Bacterial meningitis in children and adults. Changes in community-acquired disease may affect patient care

Programmatic challenges in obtaining and confirming the pneumococcal vaccination status of cochlear implant recipients

BACKGROUND

Bacterial meningitis represents a substantial concern for individuals with cochlear implants (CIs).

METHODS

Chart review and direct patient and family correspondence to ascertain vaccination status.

INTERVENTION

Information dissemination via brochure and electronic media, ongoing reminders of the importance of vaccination when confirmation of vaccination was not received.

RESULTS

Marked improvement in vaccination rates ranging from 49% to 99% across different patient populations. Importantly, many patients received their vaccinations only after follow-up reminders.

CONCLUSION

Ensuring optimal vaccination of all CI recipients against high-risk pathogens is a significantly challenging task. Maximizing vaccination rates in CI users will require an ongoing, active effort of information dissemination, documentation of compliance, and well-designed behavioral systems to streamline the pragmatic challenges in vaccination delivery.

Capsular Types and Antibiotic Susceptibility of Invasive Streptococcus pneumoniae Among Children in Sweden

To investigate the serotype distribution and antibiotic susceptibility patterns 204 isolates of Streptococcus pneumoniae obtained from blood or cerebrospinal fluid (CSF) of children < or = 18 y of age were collected from 19 clinical microbiological laboratories in Sweden during the years 1998-2001. 166 isolates were from blood only, and 38 isolates were from CSF. The most common serotypes found were 6B, 1, 7F, 14, 18C, 19F, 6A, 4, 23F, 9V and 19A, in descending order of frequency. During the study period serotype 6B increased in frequency from 14.3% in 1998 to 28.3% in 2001 and serotype 1 decreased simultaneously from 20.4% to 9.4%. Serotype 1 was the most common serotype among children > or = 2 y of age or older, but was not found among children < 2 y of age. The potential coverage rate for the heptavalent pneumococcal conjugate vaccine varied between 53 and 68% during the studied years, and was higher for children < 2 y of age (74%) than for older children (51%). The majority of isolates were susceptible to penicillin and other antibiotics tested.

Treatment of bacterial meningitis: an overview of Cochrane systematic reviews

BACKGROUND

Acute bacterial meningitis (ABM) is a rapidly developing acute inflammation of leptomeninges and underlying subarachnoid cerebrospinal fluid (CSF). ABM is caused by bacteria and has a case fatality rate of 20-30%. Most prevalent causes of ABM are Neisseria meningitis, Streptococcus pneumoniae and Haemophilus influenzae. The aim of this paper is to summarize the main findings from Cochrane systematic reviews that have considered the evidence for treatments of ABM.

METHODS

We searched the Cochrane Library (issue 1, 2007) for relevant reviews using 'meningitis' as a search term. The titles of all the search results were examined to select reviews on treatment of ABM. The full text of each of the selected reviews was studied to summarize the evidence available in Cochrane systematic reviews.

RESULTS

We found three Cochrane reviews that focused specifically on the treatment of ABM, addressing empiric antibiotic therapy, fluid therapy and effects of adjuvant corticosteroids respectively. No statistically significant difference was found between third generation cephalosporins and conventional antibiotics in the combined endpoint of death or deafness (risk difference (RD) -1%, 95% CI -4% to +2%). However, culture positivity of CSF at 10-48 h was significantly higher in the conventional antibiotic group and diarrhoea was significantly more common in the cephalosporin group. When third generation cephalosporins are not available, ampicillin-chloramphenicol combination may be used as an alternative empiric treatment, however both resistance pattern as well as availability should be considered while prescribing empiric therapy of community acquired ABM. The fluid therapy review found too few studies to provide any robust conclusion. In settings with high mortality rates and where patients present late, use of intravenous maintenance fluids seems preferable to a restricted fluid intake. The efficacy of adjuvant corticosteroids varied between high- and low-income countries suggesting greater mortality reduction in high-income countries (RR 0.74, 95% CI 0.52-1.05) than in low-income countries (RR 0.87, 95% CI 0.72-1.05) and a beneficial effect on severe hearing loss in high-income countries (RR 0.32, 95% CI 0.18-0.57), whereas, sparse data in low-income countries (RR 1.04, 95% CI 0.66-1.63). A four-day regimen of dexamethasone should be given preferably before or with the first dose of antibiotics for cases of ABM from high-income countries.

