Community-acquired bacterial meningitis in adults: in-hospital prognosis, long-term disability and determinants of outcome in a multicentre prospective cohort

Sex differences in bacterial meningitis and associations with socioeconomic indicators: a systematic review and meta-analysis with metaregression

INTRODUCTION

We aimed to describe global sex-specific proportions and case fatality ratios of bacterial meningitis and to explore their associations with the Human Development Index (HDI) and Gender Inequality Index (GII).

METHODS

Google Scholar and MEDLINE (via PubMed.gov) were searched in January 2022 using the terms "bacterial meningitis" and "mortality". Studies with a mean observation period after the year 1940 and reporting ≥10 patients with community-acquired bacterial meningitis and their survival status were included, irrespective of the participants' age. Studies that selected participants by specific risk factors, reported specific pathogens only, or had >10% missing outcomes were disregarded. Data were extracted by one researcher and validated by a second researcher. The main outcomes, sex-specific proportions and case fatality ratios, were analysed using random-effects models. Associations with HDI and GII were explored using metaregression.

RESULTS

In this meta-analysis with metaregression, from 371 studies with 157 656 meningitis episodes, 217 (58%) reported the patients' sex and 41 (11%) reported sex-specific outcomes. Proportion of males was 58% (95% CI 57%-59%, prediction interval (PI) 45%-71%). Case fatality ratios were slightly higher in females (male-to-female fatality ratio, 0.89, 95% CI 0.78 to 1.01, PI 0.53-1.49). The size of the male proportion was strongly associated with HDI (per index point, -0.64, 95% CI -0.88 to -0.40; R2 16%; p<0.001) and GII (per index point, 0.61, 95% CI 0.39 to 0.83; R2 19%; p<0.001). Sex-specific case fatality ratios were weakly associated with HDI (per index point, 0.53, 95% CI -0.19 to 1.25; R2 2%; p=0.15) and GII (per index point, -0.58, 95% CI -1.55 to 0.39; R2 7%; p=0.24).

CONCLUSION

Based on worldwide reporting from the last 80 years, we show that indicators of human development and gender inequality are associated with sex-based disparities and case fatality ratios in bacterial meningitis.

Diffusion-weighted imaging abnormalities patterns in bacterial meningitis

PURPOSE

Information on abnormal diffusion-weighted imaging (DWI) patterns in bacterial meningitis (BM) is limited. This study aimed to investigate the frequency and patterns of DWI abnormalities in BM in patients with culture-positive BM.

METHODS

The medical records of 14 consecutive patients with BM with magnetic resonance imaging evaluation, admitted to our hospital over the past 14 years, were reviewed. BM was defined by a cerebrospinal fluid (CSF) culture positive for bacteria, or the combination of CSF pleocytosis and a positive blood culture.

RESULTS

Brain DWI abnormalities were identified in 13 (93 %) of the 14 patients and classified into six patterns: ischaemic stroke (n = 9), ventriculitis (n = 4), sulcal hyperintensity (n = 7), scattered hyperintensities surrounding the cerebral hemispheres (n = 6), middle meningeal arterial sign (n = 5), or abscess (n = 1). The causes of ischaemic stroke included infective endocarditis (n = 4), vasculitis (vasculopathy; n = 2), and unclassified (n = 3).

CONCLUSION

DWI abnormalities in BM were very frequent. Based on the high frequency and wide spectrum of DWI abnormalities in BM, we suggest performing DWI for all patients with BM.

Intracranial complications in adult patients with severe pneumococcal meningitis: a retrospective multicenter cohort study

BACKGROUND

We aimed to investigate the association of intracranial complications diagnosed on neuroimaging with neurological outcomes of adults with severe pneumococcal meningitis.

METHODS

We performed a retrospective multicenter study on consecutive adults diagnosed with pneumococcal meningitis requiring at least 48 h of stay in the intensive care unit (ICU) and undergoing neuroimaging, between 2005 and 2021. All neuroimaging were reanalyzed to look for intracranial complications which were categorized as (1) ischemic lesion, (2) intracranial hemorrhage (3) abscess/empyema, (4) ventriculitis, (5) cerebral venous thrombosis, (6) hydrocephalus, (7) diffuse cerebral oedema. The primary outcome was unfavorable outcome at 90 days after ICU admission, defined by a modified Rankin Scale (mRS) score > 2.

RESULTS

Among the 237 patients included, intracranial complications were diagnosed in 68/220 patients (31%, 95%CI 0.25-0.37) who underwent neuroimaging at ICU admission and in 75/110 patients (68%, 95%CI 0.59-0.77) who underwent neuroimaging during ICU stay. At 90 days, 103 patients (44%, 95%CI 37-50) had unfavorable outcome, including 71 (30%) deaths. The most frequent intracranial complications were ischemic lesion (69/237 patients, 29%), diffuse cerebral oedema (43/237, 18%) and ventriculitis (36/237, 15%). Through multivariable analysis, we found that intracranial complications (adjusted odds ratio (aOR) 2.88, 95%CI 1.37-6.21) were associated with unfavorable outcome, along with chronic alcohol consumption (aOR 3.10, 95%CI 1.27-7.90), chronic vascular disease (aOR 4.41, 95%CI 1.58-13.63), focal neurological sign(s) (aOR 2.38, 95%CI 1.11-5.23), and cerebrospinal fluid leukocyte count < 1000 cell/microL (aOR 4.24, 95%CI 2.11-8.83). Competing risk analysis, with persistent disability (mRS score 3-5) as the primary risk and ICU-death as the competing risk, revealed that chronic alcohol consumption was the sole significant variable associated with persistent disability at 90 days (cause-specific hazard ratio 4.26, 95%CI 1.83-9.91), whereas the remaining variables were associated with mortality.

CONCLUSIONS

In adults with severe pneumococcal meninigitis, intracranial complications were independently associated with a higher risk of poor functional outcome, in the form of persistent disability or death. This study highlights the value of neuroimaging studies in this population, and provides relevant information for prognostication.

Global Case Fatality of Bacterial Meningitis During an 80-Year Period: A Systematic Review and Meta-Analysis

Importance

The impact of vaccination, antibiotics, and anti-inflammatory treatment on pathogen distribution and outcome of bacterial meningitis over the past century is uncertain.

Objective

To describe worldwide pathogen distribution and case fatality ratios of community-acquired bacterial meningitis.

Data Sources

Google Scholar and MEDLINE were searched in January 2022 using the search terms bacterial meningitis and mortality.

