Neisseria meningitidis with decreased susceptibility to penicillin G and molecular characterization of the penA gene in strains isolated at University Hospital Centers of Casablanca and Marrakech (Morocco).

Introduction: the laboratory diagnosis of meningococcal meningitis relies on conventional techniques. This study aims to evaluate the correlation between the reduced sensitivity to penicillin G of Neisseria meningitidis (N.m) strains and the expression of the altered PBP 2 gene. Methods: out of 190 strains of N.m isolated between 2010 and 2021 at the bacteriology laboratories of Ibn Rochd University Hospital Centre (IR-UHC) in Casablanca and the UHC Mohammed VI in Marrakech, 23 isolates were part of our study. We first determined their state of sensitivity to penicillin G by E-Test strips and searched for the expression of the penA gene by PCR followed by Sanger sequencing. Results: of all the confirmed cases of N.m, 93.15% (n=177) are of serogroup B, 75.2% (n = 143) are sensitive to penicillin G and 24.73% (n = 47) are of intermediate sensitivity. No resistance to penicillin G was observed. Reduced sensitivity to penicillin G in N.m is characterized by mutations namely F504 L, A510 V, I515 V, G541 N and I566 V located in the C-terminal region of the penA gene encoding the penicillin-binding protein 2 (PBP2) (mosaic gene). Conclusion: our study presents useful data for the phenotypic and genotypic monitoring of resistance to penicillin G in N.m and can contribute to the analysis of genetic exchanges between different Neisseria species.

An isothermal CRISPR- based lateral flow assay for detection of Neisseria meningitidis.

BACKGROUND: Neisseria meningitidis can cause life-threatening meningococcal meningitis and meningococcemia. Old standard microbiological results from CSF/blood cultures are time consuming. This study aimed to combine the sensitivity of loop-mediated isothermal nucleic acid amplification (LAMP) with the specificity of CRISPR/Cas12a cleavage to demonstrate a reliable diagnostic assay for rapid detection of N. meningitidis. METHODS: A total of n = 139 samples were collected from patients with suspected meningococcal disease and were used for evaluation. The extracted DNA was subjected to qualitative real-time PCR, targeting capsular transporter gene (ctrA) of N. meningitidis. LAMP-specific primer pairs, also targeting the ctrA, were designed and the LAMP products were subjected to CRISPR/Cas12 cleavage reaction. the readout was on a lateral flow strip. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of LAMP-CRISPR/Cas was compared with real-time PCR assays. The limit of detection (LOD) was established with serial dilutions of the target N. meningitidis DNA and calculated by Probit regression analysis. RESULTS: Six LAMP assay-specific primers were developed targeting the ctrA gene of N. meningitidis, which is conserved in all meningococcal serogroups. The LAMP primers did not amplify DNA from other bacterial DNA tested, showing 100% specificity. The use of 0.4 M betaine increased the sensitivity and stability of the reaction. LAMP-CRISPR/Cas detected meningococcal serogroups (B, C, W). The assay showed no cross-reactivity and was specific for N. meningitidis. The LOD was 74 (95% CI: 47-311) N. meningitidis copies. The LAMP-CRISPR/Cas performed well compared to the gold standard. In the 139 samples from suspected patients, the sensitivity and specificity of the test were 91% and 99% respectively. CONCLUSION: This developed and optimized method can complement for the available gold standard for the timely diagnosis of meningococcal meningitis and meningococcemia.

The meningitis outbreak returns to Niger: Concern, efforts, challenges, and recommendations.

Meningitis, a disease that commonly manifests in African meningitis belt, continues to be a public health problem as it is a fatal disease that leave survivors with long-term effects. Most cases of meningitis are due to bacterial and viral infection, although parasites, fungus, cancer, drugs, and immune disorders can rarely cause meningitis. Stiff neck, high temperature, light sensitivity, disorientation, headaches, and vomiting are the most typical symptoms of meningitis. Niger, being in African meningitis belt, has been affected by many meningitis outbreaks. Since 2015, a total of 20,789 cases and 1369 fatalities (CFR 6.6%) have been documented in Niger. In contrast to earlier seasons, the current outbreak of meningitis in Niger exhibits both an increase in the number of cases and a rise in the growth rate. A total of 559 cases of meningitis, including 18 fatalities (overall CFR 3.2%), were reported in the Zinder Region, southeast of Niger, from 1 November 2022 to 27 January 2023, compared to 231 cases reported from 1 November 2021 to 31 January 2022. In the current outbreak, the Neisseria meningitidis serogroup C (NmC) is responsible for the majority of laboratory confirmed cases (104/111; 93.7%). To organize the response to the outbreak, a global team of WHO and other partners, including MSF and UNICEF, has been sent to Niger. Even though there are many challenges in battle against meningitis in Niger, immunization, antibiotics administration and strong disease surveillance are recommended techniques to cope with the current meningitis outbreak in Niger.

