Invasive meningococcal disease in Italy: from analysis of national data to an evidence-based vaccination strategy

Introduction

Invasive meningococcal disease (IMD) is one of the most severe vaccine-preventable disease not yet under control. In Italy, although different anti-meningococcal vaccines are available, their offer among regions is heterogeneous. The aim of this study is to describe the epidemiology of IMD in Italy based on analysis of national surveillance data for 2011-2017 to optimize the vaccination strategy.

Methods

IMD surveillance data from the Italian National Health Institute were analysed. Microsoft Excel was used to present trend analysis, stratifying by age and serogroups.

Results

In Italy, during the period 2011-2017, the incidence of IMD increased from 0.25 cases/100,000 inhabitants in 2011 to 0.33 cases/100,000 in 2017. Most cases after 2012 were caused by non-B serogroups. The number of cases in subjects aged 25-64 years increased steadily after 2012 (36 cases in 2011, 79 in 2017), mostly due to non-B serogroups, representing more than 65% of cases in those aged 25+ years.

Conclusions

In the period from 2011 to 2017, the incidence of IMDs increased in Italy. The increase, probably due also to a better surveillance, highlights the importance of the disease in the adult population and the high level of circulation of non-B serogroups in particular after 2012. Our analysis supports an anti-meningococcal vaccination plan in Italy that should include the highest number of preventable serogroups and be aimed at vaccinating a wider population through a multicohort strategy.

The Inflammatory and Hemostatic Response in Sepsis and Meningococcemia

Meningococcemia is notorious for evasion of the host immune system and its rapid progression to fulminant disease, and serves as a unique model for pediatric sepsis. Illness severity is determined by complex interplays among host, pathogen, and environment. The inflammatory host response, including proinflammatory and anti-inflammatory responses in innate and adaptive immunity, skews toward a proinflammatory state. This leads to endothelial dysfunction and activation of the hemostatic response, which may lead to disseminated intravascular coagulation. This article reviews the pathogenesis of sepsis, in particular the inflammatory and hemostatic response in meningococcal sepsis.

Primary Meningococcal Septic Arthritis Case Report and Literature Review of an Unusual Manifestation of Meningococcal Disease

INTRODUCTION

Primary meningococcal septic arthritis (PMSA) is an unusual manifestation of meningococcal disease. It is defined as the presence of acute septic arthritis without association with meningitis or the classic meningococcemia and isolation of Neisseria meningitidis in synovial fluid and blood culture. Diagnosis and early treatment, combining antibiotic and joint drainage, are fundamental.

CASE PRESENTATION

We present the case of a healthy 17-year-old male who presented with history of an acute onset, painful knee accompanied by fever. N. meningitidis was cultured from the synovial fluid. He was treated with arthroscopic lavage and intravenous ceftriaxone for 2 weeks. He was discharged 7 days after admission receiving outpatient intravenous ceftriaxione for 6 days and was ultimately transitioned to oral ciprofloxacin for 2 weeks thereafter. At the final follow-up visit, he had returned to sports activity with a normal knee joint.

LITERATURE REVIEW

We have done an exhaustive literature review in PubMed. Forty-four articles were included, with a total of 46 patients, to which we added ours. We collected the available demographic data, analytical values, culture tests, treatment, and evolution.

PURPOSES AND CLINICAL RELEVANCE

This case illustrates an unusual presentation of N. meningitidis infection. Diagnostic suspicion is essential. Joint washing and antibiotics are the mainstays of treatment. Early and proper treatment prevents complications and mortality. Our main objective was to evaluate the diagnostics tools and treatment in PMSA. As a secondary objective, we evaluated the cases with negative cultures in order to evaluate the criteria for the diagnostic suspicion of PMSA.

Talk to Patients About: Meningococcal Disease

Talk to Patients About: Meningococcal Disease.

Increase in Meningococcal Serogroup W Disease, Victoria, Australia, 2013-2015

In Victoria, Australia, invasive meningococcal disease caused by Neisseria meningitidis serogroup W increased from 4% of all cases in 2013 to 30% in 2015. This increase resulted largely from strains similar to those in the serogroup W sequence type 11 clonal complex, previously described in the United Kingdom and South America.

Mutilating Purpura Fulminans in an Adult with Meningococcal Sepsis

We report a dramatic case of meningococcal sepsis manifesting as purpura fulminans in an elderly diabetic woman. Hemodynamic instability and severe bilateral cutaneous lesions involving her hands and feet developed rapidly. Specific antibiotic therapy and the administration of inotropic and vasopressor drugs were initiated. The severity and extension of the cutaneous lesions (attributed to purpura fulminans) worsened because of the need for vasoconstrictors for the treatment of septic shock. Bilateral transmetatarsal and metacarpal amputations were required to stabilize the patient.

