform diversity and to evade the human immune response.

Association between Meningococcal Meningitis and Santa Ana Winds in Children and Adolescents from Tijuana, Mexico: A Need for Vaccination

Background: Based on previous studies (regional and national), Tijuana, Baja California, Mexico (across the border from San Diego, California, USA), has been shown to have the highest rate of meningococcal meningitis (MeM) in the country. However, the reason for this high incidence has not yet been established. To explain this regional/endemic public health problem, we aimed to evaluate whether there is a climatic association with MeM in the region. In the “African Meningitis Belt,” the Harmattan seasons are associated with MeM outbreaks; similarly, the Santa Ana winds (SAWs) seasons are characterized by hot and dry winds (similar to Harmattan seasons) that occur seasonally in Southwest California, USA, and Northwest Baja California, Mexico. Objectives: We aimed to determine a potential association of SAWs with MeM in Tijuana, Baja California, Mexico, which in turn may partially explain the high rate of this disease in the region. Methods: Based on our previously published data obtained from thirteen years of active surveillance of MeM and a 65-year review showing the seasonal occurrence of SAWs, we estimated the risk ratio (RR) for the total case numbers of MeM (51 cases of children < 16 years old) vs. bacterial meningitis not caused by Neisseria meningitidis (NMeM, 30 cases, same age group) during seasons with and without SAWs. Results: We found an association between SAWs and MeM, but not with NMeM (RR = 2.06, p = 0.02 (95% CI 1.1 to 3.8), which may partially explain the high endemicity of this deadly disease in this part of the globe. Conclusion: This study shows a new potential climatic association with MeM and provides more information that justifies universal meningococcal vaccination in Tijuana, Mexico.

Bacterial meningitis in Africa

Bacterial meningitis differs globally, and the incidence and case fatality rates vary by region, country, pathogen, and age group; being a life-threatening disease with a high case fatality rate and long-term complications in low-income countries. Africa has the most significant prevalence of bacterial meningitis illness, and the outbreaks typically vary with the season and the geographic location, with a high incidence in the meningitis belt of the sub-Saharan area from Senegal to Ethiopia. Streptococcus pneumoniae (pneumococcus) and Neisseria meningitidis (meningococcus) are the main etiological agents of bacterial meningitis in adults and children above the age of one. Streptococcus agalactiae (group B Streptococcus), Escherichia coli, and Staphylococcus aureus are neonatal meningitis's most common causal agents. Despite efforts to vaccinate against the most common causes of bacterial neuro-infections, bacterial meningitis remains a significant cause of mortality and morbidity in Africa, with children below 5 years bearing the heaviest disease burden. The factors attributed to this continued high disease burden include poor infrastructure, continued war, instability, and difficulty in diagnosis of bacterial neuro-infections leading to delay in treatment and hence high morbidity. Despite having the highest disease burden, there is a paucity of African data on bacterial meningitis. In this article, we discuss the common etiologies of bacterial neuroinfectious diseases, diagnosis and the interplay between microorganisms and the immune system, and the value of neuroimmune changes in diagnostics and therapeutics.

Accurate, fast and cost-effective simultaneous detection of bacterial meningitis by qualitative PCR with high-resolution melting

Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae are leading causes of meningitis and acute invasive infections. PCR-based methods are widely used for the diagnosis and surveillance of bacterial pathogens because of their high sensitivity, specificity and high-throughput capabilities compared with conventional laboratory methods. This study evaluated a high-resolution melting qualitative PCR analysis method for the simultaneous detection of these three pathogens. The assay has been optimized to detect three species-specific genes of each organism isolated from clinical samples, enabling accurate identification of the etiological agent. The method proved to be highly sensitive and cheaper than the real-time PCR TaqMan^® system because it is probe-free; it could be used for the diagnosis of invasive diseases in public health laboratories of developing countries.