Skin biopsy in adult patients with meningococcal purpura fulminans: a multicenter retrospective cohort study.

BACKGROUND: Neisseria meningitidis is the leading responsible bacterium of Purpura Fulminans (PF) accounting for two thirds of PF. Skin biopsy is a simple and minimally invasive exam allowing to perform skin culture and polymerase chain reaction (PCR) to detect Neisseria meningitidis. We aimed to assess the sensitivity of skin biopsy in adult patients with meningococcal PF. METHODS: A 17-year multicenter retrospective cohort study including adult patients admitted to the ICU for a meningococcal PF in whom a skin biopsy with conventional and/or meningococcal PCR was performed. RESULTS: Among 306 patients admitted for PF, 195 had a meningococcal PF (64%) with a skin biopsy being performed in 68 (35%) of them. Skin biopsy was performed in median 1 day after the initiation of antibiotic therapy. Standard culture of skin biopsy was performed in 61/68 (90%) patients and grew Neisseria meningitidis in 28 (46%) of them. Neisseria meningitidis PCR on skin biopsy was performed in 51/68 (75%) patients and was positive in 50 (98%) of them. Among these 50 positive meningococcal PCR, five were performed 3 days or more after initiation of antibiotic therapy. Finally, skin biopsy was considered as contributive in 60/68 (88%) patients. Identification of the meningococcal serogroup was obtained with skin biopsy in 48/68 (71%) patients. CONCLUSIONS: Skin biopsy with conventional culture and meningococcal PCR has a global sensitivity of 88% and should be systematically considered in case of suspected meningococcal PF even after the initiation of antimicrobial treatment.

Sequelae at Hospital Discharge in 61 Children With Invasive Meningococcal Disease, Chile, 2009-2019.

BACKGROUND: Invasive meningococcal disease (IMD) is an unpredictable and severe infection caused by Neisseria meningitidis . Its case fatality rate could vary from 9.7% to 26% and up to 36% of survivors may experience long-term sequelae, representing a challenge for public health. AIMED: To describe the sequelae at hospital discharge caused by IMD in children between years 2009-2019. METHODS: Cross-sectional study performed in 2 pediatric hospitals. Patients with microbiologically confirmed diagnosis of IMD from 2009 to 2019 were included. Bivariate and logistic regression analysis were performed. RESULTS: The records of 61 patients were reviewed and included. Sixty-seven percent were male, median age 9 months (interquartile range 4-27), 72% were admitted to intensive care unit. Thirty-seven (60.5%) had at least 1 sequela (75% and 37% in patients with or without meningitis, respectively). The most frequents sequelae were neurological 72%, hearing loss 32%, and osteoarticular 24%. Significant differences were found comparing patients with and without sequelae: drowsiness 67.6% versus 41.7% ( P = 0.04), irritability 67.6% versus 25% ( P = 0.01), meningeal signs 62.2% versus 29.2% ( P = 0.01). In logistic regression analysis, postdischarge follow-up had OR 21.25 (95% confidence intervals [CI]: 4.93-91.44), irritability had OR 8.53 (95% CI: 1.64-44.12), meningeal signs had OR 8.21 (95% CI: 0.71-94.05), invasive mechanical ventilation had OR 8.23 (95% CI: 0.78-85.95), meningitis plus meningococcemia OR 1.70 (95% CI: 0.18-15.67) to have sequelae, while children with meningococcemia and vomiting had a OR 0.04 (95% CI: 0.00-0.36) and OR 0.27 (95% CI: 0.03-2.14), respectively. N. meningitidis serogroup W (MenW) was isolated in 54.1% (33/61), and N. meningitidis serogroup B (MenB) in 31.1% (19/61) of cases. A significant difference was found in osteoarticular sequelae ( P = 0.05) between MenB and MenW. There was a decrease in cases after the meningococcal conjugate vaccine against serogroups A, C, W and Y was implemented (2015-2019). CONCLUSIONS: IMD remains as a public health concern. A high rate of sequelae was found in pediatric patients in our series, even in the clinical manifestations other than meningitis. Neurological sequelae were the most prevalent. Multidisciplinary follow-up protocols to reduce long-term impact must be urgently established to assess all children with IMD.