Arthritis secondary to meningococcal disease: A case series of 7 patients

Arthritis secondary to invasive meningococcemia is rare and has been described as a direct result of bacteremia or as immunoallergic-type arthritis, related to the immune complex. Only a few case series have been reported.This multicenter study aimed to describe the clinical characteristics and therapeutic outcomes of arthritis secondary to meningococcal infection.We performed a 5-year retrospective study. We included all patients with inflammatory joint symptoms and proven meningococcal disease defined by the identification of Neisseria meningitidis in blood, cerebrospinal fluid, or synovial fluid. Septic arthritis was defined by the identification of N meningitidis in joint fluid. Immune-mediated arthritis was considered to be arthritis occurring after at least 1 day of invasive meningococcal disease without positive joint fluid culture.A total of 7 patients (5 males) with joint symptoms and meningococcal disease were identified. The clinical presentation was mainly oligoarticular and the knee was the most frequent joint site. Five patients had septic arthritis and 4 had immune-mediated arthritis; 2 had septic arthritis followed by immune-mediated arthritis. Immune-mediated arthritis occurred 3 to 7 days after meningococcal meningitis, and treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) led to improvement without complications.Physicians must be vigilant to the different clinical presentations in patients with arthritis associated with invasive meningococcal disease. If immune-mediated arthritis is suspected, NSAIDs are usually efficient.

Meningococcal disease in children and teenagers

Meningococcal disease is a leading cause of death in children and young people. It causes two major disease processes, meningococcal septicaemia and meningococcal meningitis, and often results in long-term health complications. It remains a difficult disease to recognise and treat. This article, part one in a two-part series, discusses the epidemiology of meningococcal disease and explains its pathophysiology as well as signs and symptoms. Part 2, to be published on 19 March, will review diagnosis, management and prevention.

Classification and pathogenesis of meningococcal infections

The clinical symptoms induced by Neisseria meningitidis reflect compartmentalized intravascular and intracranial bacterial growth and inflammation. In this chapter, we describe a classification system for meningococcal disease based on the nature of the clinical symptoms. Meningococci invade the subarachnoid space and cause meningitis in as many as 50-70% of patients. The bacteremic phase is moderate in patients with meningitis and mild systemic meningococcemia but graded high in patients with septic shock. Three landmark studies using this classification system and comprising 862 patients showed that 37-49% developed meningitis without shock, 10-18% shock without meningitis, 7-12% shock and meningitis, and 18-33% had mild meningococcemia without shock or meningitis. N. meningitidis lipopolysaccharide (LPS) is the principal trigger of the innate immune system via activation of the Toll-like receptor 4-MD2 cell surface receptor complex on myeloid and nonmyeloid human cells. The intracellular signals are conveyed via MyD88-dependent and -independent pathways altering the expression of >4,600 genes in target cells such as monocytes. However, non-LPS molecules contribute to inflammation, but 10-100-fold higher concentrations are required to reach the same responses as induced by LPS. Activation of the complement and coagulation systems is related to the bacterial load in the circulation and contributes to the development of shock, organ dysfunction, thrombus formation, bleeding, and long-term complications in patients. Despite rapid intervention and advances in patient intensive care, why as many as 30% of patients with systemic meningococcal disease develop massive meningococcemia leading to shock and death is still not understood.

[Meningococcus infection: problem actuality]

The data of literature are stated concerning the population's sickness of meningococcus infection in Ukraine and the world. The meningococcus infection is one of the most actual problems of medicine.

MenACWY-CRM, a novel quadrivalent glycoconjugate vaccine against Neisseria meningitidis for the prevention of meningococcal infection

Invasive meningococcal disease remains a major public health concern, with infants, children younger than 4 years and adolescents bearing the majority of the global disease burden. Protecting the vulnerable individuals in these age groups through vaccination remains the most rational strategy for the prevention of meningococcal disease. The formulation of polysaccharide-protein conjugate vaccines has been a major breakthrough in vaccinology, and has extended protection against pathogenic encapsulated bacteria to younger age groups. The dramatic decline in the incidence of Neisseria meningitidis serogroup C disease, observed following the introduction of glycoconjugate meningococcal C vaccines, demonstrates that vaccination can control disease at a population level. The development of quadrivalent glycoconjugate meningococcal ACWY vaccines has broadened protection against meningococcal disease. A novel meningococcal MenACWY-CRM (Menveo) glycoconjugate vaccine, formulated by selective conjugation chemistry of intermediate-chain-length meningococcal saccharides, was immunogenic in individuals aged 2 months to 65 years. The reactogenicity of MenACWY-CRM was similar to that of other licensed meningococcal glycoconjugates, yet the vaccine has the potential to extend protection against meningococcal serogroups A, Y and W-135 to children younger than 2 years of age - a need that remains unmet.

Atypical clinical presentation of laboratory-acquired meningococcal disease

We report a case of laboratory-acquired meningococcal disease in a 31-y-old female research assistant. The clinical presentation of the case was atypical with polyserositis affecting knees, pleura and pericardium, without septicaemia or meningitis. The diagnosis was made by positive PCR for Neisseria meningitidis (genogroup C, genosubtype P1.7, 16, 35 and without mutations of the penA gene) in the patient's right knee. Serology confirmed the diagnosis after recovery. This case had an atypical clinical picture, exemplifies the use of non-culture methods for diagnosis and characterization, and reminds us about the importance of safe routines for the laboratory work.