Study Selection

Included studies reported at least 10 patients with bacterial meningitis and survival status. Studies that selected participants by a specific risk factor, had a mean observation period before 1940, or had more than 10% of patients with health care-associated meningitis, tuberculous meningitis, or missing outcome were excluded.

Data Extraction and Synthesis

Data were extracted by 1 author and verified by a second author. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Random-effects models stratified by age (ie, neonates, children, adults), Human Development Index (ie, low-income or high-income countries), and decade and meta-regression using the study period's year as an estimator variable were used.

Main Outcome and Measure

Case fatality ratios of bacterial meningitis.

Results

This review included 371 studies performed in 108 countries from January 1, 1935, to December 31, 2019, describing 157 656 episodes. Of the 33 295 episodes for which the patients' sex was reported, 13 452 (40%) occurred in females. Causative pathogens were reported in 104 598 episodes with Neisseria meningitidis in 26 344 (25%) episodes, Streptococcus pneumoniae in 26 035 (25%) episodes, Haemophilus influenzae in 22 722 (22%), other bacteria in 19 161 (18%) episodes, and unidentified pathogen in 10 336 (10%) episodes. The overall case fatality ratio was 18% (95% CI, 16%-19%), decreasing from 32% (95% CI, 24%-40%) before 1961 to 15% (95% CI, 12%-19%) after 2010. It was highest in meningitis caused by Listeria monocytogenes at 27% (95% CI, 24%-31%) and pneumococci at 24% (95% CI, 22%-26%), compared with meningitis caused by meningococci at 9% (95% CI, 8%-10%) or H influenzae at 11% (95% CI, 10%-13%). Meta-regression showed decreasing case fatality ratios overall and stratified by S pneumoniae, Escherichia coli, or Streptococcus agalactiae (P < .001).

Conclusions and Relevance

In this meta-analysis with meta-regression, declining case fatality ratios of community-acquired bacterial meningitis throughout the last century were observed, but a high burden of disease remained.

Meningitis in critically ill patients admitted to intensive care unit for severe community-acquired pneumococcal pneumonia

BACKGROUND

Although it has been reported that patients with pneumococcal pneumonia may develop meningitis, lumbar puncture is not systematically recommended in these patients, even in patients with associated bacteremia or invasive pneumococcal disease. The aim of this study was to determine the characteristics and outcomes of patients admitted to intensive care unit (ICU) for pneumococcal community-acquired pneumonia who developed meningitis.

METHODS

We retrospectively included all consecutive patients admitted to our ICU from January 2006 to December 2020 for severe pneumococcal community-acquired pneumonia according to American Thoracic Society criteria. Meningitis was defined as pleocytosis > 5 cells/mm3 or a positive culture of cerebrospinal fluid for Streptococcus pneumoniae in lumbar puncture. The primary endpoint was the proportion of patients with meningitis during their ICU stay.

RESULTS

Overall, 262 patients [64(52-75) years old] were included: 154(59%) were male, 80(30%) had chronic respiratory disease, 105(39%) were immunocompromised and 6(2%) were vaccinated against S. pneumoniae. A lumbar puncture was performed in 88(34%) patients with a delay from ICU admission to puncture lumbar of 10.5 (2.8-24.1) h and after the initiation of pneumococcal antibiotherapy in 81(92%) patients. Meningitis was diagnosed in 14 patients: 16% of patients with lumbar puncture and 5% of patients in the whole population. Patients with meningitis had more frequently human immunodeficiency virus positive status (29 vs. 5%, p = 0.02), neurological deficits on ICU admission (43 vs. 16%, p = 0.03) and pneumococcal bacteremia (71 vs. 30%, p < 0.01) than those without. The ICU mortality rate (14 vs. 13%, p = 0.73) and the mortality rate at Day-90 (21 vs. 15%, p = 0.83) did not differ between patients with and without meningitis. The proportion of patients with neurological disorders at ICU discharge was higher in patients with meningitis (64 vs. 23%, p < 0.001) than in those without. The other outcomes did not differ at ICU discharge, Day-30 and Day-90 between the two groups of patients.

CONCLUSION

Meningitis was diagnosed in 16% of patients with severe pneumococcal community-acquired pneumonia in whom a lumbar puncture was performed, was more frequent in patients with pneumococcal bacteremia and was associated with more frequent neurological disorders at ICU discharge. Further studies are needed to confirm these results.

Characteristics and prognostic factors of bacterial meningitis in the intensive care unit: a prospective nationwide cohort study

BACKGROUND

Patients with bacterial meningitis can be severely ill necessitating intensive care unit (ICU) treatment. Here, we describe clinical features and prognostic factors of adults with bacterial meningitis admitted to the ICU in a nationwide prospective cohort study.

METHODS

We prospectively assessed clinical features and outcome of adults (age > 16 years) with community-acquired bacterial meningitis included in the MeninGene study between March 1, 2006 and July 1, 2022, that were initially admitted to the ICU. We identified independent predictors for initial ICU admission and for unfavourable outcome (Glasgow Outcome Scale score between 1-4) by multivariable logistic regression.

RESULTS

A total of 2709 episodes of bacterial meningitis were included, of which 1369 (51%) were initially admitted to the ICU. We observed a decrease in proportion of patients being admitted to the ICU during the Covid-19 pandemic in 2020 (decreased to 39%, p = 0.004). Median age of the 1369 patients initially admitted to the ICU was 61 years (IQR 49-69), and the rates of unfavourable outcome (47%) and mortality (22%) were high. During the Covid-19 pandemic, we observed a trend towards an increase in unfavourable outcome. Prognostic factors predictive for initial ICU admission were younger age, immunocompromised state, male sex, factors associated with pneumococcal meningitis, and those indicative of systemic compromise. Independent predictors for unfavourable outcome in the initial ICU cohort were advanced age, admittance to an academic hospital, cranial nerve palsies or seizures on admission, low leukocyte count in blood, high C-reactive protein in blood, low CSF: blood glucose ratio, listerial meningitis, need for mechanical ventilation, circulatory shock and persistent fever. 204 of 1340 episodes (15%) that were initially not admitted to the ICU were secondarily transferred to the ICU. The rates of unfavourable outcome (66%) and mortality (30%) in this group were high.

CONCLUSIONS

The majority of patients with community-acquired bacterial meningitis are admitted to the ICU, and the unfavourable outcome and mortality rates of these patients remain high. Patients that are initially admitted to non-ICU wards but secondarily transferred to the ICU also had very high rates of unfavourable outcome.