CONCLUSION

In presence of sensitive organisms, third generation cephalosporins and conventional antibiotics lead to similar outcomes. More studies are needed to determine the antimicrobial resistance pattern against various antibiotics in rural and remote areas of developing as well as developed countries. To assess the effectiveness of either restricting or maintenance fluids in populations where patients present early and on death and disability when mortality rates are low, large trials should be conducted. More trials are needed to assess the use of adjuvant dexamethasone for ABM in low-income countries.

Proteomic analysis of a meningococcal outer membrane vesicle vaccine prepared from the group B strain NZ98/254

In the absence of a suitable carbohydrate-based vaccine, outer membrane vesicle (OMV) vaccines have been used to disrupt outbreaks of serogroup B meningococcal disease for more than 20 years. Proteomic technology provides physical methods with the potential to assess the composition and consistency of these complex vaccines. 2-DE, combined with MS, were used to generate a proteome map of an OMV vaccine, developed to disrupt a long-running outbreak of group B disease in New Zealand. Seventy four spots from the protein map were identified including the outer membrane protein (OMP) antigens: PorA, PorB, RmpM and OpcA. Protein identification indicates that, in addition to OMPs, OMV vaccines contain periplasmic, membrane-associated and cytoplasmic proteins. 2-D-DIGE technology highlighted differences between preclinical development batches of vaccines from two different manufacturers.

Outer membrane vesicles of the VA-MENGOC-BC vaccine against serogroup B of Neisseria meningitidis: Analysis of protein components by two-dimensional gel electrophoresis and mass spectrometry

Neisseria meningitidis is a Gram-negative bacterium responsible for significant mortality worldwide. While effective polysaccharides-based vaccines exist against serogroups A, C, W135, and Y, no similar vaccine is suitable for children under 4 years against disease caused by serogroup B strains. Therefore, major vaccine efforts against this serogroup are based on outer membrane vesicles (OMVs), containing major outer membrane proteins. The OMV-based vaccine produced by the Finlay Institute in Cuba (VA-MENGOC-BC) contributed to the rapid decline of the epidemic in this Caribbean island. While the content of major proteins in this vaccine has been discussed, no detailed work of an outer membrane proteomic map of this, or any other, commercially available OMV-derived product has been published so far. Since OMVs exhibit a large bias toward a few major proteins and usually contain a high content of lipids, establishing the adequate conditions for high resolution, 2-DE of this kind of preparation was definitely a technical challenge. In this work, 2-DE and MS have been used to generate a proteomic map of this product, detailing the presence of 31 different proteins, and it allows the identification of new putative protective protein components it contains.

From farm to table to brain: foodborne pathogen infection and the potential role of the neuro-immune-endocrine system in neurotoxic sequelae

The American diet is among the safest in the world; however, diseases transmitted by foodborne pathogens (FBPs) still pose a public health hazard. FBPs are the second most frequent cause of all infectious illnesses in the United States. Numerous anecdotal and clinical reports have demonstrated that central nervous system inflammation, infection, and adverse neurological effects occur as complications of foodborne gastroenteritis. Only a few well-controlled clinical or experimental studies, however, have investigated the neuropathogenesis. The full nature and extent of neurological involvement in foodborne illness is therefore unclear. To our knowledge, this review and commentary is the first effort to comprehensively discuss the issue of FBP induced neurotoxicity. We suggest that much of this information supports the role of a theoretical model, the neuro-immune-endocrine system, in organizing and helping to explain the complex pathogenesis of FBP neurotoxicity.

Vaccine prevention of meningococcal disease, coming soon?

The past century has seen the use of a number of vaccines for prevention and control of meningococcal disease with varied success. The use of polysaccharide vaccines for the control of outbreaks of serogroup C infections in teenagers and young adults and epidemic serogroup A disease has been established for 30 years and an effective protein-polysaccharide conjugate vaccine against serogroup C was introduced into the UK infant immunisation schedule in 2000. The next generation of these glycoconjugate vaccines will be on the shelf soon, eventually offering the prospect of eradication of serogroups A, C, Y and W135 through routine infant immunisation. Despite these exciting prospects, serogroup B meningococci still account for a majority of infections in industrialised nations but development of safe, immunogenic and effective serogroup B meningococcal vaccines has been an elusive goal. Outer membrane vesicle vaccines for B disease are already used in some countries, and will likely be used more widely in the next few years, but efficacy for endemic disease in children has so far been disappointing. However, the innovations arising from the availability of the meningococcal genome sequence, public and scientific interest in the disease and recent pharmaceutical company investment in development of serogroup B vaccines may have started the countdown to the end of meningococcal infection in children.