Evolution of Thrombin Formation and Fibrinolysis Markers, Including Thrombin-Activatable Fibrinolysis Inhibitor, during Severe Meningococcemia

A 17-year-old girl presented with Neisseria meningitidis sepsis, with evidence of disseminated intravascular coagulation. Substitution therapy with both antithrombin and protein C concentrates was initiated, leading to clinical and biological improvement. Sequential dosages were performed for biological markers including thrombin-activatable fibrinolysis inhibitor (TAFI). Substitution therapy with both antithrombin and protein C concentrates led to a clinical and biological improvement. Biological markers showed a decrease in thrombin generation and in plasminogen activator inhibitor 1 (PAI-1) and a return of TAFI to a normal value. Discontinuation of substitutive treatment was marked by a clinical relapse at 24 h, with thrombin generation and increase in PAI-1, while TAFI remained unchanged. This report shows the evolution of hemostasis markers during septic shock and provides new data concerning the effects of a substitutive therapy.

Clinical recognition of meningococcal disease in children and adolescents

BACKGROUND

Meningococcal disease is a rapidly progressive childhood infection of global importance. To our knowledge, no systematic quantitative research exists into the occurrence of symptoms before admission to hospital.

METHODS

Data were obtained from questionnaires answered by parents and from primary-care records for the course of illness before admission to hospital in 448 children (103 fatal, 345 non-fatal), aged 16 years or younger, with meningococcal disease. In 373 cases, diagnosis was confirmed with microbiological techniques. The rest of the children were included because they had a purpuric rash, and either meningitis or evidence of septicaemic shock. Results were standardised to UK case-fatality rates.

FINDINGS

The time-window for clinical diagnosis was narrow. Most children had only non-specific symptoms in the first 4-6 h, but were close to death by 24 h. Only 165 (51%) children were sent to hospital after the first consultation. The classic features of haemorrhagic rash, meningism, and impaired consciousness developed late (median onset 13-22 h). By contrast, 72% of children had early symptoms of sepsis (leg pains, cold hands and feet, abnormal skin colour) that first developed at a median time of 8 h, much earlier than the median time to hospital admission of 19 h.

INTERPRETATION

Classic clinical features of meningococcal disease appear late in the illness. Recognising early symptoms of sepsis could increase the proportion of children identified by primary-care clinicians and shorten the time to hospital admission. The framework within which meningococcal disease is diagnosed should be changed to emphasise identification of these early symptoms by parents and clinicians.

Epidemiology of invasive meningococcal disease in France in 2003

National surveillance of invasive meningococcal disease (IMD) is based on mandatory reporting. The case definition for surveillance notification was changed in mid-2002 to include cases without microbiological confirmation. The IMD alert detection system was enhanced in 2003 with daily reporting and weekly analysis by district, serogroup, and age. Evaluation of the exhaustivity of the surveillance with capture-recapture analysis allowed correcting for underreporting. In 2003, 803 cases were reported. After correction for under-reporting, the estimated incidence was 1.78 / 100,000. After excluding 'new' cases reported with new definition criteria, the 2002-2003 increase was 4%. Incidence decreased with age, with the highest values in infants less than 1 year (20/100,000), children aged between 1 and 2 years (11/100,000) and in teenagers of 17 years old(7/100,000). The overall case fatality rate was 12%. Fifty nine per cent of cases were due to serogroup B, 32% to C, 5% to W135, and 4% to Y and non-groupable meningococci. Patients with purpura fulminans treated with intravenous antibiotics before admission to hospital were shown to have lower fatality rates than those not treated. In 2001-2003, 5 situations required particular attention: two clusters of serogroup B IMD had set off mass prophylaxis, one outbreak due to a specific B IMD clonal complex with high case fatality rate, and two districts crossed the alert threshold for serogroup C IMD, 2/100,000, and mass vaccination was recommended.

Myocardial dysfunction in meningococcal septic shock

PURPOSE OF REVIEW

The underlying pathophysiology of sepsis has long been disputed. Systemic vasodilatation is important in the development of shock and, in septic critically ill adults who have been volume resuscitated, the systemic pressure is often low and the cardiac output high. In septic children however, and especially in those with meningococcal septic shock, poor cardiac output as a consequence of depressed myocardial function seems to be important, often being the cause of death in these patients. There is much evidence for disturbance of myocardial performance, yet despite the literature, there is still no consensus on how best to manage this complication of meningococcal disease.

RECENT FINDINGS

Many mediators have been proposed as the cause of the reduced myocardial performance, most recently interleukin-6 has emerged as a possible candidate involved in the pathophysiology of the myocardial dysfunction. Cardiac troponin I has been shown to be a marker of myocardial injury and may be used to monitor left ventricular function. Newer treatments emerging to manage the dysfunction include reports of success with phosphodiesterase inhibitors.

