Community-acquired bacterial meningitis

From cytokines to chemokines: Understanding inflammatory signaling in bacterial meningitis

Bacterial meningitis is a serious central nervous system (CNS) infection, claiming millions of human lives annually around the globe. The deadly infection involves severe inflammation of the protective sheath of the brain, i.e., meninges, and sometimes also consists of the brain tissue, called meningoencephalitis. Several inflammatory pathways involved in the pathogenesis of meningitis caused by Streptococcus pneumoniae, Neisseria meningitidis, Escherichia coli, Haemophilus influenzae, Mycobacterium tuberculosis, Streptococcus suis, etc. are mentioned in the scientific literature. Many in-vitro and in-vivo analyses have shown that after the disruption of the blood-brain barrier (BBB), these pathogens trigger several inflammatory pathways including Toll-Like Receptor (TLR) signaling in response to Pathogen-Associated Molecular Patterns (PAMPs), Nucleotide oligomerization domain (NOD)-like receptor-mediated signaling, pneumolysin related signaling, NF-κB signaling and many other pathways that lead to pro-inflammatory cascade and subsequent cytokine release including interleukine (IL)-1β, tumor necrosis factor(TNF)-α, IL-6, IL-8, chemokine (C-X-C motif) ligand 1 (CXCL1) along with other mediators, leading to neuroinflammation. The activation of another protein complex, nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome, also takes place resulting in the maturation and release of IL-1β and IL-18, hence potentiating neuroinflammation. This review aims to outline the inflammatory signaling pathways associated with the pathogenesis of bacterial meningitis leading to extensive pathological changes in neurons, astrocytes, oligodendrocytes, and other central nervous system cells.

Diagnostic prediction models for bacterial meningitis in children with a suspected central nervous system infection: a systematic review and prospective validation study

OBJECTIVES

Diagnostic prediction models exist to assess the probability of bacterial meningitis (BM) in paediatric patients with suspected meningitis. To evaluate the diagnostic accuracy of these models in a broad population of children suspected of a central nervous system (CNS) infection, we performed external validation.

METHODS

We performed a systematic literature review in Medline to identify articles on the development, refinement or validation of a prediction model for BM, and validated these models in a prospective cohort of children aged 0-18 years old suspected of a CNS infection.

PRIMARY AND SECONDARY OUTCOME MEASURES

We calculated sensitivity, specificity, predictive values, the area under the receiver operating characteristic curve (AUC) and evaluated calibration of the models for diagnosis of BM.

RESULTS

In total, 23 prediction models were validated in a cohort of 450 patients suspected of a CNS infection included between 2012 and 2015. In 75 patients (17%), the final diagnosis was a CNS infection including 30 with BM (7%). AUCs ranged from 0.69 to 0.94 (median 0.83, interquartile range [IQR] 0.79-0.87) overall, from 0.74 to 0.96 (median 0.89, IQR 0.82-0.92) in children aged ≥28 days and from 0.58 to 0.91 (median 0.79, IQR 0.75-0.82) in neonates.

CONCLUSIONS

Prediction models show good to excellent test characteristics for excluding BM in children and can be of help in the diagnostic workup of paediatric patients with a suspected CNS infection, but cannot replace a thorough history, physical examination and ancillary testing.

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.

How common is otogenic meningitis? A retrospective study in southern Sweden over 18 years

BACKGROUND

Bacterial meningitis is a rare, but life-threatening disease, which sometimes occurs as a complication to acute otitis media (AOM). The proportion of meningitis cases originating from AOM is not clear.

PURPOSE

The aim of this study was to investigate the proportion of meningitis cases caused by AOM, to compare risk factors, bacteriology and outcome between otogenic and non-otogenic meningitis, and to analyse the incidence of bacterial meningitis after the introduction of conjugate pneumococcal vaccines (PCV).

METHODS

The medical charts of all patients admitted to hospitals in southern Sweden with bacterial meningitis between 2000 and 2017 were retrieved. Based on otoscopy and/or imaging, the proportion of otogenic meningitis cases was calculated, as were annual incidences.

RESULTS

A total of 216 patients were identified, 25 of whom died. The proportion of otogenic meningitis was 31% but varied from 6% among teenagers to 40% among adults. Before PCV, 23% of all meningitis cases were children < 2 years, compared to 1% post-PCV. The average incidence in the adult population, on the other hand, increased post-PCV, though there were large annual variations. S. pneumoniae was the most commonly identified pathogen in everyone but teenagers, in whom N. meningitidis was predominant.