Persistent headaches one year after bacterial meningitis: prevalence, determinants and impact on quality of life

BACKGROUND

Little is known on headaches long-term persistence after bacterial meningitis and on their impact on patients' quality of life.

METHODS

In an ancillary study of the French national prospective cohort of community-acquired bacterial meningitis in adults (COMBAT) conducted between February 2013 and July 2015, we collected self-reported headaches before, at onset, and 12 months (M12) after meningitis. Determinants of persistent headache (PH) at M12, their association with M12 quality of life (SF 12), depression (Center for Epidemiologic Studies Depression Scale) and neuro-functional disability were analysed.

RESULTS

Among the 277 alive patients at M12 87/274 (31.8%), 213/271 (78.6%) and 86/277 (31.0%) reported headaches before, at the onset, and at M12, respectively. In multivariate analysis, female sex (OR: 2.75 [1.54-4.90]; p < 0.001), pre-existing headaches before meningitis (OR: 2.38 [1.32-4.30]; p < 0.01), higher neutrophilic polynuclei percentage in the CSF of the initial lumbar puncture (OR: 1.02 [1.00-1.04]; p < 0.05), and brain abscess during the initial hospitalisation (OR: 8.32 [1.97-35.16]; p < 0.01) were associated with M12 persistent headaches. Neither the responsible microorganism, nor the corticoids use were associated with M12 persistent headaches. M12 neuro-functional disability (altered Glasgow Outcome Scale; p < 0.01), M12 physical handicap (altered modified Rankin score; p < 0.001), M12 depressive symptoms (p < 0.0001), and M12 altered physical (p < 0.05) and mental (p < 0.0001) qualities of life were associated with M12 headaches.

CONCLUSION

Persistent headaches are frequent one year after meningitis and are associated with quality of life alteration.

CLINICAL TRIAL

NCT01730690.

Cerebral vasculitis as a complication of pneumococcal meningitis: A cohort study

OBJECTIVE

Cerebral vasculitis (CV) is a severe complication of pneumococcal meningitis (PM); whether dexamethasone use can reduce its occurrence remains to be determined.

METHODS

This is a retrospective observational bicentric study analyzing all adults with proven PM hospitalized between January 2002 and December 2020 in two tertiary hospitals. Extrapolating from a standardized definition of primary angiitis of the central nervous system, we defined CV as worsened neurological symptoms associated with compatible imaging. All images were analyzed by a radiologist, and two neurologists reviewed all inconclusive cases of suspected CV for adjudication. Factors associated with CV were analyzed, including dexamethasone use. A subgroup analysis was limited to patients with a lumbar puncture at PM diagnosis.

RESULTS

Among 168 patients with PM, 49 (29.2%) had CV, occurring after a median of 8 days (IQR 5-13) of PM diagnosis. In multivariate analysis (N = 151), initial CRP was associated with CV (OR 1.28 per 50-unit increase, p = 0.003), which was marginally linked with delayed hospital admission more than 48 hours after first symptoms (OR 2.39, p = 0.06) and prior NSAID intake (OR 2.94, p = 0.05). Dexamethasone administration did not impact CV occurrence. In 133 patients having undergone lumbar puncture, CSF protein level > 4.4 g/L (OR 4.50, p = 0.006) was associated with CV.

CONCLUSIONS

In our cohort, CV was a frequent and severe complication of PM, often occurring in association with unduly delayed medical care, high CRP at admission, and high levels of protein in CSF.

Severe meningoencephalitis: epidemiology and outcomes

PURPOSE OF REVIEW

This article aims to provide an updated review on the epidemiology and outcomes of severe meningoencephalitis.

RECENT FINDINGS

Meningoencephalitis is a critical medical condition characterized by inflammation in both the meninges and brain parenchyma. Bacterial, viral, or fungal infections are common causes, although noninfectious factors, such as autoimmune causes, can also contribute. In patients requiring intensive care, meningoencephalitis is associated with a severe prognosis, including mortality rates ranging from 11 to 25% and functional disability in 15-25% of survivors. Recent multicenter studies have identified several parameters linked to poor outcomes, including older age, immunocompromised status, focal neurologic signs, abnormal brain imaging, and delayed administration of antimicrobials. The use of new multiplex PCR techniques for diagnosis has generated debate based on recent data. Investigation is still needed to determine the effectiveness of adjunctive therapies, including seizure prophylaxis, and adjunctive steroids for nonbacterial causes.

SUMMARY

Recent multicenter studies have enhanced our understanding of the current epidemiology and outcomes of severe meningoencephalitis in adult patients.

Invasive Pneumococcal Disease and COVID-19 With Acute Otitis Media and a Tegmen Tympani Defect

Streptococcus pneumoniae is a leading cause of otitis media, pneumonia, sinusitis, and meningitis. This encapsulated, gram-positive bacterium colonizes the nasopharynx. Major risk factors, including age, hyposplenism, and immunosuppression, predispose to serious infections. Viral infections are known to increase the risk of secondary bacterial infections as the initial immune response can compromise defenses against bacteria. Coronavirus disease 2019 (COVID-19) similarly poses a risk for secondary bacterial infections and coinfections, such as invasive pneumococcal disease (IPD). Still, temporal relationships between IPD and COVID-19 are not fully understood. IPD may also be a complication of untreated acute otitis media. COVID-19 and pneumococcal bacteremia, a form of IPD, have both been shown to damage the blood-brain barrier and gain access to the central nervous system, resulting in deep infections, namely, meningitis and encephalitis. Presented here is the case of a 70-year-old female partially vaccinated against pneumococcal disease, who was initially evaluated for an elevated temperature, acute encephalopathy, and COVID-19. Further investigation confirmed IPD in the form of bacteremia and meningitis. The patient had a protracted disease course complicated by sick sinus syndrome and altered mental status, which led to the identification of otitis media and a right tegmen tympani defect. Emergent implantation of a single-chamber temporary pacemaker and myringotomy with tube placement was performed. Lumbar puncture showed evidence of meningitis. Antibiotic therapy eventually narrowed to ceftriaxone and continued for a total of six weeks. The presence of comorbidities, history of incomplete pneumococcal vaccination series, and concomitant infection with COVID-19 may explain the development of IPD and other complications seen in this case. Furthermore, tegmen tympani defects and damage to the blood-brain barrier can serve as a route for otogenic intracranial sepsis and meningitis. This case serves to reinforce the importance of pneumococcal vaccination and the high clinical suspicion necessary for the prompt diagnosis and treatment of IPD. However, despite vaccination, IPD remains a life-threatening disease due to poor antibiotic penetration in the central nervous system and overlapping presentations with coinfections, such as COVID-19.