SUMMARY

Accepting that myocardial dysfunction may be an important cause of the shock state in overwhelming meningococcal disease, the approach to management may need to be tailored appropriately. Although presently there is no targeted treatment, it may be that therapy focused on inhibiting or antagonising interleukin-6 will be helpful in the future. Regardless of the importance of myocardial depression, fluid resuscitation remains a cornerstone in the management of severe meningococcal disease.

Reversible autonome Dysfunktion bei einer jungen Patientin mit septischem Multiorgan-Dysfunktionssyndrom

HISTORY

A 24-year-old woman was admitted for treatment of a meningococcal infection accompanied by fulminant autonomic dysfunction.

INVESTIGATIONS

Laboratory tests indicated acute renal failure and disseminated intravascular coagulopathy (creatinine 183 mmol, D-dimer 1.52 mg/l). The initial central venous oxygen saturation was 60-65%. The diagnosis of severe septic shock was supported by a high procalcitonin level of 66.7 ng/ml, CRP of 79.8 mg/l, and a WBC count of 12.2 Gpt/l.

TREATMENT AND COURSE

Treatment of sepsis with antibiotics (ciprofloxacin, penicillin G, ceftriaxon and erythromycin in standard dosages), activated protein-C, hydrocortisone and GMA-embedded immunoglobulin led to complete cure and restoration of normal autonomic function.

CONCLUSIONS

This case shows that even in multiple organ dysfunction syndrome autonomic dysfunction can occur which is improved by adequate treatment.

Meningococcal vaccines

Meningococcal disease is one of the most feared and serious infections in the young and its prevention by vaccination is an important goal. The high degree of antigenic variability of the organism makes the meningococcus a challenging target for vaccine prevention. Meningococcal polysaccharide vaccines against serogroup A and C are efficacious and have been widely used, often in combination with serogroup Y and W135 components. Their relative lack of immunogenicity in young children and infants can be overcome by conjugation to a protein carrier. The effectiveness of serogroup C glycoconjugate vaccines in children of all ages has been demonstrated and they have now been introduced into routine vaccination schedules. Conjugate vaccines against other serogroups, including A, Y, and W135 will soon be available and it is hoped they may emulate this success. Prevention of serogroup B disease has proven more elusive. Several serogroup B vaccines based on outer membrane vesicles have been shown to be immunogenic and reasonably effective in adults and older children, but the protection offered by them is chiefly strain-specific. Multivalent recombinant PorA vaccines have been developed to broaden the protective effect, but no efficacy data are available as yet. Intensive efforts have been directed at other outer membrane protein vaccine candidates and lipopolysaccharide, and some of these have been shown to offer protection in experimental animal models. Nonpathogenic Neisseriae spp. such as Neisseria lactamica are also possible vaccine candidates. Previously unknown proteins have been identified from in silico analysis of the meningococcal genome and their vaccine potential explored. However, none of these has yet been presented as the 'universal' protective antigen and work in this field continues to be held back by our limited knowledge concerning the mechanisms of natural protection against serogroup B meningococci.

Short-term psychiatric adjustment of children and their parents following meningococcal disease

OBJECTIVE

To assess short-term changes in child and parent psychiatric status following meningococcal disease.

DESIGN

Prospective cohort study; 3-month follow-up using parent, teacher, and child questionnaires.

SETTING

Hospital admissions to three pediatric intensive care units and 19 general pediatric wards.

PATIENTS

Sixty children aged 3-6 yrs, 60 mothers, and 45 fathers.

INTERVENTIONS

We administered measures of illness severity (Glasgow Meningococcal Septicaemia Prognostic Score, days in hospital) and psychiatric morbidity (Strengths and Difficulties Questionnaires, parent and teacher versions; Impact of Event scales; General Health Questionnaire-28).

MEASUREMENTS AND MAIN RESULTS

In children admitted to pediatric intensive care units, parental reports at 3-month follow-up showed a significant increase in emotional and hyperactivity symptoms and in related impairment; symptoms of posttraumatic stress disorder were present in four of 26 (15%) children >8 yrs old. Regarding the parents, 26 of 60 (43%) mothers in the total sample had questionnaire scores indicative of high risk for psychiatric disorder and 22 of 58 (48%) for posttraumatic stress disorder. In fathers there was high risk for psychiatric disorder in 11 of 45 (24%) and for posttraumatic stress disorder in 8 of 43 (19%). Severity of the child's physical condition on admission was significantly associated with hyperactivity and conduct symptoms at follow-up. Length of hospital admission was associated with psychiatric symptoms in the child and posttraumatic stress disorder symptoms in parents. There were also significant associations between psychiatric symptoms in children and parents.

