Changing epidemiology of bacterial meningitis

Epidemiology and antimicrobial resistance patterns of bacterial meningitis among hospitalized patients at a tertiary care hospital in Saudi Arabia: a six-year retrospective study

INTRODUCTION

Bacterial meningitis poses significant medical challenges due to its acute inflammatory nature and potential for severe neurological complications, emphasizing the need for prompt diagnosis and treatment. Limited data exists on its epidemiology and antimicrobial resistance trends among hospitalized patients in Saudi Arabia. This study aimed to investigate these factors at a tertiary care hospital over six years.

METHODS

A retrospective analysis was conducted on cerebrospinal fluid samples results from 222 bacterial meningitis cases among hospitalized patients between 2018 and 2023. Demographic, clinical, microbiological data, and antibiotic susceptibility patterns were collected and analyzed.

RESULTS

Pseudomonas aeruginosa (43%) was the predominant pathogen isolated. Neonates (16%) and children (47%) were most affected population. Nosocomial meningitis accounted for 92% of cases, mainly in the intensive care settings (50.45%). Extended-spectrum beta-lactamase was the leading resistance pattern (12.2%). Seasonal variation was observed, with a peak incidence in October-November.

CONCLUSION

The study highlights the substantial burden of bacterial meningitis among hospitalized patients, especially among high-risk groups. Emerging antimicrobial resistance emphasizes the need for optimized surveillance and stewardship. Future prospective research employing molecular techniques across multiple centers in the country is warranted to enhance understanding and guide public health strategies in Saudi Arabia.

Microbial aspects and potential markers for differentiation between bacterial and viral meningitis among adult patients

OBJECTIVES

Meningitis is a medical emergency with permanent disabilities and high mortality worldwide. We aimed to determine causative microorganisms and potential markers for differentiation between bacterial and viral meningitis.

METHODOLOGY

Adult patients with acute meningitis were subjected to lumber puncture. Cerebrospinal fluid (CSF) microorganisms were identified using Real-time PCR. PCT and CRP levels, peripheral and CSF-leucocyte count, CSF-protein and CSF-glucose levels were assessed.

RESULTS

Out of 80 patients, infectious meningitis was confirmed in 75 cases; 38 cases were bacterial meningitis, 34 cases were viral meningitis and three cases were mixed infection. Higher PCT, peripheral and CSF-leukocytosis, higher CSF-protein and lower CSF-glucose levels were more significant in bacterial than viral meningitis patients. Neisseria meningitides was the most frequent bacteria and varicella-zoster virus was the most common virus. Using ROC analyses, serum PCT and CSF-parameters can discriminate bacterial from viral meningitis. Combined ROC analyses of PCT and CSF-protein significantly improved the effectiveness in predicting bacterial meningitis (AUC of 0.998, 100%sensitivity and 97.1%specificity) than each parameter alone (AUC of 0.951 for PCT and 0.996 for CSF-protein).

CONCLUSION

CSF-protein and serum PCT are considered as potential markers for differentiating bacterial from viral meningitis and their combination improved their predictive accuracy to bacterial meningitis.

Update and advances in community acquired bacterial meningitis

PURPOSE OF REVIEW

Community-acquired bacterial meningitis continues to occur and be associated with significant morbidity and mortality despite the availability of effective conjugate vaccines for the three most important meningeal pathogens.

RECENT FINDINGS

Indications for cranial imaging in suspected bacterial meningitis varies significantly between guidelines. Cranial imaging is of no clinical utility in those patients without indications and fosters delays in performing a lumbar puncture. Delaying lumbar puncture is associated with increased costs in both adults and children with meningitis and previous antibiotic therapy impacts the yield of microbiological results. Delaying antibiotic therapy is associated with worse clinical outcomes. Adjunctive steroids have reduced the mortality of adults with pneumococcal meningitis but have been associated with increased adverse outcomes in Listeria monocytogenes and Cryptococcus neoformans.

SUMMARY

Community-acquired bacterial meningitis remains a global health concern with high morbidity and mortality especially in low-income countries. Cranial imaging should be done only in patients with an indication with an attempt to do a prompt lumbar puncture and to initiate antibiotic therapy and adjunctive steroids as soon as possible to improve clinical outcomes.

Economic analysis of rapid multiplex polymerase chain reaction testing for meningitis/encephalitis in adult patients

PURPOSE

Many patients with suspected meningitis do not require hospitalization yet are admitted, often resulting in unnecessary care and additional cost. We assessed the possible economic impact of a rapid multiplex test for suspected adult community-acquired meningitis/encephalitis.

METHODS

A model simulated diagnosis, clinical decisions, resource use/costs of standard of care (SOC) and two cerebrospinal fluid (CSF) testing strategies using the FDA-cleared BioFire® FilmArray® System (FA) which provides results in approximately one hour.

RESULTS

Pathogens detected by FA caused approximately 74% of cases, 97% of which would be accurately diagnosed with FA. False positives and false negatives more often led to extended/unnecessary admission than inappropriate discharge/missed admission. Mean cost per case ranged from 16829 to 20791. A strategy of testing all suspected cases yielded greater savings (2213/case) than testing only those with abnormal CSF (812/case) and both were less expensive than SOC.