Variable disruption of epithelial monolayers by Neisseria meningitidis carriage isolates of the hypervirulent MenW cc11 and MenY cc23 lineages

Colonization of mucosal tissues by Neisseria meningitidis requires adhesion mediated by the type IV pilus and multiple outer-membrane proteins. Penetration of the mucosa and invasion of epithelial cells are thought to contribute to host persistence and invasive disease. Using Calu-3 cell monolayers grown at an air-liquid interface, we examined adhesion, invasion and monolayer disruption by carriage isolates of two clonal complexes of N. meningitidis. Carriage isolates of both the serogroup Y cc23 and the hypervirulent serogroup W cc11 lineages exhibited high levels of cellular adhesion, and a variable disruption phenotype across independent isolates. Inactivation of the gene encoding the main pilus sub-unit in multiple cc11 isolates abrogated both adhesive capacity and ability to disrupt epithelial monolayers. Contrastingly, inactivation of the phase-variable opa or nadA genes reduced adhesion and invasion, but not disruption of monolayer integrity. Adherence of tissue-disruptive meningococci correlated with loss of staining for the tight junction protein, occludin. Intriguingly, in a pilus-negative strain background, we observed compensatory ON switching of opa genes, which facilitated continued adhesion. We conclude that disruption of epithelial monolayers occurs in multiple meningococcal lineages but can vary during carriage and is intimately linked to pilus-mediated adhesion.

The microbiome types of colorectal tissue are potentially associated with the prognosis of patients with colorectal cancer

As the second leading cause of cancer worldwide, colorectal cancer (CRC) is associated with a poor prognosis. Although recent studies have explored prognostic markers in patients with CRC, whether tissue microbes carry prognostic information remains unknown. Here, by assessing the colorectal tissue microbes of 533 CRC patients, we found that Proteobacteria (43.5%), Firmicutes (25.3%), and Actinobacteria (23.0%) dominated the colorectal tissue microbiota, which was different from the gut microbiota. Moreover, two clear clusters were obtained by clustering based on the tissue microbes across all samples. By comparison, the relative abundances of Proteobacteria and Bacteroidetes in cluster 1 were significantly higher than those in cluster 2; while compared with cluster 1, Firmicutes and Actinobacteria were more abundant in cluster 2. In addition, the Firmicutes/Bacteroidetes ratios in cluster 1 were significantly lower than those in cluster 2. Further, compared with cluster 2, patients in cluster 1 had relatively poor survival (Log-rank test, p = 0.0067). By correlating tissue microbes with patient survival, we found that the relative abundance of dominant phyla, including Proteobacteria, Firmicutes, and Bacteroidetes, was significantly associated with survival in CRC patients. Besides, the co-occurrence network of tissue microbes at the phylum level of cluster 2 was more complicated than that of cluster 1. Lastly, we detected some pathogenic bacteria enriched in cluster 1 that promote the development of CRC, thus leading to poor survival. In contrast, cluster 2 showed significant increases in the abundance of some probiotics and genera that resist cancer development. Altogether, this study provides the first evidence that the tissue microbiome of CRC patients carries prognostic information and can help design approaches for clinically evaluating the survival of CRC patients.

Safety profile of MenB-FHBp vaccine among adolescents: data from surveillance of Adverse Events Following Immunization in Puglia (Italy), 2018-2020

MenB-FHBp was licensed in Europe in 2017 from the age of 10. In the “postmarketing life” of a new vaccine, surveillance of Adverse Events Following Immunization (AEFI) is crucial, to better understand the pattern of safety and the effectiveness. This paper describes the MenB-FHBp AEFIs notified in Puglia in 2018–2021, to take a picture of the safety profile of this vaccine in the real life, four years after its introduction in Italy. This is a retrospective observational study. Data were collected from the list of AEFIs notified after MenB-FHBp vaccine administration in Puglia in 2018–2020, and the number of doses of this vaccine administered in the same period. AEFIs were classified according to WHOʻs algorithm, and causality assessment was carried out for serious AEFIs. From January 2018 to December 2020, in Puglia, 43,061 doses of MenB-FHBp were administered and 42 MenB-FHBp AEFIs (reporting rate: 97.5 per 100,000 doses administered) were reported. Among these, 12 were classified as severe (28.6%; reporting rate 27.9 per 100,000 doses). Overall, the male/female ratio in AEFIs was 1:1. The median age of people who suffered from AEFIs was 12 years (range 11–13). For the 11 serious AEFIs for which the classification was “consistent causal association,” the diagnosis was hyperpyrexia (reporting rate 13.9 per 100,000 doses), fainting (rate 4.6 per 100,000 doses), urticaria (rate 2,3 per 100,000 doses), convulsions (rate 2,3 per 100,000 doses), and vomit (rate 2,3 per 100,000 doses). No deaths or impairment were notified in studied AEFIs. The picture of MenB-FHBp vaccine supports that the risk of AEFIs is in line with previous published data and in general acceptable.