Clinical Features and a Prediction Nomogram for Prognosis in Children with Escherichia coli Meningitis

BACKGROUND

We aimed to build a prediction nomogram for early prediction of poor prognosis in children with Escherichia coli meningitis and analyzed the course of treatment and discharge criteria.

METHODS

Eighty-seven pediatric patients with E coli meningitis were retrospectively recruited from the Children's Hospital of Chongqing Medical University between June 2012 and November 2021. Univariate analysis and binary logistic analysis were used to evaluate the risk factors, and the prediction model was built.

RESULTS

E coli meningitis is more common in children <3 months old in our study (86.2%). Common complications were subdural effusion (39.1%), followed by hydrocephalus (13.8%) and repeated convulsions (12.6%). The mortality rate and sequelae rate of E coli meningitis in children was ∼10.9% and ∼6.3%, respectively. Univariate analysis showed that 13 clinical indicators were associated with poor prognosis of E coli meningitis in children. In binary logistic analysis, risk factors were seizures (P = .032) and the last cerebrospinal fluid glucose content before discharge (P = .002). A graphical nomogram was designed. The area under the receiver operating characteristic curve was 0.913. The Hosmer-Lemeshow test showed that the model was a good fit (P = .648). Internal validation proved the reliability of the prediction nomogram.

CONCLUSIONS

E coli meningitis is more common in children <3 months old in our study. The rate of complications and sequelae are high. The prediction nomogram could be used to assess the risk of poor prognosis in children with E coli meningitis by clinicians.

Addition of daptomycin for the treatment of pneumococcal meningitis: protocol for the AddaMAP study

BACKGROUND

The leading cause of acute bacterial meningitis in adults is Streptococcus pneumoniae. This infection is associated with high rates of mortality and morbidity related, among other factors, to the excessive host response to the pneumococcal lysis. Experimental in vitro and in vivo data show that the combination of corticosteroids/third-generation cephalosporins and the non-lytic antibiotic, daptomycin, has synergistic effects with (1) a rapid cerebrospinal fluid sterilisation, (2) less brain damages and (3) less loss of cognitive performances. Despite these encouraging results, daptomycin has never been evaluated in adult patients with pneumococcal meningitis.

METHODS AND ANALYSIS

The AddaMAP trial is a phase II, open-label, Simon's two-stage, multicentre trial that has been designed to assess the efficacy and safety of adding daptomycin (10 mg/kg/d for 8 days) to the recommended treatment (corticosteroids+third generation cephalosporin) in adults with confirmed pneumococcal meningitis. The main endpoint is the disability-free survival (defined as modified Rankin Scale mRS≤2) at day 30. Secondary outcomes are overall mortality, disability at D30 and D90 (mRS, Glasgow Coma Scale and Glasgow Outcome Scales, mini-mental score), hearing loss (Hearing Handicap Inventory Test at D30 and D90, routine audiometric test and Hearing-it test at D30), and quality of life (12-item Short Form Survey and WHO QOL BREF). Seventy-two analysable patients are required.

ETHICS AND DISSEMINATION

The study protocol was approved by the Institutional Review Board of the IDF 1 of the ethics committee on 16 January 2018, and authorisation was obtained from the Agence Nationale de Securité des Médicaments et des Produits de Santé on 22 September 2017. The results will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03480191.

Cerebrovascular complications in patients with community-acquired bacterial meningitis: occurrence and associated factors in the COMBAT multicenter prospective cohort

BACKGROUND

Community-acquired bacterial meningitis is a rare but severe central nervous system infection that may be associated with cerebrovascular complications (CVC). Our objective is to assess the prevalence of CVC in patients with community-acquired bacterial meningitis and to determine the first-48 h factors associated with CVC.

METHODS

We analyzed data from the prospective multicenter cohort study (COMBAT) including, between February 2013 and July 2015, adults with community-acquired bacterial meningitis. CVC were defined by the presence of clinical or radiological signs (on cerebral CT or MRI) of focal clinical symptom. Factors associated with CVC were identified by multivariate logistic regression.

RESULTS

CVC occurred in 128 (25.3%) of the 506 patients in the COMBAT cohort (78 (29.4%) of the 265 pneumococcal meningitis, 17 (15.3%) of the 111 meningococcal meningitis, and 29 (24.8%) of the 117 meningitis caused by other bacteria). The proportion of patients receiving adjunctive dexamethasone was not statistically different between patients with and without CVC (p = 0.84). In the multivariate analysis, advanced age (OR = 1.01 [1.00-1.03], p = 0.03), altered mental status at admission (OR = 2.23 [1.21-4.10], p = 0.01) and seizure during the first 48 h from admission (OR = 1.90 [1.01-3.52], p = 0.04) were independently associated with CVC.

CONCLUSIONS

CVC were frequent during community-acquired bacterial meningitis and associated with advanced age, altered mental status and seizures occurring within 48 h from admission but not with adjunctive corticosteroids.

Characteristics, management, and outcomes of patients with infectious encephalitis requiring intensive care: A prospective multicentre observational study

PURPOSE

Infectious encephalitis (IE) is a severe disease which requires intensive care unit (ICU) admission in up to 50% of cases. We aimed to describe characteristics, management and outcomes of IE patients who required ICU admission.

MATERIALS AND METHODS

Ancillary study focusing on patients with ICU admission within the ENCEIF cohort, a French prospective observational multicentre study. The primary criteria for outcome was the functional status at hospital discharge, categorized using the Glasgow outcome scale (GOS). Logistic regression model was used to identify risk factors for poor outcome, defined as a GOS ≤ 3.

RESULTS

We enrolled 198 ICU patients with IE. HSV was the primary cause (n = 72, 36% of all IE, 53% of IE with microbiological documentation). Fifty-two patients (26%) had poor outcome at hospital discharge, including 22 deaths (11%). Immunodeficiency, supratentorial focal signs on admission, lower cerebrospinal fluid (CSF) white cells count (<75/mm3), abnormal brain imaging, and time from symptoms onset to acyclovir start >2 days were independent predictors of poor outcome.

CONCLUSION

HSV is the primary cause of IE requiring ICU admission. IE patients admitted in ICU have a poor prognosis with 11% of in-hospital mortality and 15% of severe disabilities in survivors at discharge.