CONCLUSION

This economic analysis demonstrates that FA can inform more appropriate clinician decisions resulting in cost savings with greater economic benefits achievable with syndromic testing of all cases, rather than SOC or targeted syndromic testing.

Diagnosis of bacterial meningitis in Ghana: Polymerase chain reaction versus latex agglutination methods

Bacterial meningitis is a public health crisis in the northern part of Ghana, where it contributes to very high mortality and morbidity rates. Early detection of the causative organism will lead to better management and effective treatment. Our aim was to evaluate the diagnostic accuracy of Pastorex and Wellcogen latex agglutination tests for the detection of bacterial meningitis in a resource-limited setting. CSF samples from 330 suspected meningitis patients within the northern zone of Ghana were analysed for bacterial agents at the zonal Public Health Reference Laboratory in Tamale using polymerase chain reaction (PCR) and two latex agglutination test kits; Pastorex and Wellcogen. The overall positivity rate of samples tested for bacterial meningitis was 46.4%. Streptococcus pneumoniae was the most common cause of bacterial meningitis within the sub-region, with positivity rate of 25.2%, 28.2% and 28.8% when diagnosed using Wellcogen, Pastorex and PCR respectively. The Pastorex method was 97.4% sensitive while the Wellcogen technique was 87.6% sensitive. Both techniques however produced the same specificity of 99.4%. Our study revealed that the Pastorex method has a better diagnostic value for bacterial meningitis than the Wellcogen method and should be the method of choice in the absence of PCR.

Epidemiology of Meningitis and Encephalitis in Infants and Children in the United States, 2011-2014

BACKGROUND

Large epidemiologic studies evaluating the etiologies, management decisions and outcomes of infants and children with meningitis and encephalitis in the United States are lacking.

METHODS

Children 0-17 years of age with meningitis or encephalitis as assessed by International Classification of Diseases, Ninth Revision, codes available in the Premier Healthcare Database during 2011-2014 were analyzed.

RESULTS

Six thousand six hundred sixty-five patients with meningitis or encephalitis were identified; 3030 (45.5%) were younger than 1 year of age, 295 (4.4%) were 1-2 years of age, 1460 (21.9%) were 3-9 years of age, and 1880 (28.2%) were 10-17 years of age. Etiologies included enterovirus (58.4%), unknown (23.7%), bacterial (13.0%), noninfectious (3.1%), herpes simplex virus (1.5%), other viruses (0.7%), arboviruses (0.5%) and fungal (0.04%). The majority of patients were male [3847 (57.7%)] and healthy [6094 (91.4%)] with no reported underlying conditions. Most underwent a lumbar puncture in the emergency department [5363 (80%)] and were admitted to the hospital [5363 (83.1%)]. Antibiotic therapy was frequent (92.2%) with children younger than 1 year of age with the highest rates (97.7%). Antiviral therapy was less common (31.1%). Only 539 (8.1%) of 6665 of patients received steroids. Early administration of adjunctive steroids was not associated with a reduction in mortality (P = 0.266). The overall median length of stay was 2 days. Overall mortality rate (0.5%) and readmission rates (<1%) was low for both groups.

CONCLUSION

Meningitis and encephalitis in infants and children in the United States are more commonly caused by viruses and are treated empirically with antibiotic therapy and antiviral therapy in a significant proportion of cases. Adjunctive steroids are used infrequently and are not associated with a benefit in mortality.

Economic analysis of rapid multiplex polymerase chain reaction testing for meningitis/encephalitis in pediatric patients

AIM

We assessed the possible economic impact of a rapid test in pediatric patients with suspected community-acquired meningitis/encephalitis.

MATERIALS & METHODS

Modeling simulated diagnosis, clinical decisions, resource use/costs of standard of care (SOC) and two cerebrospinal fluid testing strategies using FilmArray^® (FA), a US FDA-cleared system that provides results in approximately 1 h.

RESULTS

Pathogens detected by FA caused approximately 75% of cases, 97% of which would be accurately diagnosed with FA.  Mean cost/case ranged from $17,599 to $22,025.  Syndromic testing is less expensive than SOC. Testing all suspected cases yielded greater savings ($3481/case) than testing only those with abnormal cerebrospinal fluid ($2157/case).

CONCLUSION

Greater economic benefits are achievable with syndromic testing of all cases, rather than SOC or targeted syndromic testing.

Evaluation of bacterial meningitis surveillance data of the northern region, Ghana, 2010-2015

INTRODUCTION

Bacterial meningitis is a disease of major public health importance especially for countries such as Ghana; whose northern part lies within the meningitis belt. The Northern region of Ghana has been recording cases with outbreaks over the years. In order to generate evidence to improve surveillance, we described the epidemiology of bacterial meningitis using surveillance data of the northern region.

METHODS

Bacterial meningitis datasets from January 2010 to December 2015 for all the 26 districts of the Northern region were retrieved from line lists. Data were analyzed in terms of person, place, time, and identity of causative organisms using descriptive statistics. The results were presented as proportions, rates, tables and graphs.