CONCLUSION

AOM is an important cause of meningitis in children and adults. Though bacterial meningitis almost disappeared in children < 2 years after the introduction of PCV, the incidence of pneumococcal meningitis in adults seems to have increased.

Tenascin-C in patients with central nervous system infections

BACKGROUND

The extracellular matrix protein tenascin-C has been discovered to be an important regulator of the response to tissue injury and repair in cerebrovascular diseases. This study investigated if tenascin-C is released in response to infections in the central nervous system (CNS).

METHODS

Tenascin-C concentration in the cerebrospinal fluid (CSF) was measured in patients, (>18 years) with and without CNS infections, admitted to a department of infectious diseases in Denmark. CSF tenascin-C was measured on the Meso-scale platform.

RESULTS

174 patients were included of which 140 were diagnosed with a CNS infection and 34 where this was ruled out (control group). Median CSF tenascin-C levels were significantly higher among patients with bacterial meningitis (147 pg/mL), viral meningitis (33 mg/mL), viral encephalitis (39 pg/mL) and Lyme neuroborreliosis (45 pg/mL) when compared to controls (21 pg/mL). Correlations between tenascin-C and CSF markers of inflammation and age were only moderate.

CONCLUSION

Levels of CSF tenascin-C are higher among patients with bacterial and viral neuroinfections, already on admission, but exhibit only a modest correlation with baseline indices of neuroinflammation. CSF tenascin-C is highest among patients with bacterial meningitis compared to the other CNS infections. Patients with unfavorable outcomes presented with higher median CSF tenascin-C than their counterparts.

What are the clinical and research lessons learned from immunomodulators and other therapies during the COVID-19 pandemic?

PURPOSE OF REVIEW

The development and use of immunomodulators and other therapies during the coronavirus disease 2019 (COVID-19) pandemic provided several lessons with respect to these therapies, and to how medical researchers and clinicians should approach the next pandemic.

RECENT FINDINGS

New or repurposed therapies, particularly immunomodulator treatments, for the treatment of an infectious disease will always be associated with inherent patient risk and this was the case during the COVID-19 pandemic. The concomitant development and use of effective antimicrobial therapies along with close monitoring for secondary infections is paramount for patient safety and treatment success. The development of immunomodulators and other therapies during the COVID-19 pandemic further highlighted the importance of maintaining high standards for medical research for all potential treatment with large double-blind placebo-controlled trials and peer review being the best mode of disseminating medical results rather than social media outlets.

SUMMARY

The next new and emerging pandemic will undoubtedly share many of the same challenges posed by COVID-19. It is important that researchers and clinicians learn from this experience, adhere to tried and true clinical care, all the while conducting high quality research aimed at developing definitive treatments.

Neurobrucellosis Presenting with Motor Damage or Hearing Loss, and Use of Steroids are Associated with a Higher Risk of Sequelae or Relapse: A Systematic Review of Individual Participant Data

BACKGROUND

Neurobrucellosis presents diverse clinical challenges and risks of long-term complications.

OBJECTIVE

We aimed to assess the relationship between the duration of antibiotic therapy, clinical factors, and the outcome of neurobrucellosis with a case report combined with a systematic review of the literature.

METHODS

We present a case of a 31 years-old man successfully treated at our Institution. We then searched Ovid MEDLINE, Embase and Scopus for articles that encompassed neurobrucellosis cases, duration of treatment, and outcome. The primary outcome was to assess an association between the duration of treatment and the risk of sequelae or relapses. Univariate, multivariate and sensitivity analysis were carried out to define which variables affect​ed​ the clinical outcome. Quality assessment was performed using a dedicated tool.

RESULTS

A total of 123 studies were included, totaling 221 patients. Median duration of treatment was 4 months (IQR 3 - 6), 69% patients recovered without sequelae, 27% had sequelae. Additionally, five patients had a relapse, and 4 patients died. Multivariate analysis found that the duration of treatment, age, and the use of ceftriaxone were not associated with a higher risk of sequelae or relapses. A significant association was found for corticosteroids use (OR 0.39, 95% IC 0.16 - 0.96, p = 0.038), motor impairment (OR 0.29, 95% IC 0.14 - 0.62, p = 0.002), and hearing loss (OR 0.037, 95% IC 0.01 - 0.11, p < 0.001).