Comprehensive Genome Analysis of Neisseria meningitidis from South America Reveals a Distinctive Pathogenicity-Related Prophage Repertoire

Neisseria meningitidis, a bacterium that colonizes in the human nasopharynx, occasionally causes invasive meningococcal disease leading to meningitis or septicemia. Different serogroups and lineages (clonal complexes) are related to the occurrence and epidemiology of N. meningitidis. Despite vaccines for most serogroups, N. meningitidis lineages causing unusual clinical manifestations and a higher fatality rate compared to other lineages have been reported in South America. The present study focused on exploring the diversity of N. meningitidis prophages from South America and their relationship with the epidemiological variables of these strains. We found a high diversity of prophages among the different clonal complexes. By comparing them with previously described N. meningitidis phages and prophages, we revealed groups of prophages sharing similar compositions, which could be useful for prophage comparison in N. meningitidis. Furthermore, we observed a high correlation between the prophage content and epidemiological features, e.g., pathogenicity or clonal complex. Additionally, a distinctive filamentous prophage named here as IMSAR-11 (Invasive Meningococci from South America Related to cc11) was identified. Interestingly, two versions of IMSAR-11, circular and chromosomally integrated, were found. Overall, this study reinforces the importance of the genomic characterization of circulating N. meningitidis lineages to generate new targets for lineage monitoring, diagnosis, or appropriateness of vaccine development. Further studies are necessary to understand the role of these prophages in the persistence, dispersal, and virulence of N. meningitidis in the world.

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.

Non-serogroupable Neisseria meningitidis pneumonia in an immunocompetent patient with severe COVID-19 pneumonia: A case report

Background

Non-serogroupable Neisseria meningitidis (N. meningitidis), the most common type of N. meningitidis in asymptomatic carriers, rarely causes infections. Most reported cases of infection are in patients with immunodeficiency, primarily complement deficiencies.

Case presentation

A 54-year-old immunocompetent man was transferred to our hospital to treat severe coronavirus disease 2019 (COVID-19). The patient presented with cough producing a large amount of purulent sputum, which was considered an atypical presentation of COVID-19. Gram staining of the sputum revealed a large number of gram-negative diplococci phagocytosed by many neutrophils, and a diagnosis of bacterial pneumonia was established. The culture yielded non-serogroupable N. meningitidis, and the patient was diagnosed with non-serogroupable N. meningitidis pneumonia. Potential immunodeficiency was considered; however, testing including human immunodeficiency virus and complement factors showed no abnormalities.

Conclusions

We report herein a rare case of non-serogroupable N. meningitidis pneumonia that occurred in an immunocompetent patient during the course of severe COVID-19. We consider impaired T cell function attributable to COVID-19 and dexamethasone administration may have triggered a transient immunosuppressive state and led to non-serogroupable N. meningitidis pneumonia.

Immunogenicity and safety of MenACWY-TT, a quadrivalent meningococcal tetanus toxoid conjugate vaccine recently licensed in the United States for individuals ≥2 years of age

Vaccination offers the best way to prevent invasive meningococcal disease (IMD). As demonstrated in countries with national immunization programs (NIPs) against IMD, meningococcal conjugate vaccines have contributed to significant declines in incidence. Since some meningococcal vaccines are associated with modest immunogenicity in infants, possible immunological interference upon concomitant administration with some pediatric vaccines, and administration errors resulting from improper reconstitution, opportunities for improvement exist. A quadrivalent conjugate vaccine, MenQuadfi® (Meningococcal [Serogroups A, C, Y, and W] Conjugate Vaccine; Sanofi, Swiftwater, Pennsylvania), was approved in 2020 for the prevention of IMD caused by meningococcal serogroups A, C, W, and Y in individuals ≥2 years of age in the United States. Five pivotal studies and one ancillary study supported approval in the United States; clinical trials in infants are ongoing. Data on the immunogenicity and safety of this vaccine are presented, and its potential value in clinical practice is discussed.