RESULTS

A total of 1,176 cases were reported. Of these, 53.5% (629/1,176) were males. The proportion of cases aged 0 to 29 years was 77.4%. The Overall Case Fatality Rate (CFR) was 9.7% (114/1,176). About 65% of all cases were recorded from January to April. Only 23.7% (279/1,176) of cases were laboratory-confirmed. Neisseria meningitides and Streptococcus pneumonia accounted for 91.4% of confirmed cases. Over the period, the incidence reduced from 9.0/100,000 population to 3.8/100,000 population and CFR reduced from 16.6% to 5.7%.

CONCLUSION

Most cases of bacterial meningitis were recorded in the dry season and in persons younger than 30 years. Less than a quarter of cases were laboratory confirmed, and no new bacteria species were identified. Both morbidity and mortality rates were on the decline. There is the need to consolidate these gains by intensifying meningitis surveillance and improving on the rate of laboratory case confirmation.

Acute Bacterial Meningitis in Qatar: A Hospital-Based Study from 2009 to 2013

Background and Objectives

Bacterial meningitis is a common medical condition in Qatar. The aim of this study was to describe the clinical characteristics of bacterial meningitis, the frequency of each pathogen, and its sensitivity to antibiotics and risk factors for death.

Patients and Methods

This retrospective study was conducted at Hamad General Hospital between January 1, 2009, and December 31, 2013.

Results

We identified 117 episodes of acute bacterial meningitis in 110 patients. Their mean age was 26.4 ± 22.3 years (range: 2–74) and 81 (69.2%) of them were male patients. Fifty-nine episodes (50.4%) were community-acquired infection and fever was the most frequent symptom (94%), whereas neurosurgery is the most common underlying condition. Coagulase-negative staphylococci were the most common causative agent, of which 95% were oxacillin-resistant, while 63.3% of Acinetobacter spp. showed resistance to meropenem. The in-hospital mortality was 14 (12%). Only the presence of underlying diseases, hypotension, and inappropriate treatment were found to be independent predictors of mortality.

Conclusion

Acute bacterial meningitis predominantly affected adults and coagulase-negative staphylococci species were the common causative agent in Qatar with majority of infections occurring nosocomially. More than 90% of all implicated coagulase-negative staphylococci strains were oxacillin-resistant.

Bacterial meningitis in Finland, 1995-2014: a population-based observational study

OBJECTIVES

Bacterial meningitis remains an important cause of morbidity and mortality worldwide. Its epidemiological characteristics, however, are changing due to new vaccines and secular trends. Conjugate vaccines against Haemophilus influenzae type b and Streptococcus pneumoniae (10-valent) were introduced in 1986 and 2010 in Finland. We assessed the disease burden and long-term trends of five common causes of bacterial meningitis in a population-based observational study.

METHODS

A case was defined as isolation of S. pneumoniae, Neisseria meningitidis, Streptococcus agalactiae, Listeria monocytogenes or H. influenzae from cerebrospinal fluid and reported to national, population-based laboratory surveillance system during 1995-2014. We evaluated changes in incidence rates (Poisson or negative binomial regression), case fatality proportions (χ²) and age distribution of cases (Wilcoxon rank-sum).

RESULTS

During 1995-2014, S. pneumoniae and N. meningitidis accounted for 78% of the total 1361 reported bacterial meningitis cases. H. influenzae accounted for 4% of cases (92% of isolates were non-type b). During the study period, the overall rate of bacterial meningitis per 1 00 000 person-years decreased from 1.88 cases in 1995 to 0.70 cases in 2014 (4% annual decline (95% CI 3% to 5%). This was primarily due to a 9% annual reduction in rates of N. meningitidis (95% CI 7% to 10%) and 2% decrease in S. pneumoniae (95% CI 1% to 4%). The median age of cases increased from 31 years in 1995-2004 to 43 years in 2005-2014 (p=0.0004). Overall case fatality proportion (10%) did not change from 2004 to 2009 to 2010-2014.

CONCLUSIONS

Substantial decreases in bacterial meningitis were associated with infant conjugate vaccination against pneumococcal meningitis and secular trend in meningococcal meningitis in the absence of vaccination programme. Ongoing epidemiological surveillance is needed to identify trends, evaluate serotype distribution, assess vaccine impact and develop future vaccination strategies.

Central Nervous System Device Infections

Nosocomial meningitis can occur in association with central nervous system (CNS) devices such as cerebrospinal shunts or drains, intrathecal pumps, and deep brain stimulators and carry substantial morbidity and mortality. Diagnosing and treating these infections may be challenging to physicians as cerebrospinal fluid cultures may be negative due to previous antibiotic therapy and cerebrospinal abnormalities may be secondary to the primary neurosurgical issue that prompted the placement of the CNS device (e.g., "chemical meningitis" due to intracranial hemorrhage). Besides antibiotic therapy given intravenously and sometimes intrathecally, removal of the device with repeat cultures prior to re-implantation is key in achieving successful outcomes.

Community-acquired meningitis in older adults: clinical features, etiology, and prognostic factors

OBJECTIVES

To investigate the epidemiology and outcomes of community-acquired meningitis in older adults.

DESIGN

Retrospective study.

SETTING

Participants adults in Houston, Texas, with community-acquired meningitis hospitalized between January 1, 2005, and January 1, 2010 (N = 619; n = 54, 8.7%, aged ≥65; n = 565 aged <65).

METHODS

An adverse clinical outcome was defined as a Glasgow Outcome Scale score of 4 or less.