Risk factors and pathogen characteristics associated with unfavorable outcomes among adults with pneumococcal meningitis in Japan, 2006 to 2016

PURPOSE

In this study, we aimed to clarify the risk factors associated with unfavorable outcomes in adults with pneumococcal meningitis (PnM).

METHODS

Surveillance was conducted between 2006 and 2016. Adults with PnM (n = 268) were followed up for outcomes within 28 days after admission using the Glasgow Outcome Scale (GOS). After classifying the patients into the unfavorable (GOS1-4) and favorable (GOS5) outcome groups, i) the underlying diseases, ii) biomarkers at admission, and iii) serotype, genotype, and antimicrobial susceptibility for all isolates were compared between both groups.

RESULTS

Overall, 58.6% of patients with PnM survived,15.3% died, and 26.1% had sequelae. The number of living days in the GOS1 group was highly heterogeneous. Motor dysfunction, disturbance of consciousness, and hearing loss were the commonest sequelae. Of the underlying diseases identified in 68.9% of the PnM patients, liver and kidney diseases were significantly associated with unfavorable outcomes. Of the biomarkers, creatinine and blood urea nitrogen, followed by platelet and C-reactive protein had the most significant associations with unfavorable outcomes. There was a significant difference in the high protein concentrations in the cerebrospinal fluid between the groups. Serotypes 23F, 6C, 4, 23A, 22F, 10A, and 12F were associated with unfavorable outcomes. These serotypes were not penicillin-resistant isolates possessing three abnormal pbp genes (pbp1a, 2x, and 2b), except for 23F. The expected coverage rate of the pneumococcal conjugate vaccine (PCV) was 50.7% for PCV15 and 72.4% for PCV20.

CONCLUSIONS

In the introduction of PCV for adults, the risk factors for underlying diseases should be prioritized over age, and serotypes with unfavorable outcomes should be considered.

High risk and low prevalence diseases: Adult bacterial meningitis

INTRODUCTION

Acute bacterial meningitis in adults is a rare but serious condition that carries a high rate of morbidity.

OBJECTIVE

This review highlights pearls and pitfalls of acute bacterial meningitis in adults, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Meningitis encompasses a broad spectrum of disease involving inflammation of the meninges and subarachnoid space. It classically presents with fever, nuchal rigidity, and altered mental status, but this triad is not present in all cases. Up to 95% of patients will have at least two of the following four cardinal symptoms: fever, nuchal rigidity, altered mental status, and headache. The most common bacterial etiologies are S. pneumoniae and N. meningitidis. Cerebrospinal fluid testing obtained by lumbar puncture remains the gold standard in diagnosis. Head computed tomography prior to lumbar puncture may not be necessary in most patients. Empiric treatment consists of vancomycin, ceftriaxone, and dexamethasone. Elevated intracranial pressure should be managed using established neurocritical care strategies.

CONCLUSION

A better understanding of the pearls and pitfalls of acute bacterial meningitis can assist emergency clinicians in pursuing its timely diagnosis and management.

Meningitis patients with pneumonia: correlation between blood parameters and clinical features

Background: This research aimed to explore the possible relationship between the main experimental parameters and clinical status in meningitis patients with pneumonia infection. Methods: A retrospective analysis of the demographic characteristics, clinical features and laboratory parameters of meningitis patients was performed. Results: D-dimer, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) exhibited good diagnostic ability for meningitis complicated with pneumonia. Additionally, we observed a positive correlation between D-dimer and CRP in cases of meningitis with pneumonia infection. D-dimer, ESR and Streptococcus pneumoniae (S. pneumoniae) were independently associated with meningitis patients with pneumonia infection. Conclusion: D-dimer, CRP, ESR and S. pneumoniae infection may effectively anticipate disease progression and adverse consequences in meningitis patients with pneumonia infection.

Sex and Gender Differences in Bacterial Infections

There is a growing awareness of the importance of sex and gender in medicine and research. Women typically have stronger immune responses to self and foreign antigens than men, resulting in sex-based differences in autoimmunity and infectious diseases. In both animals and humans, males are generally more susceptible than females to bacterial infections. At the same time, gender differences in health-seeking behavior, quality of health care, and adherence to treatment recommendations have been reported. This review explores our current understanding of differences between males and females in bacterial diseases. We describe how genetic, immunological, hormonal, and anatomical factors interact to influence sex-based differences in pathophysiology, epidemiology, clinical presentation, disease severity, and prognosis, and how gender roles affect the behavior of patients and providers in the health care system.

Real-time metagenomics-based diagnosis of community-acquired meningitis: A prospective series, southern France

BACKGROUND

Point-Of-Care (POC) diagnosis of life-threatening community-acquired meningitis currently relies on multiplexed RT-PCR assays, that lack genotyping and antibiotic susceptibility profiling. We assessed the usefulness of real-time metagenomics (RTM) directly applied to the cerebrospinal fluid (CSF) for the identification, typing and susceptibility profiling of pathogens responsible for community-acquired meningitis.

METHODS

A series of 52 CSF samples from patients suspected of having community-acquired meningitis, were investigated at POC by direct RTM in parallel to routine real-time multiplex PCR (RT-PCR) and bacterial culture, for the detection of pathogens. RTM-generated sequences were blasted in real-time against an in-house database incorporating the panel of 12 most prevalent pathogens and against NCBI using EPI2ME online software, for pathogen identification. In-silico antibiogram and genotype prediction were determined using the ResFinder bio-tool and MLST online software.

FINDINGS

Over eight months, routine multiplex RT-PCR yielded 49/52 positive CSFs, including 21 Streptococcus pneumoniae, nine Neisseria meningitidis, eight Haemophilus influenzae, three Streptococcus agalactiae, three Herpesvirus-1, two Listeria monocytogenes, and one each of Escherichia coli, Staphylococcus aureus and Varicella-Zoster Virus. Parallel RTM agreed with the results of 47/52 CSFs and revealed two discordant multiplex RT-PCR false positives, one H. influenzae and one S. pneumoniae. Both multiplex RT-PCR and RTM agreed on the negativity of three CSFs. While multiplex RT-PCR routinely took 90 min, RTM took 120 min, although the pipeline analysis detected the pathogen genome after 20 min of sequencing in 33 CSF samples; and after two hours in 14 additional CSFs; yielding > 50% genome coverage in 19 CSFs. RTM identified 14 pathogen genotypes, including a majority of H. influenzae b, N. meningitidis B and S. pneumoniae 11A and 3A. In all 16 susceptible cultured bacteria, the in-silico antibiogram agreed with the in-vitro antibiogram in 10 cases, available within 48 h in routine bacteriology.