Neisseria meningitidis Serogroup C Clonal Complex 10217 Outbreak in West Kpendjal Prefecture, Togo 2019.

Togo has reported seasonal meningitis outbreaks caused by non-Neisseria meningitidis serogroup A (NmA) pathogens since the introduction of meningococcal serogroup A conjugate vaccine (MACV, MenAfriVac) in 2014. From 2016 to 2017, NmW caused several outbreaks. In early 2019, a NmC outbreak was detected in the Savanes region of Togo and its investigation is described here. Under case-based surveillance, epidemiological and clinical data, and cerebrospinal fluid specimens were collected for every suspected case of meningitis. Specimens were tested for meningitis pathogens using confirmatory microbiological and molecular methods. During epidemic weeks 9 to 15, 199 cases were reported, with 179 specimens being available for testing and 174 specimens (97.2%) were tested by at least one confirmatory method. The NmC was the predominant pathogen confirmed (93.9%), belonging to sequence type (ST)-9367 of clonal complex (CC) 10217. All NmC cases were localized to the West Kpendjal district of the Savanes region with attack rates ranging from 4.1 to 18.8 per 100,000 population and case fatality rates ranging up to 2.2% during weeks 9 to 15. Of the 93 NmC confirmed cases, 63.4% were males and 88.2% were in the 5 to 29 age group. This is the first report of a NmC meningitis outbreak in Togo. The changing epidemiology of bacterial meningitis in the meningitis belt post-MACV highlights the importance of monitoring of emerging strain and country preparedness for outbreaks in the region. IMPORTANCE The recent emergence of an invasive NmC strain in Togo is an example of the changing bacterial meningitis epidemiology in the meningitis belt post-MACV. The current epidemiology includes the regional circulation of various non-NmA serogroups, which emphasizes the need for effective molecular surveillance, laboratory diagnosis, and a multivalent vaccine that is effective against all serogroups in circulation.

Anti-glycan antibodies: roles in human disease.

Carbohydrate-binding antibodies play diverse and critical roles in human health. Endogenous carbohydrate-binding antibodies that recognize bacterial, fungal, and other microbial carbohydrates prevent systemic infections and help maintain microbiome homeostasis. Anti-glycan antibodies can have both beneficial and detrimental effects. For example, alloantibodies to ABO blood group carbohydrates can help reduce the spread of some infectious diseases, but they also impose limitations for blood transfusions. Antibodies that recognize self-glycans can contribute to autoimmune diseases, such as Guillain-Barre syndrome. In addition to endogenous antibodies that arise through natural processes, a variety of vaccines induce anti-glycan antibodies as a primary mechanism of protection. Some examples of approved carbohydrate-based vaccines that have had a major impact on human health are against pneumococcus, Haemophilus influeanza type b, and Neisseria meningitidis. Monoclonal antibodies specifically targeting pathogen associated or tumor associated carbohydrate antigens (TACAs) are used clinically for both diagnostic and therapeutic purposes. This review aims to highlight some of the well-studied and critically important applications of anti-carbohydrate antibodies.

Genome-wide methylome analysis of two strains belonging to the hypervirulent Neisseria meningitidis serogroup W ST-11 clonal complex.

A rising incidence of meningococcal serogroup W disease has been evident in many countries worldwide. Serogroup W isolates belonging to the sequence type (ST)-11 clonal complex have been associated with atypical symptoms and increased case fatality rates. The continued expansion of this clonal complex in the later part of the 2010s has been largely due to a shift from the so-called original UK strain to the 2013 strain. Here we used single-molecule real-time (SMRT) sequencing to determine the methylomes of the two major serogroup W strains belonging to ST-11 clonal complex. Five methylated motifs were identified in this study, and three of the motifs, namely 5'-GATC-3', 5'-GAAGG-3', 5'-GCGCGC-3', were found in all 13 isolates investigated. The results showed no strain-specific motifs or difference in active restriction modification systems between the two strains. Two phase variable methylases were identified and the enrichment or depletion of the methylation motifs generated by these methylases varied between the two strains. Results from this work give further insight into the low diversity of methylomes in highly related strains and encourage further research to decipher the role of regions with under- or overrepresented methylation motifs.