RESULTS

Older adults had higher rates of comorbidities, abnormal neurological and laboratory (serum white blood cell count >12,000/μL, and cerebrospinal fluid protein >100 mg/dL) findings (P < .001), abnormalities on computed tomography and magnetic resonance imaging of the head (P = .002), and adverse clinical outcomes (ACOs) (P < .001). The majority of participants (65.8%) had meningitis of unknown etiology. Bacterial meningitis was an infrequent cause of community-acquired meningitis (7.4%). Of the known causes, bacterial meningitis and West Nile virus were more common in older than younger adults; younger participants more frequently had cryptococcal and viral meningitis. On logistic regression, female sex was predictive of a poor outcome in the older participants (P = .002), whereas abnormal neurological examination (P < .001), fever (P = .01), and a cerebrospinal fluid glucose level less than 45 mg/dL (P = .002) were significant poor prognostic factors in younger participants.

CONCLUSION

Most cases of community-acquired meningitis are of unknown origin. Older adults are more likely than younger adults to have bacterial meningitis and West Nile virus infection when a cause can be identified. They also have more neurological abnormalities, laboratory and imaging abnormalities, and adverse clinical outcomes.

Epidemiology of bacterial meningitis in the USA from 1997 to 2010: a population-based observational study

BACKGROUND

Bacterial meningitis continues to be a substantial cause of morbidity and mortality, but the epidemiological trends after adjunctive dexamethasone recommendations are unknown in the USA. We aimed to describe the changing patterns among the most common bacterial causes in the USA after conjugate vaccination and to assess the association between adjunctive dexamethasone and mortality.

METHODS

For this population-based observational study, we searched information available from hospital discharges about incidence and inpatient mortality for the most important causes of community and nosocomial bacterial meningitis based on International Classification of Diseases coding across all hospitals in the USA between 1997 and 2010 with the HealthCare Cost Utilization Project (HCUP) network database. We calculated incidences according to US Census Bureau data and used a negative binomial regression model to evaluate the significance of changes over time. We assessed mortality from pneumococcus for three periods 1997-2001 (baseline), 2002-04 (transition years), and 2005-08 (after corticosteroid recommendations were available).

FINDINGS

Streptococcus pneumoniae incidence fell from 0·8 per 100 000 people in 1997, to 0·3 per 100 000 people by the end of 2010 (RR 0·3737, 95% CI 0·1825-0·7656). Mortality from pneumococcal meningitis decreased between 2005 (0·049 per 100 000 people) and 2008 (0·024 per 100 000 people) compared with between 2002 (0·073 per 100 000 people) and 2004 (0·063 per 100 000 people; RR 0·5720, 95% CI 0·4303-0·7582). The incidence of Neisseria meningitidis infection decreased from 0·721 per 100 000 people in 1997, to 0·123 per 100 000 people in 2010 (RR 0·1386, 95% CI 0·048-0·4284), which has placed this pathogen close to common bacterial causes of nosocomial meningitis such as staphylococcus and Gram-negative bacteria and to Haemophilus influenzae.

INTERPRETATION

S pneumoniae continues to be the leading identifiable cause of bacterial meningitis in the USA, but with a significant decrease in incidence and mortality associated with the introduction of conjugated vaccines and a mortality decrease that is associated with the introduction of recommendations for use of adjunctive dexamethasone for pneumococcal meningitis.

FUNDING

National Center for Research Resources.

Role of Clinical Presentations and Routine CSF Analysis in the Rapid Diagnosis of Acute Bacterial Meningitis in Cases of Negative Gram Stained Smears

Background and Aim. Bacterial meningitis is a lethal, disabling endemic disease needing prompt antibiotic management. Gram stained smears is rapid accurate method for diagnosis of bacterial meningitis. In cases of negative gram stained smears diagnosis is delayed till culture results. We aim to assess the role of clinical presentations and routine CSF analysis in the cost-effective rapid diagnosis of negative gram stained smears bacterial meningitis. Methods. Cross sectional study including 623 acute meningitis patients divided into two groups: bacterial meningitis and nonbacterial meningitis groups. The clinical presentations, systemic inflammatory parameters, and CSF analysis were evaluated and compared in both groups. Results. Altered conscious level, localizing neurological signs, Kernig's and Brudzinski's signs together with peripheral leucocytosis (>10.000/mm(3)), high CRP (>6) together with high CSF protein (>50 gl/dL), CSF neutrophilic count (≥50% of total CSF leucocytic count), and low CSF glucose level (<45 gm/dL) and CSF/serum glucose ≤0.6 were significantly diagnostic in bacterial meningitis patients. From the significant CSF analysis variables CSF protein carried the higher accuracy of diagnosis 78% with sensitivity 88% and specificity 72%. Conclusions. High CSF protein (>50 mg/dL) together with plasma inflammatory markers and CSF cytochemical parameters can diagnose bacterial meningitis in gram stain negative smear till culture results.