INTERPRETATION

In addition to pathogen detection, RTM applied to CSF samples offered supplementary information on bacterial profiling and genotyping. These data provide the proof-of-concept that RTM could be implemented in a POC laboratory for one-shot diagnostic and genomic surveillance of pathogens responsible for life-threatening meningitis.

FUNDING

This work was supported by the French Government under the Investments in the Future programme managed by the National Agency for Research reference: Méditerranée Infection 10-IAHU-03.

Long-term neuro-functional disability in adult patients with community-acquired bacterial meningitis

PURPOSE

To investigate the prevalence of neuro-functional disability and its determinants 12 months after community-acquired bacterial meningitis (CABM) in adult patients.

METHODS

In a prospective multicenter cohort study (COMBAT), all consecutive cases of CABM were enrolled and followed up for 12 months. Neuro-functional disability at 12 months was evaluated using a combination of the Glasgow Outcome Scale (functional disability), and the modified Rankin Disability Scale (physical disability). Factors associated with neuro-functional disability were identified by multivariate logistic regression.

RESULTS

Among 281 patients, 84 (29.9%) patients exhibited neuro-functional disability at 12 months: 79 (28.1%) with functional disability and 51 (18.1%) with physical disability. Overall, 6 patients (2.1%) died during the follow-up. The most common pathogen identified was Streptococcus pneumoniae (131/272, 48.2%); 77/268 patients (28.7%) had a physical disability at hospital discharge. Factors independently associated with 12-month neuro-functional disability were a pneumococcal meningitis (adjusted OR = 2.8; 95% confidence interval (CI) = [1.3; 6.7]), the presence of a physical disability at hospital discharge (aOR = 2.3; 95%CI = [1.2; 4.4]) and the presence of behavioral disorders at hospital-discharge (aOR = 5.9; 95%CI = [1.6; 28.4]). Dexamethasone use was not significantly associated with neuro-functional disability (OR = 0.2; 95%CI = [< 0.1;1.3]).

CONCLUSION

Neuro-functional disability is frequently reported 12 months after CABM. Detailed neurological examination at discharge is needed to improve the follow-up.

TRIAL REGISTRATION

NCT01730690.

One-Year Sequelae and Quality of Life in Adults with Meningococcal Meningitis: Lessons from the COMBAT Multicentre Prospective Study

INTRODUCTION

COMBAT is a prospective, multicentre cohort study that enrolled consecutive adults with community-acquired bacterial meningitis (CABM) in 69 participating centres in France between February 2013 and July 2015 and followed them for 1 year.

METHODS

Patients aged at least 18 years old, hospitalised with CABM were followed during their hospitalisation and then contacted by phone 12 months after enrolment. Here we present the prevalence of sequelae at 12 months in a subgroup of patients with meningococcal meningitis.

RESULTS

Five of the 111 patients with meningococcal meningitis died during initial hospitalisation and two died between discharge and 12 months, leaving 104 patients alive 1 year after enrolment, 71 of whom provided 12-month follow-up data. The median age was 30.0 years and 54.1% of the patients had no identified risk factor for meningitis. More than 30% reported persistent headache, more than 40% were not satisfied with their sleep and 10% had concentration difficulties. Hearing loss was present in about 15% of the patients and more than 30% had depressive symptoms. About 13% of the patients with a previous professional activity had not resumed work. On the SF-12 Health Survey, almost 50% and 30% had physical component or mental component scores lower than the 25th percentile of the score distribution in the French general population. There was a non-significant improvement in the patients' disability scores from hospital discharge to 12 months (p = 0.16), but about 10% of the patients had residual disability.

CONCLUSIONS

Although most patients in our cohort survive meningococcal meningitis, the long-term burden is substantial and therefore it is important to ensure a prolonged follow-up of survivors and to promote preventive strategies, including vaccination.

TRIAL REGISTRATION

ClinicalTrial.Gov identification number NCT01730690.

Combined Bacterial Meningitis and Infective Endocarditis: When Should We Search for the Other When Either One is Diagnosed?

Introduction

We aimed to describe patients with coexisting infective endocarditis (IE) and bacterial meningitis (BM).

Methods

We merged two large prospective cohorts, an IE cohort and a BM cohort, with only cases of definite IE and community-acquired meningitis. We compared patients who had IE and BM concurrently to patients with IE only and BM only.

Results

Among the 1030 included patients, we identified 42 patients with IE–BM (4.1%). Baseline characteristics of patients with IE–BM were mostly similar to those of patients with IE, but meningitis was the predominant presentation at admission (39/42, 92.3%). Causative pathogens were predominantly Streptococcus pneumoniae (18/42, 42.9%) and Staphylococcus aureus (14/42, 33.3%). All pneumococcal IE were associated with BM (18/18). BM due to oral and group D streptococci, Streptococcus agalactiae, and S. aureus were frequently associated with IE (14/30, 46.7%). Three-month mortality was 28.6% in patients with IE–BM, 20.5% in patients with IE, and 16.6% in patients with BM.

Conclusions

Patients with pneumococcal IE or altered mental status during IE must be investigated for BM. Patients with S. aureus, oral and group D streptococcal or enterococcal BM, or unfavorable outcome in pneumococcal meningitis would benefit from an echocardiography. Patients with the dual infection have the worst prognosis. Their identification is mandatory to initiate appropriate treatment.

Hearing loss after bacterial meningitis, a retrospective study

BACKGROUND

Hearing loss is a common sequela after bacterial meningitis, but risk factors for this are poorly studied, particularly in relation to concurrent acute otitis media (AOM).

AIMS

The aim of this study was to investigate incidence and risk factors for hearing loss in patients treated for bacterial meningitis.

METHODS

In this retrospective study, medical records for patients admitted to hospital with bacterial meningitis in Skåne county, Sweden, between 2000 and 2017 were retrieved. The association between risk factors and hearing loss was estimated using logistic regression.

RESULTS

During the 18 years, 187 cases of meningitis were identified. Hearing loss was confirmed in 71 of the 119 patients who had done an audiometry. It was significantly more common in adults. There was also evidence of an association between hearing loss and AOM, and between hearing loss and pneumococcal infection.

CONCLUSION

Age, concurrent AOM and pneumococcal infection were risk factors for developing hearing loss. Despite being recommended in the national guidelines, more than a third of the patients had not done a hearing test after recovering from bacterial meningitis. The findings strengthen the demand for prompt ear examination and - if needed - tympanocentesis in meningitis patients.