Molecular characteristics of Neisseria meningitidis in Qatar.

The aim of the current study is to review the molecular characteristics of Neisseria meningitidis (N. meningitidis) in Hamad Medical Corporation, which is the provider of secondary and tertiary care in the state of Qatar. A total of 39 isolates of N. meningitidis from the period of 2013 to 2018 were revived and identified by Vitek, and susceptibility on the basis of the E test was retrieved from the patient's files. The revived isolates were subjected to multilocus sequence typing. The most common serogroup (19) of N. meningitidis was W135, of which 12 were isolated from blood and CSF. ST-11 was the most predominant ST clonal complex causing N. meningitidis cases (61.53%). Clonal complex ST-41/44 was the second most observed complex (3, 2 of which were related to serogroup B). The most frequent sequence type was 9596 (8 isolates). Determining the molecular pattern of N. meningitidis in Qatar is helpful for understanding the strains circulating in Qatar, and the study of the resistance trend of such strains may be very helpful for empirical treatment of future patients.

Encephalitis and meningitis in Western Africa: a scoping review of pathogens.

OBJECTIVE: To give an overview of the recently reported literature on the aetiologies of meningitis and encephalitis in western sub-Saharan Africa. METHODS: We conducted a scoping review following PRISMA guidance on published meningitis and encephalitis cases in the 16 countries of the United Nations-defined western sub-Saharan African region as identified in cohort studies, case series, and case reports, published 01/01/2000-08/01/2020, and available in four databases in August 2020 with an abstract in English, French or Italian. RESULTS: There were 38 distinct pathogens identified from 91 cohort studies' data and 48 case reports or case series' data. In cohort-level data, the majority of cases were caused by Neisseria meningitidis (71.5%), Streptococcus pneumoniae (17.6%) and Haemophilus influenzae (7.3%). In case report- and case series-level data, 40.5% of patients were <18 years old, 28.6% were female, and 28.6% were known to be immunocompromised. The case fatality rate was 39.3%. The most commonly reported pathogens among immunocompetent patients were Salmonella species (13 cases) and Ebola virus (9 cases), and the most commonly reported pathogen among immunocompromised patients was Cryptococcus neoformans (18 cases). Most cohort cases (52.3%) derived from Niger followed by Burkina Faso (28.6%). Most cases from single reports or series were reported from Nigeria (21.4%), Mali (20.2%) and Burkina Faso (19.0%). CONCLUSIONS: Given the small number of pathogens reported, our findings underscore the need to better screen, diagnose and monitor populations in western sub-Saharan Africa for additional CNS pathogens, including those posing significant outbreak risks.

Genomic analysis of the meningococcal ST-4821 complex-Western clade, potential sexual transmission and predicted antibiotic susceptibility and vaccine coverage.

INTRODUCTION: The ST-4821 complex (cc4821) is a leading cause of serogroup C and serogroup B invasive meningococcal disease in China where diverse strains in two phylogenetic groups (groups 1 and 2) have acquired fluoroquinolone resistance. cc4821 was recently prevalent among carriage isolates in men who have sex with men in New York City (USA). Genome-level population studies have thus far been limited to Chinese isolates. The aim of the present study was to build upon these with an extended panel of international cc4821 isolates. METHODS: Genomes of isolates from Asia (1972 to 2017), Europe (2011 to 2018), North America (2007), and South America (2014) were sequenced or obtained from the PubMLST Neisseria database. Core genome comparisons were performed in PubMLST. RESULTS: Four lineages were identified. Western isolates formed a distinct, mainly serogroup B sublineage with alleles associated with fluoroquinolone susceptibility (MIC <0.03 mg/L) and reduced penicillin susceptibility (MIC 0.094 to 1 mg/L). A third of these were from anogenital sites in men who have sex with men and had unique denitrification gene alleles. Generally 4CMenB vaccine strain coverage was reliant on strain-specific NHBA peptides. DISCUSSION: The previously identified cc4821 group 2 was resolved into three separate lineages. Clustering of western isolates was surprising given the overall diversity of cc4821. Possible association of this cluster with the anogenital niche is worthy of monitoring given concerns surrounding antibiotic resistance and potential subcapsular vaccine escape.

Structure of a protective epitope reveals the importance of acetylation of Neisseria meningitidis serogroup A capsular polysaccharide.