Optimising assessments of the epidemiological impact in The Netherlands of paediatric immunisation with 13-valent pneumococcal conjugate vaccine using dynamic transmission modelling

This work is the first attempt to quantify the overall effects of a 13-valent pneumococcal conjugate vaccine (PCV13) vaccination programme in the Dutch population taking into account all the direct and indirect effects of the vaccine on invasive pneumococcal disease. Using available Dutch data, a dynamic transmission model for the spread of pneumococci and potential subsequent invasive pneumococcal disease has been adapted to the Dutch setting. Overall, invasive pneumococcal disease cases in the Netherlands are predicted to decrease from a pre-vaccination level of 2623 cases annually to 2475, 2289, 2185, 2179, and 2178 cases annually 5-, 10-, 20-, 30-, and 40-years, respectively, post-vaccination. Therefore, vaccination with PCV13 in the Netherlands is predicted to lower invasive pneumococcal disease cases per year by up to 445 cases in the medium- to long-term. The results are quite robust for the sensitivity analyses performed on the parameters that regulate herd immunity and competition between vaccine and non-vaccine types.

Meningitis

Meningitis is defined as inflammation of the meninges, in almost all cases identified by an abnormal number of white blood cells in the cerebrospinal fluid and specific clinical signs/symptoms. Onset may be acute or chronic, and clinical symptoms of acute disease develop over hours to days. This article reviews the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of acute meningitis, and provides a list of key points for primary care practitioners. Aseptic and bacterial meningitis vary significantly and are discussed separately.

[Current cerebrospinal fluid diagnostics for pathogen-related diseases]

Cerebrospinal fluid (CSF) analysis is of utmost importance to establish an early diagnosis of central nervous system (CNS) infections and to start appropriate therapy. The CSF white cell count, lactate concentration and total protein levels are usually available very quickly even from non-specialized laboratories and the combination of these parameters often provides sufficient information for decision-making in emergency cases. It is, however, not always possible to identify the underlying infective agent despite further CSF analyses, such as bacterial and fungal staining, evaluation of the blood-CSF barrier function, intrathecal immunoglobulin synthesis and oligoclonal IgG bands. Therefore, close communication between the laboratory and the clinician is an important prerequisite to specify additional pathogen-related diagnostic measures for successful confirmation of the diagnosis.

Application of a prediction rule to discriminate between aseptic and bacterial meningitis in adults

INTRODUCTION

Differentiating between aseptic and bacterial meningitis presents a difficult diagnostic challenge. Accurately ruling out bacterial meningitis may reduce unnecessary hospitalization, patient morbidity, and utilization of resources. This study applies a prediction rule previously developed in the pediatric population to an adult cohort.

METHODS

We performed a retrospective chart review of all patients admitted to an urban community hospital in the United States between 1994 and 2007.

RESULTS

One hundred eleven patients met the inclusion criteria. Twenty-two (20%) had bacterial meningitis and 89 (80%) had aseptic meningitis. The prediction rule generated a negative predictive value of 100% and a sensitivity of 100%, successfully ruling out all patients with aseptic meningitis.

CONCLUSIONS

The prediction rule, previously validated in a pediatric population, was accurate in ruling out bacterial meningitis in an adult cohort. Prospective validation in an adult population is warranted.

U.S. emergency department visits for meningitis, 1993-2008

OBJECTIVES

Large-scale epidemiologic studies of meningitis in the emergency department (ED) setting are lacking. Using a nationwide sample, the authors determined the frequency of meningitis visits and characterize management.

METHODS

Using National Hospital Ambulatory Medical Care Survey (NHAMCS) data, 1993 through 2008, meningitis diagnoses were studied and national rates were estimated via standard weighting procedures.

RESULTS

Meningitis was diagnosed at 1,048,000 visits (95% confidence interval [CI] = 893,000 to 1,203,000) during 1993 through 2008. This is 66,000 cases annually, or 62 per 100,000 visits, with no change over time (p = 0.20). ED diagnoses were unspecified (60%), viral (31%), bacterial (8%), and fungal (1%) meningitis. Median age was 24 years (interquartile range = 9 to 40 years). While 1.97 times as many adults were diagnosed with meningitis (95% CI = 1.83 to 2.13), meningitis accounted for a similar proportion of visits among children and adults (ratio = 1.33, 95% CI = 0.58 to 2.63). Per population, children were more likely to have a meningitis visit (31 vs. 21 per 100,000; ratio = 1.48, 95% CI =1.003 to 2.10); children aged younger than 3 years had the highest rate (98 per 100,000, 95% CI =63 to 133). Spring and summer visits were 1.25 times as numerous as fall a nd winter (95% CI= 1.15 to 1.36). Third-generation cephalosporins were administered in 42%, analgesics in 19%, and antiemetics in 15% of cases, and 66% were admitted to the hospital (95% CI= 58% to 73%).

CONCLUSIONS

Meningitis is rare, diagnosed at 62 per 100,000 ED visits. Rates have been stable over time. Children are 1.48 times more likely to have a visit for meningitis, although adults make twice as many visits. Absence of consensus guidelines for patients suspected of having viral meningitis but being tested for bacterial meningitis may lead to variability in admission and prescribing decisions.

