Epidemiology of paediatric meningitis in central Côte d'Ivoire after the implementation of Haemophilus influenzae type b vaccination

Infectious meningitis accounts for enormous morbidity worldwide, but there is a paucity of data on its regional epidemiology in resource-constrained settings of sub-Saharan Africa. Here, we present a study on the aetiology of paediatric meningitis in central Côte d'Ivoire. Between June 2012 and December 2013, all cerebrospinal fluid (CSF) samples drawn at the University Teaching Hospital Bouaké were examined for the presence of bacterial and fungal pathogens. A causative agent was detected in 31 out of 833 CSF specimens (3.7%), with the most prevalent pathogens being Streptococcus pneumoniae (n=15) and Neisseria meningitidis (n=5). With the exception of neonates, these two bacteria were the most common agents in all age groups. Of note, only a single case of Haemophilus influenzae meningitis was detected. Hence, this study reports a considerable shift in the epidemiology of paediatric meningitis in central Côte d'Ivoire. Following the implementation of a nation-wide childhood vaccination programme against H. influenzae type b, this pathogen was much less frequently reported than in previous studies. The integration of specific vaccines against S. pneumoniae and N. meningitidis into the childhood vaccination programme in Côted'Ivoire holds promise to further reduce the burden due to infectious meningitis.

Thrombin-activatable fibrinolysis inhibitor influences disease severity in humans and mice with pneumococcal meningitis

BACKGROUND

Mortality and morbidity in patients with bacterial meningitis result from the proinflammatory response and dysregulation of coagulation and fibrinolysis. Thrombin-activatable fibrinolysis inhibitor (TAFI) is activated by free thrombin or thrombin in complex with thrombomodulin, and plays an antifibrinolytic role during fibrin clot degradation, but also has an anti-inflammatory role by inactivating proinflammatory mediators, such as complement activation products.

OBJECTIVE

To assess the role of TAFI in pneumococcal meningitis.

METHODS

We performed a prospective nationwide genetic association study in patients with bacterial meningitis, determined TAFI and complement levels in cerebrospinal fluid (CSF), and assessed the function of TAFI in a pneumococcal meningitis mouse model by using Cpb2 (TAFI) knockout mice.

RESULTS

Polymorphisms (reference sequences: rs1926447 and rs3742264) in the CPB2 gene, coding for TAFI, were related to the development of systemic complications in patients with pneumococcal meningitis. Higher protein levels of TAFI in CSF were significantly associated with CSF complement levels (C3a, iC3b, and C5b-9) and with more systemic complications in patients with bacterial meningitis. The risk allele of rs1926447 (TT) was associated with higher levels of TAFI in CSF. In the murine model, consistent with the human data, Cpb2-deficient mice had decreased disease severity, as reflected by lower mortality, and attenuated cytokine levels and bacterial outgrowth in the systemic compartment during disease, without differences in the brain compartment, as compared with wild-type mice.

CONCLUSIONS

These findings suggest that TAFI plays an important role during pneumococcal meningitis, which is likely to be mediated through inhibition of the complement system, and influences the occurrence of systemic complications and inflammation.

[Community acquired bacterial meningitis in patients over 60]

Acute bacterial meningitis has a global mortality rate of 135000 cases per year. In Argentina over the last 12 years, the annual incidence rate has been 5.5/100 000. About 20% of patients present neurological sequelae, which are more common in patients aged 60 or older. Our objective here is to determine the clinical characteristics, the most common causes and to measure evolution in patients over 60 years old diagnosed with meningitis and treated at the Hospital de Clinicas José de San Martín. This is a retrospective study based on a review of medical records from 2003 to 2013 that takes into account patients older than 60 who were diagnosed with acute bacterial meningitis acquired in the community by a microbiological diagnosis of CSF or those included due to a high suspicion of bacterial meningitis (pleocitosis > 2000 cells/mm3, proteins > 220 mg/dl, glycorrhachia < 34 mg/dl, glycorrhachia/glucose index < 0.23). Cases of TB meningitis, nosocomial, postoperative and other nonbacterial meningitis were excluded. Sixty nine patients were included, 45 (65%) were women with an average age of 78 ± 10.6 years. Only 40% had the triad of classical meningitis symptoms (stiff neck, fever and altered mental status). In 52% of the patients germs developed in the CSF, the most frequent being Streptococcus pneumoniae present in 47% of cases. Lethality rate was 41%, all of them by methicillin-sensitive Staphylococcus aureus. Only 24 (35%) cases were admitted into intensive care. The main sequelae present were motor disorders (12%) and hearing loss (5%).