CONCLUSIONS

Admission of children to pediatric intensive care units for meningococcal disease is associated with an increase in and high levels of psychiatric and posttraumatic stress disorder symptoms in children and parents. Length of admission is associated with psychiatric symptoms in children and posttraumatic stress disorder symptoms in parents. Pediatric follow-up should explore psychiatric as well as physical sequelae in children and parents.

Early application of generic mortality risk scores in presumed meningococcal disease

OBJECTIVE

Mortality from meningococcal disease typically occurs within 24 hrs of intensive care unit (ICU) admission. An early, accurate mortality-risk tool may aid in trial design for novel therapies. We assessed the performance of two generic scores that assign mortality risk within 1 hr of ICU admission: the Preintensive Care Pediatric Risk of Mortality (Pre-ICU PRISM) and Pediatric Index of Mortality (PIM).

DESIGN

Prospective, observational study over 21 months.

SETTING

Two tertiary pediatric ICUs accepting referrals from southeast England.

PATIENTS

Patients were 165 consecutive children with meningococcal disease. Ages ranged from 0.1 to 17 yrs (median 2.3 yrs).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PIM demonstrated greater sensibility, with complete data collected in 93% of cases, compared with 35% for the pre-ICU PRISM. Both scores discriminated well. The area under the receiver operating characteristic curve was 0.90 (95% confidence interval, 0.81-1.00) for PIM and 0.94 (95% confidence interval, 0.88-0.98) for Pre-ICU PRISM; this did not change when applied to the subgroup of patients with complete data. Both scores calibrated poorly, overestimating mortality in the medium-risk strata (and also in the high-risk stratum in the case of Pre-ICU PRISM). When used as a stratification tool for a hypothetical trial (60% reduction in mortality, 80% power), the scores allowed for a reduction in study size by 50% (PIM) and 43% (pre-ICU PRISM).

CONCLUSIONS

Pre-ICU PRISM and PIM both discriminate well but calibrate poorly when applied to a cohort of children with meningococcal sepsis. Both scores provide an effective means of stratification for clinical trial purposes. The main advantage for PIM appears to be ease of data collection.

Management of meningococcemia

Meningococcemia causes substantial morbidity and mortality worldwide, usually in the term of fulminant disease. This paper reviews the background, pathophysiology, clinical manifestations, and treatment of this entity, along with prevention measures and public health issues to be considered. The authors present updated information on breakthroughs in the understanding of genetic predisposition to invasive disease. The status of adjunctive treatment modalities such as monoclonal antibodies and activated protein C, and progress in conjugate vaccine development and implementation are also addressed.

Complement activation and complement-dependent inflammation by Neisseria meningitidis are independent of lipopolysaccharide

Fulminant meningococcal sepsis has been termed the prototypical lipopolysaccharide (LPS)-mediated gram-negative septic shock. Systemic inflammation by activated complement and cytokines is important in the pathogenesis of this disease. We investigated the involvement of meningococcal LPS in complement activation, complement-dependent inflammatory effects, and cytokine or chemokine production. Whole blood anticoagulated with lepirudin was stimulated with wild-type Neisseria meningitidis H44/76 (LPS+), LPS-deficient N. meningitidis H44/76lpxA (LPS-), or purified meningococcal LPS (NmLPS) at concentrations that were relevant to meningococcal sepsis. Complement activation products, chemokines, and cytokines were measured by enzyme-linked immunosorbent assays, and granulocyte CR3 (CD11b/CD18) upregulation and oxidative burst were measured by flow cytometry. The LPS+ and LPS- N. meningitidis strains both activated complement effectively and to comparable extents. Purified NmLPS, used at a concentration matched to the amount present in whole bacteria, did not induce any complement activation. Both CR3 upregulation and oxidative burst were also induced, independent of LPS. Interleukin-1beta (IL-1beta), tumor necrosis factor alpha, and macrophage inflammatory protein 1alpha production was predominantly dependent on LPS, in contrast to IL-8 production, which was also markedly induced by the LPS- meningococci. In this whole blood model of meningococcal sepsis, complement activation and the immediate complement-dependent inflammatory effects of CR3 upregulation and oxidative burst occurred independent of LPS.

GNA33 of Neisseria meningitidis is a lipoprotein required for cell separation, membrane architecture, and virulence

GNA33 is a membrane-bound lipoprotein with murein hydrolase activity that is present in all Neisseria species and well conserved in different meningococcal isolates. The protein shows 33% identity to a lytic transglycolase (MltA) from Escherichia coli and has been shown to be involved in the degradation of both insoluble murein sacculi and unsubstituted glycan strands. To study the function of the gene and its role in pathogenesis and virulence, a knockout mutant of a Neisseria meningitidis serogroup B strain was generated. The mutant exhibited retarded growth in vitro. Transmission electron microscopy revealed that the mutant grows in clusters which are connected by a continuous outer membrane, suggesting a failure in the separation of daughter cells. Moreover, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of culture supernatant revealed that the mutant releases several proteins in the medium. The five most abundant proteins, identified by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis, belong to the outer membrane protein family. Finally, the mutant showed an attenuated phenotype, since it was not able to cause bacteremia in the infant rat model. We conclude that GNA33 is a highly conserved lipoprotein which plays an important role in peptidoglycan metabolism, cell separation, membrane architecture, and virulence.