Identification of a novel pneumococcal vaccine antigen preferentially expressed during meningitis in mice

Streptococcus pneumoniae is the most common cause of severe bacterial meningitis in children, the elderly, and immunocompromised individuals. To identify virulence factors preferentially expressed during meningitis, we conducted niche-specific genome-wide in vivo transcriptomic analysis after intranasal infection of mice with serotype 4 or 6A pneumococci. The expression of 34 bacterial genes was substantially altered in brain tissue of mice infected with either of the 2 strains. Ten upregulated genes were common to both strains, 7 of which were evaluated for their role in the development of meningitis. One previously uncharacterized protein, α-glycerophosphate oxidase (GlpO), was cytotoxic for human brain microvascular endothelial cells (HBMECs) via generation of H(2)O(2). A glpO deletion mutant was defective in adherence to HBMECs in vitro as well as in progression from the blood to the brain in vivo. Mutant bacteria also induced markedly reduced meningeal inflammation and brain pathology compared with wild type, despite similar levels of bacteremia. Immunization of mice with GlpO protected against invasive pneumococcal disease and provided additive protection when formulated with pneumolysin toxoid. Our results provide the basis of a strategy that can be adapted to identify genes that contribute to the development of meningitis caused by other pathogens.

Is adjunctive corticosteroid beneficial in pneumococcal meningitis in a region with high rates of resistance to penicillin and ceftriaxone?

The role of adjunctive corticosteroids remains controversial in meningitis by penicillin-resistant pneumococci. We determined the effect of adjunctive corticosteroids in adults with pneumococcal meningitis in a region with a high rate of penicillin resistance. A multicenter, retrospective cohort study was conducted between 1998 and 2008 in Korea. The mortality and neurological sequelae were evaluated. Among 93 patients with pneumococcal meningitis, adequate adjunctive corticosteroids were given in 45.2%. The penicillin resistance rate was 60.0%, and 42.1% were nonsusceptible to ceftriaxone. The 30-day mortality rates in the group receiving adequate corticosteroid therapy, the group in which corticosteroid was not given, and that inadequately given were 24.3, 31.6, and 27.3%, respectively, and there was no difference between the groups. The rates of development of neurological sequelae were 34.3, 33.3, and 43.5%, respectively. Multivariate analysis showed that adequate corticosteroids did not reduce mortality (HR 0.773, 95% CI 0.293-2.040) and neurologic sequelae (HR 0.604, CI 0.262-1.393). Propensity-adjusted analysis showed that adjunctive corticosteroid was not associated with time to death (HR 0.949, CI 0.374-2.408), however, a decreasing tendency was shown in neurologic sequelae in the adequate corticosteroid group (HR 0.479, CI 0.207-1.110). In conclusion, adjunctive corticosteroids did not affect mortality in adults with pneumococcal meningitis in a region with high rates of resistance to penicillin and ceftriaxone; however, the patients receiving adequate corticosteroid therapy tended to develop neurologic sequelae less frequently.

The burden of pneumococcal disease in children less than 5 years of age in Abu Dhabi, United Arab Emirates

BACKGROUND AND OBJECTIVE

Streptococcus pneumoniae is a major cause of mortality and morbidity in both developing and industrialized countries, especially among young children and in both immunocompromised and immunocompetent individuals. It is implicated in both invasive (e.g. meningitis and septicemia) as well as noninvasive disease (community-acquired pneumonia and otitis media). The objective of the current study was to describe the overall epidemiology of both invasive and noninvasive pneumococcal disease in Abu Dhabi over a 5-year period.

DESIGN AND SETTING

Retrospective review of all pediatric (≤ 5 year old) pneumococcal disease admissions to Shaikh Khalifa Medical City (SKMC) and Mafraq Hospital in Abu Dhabi from 1 January 2001 till 31 December 2005.th

METHODS

We retrieved computerized data from the health information management systems (International Classification of Diseases, 9th Revision (ICD9) diagnosis codes) as well as manual surveillance in the laboratory record of pneumococcal isolates.

RESULTS

The incidence of invasive pneumococcal disease was 13.6/100, 000 per year (95% CI, 6.5-24.9) and the incidence of noninvasive pneumococcal disease was 172.5/100,000 per year (95% CI, 143.8-205.2). The total incidence rate was 186.0/100, 000 per year (95% CI, 156.2-219.9).

CONCLUSION

This epidemiological survey indicates that the incidence rates in the United Arab Emirate are higher than in Western countries where conjugate pneumococcal vaccine has been introduced. This study is important as it documents the incidence of pneumococcal disease in the era before introduction of the conjugate pneumococcal vaccine and allows for future research to document the impact of a new vaccine considering the geographic variation of pneumococcal serotypes.

Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis

The epidemiology of bacterial meningitis has changed as a result of the widespread use of conjugate vaccines and preventive antimicrobial treatment of pregnant women. Given the significant morbidity and mortality associated with bacterial meningitis, accurate information is necessary regarding the important etiological agents and populations at risk to ascertain public health measures and ensure appropriate management. In this review, we describe the changing epidemiology of bacterial meningitis in the United States and throughout the world by reviewing the global changes in etiological agents followed by specific microorganism data on the impact of the development and widespread use of conjugate vaccines. We provide recommendations for empirical antimicrobial and adjunctive treatments for clinical subgroups and review available laboratory methods in making the etiological diagnosis of bacterial meningitis. Finally, we summarize risk factors, clinical features, and microbiological diagnostics for the specific bacteria causing this disease.

Community acquired bacterial meningitis in Cuba: a follow up of a decade

Background

Community acquired Bacterial Meningitis (BM) remains a serious threat to global health. Cuban surveillance system for BM allowed to characterize the main epidemiological features of this group of diseases, as well as to assess the association of some variables with mortality. Results of the BM surveillance in Cuba are presented in this paper.