A phase II, single-center, randomized, double-blind, parallel control clinical study evaluating the immunogenicity and safety of a two-dose schedule of serogroups ACYW meningococcal polysaccharide conjugate vaccine

BACKGROUND

This was a single-center, randomized, double-blind, parallel control study evaluating the immunogenicity and safety of a two-dose schedule of serogroups ACYW meningococcal polysaccharide conjugate vaccine with tetanus toxoid (TT) conjugate protein, in infants and toddlers of 3-35 months old.

METHOD

720 participants were stratified according to the age of 3-5 months old, 6-11 months old, and 12-35 months old and randomly assigned with an equal ratio to two different dose groups, i.e., 40- and 20-μg doses. Blood samples were taken from all participants before the first vaccination and 30 days after the full-course vaccination to detect the serogroups ACYW meningococcal antibodies. All adverse events occurred within 30 days after vaccination of each dose, and serious adverse events occurred within six months after full-course vaccination were collected for safety evaluation. This study was registered at the China drug trial registration with the identifier CTR 20182031.

RESULTS

After 30 days of full-course vaccination, 92.78 % (95 % CI: 85.70 %-100.00 %) showed the immune response against all serogroups in both high-dose and low-dose groups by rabbit serum bactericidal antibody assay (rSBA) and the geometric mean titer (GMT) of all serogroups showed a high level (74.6-505.8, 95 % CI: 56.4-615.7). However, no significant difference between different dose groups was observed (P > 0.05). The common local and systemic adverse events in both groups were redness (3 %-7%), and fever (26 %-65 %), respectively. In addition, the grade 3 adverse event related to the vaccine was fever (1.67 %-12.50 %). No serious adverse event was reported to be associate with the vaccination.

CONCLUSION

The serogroups ACYW meningococcal polysaccharide conjugate vaccine was safe and effective in the population aged 3-35 months. The vaccine efficacy and safety of the 20-μg dose group were not less than that of the 40-μg dose group.

Development of a multicellular in vitro model of the meningeal blood-CSF barrier to study Neisseria meningitidis infection

Background

Bacterial meningitis is a life-threatening disease that occurs when pathogens such as Neisseria meningitidis cross the meningeal blood cerebrospinal fluid barrier (mBCSFB) and infect the meninges. Due to the human-specific nature of N. meningitidis, previous research investigating this complex host–pathogen interaction has mostly been done in vitro using immortalized brain endothelial cells (BECs) alone, which often do not retain relevant barrier properties in culture. Here, we developed physiologically relevant mBCSFB models using BECs in co-culture with leptomeningeal cells (LMCs) to examine N. meningitidis interaction.

Methods

We used BEC-like cells derived from induced pluripotent stem cells (iBECs) or hCMEC/D3 cells in co-culture with LMCs derived from tumor biopsies. We employed TEM and structured illumination microscopy to characterize the models as well as bacterial interaction. We measured TEER and sodium fluorescein (NaF) permeability to determine barrier tightness and integrity. We then analyzed bacterial adherence and penetration of the cell barrier and examined changes in host gene expression of tight junctions as well as chemokines and cytokines in response to infection.

Results

Both cell types remained distinct in co-culture and iBECs showed characteristic expression of BEC markers including tight junction proteins and endothelial markers. iBEC barrier function as determined by TEER and NaF permeability was improved by LMC co-culture and remained stable for seven days. BEC response to N. meningitidis infection was not affected by LMC co-culture. We detected considerable amounts of BEC-adherent meningococci and a relatively small number of intracellular bacteria. Interestingly, we discovered bacteria traversing the BEC-LMC barrier within the first 24 h post-infection, when barrier integrity was still high, suggesting a transcellular route for N. meningitidis into the CNS. Finally, we observed deterioration of barrier properties including loss of TEER and reduced expression of cell-junction components at late time points of infection.

Conclusions

Here, we report, for the first time, on co-culture of human iPSC derived BECs or hCMEC/D3 with meningioma derived LMCs and find that LMC co-culture improves barrier properties of iBECs. These novel models allow for a better understanding of N. meningitidis interaction at the mBCSFB in a physiologically relevant setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00379-z.

Carriage of Neisseria meningitidis Among Umrah Pilgrims: Circulating Serogroups and Antibiotic Resistance

Background

Meningococcal disease and outbreaks are a risk during mass gatherings such as the Umrah religious pilgrimage to the Kingdom of Saudi Arabia (KSA). We aimed to investigate the carriage of Neisseria meningitidis among the 2019 Umrah pilgrims and determine the circulating serogroups and their antibiotic susceptibility profiles.