CONCLUSIONS

This study highlights the variability in clinical presentations and treatment approaches for neurobrucellosis. Patients with factors indicating higher sequelae risk require meticulous follow-up.

Cerebrospinal Fluid Neutrophil Gelatinase-Associated Lipocalin as a Novel Biomarker for Postneurosurgical Bacterial Meningitis: A Prospective Observational Cohort Study

BACKGROUND AND OBJECTIVES

Postneurosurgical bacterial meningitis (PNBM) was a significant clinical challenge, as early identification remains difficult. This study aimed to explore the potential of neutrophil gelatinase-associated lipocalin (NGAL) as a novel biomarker for the early diagnosis of PNBM in patients who have undergone neurosurgery.

METHODS

A total of 436 postneurosurgical adult patients were enrolled in this study. Clinical information, cerebrospinal fluid (CSF), and blood samples were collected. After the screening, the remaining 267 patients were divided into the PNBM and non-PNBM groups, and measured CSF and serum NGAL levels to determine the diagnostic utility of PNBM. Subsequently, patients with PNBM were categorized into gram-positive and gram-negative bacterial infection groups to assess the effectiveness of CSF NGAL in differentiating between these types of infections. We analyzed the changes in CSF NGAL expression before and after anti-infection treatment in PNBM. Finally, an additional 60 patients were included as an independent validation cohort to further validate the diagnostic performance of CSF NGAL.

RESULTS

Compared with the non-PNBM group, CSF NGAL was significantly higher in the PNBM group (305.1 [151.6-596.5] vs 58.5 [30.7-105.8] ng/mL; P < .0001). The area under the curve of CSF NGAL for diagnosing PNBM was 0.928 (95% CI: 0.897-0.960), at a threshold of 119.7 ng/mL. However, there was no significant difference in serum NGAL between the 2 groups (142.5 [105.0-248.6] vs 161.9 [126.6-246.6] ng/mL, P = .201). Furthermore, CSF NGAL levels were significantly higher in patients with gram-negative bacterial infections than those with gram-positive bacteria (P = .023). In addition, CSF NGAL levels decrease after treatment compared with the initial stage of infection (P < .0001). Finally, in this validation cohort, the threshold of 119.7 ng/mL CSF NGAL shows good diagnostic performance with a sensitivity and specificity of 90% and 80%, respectively.

CONCLUSION

CSF NGAL holds promise as a potential biomarker for the diagnosis, early drug selection, and efficacy monitoring of PNBM.

Bacterial load in cerebrospinal fluid predicts unfavourable outcome in pneumococcal meningitis: a prospective nationwide cohort study

OBJECTIVES

The objective of this study was to determine the role of cerebrospinal fluid (CSF) bacterial load in adults with pneumococcal meningitis.

METHODS

We quantified bacterial load in CSF samples from the diagnostic lumbar puncture of adults with community-acquired pneumococcal meningitis. We also measured CSF concentrations of complement component 5a (C5a), and determined associations between bacterial load, clinical characteristics, C5a and unfavourable outcome (Glasgow Outcome Scale score <5).

RESULTS

Bacterial load was quantified in 152 CSF samples. Median age of these patients was 61 years (interquartile range [IQR] 51-68), and 69 of 152 (45%) were female. Median CSF bacterial load was 1.6 × 104 DNA copies/mL (IQR 3.4 × 103-1.2 × 105), and did not correlate with CSF white cell count nor with CSF protein concentrations. Median CSF C5a concentration was 35.8 mg/L (IQR 15.9-105.6), and was moderately correlated with CSF bacterial loads (Spearman's rho = 0.42; p < 0001). High bacterial loads were associated with development of complications, such as circulatory shock (OR per logarithmic increase: 2.4, 95% CI: 2.0-2.9; p < 0.001) and cerebrovascular complications [OR: 1.9, 95% CI: 1.6-2.3; p < 0.001]). High bacterial loads were also associated with unfavourable outcome (OR: 2.8, 95% CI: 2.4-3.3; p < 0.001) and death (OR: 3.1, 95% CI: 2.6-3.8; p < 0.001). In a multivariable regression model including age, immunocompromised state, extrameningeal infection focus, admission Glasgow Coma Scale score and CSF C5a concentration, CSF bacterial load remained an independent predictor of unfavourable outcome (adjusted OR: 2.5, 95% CI: 1.6-3.9; p < 0.001).