Role of interleukin 6 in myocardial dysfunction of meningococcal septic shock

BACKGROUND

Myocardial failure has a central role in the complex pathophysiology of septic shock and contributes to organ failure and death. During the sepsis-induced inflammatory process, specific factors are released that depress myocardial contractile function. We aimed to identify these mediators of myocardial depression in meningococcal septic shock.

METHODS

We combined gene-expression profiling with protein and cellular methods to identify a serum factor causing cardiac dysfunction in meningococcal septic shock. We identified genes that were significantly upregulated in blood after exposure to meningococci. We then selected for further analysis those genes whose protein products had properties of a myocardial depressant factor--specifically a 12-25 kDa heat-stable protein that is released into serum shortly after onset of meningococcal infection.

FINDINGS

We identified 174 significantly upregulated genes in meningococcus-infected blood: six encoded proteins that were of the predicted size and had characteristics of a myocardial depressant factor. Of these, interleukin 6 caused significant myocardial depression in vitro. Removal of interleukin 6 from serum samples of patients with meningococcaemia and from supernatants of inflammatory cells stimulated by meningococci in vitro abolished the negative inotropic activity. Furthermore, concentrations in serum of interleukin 6 strongly predicted degree of myocardial dysfunction and severity of disease in children with meningococcal septic shock.

INTERPRETATION

Interleukin 6 is a mediator of myocardial depression in meningococcal disease. This cytokine and its downstream mediators could be a target for future treatment strategies.

Identification of meningococcal LPS as a major monocyte activator in IL-10 depleted shock plasmas and CSF by blocking the CD14-TLR4 receptor complex

We have examined the in vitro stimulatory effects of lipopolysaccharide (LPS)-containing samples (meningococcal shock plasma, n = 10; non-shock plasma, n = 10; cerebrospinal fluid (CSF), n = 7) before and after immunodepletion of interleukin (IL)-10 in a monocyte target assay. We also studied the stimulatory effects of plasma collected from 3 patients with lethal septicemia caused by Streptococcus pneumoniae without detectable LPS but with 100-fold increased levels of heat-shock protein 70 (HSP70). HSP70 may, like LPS, activate monocytes via the Toll-like receptor 4 (TLR4). The samples were analyzed for LPS, tumor necrosis factor (TNF)-alpha, IL-10 and HSP70; applied on human monocytes (purity > 95%) before and after IL-10 immunodepletion, in the absence or presence of CD14 blocking mAb (60bca) or the lipid A antagonist, Rhodobacter sphaeroides diphosphoryl lipid A (RsDPLA) which blocks TLR4. Monocyte activation was measured by increased TNF-alpha secretion and tissue factor (TF) up-regulation by monocyte procoagulant activity (PCA). There was a positive correlation between patient plasma LPS levels (n = 10) and increases in TNF-alpha secretion by the monocytes after immunodepletion of IL-10 (r = 0.82). Pretreatment of the monocytes with mAbCD14 or RsDPLA reduced TNF-alpha secretion to median 5% and 12%, respectively, of the levels before the receptor complex was blocked. The median levels of HSP70 were 543 ng/ml (range, 468-962 ng/ml) in pneumococcal shock plasma, 81.5 ng/ml (range, 41-331 ng/ml) in meningococcal shock plasma and 24 ng/ml (range, < 0.8-41 ng/ml) in meningococcal non-shock plasma. Pneumococcal septic shock plasmas with significantly higher levels of HSP70 (P < 0.05) did not induce TNF-alpha secretion in the monocytes. The results strongly suggest that LPS in meningococcal shock plasma is the major activator of monocytes whereas HSP70 (in plasma concentrations up to 963 ng/ml) does not activate monocytes in this assay.

Viroses respiratoires et surinfections bactériennes invasives

The pathophysiology of bacterial superinfections of influenza, including meningococcal diseases, remains obscure. Mice, normally resistant to the meningococcus, become susceptible after previous influenza A virus infection. This immunosuppressive effect is transitory and is associated with the peak of the inflammatory anti-virus reaction. These results underline the importance of preventing bacterial superinfections of influenza by the surveillance of any relapse of fever after improvement of the influenza syndrome. At the community level, influenza vaccine, beside its specific effects, might also prevent many cases of invasive superinfections, including meningococcal diseases.