Methods

We conducted a cross-sectional study among adult Umrah pilgrims from 17th to 29th April 2019 in Mecca city, KSA. A questionnaire was administered to each participant, and an oropharyngeal swab was obtained. Microbiological techniques were used to isolate, identify and serogroup N. meningitidis from the swabs. E-tests were used to determine the susceptibility of the isolates to nine antibiotics.

Results

The study enrolled 616 pilgrims from 17 countries with a mean age of 53.8 years (±13.1, range = 19–91) and a male-to-female ratio of 1.1:1. Nearly 39% of the respondents had no formal education, 32.5% declared having an underlying health condition and 17.2% were current or past smokers. During their Umrah stay, most pilgrims reported sharing accommodation (98.5%) and never using a face mask (98.5%). Also, 34.6% reported suffering from influenza-like symptoms and 11.8% used antibiotics. N. meningitidis was isolated from three pilgrims (carriage rate of 0.49%), two were serogroup A and one was serogroup B. Antibiotic susceptibility results were available for one isolate (serogroup B) which showed resistance to ciprofloxacin and decreased susceptibility to trimethoprim-sulfamethoxazole.

Conclusion

Carriage of N. meningitidis among Umrah pilgrims was low. However, invasive serogroups were identified, including an isolate resistant to ciprofloxacin used for chemoprophylaxis. Meningococcal disease preventive measures for Umrah should be regularly reviewed and updated accordingly to reduce the risk of the disease and future pilgrimage-associated outbreaks.

Intranasal and Intramuscular Immunization with Outer Membrane Vesicles from Serogroup C Meningococci Induced Functional Antibodies and Immunologic Memory

BACKGROUND

Immunization is the key to prevent invasive meningococcal disease (IMD), caused by Neisseria meningitidis. Outer membrane vesicles (OMVs) can be used as meningococcal antigens.

METHODS

Isogenic mice A/Sn (H2^a) were immunized with low antigenic doses of OMVs of an N. meningitidis C:2a:P1.5 strain, via intranasal/intramuscular route, adjuvanted by cholera toxin subunit B (CTB) or via intramuscular route only, adjuvanted by aluminium hydroxide (AH). Mice were followed until old age and humoral and cellular responses were assessed by ELISA, Immunoblotting, Dot-blot, Serum-bactericidal assay, Immunohistochemistry and ELISpot.

RESULTS

OMV+CTB and OMV+AH groups presented statistically higher antibodies titers, which persisted until middle and old ages. IgG isotypes point to a Th2 type of response. Avidity indexes were considered high, regardless of adjuvant use, but only groups immunized with OMVs and adjuvants (OMV+CTB and OMV+AH) presented bactericidal activity. The antibodies recognized antigens of molecular weights attributed to porin and cross-reactivity proteins. Although the spleen of old mice did not present differences in immunohistochemistry marking of CD68+, CD4+, CD79+ and CD25+ cells, splenocytes of immune groups secreted IL-4 and IL-17 when stimulated with OMVs and meningococcal C polysaccharide.

CONCLUSION

We concluded that both adjuvants, CTB and AH, improved the immunogenicity of low doses of OMVs and contributed to a persistent immune response. Even though AH is well established in the vaccinology area, CTB seems to be a promising adjuvant candidate for meningococcal vaccines: it is suitable for mucosal delivery and supports a Th2 type of response. Therefore, OMVs are still a relevant vaccine platform.

Predictors of meningococcal vaccine uptake in university and college students: a systematic review and meta-analysis

Objective: To identify predictors of meningococcal vaccine uptake among university and college students, the most common carriers of meningococcal disease. Participants: University or college students aged 18 to 25 years. Methods: Multiple databases, citations, and gray literature were systematically searched in April 2017 and January 2019, for articles reporting rates and predictors of vaccine uptake. Included studies underwent quality appraisal, and, where suitable, meta-analyses were performed. Results: Twenty-one articles, covering 18 studies from six countries, were included. They were mostly cross-sectional surveys of routine vaccination. Meta-analyses were conducted on six predictors. Higher vaccination uptake was associated with being a first year student, an undergraduate student, not being an international student, perceiving meningococcal disease as a risk, and being female. Conclusion: Identified key predictors correspond with previous studies and other vaccines. The findings should inform the delivery and communication of meningococcal vaccination to university and college students.