DISCUSSION

High CSF bacterial load predicts the development of complications and unfavourable outcome in adults with pneumococcal meningitis.

Limited protection of pneumococcal vaccines against emergent Streptococcus pneumoniae serotype 14/ST876 strains

PURPOSE

Streptococcus pneumoniae (Spn) is a major cause of child death. We investigated the epidemiology of S. pneumoniae in a pediatric fever clinic and explored the genomics basis of the limited vaccine response of serotype 14 strains worldwide.

METHODS

Febrile disease and pneumonia were diagnosed following criteria from the WHO at the end of 2019 at a tertiary children's hospital. Spn was isolated by culture from nasopharyngeal (NP) swabs. The density was determined by lytA-base qPCR. Isolates were serotyped by Quellung and underwent antimicrobial susceptibility testing. Whole-genome sequencing was employed for molecular serotyping, MLST, antibiotic gene determination, SNP calling, recombination prediction, and phylogenetic analysis.

RESULTS

The presence of pneumococcus in the nasopharynx (87.5%, 7/8, p = 0.0227) and a high carriage (100%, 7/7, p = 0.0123) were significantly associated with pneumonia development. Living with siblings (73.7%, 14/19, p = 0.0125) and non-vaccination (56.0%, 28/50, p = 0.0377) contributed significantly to the Spn carriage. Serotype 14 was the most prevalent strain (16.67%, 5/30). The genome analysis of 1497 serotype 14 strains indicated S14/ST876 strains were only prevalent in China, presented limited vaccine responses with higher recombination activities within its cps locus, and unique variation patterns in the genes wzg and lrp.

CONCLUSION

With the lifting of the one-child policy, it will be crucial for families with multiple children to get PCV vaccinations in China. Due to the highly variant cps locus and distinctive variation patterns in capsule shedding and binding proteins genes, the prevalent S14/ST876 strains have shown poor response to current vaccines. It is necessary to continue monitoring the molecular epidemiology of this vaccine escape clone.

Neutrophil extracellular trap-associated protein in cerebrospinal fluid for prognosis evaluation of adult bacterial meningitis: a retrospective case-control study

BACKGROUND AND OBJECTIVES

Central nervous system infections, typified by bacterial meningitis, stand as pivotal emergencies recurrently confronted by neurologists. Timely and precise diagnosis constitutes the cornerstone for efficacious intervention. The present study endeavors to scrutinize the influence of inflammatory protein levels associated with neutrophils in cerebrospinal fluid on the prognosis of central nervous system infectious maladies.

METHODS

This retrospective case series study was undertaken at the Neurology Department of the Second Hospital of Shandong University, encompassing patients diagnosed with infectious encephalitis as confirmed by PCR testing and other diagnostic modalities spanning from January 2018 to January 2024. The quantification of MPO and pertinent inflammatory proteins within patients' cerebrospinal fluid was accomplished through the utilization of ELISA.

RESULTS

We enlisted 25 patients diagnosed with bacterial meningitis, ascertained through PCR testing, and stratified them into two groups: those with favorable prognoses (n = 25) and those with unfavorable prognoses (n = 25). Following assessments for normality and variance, notable disparities in CSF-MPO concentrations emerged between the prognostic categories of bacterial meningitis patients (P < 0.0001). Additionally, scrutiny of demographic data in both favorable and unfavorable prognosis groups unveiled distinctions in CSF-IL-1β, CSF-IL-6, CSF-IL-8, CSF-IL-18, CSF-TNF-α levels, with correlation analyses revealing robust associations with MPO. ROC curve analyses delineated that when CSF-MPO ≥ 16.57 ng/mL, there exists an 83% likelihood of an adverse prognosis for bacterial meningitis. Similarly, when CSF-IL-1β, CSF-IL-6, CSF-IL-8, CSF-IL-18, and CSF-TNF-α levels attain 3.83pg/mL, 123.92pg/mL, 4230.62pg/mL, 35.55pg/mL, and 35.19pg/mL, respectively, there exists an 83% probability of an unfavorable prognosis for bacterial meningitis.