Meningococcal meningitis remains a substantial cause of mortality and morbidity worldwide. Until recently, countries in the African meningitis belt were susceptible to devastating outbreaks, largely attributed to serogroup A Neisseria meningitidis (MenA). Vaccination with glycoconjugates of MenA capsular polysaccharide led to an almost complete elimination of MenA clinical cases. To understand the molecular basis of vaccine-induced protection, we generated a panel of oligosaccharide fragments of different lengths and tested them with polyclonal and monoclonal antibodies by inhibition enzyme-linked immunosorbent assay, surface plasmon resonance, and competitive human serum bactericidal assay, which is a surrogate for protection. The epitope was shown to optimize between three and six repeating units and to be O-acetylated. The molecular interactions between a protective monoclonal antibody and a MenA capsular polysaccharide fragment were further elucidated at the atomic level by saturation transfer difference NMR spectroscopy and X-ray crystallography. The epitope consists of a trisaccharide anchored to the antibody via the O- and N-acetyl moieties through either H-bonding or CH-π interactions. In silico docking showed that 3-O-acetylation of the upstream residue is essential for antibody binding, while O-acetate could be equally accommodated at three and four positions of the other two residues. These results shed light on the mechanism of action of current MenA vaccines and provide a foundation for the rational design of improved therapies.

Interactions and Signal Transduction Pathways Involved during Central Nervous System Entry by Neisseria meningitidis across the Blood-Brain Barriers.

The Gram-negative diplococcus Neisseria meningitidis, also called meningococcus, exclusively infects humans and can cause meningitis, a severe disease that can lead to the death of the afflicted individuals. To cause meningitis, the bacteria have to enter the central nervous system (CNS) by crossing one of the barriers protecting the CNS from entry by pathogens. These barriers are represented by the blood-brain barrier separating the blood from the brain parenchyma and the blood-cerebrospinal fluid (CSF) barriers at the choroid plexus and the meninges. During the course of meningococcal disease resulting in meningitis, the bacteria undergo several interactions with host cells, including the pharyngeal epithelium and the cells constituting the barriers between the blood and the CSF. These interactions are required to initiate signal transduction pathways that are involved during the crossing of the meningococci into the blood stream and CNS entry, as well as in the host cell response to infection. In this review we summarize the interactions and pathways involved in these processes, whose understanding could help to better understand the pathogenesis of meningococcal meningitis.

Epidemiology and antibiotic resistance profile of bacterial meningitis in Morocco from 2015 to 2018.

Over a 4-year study period from 2015 to 2018, altogether 183 isolates of bacterial meningitis were collected from 12 hospitals covering the entire Moroccan territory. Neisseria meningitidis represented 58.5%, Streptococcus pneumoniae 35.5%, and Haemophilus influenzae type b 6%. H. influenzae type b mainly affected 5-year-olds and unvaccinated adults. N. meningitidis serogroup B represented 90.7% followed by serogroup W135 with 6.5%. Decreased susceptibility to penicillin G (DSPG) for all isolates accounted for 15.7%, with 11.6% being resistant to penicillin G (PG) and 4.1% decreased susceptibility. Cumulative results of all strains showed 2.7% decreased susceptibility to amoxicillin and 3.3% resistant, 2.2% of isolates were resistant to third-generation cephalosporin and 2.2% were decreased susceptible, 5.5% were resistant to chloramphenicol and 2.7% were resistant to rifampin. The frequency of DSPG observed in our study is more common in S. pneumoniae than in N. meningitidis (P < 0.05). These isolates have been found to be highly susceptible to antibiotics used for treatment and prophylaxis chemotherapy and the observed resistance remains rare. The impact of introduction of conjugate vaccines against H. influenzae type b and S. pneumoniae (PCVs) is an advantage in reducing meningitis cases due to these two species.

4CMenB vaccine induces elite cross-protective human antibodies that compete with human factor H for binding to meningococcal fHbp.