[Meningitis due to Listeria monocytogenes in adults]

INTRODUCTION

Listeria monocytogenes is the third most common cause of community-acquired bacterial meningitis in adults.

AIMS

To describe the characteristics of meningitis caused by Listeria (LM) in adults and to compare them with those of meningitis due to other causations (nLM).

PATIENTS AND METHODS

A retrospective analysis of a series of hospital cases was conducted, including patients aged between ≥ 14 years diagnosed with LM in a referral hospital between 1982 and 2011.

RESULTS

The study involves 16 cases of LM, 12.1% of the cases of community-acquired meningitis with an identified aetiology. Predisposing factors were age (mean of 65 versus 52 years; p = 0.019) and immunosuppression/comorbidity (62.5% versus 3.4%; p < 0.001), treatment with corticoids (37.5%) and chronic liver disease (25%) being the most frequent. The classical triads of acute bacterial meningitis, clinical features and analysis of the cerebrospinal fluid (CSF) were observed in 50 and 75% of the cases, respectively. Patients with LM presented lower leukocyte counts in CSF, a lower percentage of neutrophils, a greater frequency of lymphocytic pleocytosis and a lower frequency of Gram stain positive than those with nLM. The mortality rate was 12.5%, similar to that of patients with nLM.

CONCLUSIONS

LM mainly affects patients who are immunosuppressed or with comorbidity, as well as elderly patients, although it may occur in the absence of risk factors. Clinically it does not differ from other causes of meningitis, but the initial CSF study may suggest it. Its mortality rate is similar to that of meningitis due to other aetiologies.

Dilemmas in the diagnosis of acute community-acquired bacterial meningitis

Rapid diagnosis and treatment of acute community-acquired bacterial meningitis reduces mortality and neurological sequelae, but can be delayed by atypical presentation, assessment of lumbar puncture safety, and poor sensitivity of standard diagnostic microbiology. Thus, diagnostic dilemmas are common in patients with suspected acute community-acquired bacterial meningitis. History and physical examination alone are sometimes not sufficient to confirm or exclude the diagnosis. Lumbar puncture is an essential investigation, but can be delayed by brain imaging. Results of cerebrospinal fluid (CSF) examination should be interpreted carefully, because CSF abnormalities vary according to the cause, patient's age and immune status, and previous treatment. Diagnostic prediction models that use a combination of clinical findings, with or without test results, can help to distinguish acute bacterial meningitis from other causes, but these models are not infallible. We review the dilemmas in the diagnosis of acute community-acquired bacterial meningitis, and focus on the roles of clinical assessment and CSF examination.

Identifying low-risk patients for bacterial meningitis in adult patients with acute meningitis

OBJECTIVE

To derive and validate a clinical prediction model with high sensitivity for differentiating aseptic meningitis (AM) patients from bacterial meningitis (BM) patients.

METHODS

We developed the model using the derivation cohort in a community rural hospital in Okinawa and assessed its performance using the validation cohort in a metropolitan urban hospital in Tokyo. There were 66 (39.5%) and 5 (17.9%) adult patients with BM among the derivation (n=167) and the validation cohort (n=28), respectively. Recursive partitioning analysis was used to determine the important classification variables and to develop a sensitive model to safely exclude BM.

RESULTS

The model produced high- and low-risk groups based on the following: 1) Gram stain, 2) CSF neutrophil percent < or =15%, 3) CSF neutrophil count < or =150 cells/mm(3), and, 4) mental status change. Among the derivation cohort, there were 65 patients with BM in the high-risk group (n=76), while only one patient with BM was noted (sensitivity, 99%) in the low-risk group (n=91). Among the validation cohort, there were 5 patients with BM in the high-risk group (n=7), while no patient was classified with BM (sensitivity, 100%) in the low-risk group (n=21).

CONCLUSION

This simple and sensitive model might be useful to safely identify low-risk patients for BM who would not require antibiotic treatment.