NLRP3 in the Cerebrospinal Fluid as a Potential Biomarker for the Diagnosis and Prognosis of Community-Acquired Bacterial Meningitis in Adults

Objective

To discover the levels of NLR family pyrin domain-containing 3 (NLRP3) in the cerebrospinal fluid (CSF) from adult patients with community-acquired bacterial meningitis (CABM).

Methods

We enrolled 34 patients with CABM, 20 patients with viral meningitis (VM), and 25 patients with non-inflammatory neurological disease. Data on standard clinical parameters, scores, and outcomes were obtained from clinical records, and inflammasome levels in the CSF were measured by an enzyme-linked immunosorbent assay. The area under the receiver operating characteristic curve (AUROC) was used to quantify the diagnostic and prognostic performance of CSF NLRP3 as a biomarker of CABM.

Results

The levels of NLRP3 were elevated in the CSF of patients with CABM, but levels for ASC, caspase-1, or other inflammasomes did not vary significantly. CSF NLRP3 was positively correlated with clinical severity and with the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte count, albumin quotient (Qalb), and immunoglobulin G quotient (QIgG). Patients with unfavorable outcomes had higher levels of NLRP3 in the CSF, which were correlated with several blood indicators, including NLR, PLR, and lymphocyte and monocyte counts.

Conclusions

Our results suggested that the level of CSF NLRP3 could represent the severity of CABM in adults. CSF NLRP3 may be a good biomarker for the diagnosis of CABM and for the discrimination between CABM and VM. It may also be a better biomarker for predicting the prognosis of adult patients with CABM when compared to the NLR or the lymphocyte and monocyte counts.

Meningitis, meningoencephalitis and encephalitis in Bern: an observational study of 258 patients

Background

Depending on geographic location, causes of encephalitis, meningoencephalitis and meningitis vary substantially. We aimed to identify the most frequent causes, clinical presentation and long-term outcome of encephalitis, meningoencephalitis and meningitis cases treated in the Inselspital University Hospital Bern, Switzerland.

Methods

In this monocentric, observational study, we performed a retrospective review of clinical patient records for all patients treated within a 3-year period. Patients were contacted for a telephone follow-up interview and to fill out questionnaires, especially related to disturbances of sleep and wakefulness.

Results

We included 258 patients with the following conditions: encephalitis (18%), nonbacterial meningoencephalitis (42%), nonbacterial meningitis (27%) and bacterial meningoencephalitis/meningitis (13%). Herpes simplex virus (HSV) was the most common cause of encephalitis (18%); tick-borne encephalitis virus (TBEV) was the most common cause of nonbacterial meningoencephalitis (46%), enterovirus was the most common cause of nonbacterial meningitis (21%) and Streptococcus pneumoniae was the most common cause of bacterial meningoencephalitis/meningitis (49%). Overall, 35% patients remained without a known cause. After a median time of 16 months, 162 patients participated in the follow-up interview; 56% reported suffering from neurological long-term sequelae such as fatigue and/or excessive daytime sleepiness (34%), cognitive impairment and memory deficits (22%), headache (14%) and epileptic seizures (11%).

Conclusions

In the Bern region, Switzerland, TBEV was the overall most frequently detected infectious cause, with a clinical manifestation of meningoencephalitis in the majority of cases. Long-term neurological sequelae, most importantly cognitive impairment, fatigue and headache, were frequently self-reported not only in encephalitis and meningoencephalitis survivors but also in viral meningitis survivors up to 40 months after acute infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02502-3.

Dose optimisation of antibiotics used for meningitis

PURPOSE OF REVIEW

Central nervous system (CNS) infections such as ventriculitis and meningitis are associated with significant morbidity and mortality. In part, this may be due to increased difficulties in achieving a therapeutic antibiotic concentration at the site of infection due to both the pharmacokinetic (PK) changes observed during critical illness and the reduced antibiotic penetration through the blood brain barrier. This paper reviews the pharmacodynamics (PD) and CNS PKs of antibiotics used for Gram-negative bacterial CNS infections to provide clinicians with practical dosing advice.

RECENT FINDINGS

Recent PK studies have shown that currently used intravenous antibiotic dosing regimens may not achieve a therapeutic exposure within the CNS, even for reportedly 'susceptible' bacteria per the current clinical meningitis breakpoints. Limited data exist for new β-lactam antibiotic/β-lactamase inhibitor combinations, which may be required for multidrug resistant infections. Intraventricular antibiotic administration, although not a new concept, has further evidence demonstrating improved patient outcomes compared with intravenous therapy alone, despite the ongoing paucity of PK studies guiding dosing recommendations.

SUMMARY

Clinicians should obtain the bacterial minimum inhibitory concentration when treating patients with CNS Gram-negative bacterial infections and consider the underlying PK/PD principles when prescribing antibiotics. Therapeutic drug monitoring, where available, should be considered to guide dosing. Intraventricular therapy should also be considered for patients with ventricular drains to optimise clinical outcomes.

Existing Data Sources for Clinical Epidemiology: The Danish Study Group of Infections of the Brain Database (DASGIB)

Central nervous system (CNS) infections are rare diseases that are associated with considerable morbidity and mortality. Increased knowledge based on contemporary data is a prerequisite for improved management and prevention of these serious conditions. Yet, population-based databases of patients hospitalized with CNS infections remain scarce. The Danish Study Group of Infections of the Brain (DASGIB) has prospectively registered information on all adults ≥18 years of age admitted with CNS infections at departments of infectious diseases in Denmark since 2015. The main variables collected are baseline demographics, blood and cerebrospinal fluid tests, imaging results, and outcome using the Glasgow Outcome Scale score. To investigate important aspects for each type of CNS infections, additional variables are included specifically for bacterial meningitis, viral meningitis, encephalitis, brain abscess, neurosyphilis, and Lyme neuroborreliosis. From 2015 to 2020, a total of 3579 cases of CNS infections have been recorded in the DASGIB database. Using the unique civil registration number assigned to all Danish residents, the database can be unambiguously linked with nationwide healthcare registries at the individual level. This enables researchers to conduct detailed population-based and longitudinal observational studies of risk and prognosis of CNS infections and to compare them with matched population cohorts. The database is well-suited for epidemiological research and the DASGIB network forms a solid infrastructure for future national and international collaborations.