Investigating the Role of Antigen Orientation on the Immune Response Elicited by Neisseria meningitidis Factor H Binding Protein on GMMA

GMMA are outer membrane vesicles (OMVs) released from Gram-negative bacteria genetically modified to enhance OMVs formation that have been shown to be optimal systems to enhance immunogenicity of protein antigens. Here, we selected Neisseria meningitidis factor H binding protein (fHbp) and used the conjugation chemistry as a tool to alter antigen orientation on GMMA. Indeed, fHbp was randomly linked to GMMA or selectively attached via the N-terminus to mimic native presentation of the protein on the bacterial surface. Interestingly, protein and peptide array analyses confirmed that antibodies induced by the selective and the random conjugates showed a pattern very similar to fHbp natively expressed on bacterial surfaces or to the recombinant protein mixed with GMMA, respectively. However, the two conjugates elicited antibodies with similar serum bactericidal activity against meningococcal strains, superior to the protein alone or physically mixed with GMMA. Presentation of fHbp on GMMA strongly enhances the functional immune response elicited by the protein but its orientation on the bacterial surface does not have an impact. This study demonstrates the flexibility of the GMMA platform as a display and delivery system for enhancing antigen immunogenicity and further supports the use of such promising technology for the development of effective vaccines.

Pathogenomic in silico approach identifies NSP-A and Fe-IIISBP as possible drug targets in Neisseria Meningitidis MC58 and development of pharmacophores as novel therapeutic candidates

Meningitis creates a life-threatening clinical crisis. Moreover, the administered antibiotics result into multi-drug resistance, thereby necessitating development of alternative therapeutic strategies. This study aimed at identifying novel-drug targets in Neisseria meningitidis and therapeutic molecules which can be exploited for the treatment of meningitis. Novel targets were identified by applying a pathogenomic approach involving protein data-set mining, subtractive channel analysis and subsequent qualitative analysis comprising of in silico pharmacokinetics, molecular docking and pharmacophore generation. Pathogenomic studies revealed Neisserial Surface Protein A (NSP-A) and Iron-III-Substrate Binding Protein (Fe-IIISBP) as potential targets. Two pharmacophore models comprising of 2-(biaryl) carbapenems, efavirenz, praziquantel and pyrimethamine for NSP-A and 2-(biaryl) carbapenems, trimipramine and pyrimethamine for Fe-IIISBP, showed successful docking, followed drug-likeness criteria and generated pharmacophore model with a score of 8.08 and 8.818, respectively, which had further been docked to the target stably. Thus, our study identifies NSP-A and Fe-IIISBP as novel targets in Neisseria meningitidis for which 2-(biaryl) carbapenems, efavirenz, praziquantel, trimipramine and pyrimethamine may be employed for effective treatment of meningitis.

Global genomic and proteomic analysis indicates co-evolution of Neisseria species and with their human host

Neisseria, a genus from the beta-proteobacteria class, is of potential clinical importance. This genus contains both pathogenic and commensal strains. Gonorrhea and meningitis are two major diseases caused by pathogens belonging to this genus. With the increased use of antimicrobial agents against these pathogens they have evolved the antimicrobial resistance capacity making these diseases nearly untreatable. The set of anti-bacterial resistance genes (resistome) and genes associated with signal processing (secretomes) are crucial for the host-microbial interaction. With the virtue of whole-genome sequences and computational biology, it is now possible to study the genomic and proteomic riddles of Neisseria along with their comprehensive evolutionary and metabolic profiling. We have studied relative synonymous codon usage, amino acid usage, reverse ecology, comparative genomics, evolutionary analysis and pathogen-host (Neisseria-human) interaction through bioinformatics analysis. Our analysis revealed the co-evolution of Neisseria genomes with the human host. Moreover, the co-occurrence of Neisseria and humans has been supported through reverse ecology analysis. A differential pattern of the evolutionary rate of resistomes and secretomes was evident among the pathogenic and commensal strains. Comparative genomics supported the presence of virulent genes in both pathogenic and commensal strains of the select genus. Our analysis also indicated a transition from commensal to pathogenic Neisseria strains through the long run of evolution.