Methods

A follow up of BM cases reported to the Institute "Pedro Kourí" by the National Bacterial Meningitis Surveillance System from 1998 to 2007 was completed. Incidence and case-fatality rate (CFR) were calculated. Univariate analysis and logistic regression were used to elucidate associated factors to mortality comparing death versus survival. Relative Risk (RR) or odds ratio and its 95% confidence interval (CI 95%) were estimated, using either a Chi-squared Test or Fisher's Exact Test as appropriate. A Holt-Winters model was used to assess seasonality.

Results

4 798 cases of BM (4.3 per 100 000 population) were reported, with a decreasing trend of the incidence. Highest incidence was observed in infants and elderly. Overall CFR reached 24.1% affecting mostly older adults. S. pneumoniae (23.6%), N. meningitidis(8.2%) and H. influenzaetype b (6.0%) were the main causative agents. Males predominate in the incidence. Highest incidence and CFR were mainly clustered in the centre of the island. The univariate analysis did not show association between delayed medical consultation (RR = 1.20; CI = 1.07-1.35) or delayed hospitalization (RR = 0.98; CI = 0.87-1.11) and the fatal outcome. Logistic regression model showed association of categories housewife, pensioned, imprisoned, unemployed, S. peumoniae and other bacteria with mortality. Seasonality during September, January and March was observed.

Conclusions

The results of the National Program for Control and Prevention of the Neurological Infectious Syndrome evidenced a reduction of the BM incidence, but not the CFR. Multivariate analysis identified an association of mortality with some societal groups as well as with S. peumoniae.

Bacterial meningitis: epidemiology, pathogenesis and management update

Bacterial meningitis continues to be an important disease throughout the world and can be a life-threatening emergency if not suspected, appropriately diagnosed and managed expeditiously. The epidemiology of bacterial meningitis has changed dramatically over the last 20 years, primarily as a result of the introduction of conjugate vaccines against the common meningeal pathogens, such that in the developed world where vaccination is routinely utilized, bacterial meningitis has become a disease of adults rather than of infants and children. The management approach to patients with suspected or proven bacterial meningitis includes emergent cerebrospinal fluid analysis and initiation of appropriate antimicrobial and adjunctive therapies. The choice of empirical antimicrobial therapy is based on the patient's age and underlying disease status; once the infecting pathogen is isolated, antimicrobial therapy can be modified for optimal treatment. Many patients with suspected or proven bacterial meningitis should also receive adjunctive dexamethasone therapy. This is based on experimental animal model data which demonstrated that the subarachnoid space inflammatory response that results from antimicrobial-induced bacterial lysis can contribute to morbidity and mortality. Clinical studies have demonstrated the benefit of adjunctive dexamethasone in infants and children with Haemophilus influenzae type B meningitis, and adults with pneumococcal meningitis, in which mortality and adverse outcome are reduced. Use of adjunctive dexamethasone in adults with meningitis caused by other bacteria, and in infants and children with pneumococcal meningitis, is controversial. To be effective, adjunctive dexamethasone should be administered concomitant with or just prior to the first antimicrobial dose for maximal effect on the subarachnoid space inflammatory response.

Effect of pneumococcal conjugate vaccine on pneumococcal meningitis

BACKGROUND

Invasive pneumococcal disease declined among children and adults after the introduction of the pediatric heptavalent pneumococcal conjugate vaccine (PCV7) in 2000, but its effect on pneumococcal meningitis is unclear.

METHODS

We examined trends in pneumococcal meningitis from 1998 through 2005 using active, population-based surveillance data from eight sites in the United States. Isolates were grouped into PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F), PCV7-related serotypes (6A, 9A, 9L, 9N, 18A, 18B, 18F, 19B, 19C, 23A, and 23B), and non-PCV7 serotypes (all others). Changes in the incidence of pneumococcal meningitis were assessed against baseline values from 1998-1999.

RESULTS

We identified 1379 cases of pneumococcal meningitis. The incidence declined from 1.13 cases to 0.79 case per 100,000 persons between 1998-1999 and 2004-2005 (a 30.1% decline, P<0.001). Among persons younger than 2 years of age and those 65 years of age or older, the incidence decreased during the study period by 64.0% and 54.0%, respectively (P<0.001 for both groups). Rates of PCV7-serotype meningitis declined from 0.66 case to 0.18 case (a 73.3% decline, P<0.001) among patients of all ages. Although rates of PCV7-related-serotype disease decreased by 32.1% (P=0.08), rates of non-PCV7-serotype disease increased from 0.32 to 0.51 (an increase of 60.5%, P<0.001). The percentages of cases from non-PCV7 serotypes 19A, 22F, and 35B each increased significantly during the study period. On average, 27.8% of isolates were nonsusceptible to penicillin, but fewer isolates were nonsusceptible to chloramphenicol (5.7%), meropenem (16.6%), and cefotaxime (11.8%). The proportion of penicillin-nonsusceptible isolates decreased between 1998 and 2003 (from 32.0% to 19.4%, P=0.01) but increased between 2003 and 2005 (from 19.4% to 30.1%, P=0.03).