Presentation, time to antibiotics, and mortality of patients with bacterial meningitis at an urban county medical center

Our objective was to analyze the presentation, time to antibiotics, treatment, and mortality of patients with bacterial meningitis at a large urban county hospital over a 10-year period. A retrospective chart review of all patients with the diagnosis of bacterial meningitis was done. Information concerning presentation, etiologic organisms, treatment (including time to antibiotics), and outcomes were collected and analyzed. There were 165 charts reviewed with 171 total cases of bacterial meningitis. For adults with community-acquired meningitis, the mortality rate was 14%, for children it was 1.6%. Seventy-six percent of patients received antibiotics in the Emergency Department (ED) with a mean time to antibiotics of 1:08 h +/- 13 min. The rest received them as inpatients with a mean time to antibiotics of 6 +/- 9 h. The mortality rate for patients with community-acquired disease who received an Emergency Department antibiotic was 7.9%; for patients who received their antibiotics as inpatients the mortality rate was 29%. Our results indicate that the mortality rates from bacterial meningitis at our institution are lower than previously published results. Furthermore, our study supports the concept that the early administration of antibiotics in the ED may reduce mortality and may be an explanation of the lower mortality rates seen here.

Epidemiology of pneumococcal infections in Swedish children

OBJECTIVE

This paper provides an overview of pneumococcal infections in Swedish children.

METHOD

Data supplied by the Swedish Institute for Infectious Disease Control (SMI) provided information on invasive pneumococcal isolates and on isolates with reduced susceptibility to penicillin. Disease burden was estimated from data collected in northern Stockholm and Malmöhus County.

RESULTS

Only 3-6% of the total number of invasive pneumococcal isolates came from children 0-15 years of age. Predominant serotypes in descending frequency were 7, 6, 14, and 23. Strains from all sources with reduced sensitivity to penicillin (MIC > or = 0.5 mg/l) were found in 3% of children and varied between 0.2% and 11%, with the highest value found in Southern Sweden (predominating strains were 9, 19, 15, 6, and 23). A 10-year review of all cases of meningitis in Northern Stockholm reflected an incidence of 10/100,000 (0-2 years) or 5.8/100,000 (0-5 years), with severe sequelae occurring in 20% of children. This information can be used to predict an annual incidence of 30 cases of meningitis in Sweden.

CONCLUSION

The large proportion of serotype 7 among invasive isolates is distressing since this serotype is not represented in the present 7- and 9-valent protein-conjugated vaccines under development. However, the heptavalent vaccine, including serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F would (at a serotype level) provide coverage against 83% of the resistant isolates in Southern Sweden.

Acute Meningitis

Recent major epidemiologic trends in bacterial meningitis include a dramatic decline in the incidence of Haemophilus influenzae meningitis since the introduction of the protein-conjugated H. influenzae vaccines, and a worldwide increase in infections with antibiotic-resistant strains of bacterial pathogens. Cases of meningitis caused by resistant strains require an alternative therapeutic strategy. Animal studies have identified inflammatory mediators, eg, chemokines, excitatory amino acids, and endothelins, which are involved in the pathophysiology of bacterial meningitis. There is increasing evidence that reactive oxygen species (ROS), reactive nitrogen species, peroxynitrite, and matrix metalloproteinases contribute to brain damage during bacterial meningitis. The cytotoxic effects of ROS and peroxynitrite include the initiation of lipid peroxidation and the induction of DNA single-strand breakage. Damaged DNA activates poly(ADP-ribose) polymerase (PARP). Recent experimental data suggest that lipid peroxidation and PARP activation play a role in the development of meningitis-associated intracranial complications and brain injury. Agents that interfere with the production of ROS and peroxynitrite, and interfere with lipid peroxidation and PARP activation, may represent novel, therapeutic strategies by which meningitis-associated brain damage can be limited, therefore improving the outcome of this serious disease.

Central nervous system imaging. When is CT more appropriate than MRI?

Over the past 25 years, the development of noninvasive imaging techniques has allowed exquisite display of the anatomic structures of the brain and spinal cord in normal and disease states. CT remains useful because of short imaging times, widespread availability, ease of access, sensitive detection of calcification and hemorrhage, and resolution of bony detail. MRI offers superior soft-tissue contrast, excellent visualization of vascular structures, fewer artifacts, and imaging in any plane. Cost and use of ionizing radiation are considerations in choosing the most appropriate procedure. In the future, CT and MRI applications that concentrate on functional and physiologic display of the CNS will add greatly to the clinical utility of these imaging tools.