Severe meningococcal disease is characterized by early neutrophil but not platelet activation and increased formation and consumption of platelet-neutrophil complexes

Approximately 25% of polymorphonuclear leukocytes (PMNL) circulate in heterotypic complexes with one or more activated platelets. These platelet-neutrophil complexes (PNC) require platelet CD62P expression for their formation and represent activated subpopulations of both cell types. In this study, we have investigated the presence, time course, and mechanisms of PNC formation in 32 cases of severe pediatric meningococcal disease (MD) requiring intensive care. There were marked early increases in PMNL CD11b/CD18 expression and activation, and reduced CD62L expression compared with intensive care unit control cases. Minimal platelet expression of the active form of alphaIIbbeta3 (GpIIb/IIIa) was seen. PNC were reduced on presentation and fell to very low levels after 24 h. Immunostaining of skin biopsies demonstrated that PNC appear outside the circulation in MD. In vitro studies of anticoagulated whole blood inoculated with Neisseria meningitidis supported these clinical findings with marked increases in PMNL CD11b/CD18 expression and activation but no detectable changes in platelet-activated alphaIIbbeta3 or CD62P expression. In vitro PMNL activation with N. meningitidis (or other agonists) potentiated the formation of PNC in response to platelet activation with adenine diphosphate. Therefore, in severe MD, PMNL activation is likely to promote PNC formation, and we suggest that the reduced levels of PNC seen in established MD reflect rapid loss of PNC from the circulation rather than reduced formation.

Meningococcal disease in the republic of Korea army: incidence and serogroups determined by PCR

This study was performed to determine the incidence and serogroups of meningococcal disease in the Korean Army. From August 2000 to July 2001, we identified prospective cases in the Korean Army. Meningococcal disease was confirmed by isolation of Neisseria meningitidis or detection of its antigen by latex agglutination from cerebrospinal fluid (CSF) or blood. Polymerase chain reactions (PCRs) were performed in the crgA gene to identify N. meningitidis regardless of its serogroup, and then in orf-2 (serogroup A) and siaD (serogroups B, C, Y, and W135) respectively for serogroup prediction. During the study period, twelve patients (four meningitis and eight septicaemia) were identified. The annual incidence was 2.2 per 100,000 (95% confidence interval, 1.3-3.8) among 550,000 private soldiers. Latex agglutinations were positive to A/C/Y/W135 polyvalent latex, but not to B latex in all patients. PCRs of crgA gene were positive in ten patients, whose samples (2 isolates from CSF, 2 CSFs, and 6 sera) were stored. In PCRs for serogroup prediction, one isolate was serogroup A, and one isolate and two sera were serogroup C. The need for meningococcal vaccination would be considered in the Korean Army through the cost-benefit analysis based on the result of this study.

Development and evaluation of an improved mouse model of meningococcal colonization

Studies of meningococcal pathogenesis have been severely restricted due to the absence of an adequate animal model. Given the significance of iron in meningococcal pathogenesis, we developed a model of Neisseria meningitidis colonization in outbred adult mice that included daily administration of iron dextran. While receiving iron, the animals were inoculated intranasally with the initial doses of bacterial suspension. Meningococci were recovered from the animals by nasopharyngeal washes. Approximately half of the animals inoculated with 10(7) CFU remained colonized 13 days after the initial bacterial inoculation. The model was further evaluated with genetically defined isogenic serogroup B mutant strains, and the colonization capabilities of the mutants were compared to that of the wild-type parent. A mutant that produces truncated lipooligosaccharide (KDO(2)-lipid A) and a mutant defective in capsule transport were dramatically impaired in colonization. A mutant defective in pilus transport (pilQ) showed moderately impaired colonization. The immunological aspect of the model was also evaluated by challenging mice after immunization with homologous whole-cell meningococci. The immunized mice were protected from colonization of the homologous strain. In this model, long-term meningococcal colonization was maintained, allowing us to study the effects of specific genetic mutation on colonization. In addition, this model allows investigation of the role of active immune response against meningococci.

Severe meningococcal disease in childhood

Meningococcal disease remains an important cause of illness in the UK (Commun Dis Rep CDR Suppl 1999; 9: S5), and is the commonest infective cause of death in children outwith the neonatal period. Although most common in children, adults are also affected. Meningococcal vaccines offer long-term protection only against Group C disease, which causes less than half of invasive meningococcal disease (Commun Dis Rep CDR Wkly 1998; 8: 2) in the UK.

Calciphylaxis, proteases, and purpura: an alternative hypothesis for the severe shock, rash, and hypocalcemia associated with meningococcal septicemia

The hallmarks of severe meningococcal sepsis include the rapid onset of shock, purpuric rash, and metabolic derangement, in particular, hypocalcemia. The severe ecchymoses and purpura associated with meningococcal sepsis are usually attributed to acute thrombotic episodes, attributable to the associated procoagulation disorder. An alternative explanation for the rash is a sudden extravasation of calcium from the intravascular space into the tissues. We will argue that in meningococcal sepsis, cleavage of albumin into fragments by protease(s) occurs and these fragments, along with calcium, cross the endothelium into the interstitium. The fragmentation of albumin and its loss through the endothelium would also provide a more rational explanation for the rapidity of the shock and the hypocalcemia that is so characteristic of the disease.

