Search results for "Neisseria meningitidis"
showing 10 items of 21 documents
Cocirculation of Hajj and non-Hajj strains among serogroup W meningococci in Italy, 2000 to 2016
2019
In Italy, B and C are the predominant serogroups among meningococci causing invasive diseases. Nevertheless, in the period from 2013 to 2016, an increase in serogroup W Neisseria meningitidis (MenW) was observed. This study intends to define the main characteristics of 63 MenW isolates responsible of invasive meningococcal disease (IMD) in Italy from 2000 to 2016. We performed whole genome sequencing on bacterial isolates or single gene sequencing on culture-negative samples to evaluate molecular heterogeneity. Our main finding was the cocirculation of the Hajj and the South American sublineages belonging to MenW/clonal complex (cc)11, which gradually surpassed the MenW/cc22 in Italy. All M…
2017
Summary Objectives Neisseria meningitidis is the major cause of seasonal meningitis epidemics in the African meningitis belt. In the changing context of a reduction in incidence of serogroup A and an increase in incidence of serogroups W and C and of Streptococcus pneumoniae , a better understanding of the determinants driving the disease transmission dynamics remains crucial to improving bacterial meningitis control. Methods The literature was searched to provide a multi-disciplinary overview of the determinants of meningitis transmission dynamics in the African meningitis belt. Results Seasonal hyperendemicity is likely predominantly caused by increased invasion rates, sporadic localized …
Antibody Response to Meningococcal Polysaccharides A and C in Patients with Complement Defects
1993
Patients with defects of terminal complement components are particularly exposed to the risk of developing neisserial infections and seem to respond poorly to meningococcal capsular polysaccharide (PS) C via natural immunization. The sole meningococcal PSC is. on the other hand, an excellent immunogen in normal people. Considering the great importance of vaccine prophylaxis for the prevention of meningococcal infections in patients with complement defects, it is crucial to study the antibody response to the sole meningococcal PS in these patients. We therefore analysed the levels of anti-PSA and PSC antibodies in the members of four families including patients with homozygous and heterozygo…
Culture and Real-time Polymerase Chain reaction sensitivity in the diagnosis of invasive meningococcal disease: Does culture miss less severe cases?
2019
BackgroundInvasive meningococcal disease (IMD) is a highly lethal disease. Diagnosis is commonly performed by culture or Realtime-PCR (qPCR).AimsOur aim was to evaluate, retrospectively, whether culture positivity correlates with higher bacterial load and fatal outcome. Our secondary aim was to compare culture and qPCR sensitivity.MethodsThe National Register for Molecular Surveillance was used as data source. Cycle threshold (CT), known to be inversely correlated with bacterial load, was used to compare bacterial load in different samples.ResultsThree-hundred-thirteen patients were found positive for Neisseria meningitidis by qPCR, or culture, or both; 41 died (case fatality rate 13.1%); 1…
Antiidiotypic DNA vaccination induces serum bactericidal activity and protection against group B meningococci
2006
No vaccine is available for preventing infections by serogroup B Neisseria meningitidis (MenB), which accounts for a major portion of meningococcal cases in developed countries, because of the poor immunogenicity of the capsular polysaccharide (CP) even after protein conjugation. We have previously induced anticapsular antibodies by immunization with a single chain variable fragment (scFv), which mimics a protective CP epitope. This surrogate antigen, however, was ineffective at inducing serum bactericidal activity, an accepted marker of protection in humans. Serum bactericidal activity was consistently achieved by immunizing mice with the scFv-encoding gene. Immunization with vectors witho…
Antibody persistence and immune memory 15 months after priming with an investigational tetravalent meningococcal tetanus toxoid conjugate vaccine (Me…
2012
The present extension study, conducted in children originally vaccinated at 12–14 mo or 3–5 y of age, assessed antibody persistence and immune memory induced by an investigational tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine (MenACWY-TT). In the original study, participants were randomized to receive one dose of MenACWY-TT or licensed age-appropriate meningococcal control vaccines. Fifteen months post-vaccination, all participants underwent serum sampling to evaluate antibody persistence and participants previously vaccinated as toddlers received a polysaccharide challenge to assess immune memory development. Exploratory comparisons showed that (…
Two versus three doses of a meningococcal C conjugate vaccine concomitantly administered with a hexavalent DTaP-IPV-HBV/Hib vaccine in healthy infant…
2007
The immunogenicity and reactogenicity of a meningococcal serogroup C (MenC) conjugate vaccine given concomitantly with DTaP-IPV-HBV/Hib vaccine according to a two- or three-dose schedule in healthy infants was evaluated. At 1 month post-vaccination, 98% (two doses) and 100% (three doses) of subjects had serum bactericidal antibody using human complement assay (hSBA) titres > or =1:8; at 12 months of age > or =89% of subjects in each group remained seroprotected. Induction of immunological memory, as evaluated by administration of a meningococcal serogroup A/C polysaccharide vaccine challenge dose, was similar for both regimens and no interference was observed in the immune response to MenC …
Persistence of Bactericidal Antibodies After Infant Serogroup B Meningococcal Immunization and Booster Dose Response at 12, 18 or 24 Months of Age
2016
Background: A serogroup B meningococcal vaccine (4CMenB) is licensed for infant use in countries including Canada, Australia and those of the European Union. Data on serum bactericidal antibody (hSBA) waning and the ideal timing of a "toddler" booster dose are essential to optimize vaccine utilization. Methods: An open-labeled, multicenter phase-2b follow-on European study conducted from 2009 to 2012. Participants previously receiving 4CMenB with routine vaccines at 2, 4 and 6 or 2, 3 and 4 months (246Con and 234Con) or at 2, 4 and 6 months intercalated with routine vaccines (246Int) received a booster dose at 12, 18 or 24 months. 4CMenB-naive "Control" participants aged 12, 18 or 24 months…
Recognition of Neisseria meningitidis by the long pentraxin PTX3 and its role as an endogenous adjuvant.
2015
Long pentraxin 3 (PTX3) is a non-redundant component of the humoral arm of innate immunity. The present study was designed to investigate the interaction of PTX3 with Neisseria meningitidis. PTX3 bound acapsular meningococcus, Neisseria-derived outer membrane vesicles (OMV) and 3 selected meningococcal antigens (GNA0667, GNA1030 and GNA2091). PTX3-recognized microbial moieties are conserved structures which fulfil essential microbial functions. Ptx3-deficient mice had a lower antibody response in vaccination protocols with OMV and co-administration of PTX3 increased the antibody response, particularly in Ptx3-deficient mice. Administration of PTX3 reduced the bacterial load in infant rats c…
Immunogenicity and tolerability of recombinant serogroup B meningococcal vaccine administered with or without routine infant vaccinations according t…
2012
CONTEXT: In the absence of an effective vaccine, serogroup B Neisseria meningitidis (MenB) remains a major cause of invasive disease in early childhood in developed countries. OBJECTIVE: To determine the immunogenicity and reactogenicity of a multicomponent MenB vaccine (4CMenB) and routine infant vaccines when given either concomitantly or separately. DESIGN, SETTING, AND PARTICIPANTS: Phase 2b, multicenter, open-label, parallel-group, randomized controlled study of 1885 infants enrolled at age 2 months from August 2008 to July 2010 in Europe. INTERVENTION: Participants were randomized 2:2:1:1 to receive (1) 4CMenB at 2, 4, and 6 months with routine vaccines (7-valent pneumococcal and comb…