CONCLUSION

The detection of neutrophil extracellular traps MPO and associated inflammatory protein levels in cerebrospinal fluid samples holds promise in prognosticating bacterial meningitis, thereby assuming paramount significance in the prognostic evaluation of patients afflicted with this condition.

Clinical Picture and Risk Factors for Poor Outcome in Streptococcus pneumoniae Meningitis of Childhood on Three Continents

BACKGROUND

Streptococcus pneumoniae meningitis (SpM) remains a major health burden worldwide, particularly in low- and middle-income countries. Identifying the patients at highest risk for mortality and disabling sequelae may reveal potentially avoidable predisposing factors and identify patients most in need of intensive care. We searched for factors that do not require laboratory facilities.

METHODS

This study was a secondary analysis of prospectively collected data from 5 clinical trials of childhood bacterial meningitis on 3 continents between 1984 and 2017. SpM cases were analyzed by study site and predictors for poor outcome (death or severe sequelae) were identified from the whole series, Latin America and Angola.

RESULTS

Among a total of 1575 children (age range: 2 months to 15 years), 505 cases were due to pneumococci. Compared to other etiologies, SpM doubled the death rate (33% vs. 17%) and tripled poor outcome (15% vs. 6%). In SpM, Glasgow Coma Score <13 [odds ratio (OR): 4.73] and previous antibiotics in Angola (OR: 1.70) were independent predictors for death. Predictors for poor outcome were age <1 year (OR: 2.41) and Glasgow Coma Score <13 (OR: 6.39) in the whole series, seizures in Latin America (OR: 3.98) and previous antibiotics in Angola (OR: 1.91). Angolan children had a 17-fold increased risk for poor outcome when compared with Finnish children ( P = 0.011).

CONCLUSIONS

Our study proved the severity of SpM when compared with other etiologies. The outcome was especially poor in Angola. Most patients at risk for poor outcome are easily identified by clinical factors on admission.

Bioengineered Neutrophils for Smart Response in Brain Infection Management

Brain infections, frequently accompanied by significant inflammation, necessitate comprehensive therapeutic approaches targeting both infections and associated inflammation. A major impediment to such combined treatment is the blood-brain barrier (BBB), which significantly restricts therapeutic agents from achieving effective concentrations within the central nervous system. Here, a neutrophil-centric dual-responsive delivery system, coined "CellUs," is pioneered. This system is characterized by live neutrophils enveloping liposomes of dexamethasone, ceftriaxone, and oxygen-saturated perfluorocarbon (Lipo@D/C/P). CellUs is meticulously engineered to co-deliver antibiotics, anti-inflammatory agents, and oxygen, embodying a comprehensive strategy against brain infections. CellUs leverages the intrinsic abilities of neutrophils to navigate through BBB, accurately target infection sites, and synchronize the release of Lipo@D/C/P with local inflammatory signals. Notably, the incorporation of ultrasound-responsive perfluorocarbon within Lipo@D/C/P ensures the on-demand release of therapeutic agents at the afflicted regions. CellUs shows considerable promise in treating Staphylococcus aureus infections in mice with meningitis, particularly when combined with ultrasound treatments. It effectively penetrates BBB, significantly eliminates bacteria, reduces inflammation, and delivers oxygen to the affected brain tissue, resulting in a substantial improvement in survival rates. Consequently, CellUs harnesses the natural chemotactic properties of neutrophils and offers an innovative pathway to improve treatment effectiveness while minimizing adverse effects.

The single D380 amino acid substitution increases pneumolysin cytotoxicity toward neuronal cells

Bacterial meningitis, frequently caused by Streptococcus pneumoniae (pneumococcus), represents a substantial global health threat leading to long-term neurological disorders. This study focused on the cholesterol-binding toxin pneumolysin (PLY) released by pneumococci, specifically examining clinical isolates from patients with meningitis and comparing them to the PLY-reference S. pneumoniae strain D39. Clinical isolates exhibit enhanced PLY release, likely due to a significantly higher expression of the autolysin LytA. Notably, the same single amino acid (aa) D380 substitution in the PLY D4 domain present in all clinical isolates significantly enhances cholesterol binding, pore-forming activity, and cytotoxicity toward SH-SY5Y-derived neuronal cells. Scanning electron microscopy of human neuronal cells and patch clamp electrophysiological recordings on mouse brain slices confirm the enhanced neurotoxicity of the PLY variant carrying the single aa substitution. This study highlights how a single aa modification enormously alters PLY cytotoxic potential, emphasizing the importance of PLY as a major cause of the neurological sequelae associated with pneumococcal meningitis.