The value of serial cerebrospinal fluid 14-3-3 protein levels in adult community-acquired bacterial meningitis

BACKGROUND

Increased levels of cerebrospinal fluid (CSF) 14-3-3 proteins have been reported in acute bacterial meningitis. We tested the hypothesis that CSF 14-3-3 protein levels are substantially increased in acute bacterial meningitis and decreased after anti-microbial therapy, and that CSF 14-3-3 protein levels can predict treatment outcomes.

METHODS

We examined serial pan-CSF 14-3-3 (14-3-3-P) protein and five major isoform (beta, gamma, epsilon, eta, zeta) levels in 29 adult community-acquired bacterial meningitis (ACABM) patients. The CSF 14-3-3 protein levels were also evaluated in 12 aseptic meningitis patients during the study period.

RESULTS

All of the meningitis patients had a positive result on admission. Levels of CSF 14-3-3 protein in ACABM cases were significantly increased initially, and substantially decreased thereafter. Most of those who survived (survivors = 25 and non-survivors = 4) had nearly cleared their 14-3-3 protein from the CSF before discharge. Conversely, patients who died never cleared their CSF 14-3-3 protein. The median value of CSF 14-3-3-P and 14-3-3 gamma, 14-3-3 eta and 14-3-3 epsilon isoforms on admission in the bacterial meningitis group were 173.7, 137.7, 42.2 and 9.1, respectively, which were statistically significant than those of the aseptic meningitis group (48.4, 39.6, 2.5 and 0, respectively). Stepwise logistic regression analysis showed only CSF 14-3-3 gamma isoform on admission was independently associated with outcome (P = 0.05, OR = 0.991).

CONCLUSION

Serial 14-3-3 protein gamma isoform actually meets the major requirements for outcome prediction in the treatment of ACABM patients. Assay of the 14-3-3 protein gamma isoform should be added as a neuro-pathologic marker among the panel of conventional CSF parameters.

Community-acquired Haemophilus influenzae meningitis in adults

Haemophilus influenzae is an uncommon cause of bacterial meningitis in adults. This report describes a prospective evaluation of 16 episodes of community-acquired H. influenzae meningitis in a nationwide study on bacterial meningitis. Predisposing conditions were present in eight (50%) of the 16 episodes; the most common predisposing conditions were otitis or sinusitis (five episodes; 31%) and remote neurosurgery or head trauma (three episodes; 19%). One (6%) episode was fatal and hearing loss occurred in four (25%) episodes. It was concluded that H. influenzae meningitis in adults is a disease with a rather benign clinical course and a relatively good prognosis compared with pneumococcal meningitis.

Cerebrospinal fluid adenosine deaminase activity for the diagnosis of tuberculous meningitis in adults

We studied adenosine deaminase (ADA) activity in cerebrospinal fluid (CSF) of 16 cases of tuberculous meningitis, 4 cases of cryptococcal meningitis, 5 cases of bacterial meningitis, 12 cases of eosinophilic meningitis, 26 cases of aseptic meningitis, 6 cases of carcinomatous meningitis and 108 cases with normal CSF. The mean CSF ADA values for the different groups were: 39.44 +/- 41.46, 13.00 +/- 7.43, 34.20 +/- 40.81, 3.17 +/- 4.82, 10.03 +/- 9.23, 8.67 +/- 13.60, and 2.58 +/- 2.90 U/I, respectively. Comparing the ADA activity between patients with tuberculous meningitis and non-tuberculous meningitis, the receiver-operating characteristic (ROC) curve identified a CSF ADA level of 15.5 U/I as the best cut-off value to differentiate between the two, with a sensitivity of 75% and a specificity of 93%, with an area under the curve of 0.92. When tuberculous meningitis was compared with aseptic and carcinomatous meningitis, the ROC curve identified a CSF ADA level of 19.0 U/I as the best cut-off value for differentiation, with a sensitivity of 69% and a specificity of 94%, with an area under the curve of 0.83. The level of CSF ADA may be useful as a complementary tool in the early diagnosis of tuberculous meningitis.

Bacterial meningitis in Hong Kong: 10-years’ experience

OBJECTIVE

We studied the etiology, clinical features and outcome of patients with bacterial meningitis from an urban Chinese city over a 10-years period.