Neisseria meningitidis serogroup B (MenB) is the leading cause of meningococcal meningitis and sepsis in industrialized countries, with the highest incidence in infants and adolescents. Two recombinant protein vaccines that protect against MenB are now available (i.e. 4CMenB and MenB-fHbp). Both vaccines contain the Factor H Binding Protein (fHbp) antigen, which can bind the Human Factor H (fH), the main negative regulator of the alternative complement pathway, thus enabling bacterial survival in the blood. fHbp is present in meningococcal strains as three main variants which are immunologically distinct. Here we sought to obtain detailed information about the epitopes targeted by anti-fHbp antibodies induced by immunization with the 4CMenB multicomponent vaccine. Thirteen anti-fHbp human monoclonal antibodies (mAbs) were identified in a library of over 100 antibody fragments (Fabs) obtained from three healthy adult volunteers immunized with 4CMenB. Herein, the key cross-reactive mAbs were further characterized for antigen binding affinity, complement-mediated serum bactericidal activity (SBA) and the ability to inhibit binding of fH to live bacteria. For the first time, we identified a subset of anti-fHbp mAbs able to elicit human SBA against strains with all three variants and able to compete with human fH for fHbp binding. We present the crystal structure of fHbp v1.1 complexed with human antibody 4B3. The structure, combined with mutagenesis and binding studies, revealed the critical cross-reactive epitope. The structure also provided the molecular basis of competition for fH binding. These data suggest that the fH binding site on fHbp v1.1 can be accessible to the human immune system upon immunization, enabling elicitation of human mAbs broadly protective against MenB. The novel structural, biochemical and functional data are of great significance because the human vaccine-elicited mAbs are the first reported to inhibit the binding of fH to fHbp, and are bactericidal with human complement. Our studies provide molecular insights into the human immune response to the 4CMenB meningococcal vaccine and fuel the rationale for combined structural, immunological and functional studies when seeking deeper understanding of the mechanisms of action of human vaccines.

Random Switching of the ModA11 Type III DNA Methyltransferase of Neisseria meningitidis Regulates Entner-Doudoroff Aldolase Expression by a Methylation Change in the eda Promoter Region.

Phase-variable DNA methyltransferases (Mods) mediate epigenetic regulation of gene expression. These phase-variable regulons, called phasevarions, have been shown to regulate virulence and immunoevasion in multiple bacterial pathogens. How genome methylation switching mediates gene regulation is unresolved. Neisseria meningitidis remains a major cause of sepsis and meningitis worldwide. Previously, we reported that phase variation (rapid on/off switching) of the meningococcal ModA11 methyltransferase regulates 285 genes. Here we show a bioinformatic analysis that reveals only 26 of the regulated genes have a methylation site located upstream of the gene with potential for direct effect of methylation on transcription. To investigate how methylation changes are "read" to alter gene expression, we used a lacZ gene fusion approach. We showed a 182-nucleotide region upstream of the eda gene (Entner-Doudoroff aldolase) is sufficient to impart methylation-dependent regulation of eda. Site-directed mutagenesis of the 5'-ACGTm6AGG-3' ModA11 site upstream of the eda gene showed that methylation of this site modulates eda expression. We show that eda is regulated by the PhoB homolog MisR, and that a MisR binding motif overlaps with the ModA11 methylation site. In a MisR mutant, regulation of eda is uncoupled from regulation by ModA11 phasevarion switching. The on/off switching of ModA11 leads to the presence or absence of a N6-methyladenine modification at thousands of sites in the genome. Most of these modifications have no impact on gene regulation. Moreover, the majority of the 285 gene regulon that is controlled by ModA11 phasevarion switching (259/285) are not directly controlled by methylation changes in the promoter region of the regulated genes. Our data are consistent with direct control via methylation of a subset of the regulon, like Eda, whose regulation will trigger secondary effects in expression of many genes.

Neisseria meningitidis carriage and risk factors among teenagers in Suizhou city in China.

Teenagers are important carriers of Neisseria meningitidis, which is a leading cause of invasive meningococcal disease. In China, the carriage rate and risk factors among teenagers are unclear. The present study presents a retrospective analysis of epidemiological data for N. meningitidis carriage from 2013 to 2017 in Suizhou city, China. The carriage rates were 3.26%, 2.22%, 3.33%, 3.53% and 9.88% for 2013, 2014, 2015, 2016 and 2017, respectively. From 2014 to 2017, the carriage rate in the 15- to 19-year-old age group (teenagers) was the highest and significantly higher than that in remain age groups. Subsequently, a larger scale survey (December 2017) for carriage rate and relative risk factors (population density, time spent in the classroom, gender and antibiotics use) were investigated on the teenagers (15- to 19-year-old age) at the same school. The carriage rate was still high at 33.48% (223/663) and varied greatly from 6.56% to 52.94% in a different class. Population density of the classroom was found to be a significant risk factor for carriage, and 1.4 persons/m2 is recommended as the maximum classroom density. Further, higher male gender ratio and more time spent in the classroom were also significantly associated with higher carriage. Finally, antibiotic use was associated with a significantly lower carriage rate. All the results imply that attention should be paid to the teenagers and various measures can be taken to reduce the N. meningitidis carriage, to prevent and control the outbreak of IMD.