[Physiopathology and curative treatment of meningococcal diseases: current aspects]

Early administration of antibiotics as soon as the diagnosis of meningococcemia has been evoked is a significant therapeutic advance. However, the poor outcome of these diseases whose mortality remains high despite the current techniques of reanimation shows that improving the vaccination against meningococci is still of actuality. Diagnosing rapidly severe meningococcal disease is also a means for acting against the pathological activation of the inflammatory and coagulation pathways. Significant advances have been made in understanding the physiopathology of the meningococcal purpura fulminans especially about the deleterious role of the deficiency of the protein C and the antithrombin III. It is too soon to advance that the prognosis of these diseases has been improved by these new therapeutic approaches but the results of preliminary clinical studies are encouraging. However, informing parents about the first skin abnormalities seen in infants with purpura fulminans is essential in attempt to improve the efficiency of these new therapeutic strategies.

Characterization of a myocardial depressant factor in meningococcal septicemia

OBJECTIVE

Identification and characterization of myocardial depressant factors present in meningococcal septicemia.

DESIGN

Laboratory investigation of myocardial depression that used isolated cardiac myocytes as an model of cardiac contractile function.

SETTING

University hospital and laboratories.

PATIENTS

Children with severe meningococcal septic shock requiring intensive care.

ANIMALS

Myocytes obtained from adult male Sprague-Dawley rats.

INTERVENTIONS

Serum samples obtained from the acute phase of sepsis were evaluated for the presence of myocardial depressant activity. Further characterization of the myocardial depressant factor was undertaken by using cell culture supernatants from whole blood and peripheral blood mononuclear cells that had been exposed to heat-killed meningococci.

MEASUREMENTS AND MAIN RESULTS

Myocardial depressant activity was measured by using isolated rat left-ventricular myocytes. Changes in amplitude of contraction and in the speed of contraction and relaxation were determined after cells were exposed to various stimuli. Serum from patients with meningococcal disease had myocardial depressant activity. This activity was also present in whole blood and peripheral blood mononuclear cells exposed to meningococci. Myocardial depressant activity was found to be heat stable, proteinaceous, and of a molecular weight range of 10-25 kDa. The activity did not elevate concentrations of cyclic guanylic acid. Lipopolysaccharide-binding protein augmented the release of myocardial depressant factor by peripheral blood mononuclear cells exposed to meningococci.

CONCLUSIONS

Myocardial depression in meningococcal sepsis is mediated in part by circulating myocardial depressant factors. Myocardial depressant factors are also released when whole blood or peripheral blood mononuclear cells of healthy donors are exposed to heat-killed meningococci. Release of the factors appears to be mediated through endotoxin-induced activation of peripheral blood mononuclear cells, since lipopolysaccharide-binding protein augments release in a dose-responsive manner. Partial physicochemical characterization of the factors has been achieved.

Assessment of adrenal function in the initial phase of meningococcal disease

OBJECTIVE

To determine the status of the hypothalamic-pituitary-adrenal axis in children who had meningococcal disease and were admitted to 2 regional pediatric intensive care units.

METHODS

Sixty-five children (34 boys; median age: 2.5 years; range: 0.2-15 years) had cortisol and adrenocorticotropic hormone (ACTH) levels measured on admission, then at 8 AM and 8 PM during the next 48 hours. At 48 hours, a low-dose short Synacthen test (LDST) (500 ng of 1-24 corticotropin/m2) was performed in 42 patients (19 boys). Normal ranges for 8 AM cortisol and ACTH levels in unstressed children were 140 to 500 nmol/L and 2 to 11.3 pmol/L, respectively. Adrenal insufficiency (AI) was defined as a peak cortisol <500 nmol/L on the LDST or an 8 AM cortisol value <140 nmol/L.

RESULTS

Five (7.7%) of the 65 children died, including 1 with primary AI. Cortisol levels were elevated on admission (median: 1122 mmol/L; range: 65-2110 nmol/L) with 81% of values more than the 8 AM normal range. The median ACTH level on admission was within the 8 AM normal range, but 40% of values were more than the 8 AM normal range. However, 7% and 8% of cortisol and ACTH values, respectively, were less than the normal range. Both cortisol and ACTH levels fell thereafter and showed no diurnal variation during the 48-hour profile. Six (14%) of the 42 failed the LDST. These patients had significantly lower mean 8 AM cortisol values than those with a normal peak value on the LDST. Five additional patients who did not have the LDST had 8 AM cortisol values <140 nmol/L. In the diagnosis of AI, the sensitivity of the 8 AM mean cortisol value at a cutoff of 400 nmol/L, judged against the LDST, was 83%; the specificity was 81%.

CONCLUSIONS

During the initial phase of meningococcal disease, raised cortisol and ACTH levels indicate an appropriate stress response within the hypothalamic-pituitary-adrenal axis. However, a substantial subpopulation (11 [16.9%] of 65) has evidence of adrenal dysfunction during this period. Morning cortisol values in the initial phase of meningococcal disease could be used as a potential early index of AI.