METHODS

We reviewed the files of all persons aged 15-years old or above diagnosed with community-acquired bacterial meningitis from a regional hospital. The clinical findings, relevant laboratory and imaging results as well as outcome were recorded in cases with microbiological evidence of meningitis. Neurosurgical and pediatric patients were excluded.

RESULTS

Sixty-five patients between the ages of 15 and 86 years of age (mean 52 years) were identified of whom 18 (28%) died. The four most common causes were Mycobacteria tuberculosis (46%), Streptococcus pneumoniae (11%), Streptococcus suis (9%) and Klebsiella pneumoniae (8%). Neisseria meningitidis and Haemophilus influenzae were rare pathogens. The annual incidence of community-acquired bacterial meningitis was 1.27/100,000 adults. Delay in treatment was associated with a poorer prognosis (p<0.001, OR=38.84, CI=7.33-205.80).

CONCLUSION

The causative organisms found in this region of China differ from that reported from Europe and the US; tuberculous meningitis is the most common cause of bacterial meningitis.

Treatment of meningitis due to methicillin-resistant Staphylococcus epidermidis with linezolid

Methicillin-resistant Staphylococcus epidermidis (MRSE) can cause nosocomial meningitis in the presence of prosthetic devices. Vancomycin is the treatment of choice, but its penetration into the cerebrospinal fluid is poor, especially in cases without severe meningeal inflammation. We successfully used linezolid to treat a case of posttraumatic MRSE meningitis with a low-level inflammatory response. Therapeutic effectiveness was documented microbiologically and by the simultaneous measurement of linezolid levels in serum and cerebrospinal fluid.

Acute meningitis with a negative Gram's stain: clinical and management outcomes in 171 episodes

PURPOSE

To characterize the diagnostic spectrum and physician management decisions of patients presenting to an emergency department with an acute, community-acquired illness, cerebrospinal fluid (CSF) white blood cell count > 5/mm3, and a negative Gram's stain for bacteria.

PATIENTS AND METHODS

In this retrospective cohort study over a 2-year period, symptoms, examination findings, paraclinical data, physician management, and clinical outcomes were assessed for each patient.

RESULTS

One hundred sixty-eight patients (171 patient episodes) were evaluated. Almost half of the cohort presented in nonsummer months (48%); 20% of concurrent comorbid disease, and 15% had identified immunocompromising conditions. The reported examination findings were diverse, with diverse, with fever [49%] and neck stiffness [39%] being the most frequent findings. The majority were hospitalized (70%), with a median stay of 4 days. Approximately one half underwent computed tomography or magnetic resonance imaging (49%), and received empiric treatment with antibiotics (52%). A diagnostic cause was established in 23%, with the majority being inherently treatable diseases (including syphilis, bacteremia, Lyme disease). Variables significantly associated with a subsequent proven diagnostic cause included: age > 60 years; presence of comorbid disease (especially immunodeficiency); and presentation in winter months.

CONCLUSIONS

A large proportion of patients presenting with acute meningitis and a negative CSF Gram's stain undergo hospitalization, noninvasive cranial imaging, and receive empiric antibiotic therapy. Better clinical guidelines are needed to identify the diagnostic and management decisions that benefit patient outcome.

Cerebrospinal fluid penetration of amikacin in children with community-acquired bacterial meningitis

The penetration of amikacin into the cerebrospinal fluid (CSF) was studied with 16 children (mean age, 1 year and 9 months; range, 4 months to 8 years) with community-acquired bacterial meningitis. Amikacin was given intravenously at a dose of 7.5 mg/kg of body weight twice daily. CSF was collected on day 1, at the expected peak concentration of amikacin in CSF. The mean (standard deviation) concentration of amikacin in CSF was 1.65 (1.6) mg/liter. Concentrations of amikacin in CSF correlated significantly with CSF glucose levels on admission. The mean concentrations of amikacin in CSF were 2.9, 1.1, and 0.20 mg/liter in patients with CSF glucose levels of < 1, 1 to 2, and > 2 mmol/liter, respectively. Thus, amikacin penetrates the blood-brain barrier substantially in children with bacterial meningitis and achieves particularly high concentrations when CSF glucose level is < 1 mmol/liter on admission.