An Update on Meningococcal Vaccination.

Neisseria meningitidis bacterial infection can cause severe life-threatening meningitis. Individuals who survive may be left with profound sequelae. In epidemic regions such as the meningitis belt of Africa, the case rate is drastically higher than in nonepidemic regions and is due to distinct outbreak serogroups. Two highly effective conjugate meningococcal vaccine against serogroups A, C, W and Y are licensed and indicated for prevention in childhood vaccination schedules and for travelers to outbreak regions. In the US, meningococcus serogroup B is the main cause of outbreaks, in areas with crowding such as college dorms. It has taken over 40 years to develop a meningitis type B vaccine and now there are 2 brands available for children and teens. All college-bound individuals should complete schedules of both conjugate ACWY serotypes and meningitis B vaccine series. This paper reviews details on who to vaccinate and how to use the currently available meningococcal meningitis vaccines.

Diversification in immunogenicity genes caused by selective pressures in invasive meningococci.

We studied population genomics of 486 Neisseria meningitidis isolates causing meningitis in the Netherlands during the period 1979-2003 and 2006-2013 using whole-genome sequencing to evaluate the impact of a hyperendemic period of serogroup B invasive disease. The majority of serogroup B isolates belonged to ST-41/44 (41 %) and ST-32 complex (16 %). Comparing the time periods, before and after the decline of serogroup B invasive disease, there was a decrease of ST-41/44 complex sequences (P=0.002). We observed the expansion of a sub-lineage within ST-41/44 complex sequences being associated with isolation from the 1979-2003 time period (P=0.014). Isolates belonging to this sub-lineage expansion within ST-41/44 complex were marked by four antigen allele variants. Presence of these allele variants was associated with isolation from the 1979-2003 time period after correction for multiple testing (Wald test, P=0.0043 for FetA 1-5; P=0.0035 for FHbp 14; P=0.012 for PorA 7-2.4 and P=0.0031 for NHBA two peptide allele). These sequences were associated with 4CMenB vaccine coverage (Fisher's exact test, P<0.001). Outside of the sub-lineage expansion, isolates with markedly lower levels of predicted vaccine coverage clustered in phylogenetic groups showing a trend towards isolation in the 2006-2013 time period (P=0.08). In conclusion, we show the emergence and decline of a sub-lineage expansion within ST-41/44 complex isolates concurrent with a hyperendemic period in meningococcal meningitis. The expansion was marked by specific antigen peptide allele combinations. We observed preliminary evidence for decreasing 4CMenB vaccine coverage in the post-hyperendemic period.

A pooled analysis of the LAMP assay for the detection of Neisseria meningitidis.

BACKGROUND: Neisseria meningitidis is a major cause of bacterial meningitis, and these infections are associated with a high mortality rate. Rapid and reliable diagnosis of bacterial meningitis is critical in clinical practice. However, this disease often occurs in economically depressed areas, so an inexpensive, easy to use, and accurate technology is needed. We performed a pooled-analysis to assess the potential of the recently developed loop-mediated isothermal amplification (LAMP) assay for detection of meningococcus. METHODS: Pubmed, Embase, and Web of Science were searched to identify original studies that used the LAMP assay to detect meningococcus. After pooling of data, the sensitivity and specificity were calculated, a summary receiver operating characteristic (SROC) curve was determined, and the area under the SROC curve was computed to determine diagnostic accuracy. Publication bias was assessed using Deek's funnel plot. RESULTS: We examined 14 studies within 6 publications. The LAMP assay had high sensitivity (94%) and specificity (100%) in the detection of meningococcus in all studies. The area under the SROC curve (0.980) indicated high overall accuracy of the LAMP assay. There was no evidence of publication bias. DISCUSSION: The LAMP assay has accuracy comparable to bacterial culture and PCR for detection of meningococcus, but is less expensive and easier to use. We suggest the adoption of the LAMP assay to detect meningococcus, especially in economically depressed areas.