Use of a new multiplex quantitative polymerase chain reaction based assay for simultaneous detection of Neisseria meningitidis, Escherichia coli K1 , Streptococcus agalactiae, and Streptococcus pneumoniae

Background and Objectives

Neisseria meningitidis, Escherichia coli K₁, Streptococcus agalactiae, and Streptococcus pneumoniae cause 90% of bacterial meningitis. Almost all infected people die or have irreversible neurological complications. Therefore, it is essential to have a diagnostic kit with the ability to quickly detect these fatal infections.

Materials and Methods

The project involved 212 patients from whom cerebrospinal fluid samples were obtained. After total genome extraction and performing multiplex quantitative polymerase chain reaction (qPCR), the presence or absence of each infectious factor was determined by comparing with standard strains.

Results

The specificity, sensitivity, positive predictive value, and negative predictive value calculated were 100%, 92.9%, 50%, and 100%, respectively. So, due to the high specificity and sensitivity of the designed primers, they can be used instead of bacterial culture that takes at least 24 to 48 hours.

Conclusion

The remarkable benefit of this method is associated with the speed (up to 3 hours) at which the procedure could be completed. It is also worth noting that this method can reduce the personnel unintentional errors which may occur in the laboratory. On the other hand, as this method simultaneously identifies four common factors that cause bacterial meningitis, it could be used as an auxiliary method diagnostic technique in laboratories particularly in cases of emergency medicine.

Relationship between serotypes, disease characteristics and 30-day mortality in adults with invasive pneumococcal disease

PURPOSE

Invasive pneumococcal disease (IPD) is responsible for substantial mortality and morbidity worldwide. We aimed to identify host and bacterial factors associated with 30-day mortality in 18-year-old patients hospitalized with IPD in France from 2013 to 2015.

METHODS

This study analyzed data collected from consecutives IPD cases included in two parallel multi-center cohort studies: COMBAT study (280 patients with pneumococcal community-acquired bacterial meningitis) and SIIP study (491 patients with non-meningitis IPD). Factors associated with 30-day mortality were identified using logistic regression.

RESULTS

Among the 771 enrolled patients (median age 66 years, IQR [52.0-79.7]), 592/767 (77.2%) had at least one chronic disease. Patients with meningitis were younger (60.2 vs 70.9 years; p < 0.001) and had fewer chronic diseases than those with non-meningitis IPD (73.3% vs 79.4%; p = 0.05). Non-vaccine serotypes were more frequent in meningitis patients than in those with other IPD (36.1% vs 23.1%; p < 0.001). The overall 30-day mortality was 16.7% and patients with concurrent meningitis and extra-cerebral IPD had the highest 30-day mortality rate (26.5%). On multivariate analyses, older age, history of malignant solid tumor, meningeal IPD and serotypes previously identified with high mortality potential were independently associated with 30-day mortality. Of the serotypes with high mortality potential, 80% were included in licensed (PCV13 or PPV23) vaccines.

CONCLUSION

We observed an effect of both host factors and pneumococcal serotypes on 30-day mortality in IPD. This highlights the need for a focused strategy to vaccinate at-risk patients.

CLINICAL TRIAL

ClinicalTrial. Gov identification number: NCT01730690.

Endothelial Dysfunction and Impaired Neurovascular Coupling Responses Precede Cognitive Impairment in a Mouse Model of Geriatric Sepsis

Sepsis is a life-threatening condition, the incidence of which is significantly increased in elderly patients. One of the long-lasting effects of sepsis is cognitive impairment defined as a new deficit or exacerbation of preexisting deficits in global cognition or executive function. Normal brain function is dependent on moment-to-moment adjustment of cerebral blood flow to match the increased demands of active brain regions. This homeostatic mechanism, termed neurovascular coupling (NVC, also known as functional hyperemia), is critically dependent on the production of vasodilator NO by microvascular endothelial cells in response to mediators released from activated astrocytes. The goal of this study was to test the hypothesis that sepsis in aging leads to impairment of NVC responses early after treatment and that this neurovascular dysfunction associates with impairments in cognitive performance and vascular endothelial dysfunction. To test this hypothesis, we used a commonly studied bacterial pathogen, Listeria monocytogenes, to induce sepsis in experimental animals (males, 24 months of age) and subjected experimental animals to a standard clinical protocol of 3 doses of ampicillin i.p. and 14 days of amoxicillin added to the drinking water. NVC responses, endothelial function and cognitive performance were measured in septic and age-matched control groups within 14 days after the final antibiotic treatment. Our data demonstrate that sepsis in aging significantly impairs NVC responses measured in somatosensory cortex during whisker stimulation, significantly impairs endothelial function in isolated and pressure cannulated aorta rings in response to acetylcholine stimulation. No significant impairment of cognitive function in post-sepsis aged animals has been observed when measured using the PhenoTyper homecage based system. Our findings suggest that sepsis-associated endothelial dysfunction and impairment of NVC responses may contribute to long-term cognitive deficits in older sepsis survivors.

In vitro antimicrobial activity of daptomycin alone and in adjunction with either amoxicillin, cefotaxime or rifampicin against the main pathogens responsible for bacterial meningitis in adults

OBJECTIVES

As daptomycin adjunction is currently under clinical evaluation in the multicentre phase II AddaMAP study to improve the prognosis of pneumococcal meningitis, the present work aimed at evaluating the in vitro antimicrobial activity of daptomycin-based combinations against some of the most frequent species responsible for bacterial meningitis.

METHODS

Clinically relevant strains of Streptococcus pneumoniae, Listeria monocytogenes, Haemophilus influenzae and Neisseria meningitidis were obtained from National Reference Centers. The antimicrobial activity of amoxicillin, cefotaxime and rifampicin, either alone or in association with daptomycin, was explored through the determination of minimum inhibitory concentration (MIC) and fractional inhibitory concentration index (FICI) as well as time-kill assay (TKA) using the broth microdilution method.

RESULTS

All species taken together, the adjunction of daptomycin had no deleterious impact on the antimicrobial activity of amoxicillin, cefotaxime or rifampicin in vitro. Regarding Gram-positive bacteria, FICI and TKA analysis confirmed a global improvement of growth inhibition and bactericidal activity due to the adjunction of daptomycin. The synergistic effect prevailed for L. monocytogenes as demonstrated by FICI mainly <0.5 and a dynamic TKA-based synergy rate >50%. In addition, daptomycin-based associations did not modify the activity of β-lactam antibiotics or rifampicin against Gram-negative bacteria, notably N. meningitidis.

CONCLUSION

These results bring comforting evidence towards the clinical potential of daptomycin adjunction in the treatment of bacterial meningitis, which supports the ongoing AddaMAP clinical trial.