CONCLUSIONS

Rates of pneumococcal meningitis have decreased among children and adults since PCV7 was introduced. Although the overall effect of the vaccine remains substantial, a recent increase in meningitis caused by non-PCV7 serotypes, including strains nonsusceptible to antibiotics, is a concern.

Fever in Common Infectious Diseases

#x203A; Infection of the respiratory tract is the most common reason for seeking medical advice and hospital admission in children. A viral upper respiratory tract infection (URTI) is the most common infection of the respiratory tract.

› In developing countries, acute respiratory infection remains a leading cause of childhood mortality, causing an estimated 1.5–2 million deaths annually in children younger than 5 years of age.

› In developed countries, viruses are responsible for most upper and lower respiratory tract infections, including pharyngitis and pneumonia.

› Although the degree of fever cannot differentiate between viral and bacterial diseases, high fever is associated with a greater incidence of serious bacterial diseases such as pneumonia or meningitis.

› Worldwide, diarrheal disease is the leading cause of childhood deaths under 5 years of age.

› If the fever does not have an evident source, urinary tract infection (UTI) should be considered, particularly if the fever is greater than 39.0°C and persists for longer than 24–48 h.

› Widespread vaccinations against bacteria causing meningitis, such as Hib, and vaccines against meningococci and pneumococci have dramatically reduced the incidence of meningitis.

› A child with fever and nonblanching rash should be promptly evaluated to exclude meningococcal diseases.

› Young children with malaria may present with irregular fever and not with typical paroxysms of fever, occurring particularly in early falciparum infection or as a consequence of previous chemoprophylaxis, which modifies the typical pattern of fever.

Toll-like receptors in bacterial meningitis

Bacterial meningitis is still an important infectious disease with a high morbidity and mortality rate. Bacterial infection of the cerebrospinal fluid (CSF) space causes a powerful inflammatory reaction that is largely responsibly for meningitis-induced tissue damage and adverse outcome of the disease. In a landmark series of experiments in the mid-1980s, cell wall components including lipooligosaccharides and lipoteichoic acid were indicated to be the key bacterial elements that can trigger the host inflammatory response in the CSF. Ten years ago, the discovery of Toll-like receptor proteins (TLRs) that allow the detection of microbial components and initiate the host immune response opened up new horizons in research on the pathophysiology of meningitis. Cell culture approaches provided the first evidence for a crucial role of TLRs in sensing meningeal pathogens including Streptococcus pneumoniae, Neisseria meningitidis, Streptococcus agalactiae, and Listeria monocytogenes. Subsequently, studies in mice with single or combined deficiencies in TLRs demonstrated that TLR activation is a key event in meningeal inflammation and, even more interestingly, a pivotal factor for meningitis-associated tissue damage. A detailed understanding of the mechanisms of host-pathogen interactions in the CSF space may generate new opportunities for specific treatment strategies for bacterial meningitis.

Bacterial meningitis and epilepsy

The high incidence and prevalence of epilepsy in developing countries has partly been attributed to an increased frequency of central nervous system (CNS) infections. Of the CNS infections, bacterial meningitis is endemic in many countries and several epidemics have also been reported in these regions. Unprovoked seizures and epilepsy (recurrent unprovoked seizures) can be long-term sequelae of bacterial meningitis. The probability of developing an unprovoked seizure or epilepsy varies according to the etiologic agent responsible for meningitis and this probability appears to be higher for Streptococcus pneumoniae. The risk factors for late unprovoked seizures/epilepsy include early seizures during the acute phase of meningitis and persistent neurological deficits other than sensorineural hearing loss. The majority of unprovoked seizures occur within 5 years of the meningitis episode and tend to be recurrent. The burden of epilepsy associated with bacterial meningitis depends upon the incidence of the latter and hence is to some extent preventable. Implementing vaccination programs against the three most important meningeal pathogens can reduce the incidence of bacterial meningitis. In developed countries, a decline in the incidence of bacterial meningitis has been accomplished with the implementation of vaccination programs.

The diagnosis and management of acute bacterial meningitis in resource-poor settings

Acute bacterial meningitis is more common in resource-poor than resource-rich settings. Survival is dependent on rapid diagnosis and early treatment, both of which are difficult to achieve when laboratory support and antibiotics are scarce. Diagnostic algorithms that use basic clinic and laboratory features to distinguish bacterial meningitis from other diseases can be useful. Analysis of the CSF is essential, and simple techniques can enhance the yield of diagnostic microbiology. Penicillin-resistant and chloramphenicol-resistant bacteria are a considerable threat in resource-poor settings that go undetected if CSF and blood can not be cultured. Generic formulations of ceftriaxone are becoming more affordable and available, and are effective against meningitis caused by penicillin-resistant or chloramphenicol-resistant bacteria. However, infection with Streptococcus pneumoniae with reduced susceptibility to ceftriaxone is reported increasingly, and alternatives are either too expensive (eg, vancomycin) or can not be widely recommended (eg, rifampicin, which is the key drug to treat tuberculosis) in resource-poor settings. Additionally, improved access to affordable antibiotics will not overcome the problems of poor access to hospitals and the fatal consequences of delayed treatment. The future rests with the provision of effective conjugate vaccines against S pneumoniae, Haemophilus influenzae, and Neisseria meningitides to children in the poorest regions of the world.