Adjunctive treatments for pneumococcal meningitis: a systematic review of experimental animal models

New treatments are needed to improve the prognosis of pneumococcal meningitis. We performed a systematic review on adjunctive treatments in animal models of pneumococcal meningitis in order to identify treatments with the most potential to progress to clinical trials. Studies testing therapy adjunctive to antibiotics in animal models of pneumococcal meningitis were included. A literature search was performed using Medline, Embase and Scopus for studies published from 1990 up to 17 February 2023. Two investigators screened studies for inclusion and independently extracted data. Treatment effect was assessed on the clinical parameters disease severity, hearing loss and cognitive impairment and the biological parameters inflammation, brain injury and bacterial load. Adjunctive treatments were evaluated by their effect on these outcomes and the quality, number and size of studies that investigated the treatments. Risk of bias was assessed with the SYRCLE risk of bias tool. A total of 58 of 2462 identified studies were included, which used 2703 experimental animals. Disease modelling was performed in rats (29 studies), rabbits (13 studies), mice (12 studies), gerbils (3 studies) or both rats and mice (1 study). Meningitis was induced by injection of Streptococcus pneumoniae into the subarachnoid space. Randomization of experimental groups was performed in 37 of 58 studies (64%) and 12 studies (12%) were investigator-blinded. Overall, 54 treatment regimens using 46 adjunctive drugs were evaluated: most commonly dexamethasone (16 studies), daptomycin (5 studies), complement component 5 (C5; 3 studies) antibody and Mn(III)tetrakis(4-benzoicacid)porphyrin chloride (MnTBAP; 3 studies). The most frequently evaluated outcome parameters were inflammation [32 studies (55%)] and brain injury [32 studies (55%)], followed by disease severity [30 studies (52%)], hearing loss [24 studies (41%)], bacterial load [18 studies (31%)] and cognitive impairment [9 studies (16%)]. Adjunctive therapy that improved clinical outcomes in multiple studies was dexamethasone (6 studies), C5 antibodies (3 studies) and daptomycin (3 studies). HMGB1 inhibitors, matrix metalloproteinase inhibitors, neurotrophins, antioxidants and paquinimod also improved clinical parameters but only in single or small studies. Evaluating the treatment effect of adjunctive therapy was complicated by study heterogeneity regarding the animal models used and outcomes reported. In conclusion, 24 of 54 treatment regimens (44%) tested improved clinically relevant outcomes in experimental pneumococcal meningitis but few were tested in multiple well-designed studies. The most promising new adjunctive treatments are with C5 antibodies or daptomycin, suggesting that these drugs could be tested in clinical trials.

Enhancing sensitivity of qPCR assays targeting Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae by using a mutant Taq DNA polymerase

AIMS

Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae are important causes of bacterial meningitis. In this study, the DNA binding site of the wild type Taq DNA polymerase was modified to produce a mutant enzyme with enhanced DNA affinity and PCR performance. The engineered and the wild type enzymes were integrated into qPCR-based assays for molecular detection of S. pneumoniae, N. meningitidis, H. influenzae, and serogroups and serotypes of these three pathogens.

METHODS

Bio-Speedy® Bacterial DNA Isolation Kit (Bioeksen R&D Technologies, Turkiye) and 2× qPCR-Mix for hydrolysis probes (Bioeksen R&D Technologies, Turkiye) and CFX96 Instrument (Biorad Inc., USA) were used for all molecular analyses. Spiked negative clinical specimens were tested using the developed qPCR assays and the culture-based conventional methods for the analytical performance evaluation.

RESULTS

All qPCR assays did not produce any positive results for the samples spiked with potential cross-reacting bacteria. Limit of detection (LOD) of the assays containing the mutant enzyme was 1 genome/reaction (10 cfu/mL sample) which is at least 3 times lower than the previously reported LOD levels for DNA amplification based molecular assays. LODs for the spiked serum and cerebrospinal fluid (CSF) samples decreased 2.3-4.7 and 1.2-3.5 times respectively when the mutant enzyme was used instead of the wild type Taq DNA polymerase.

CONCLUSIONS

It is possible to enhance analytical sensitivity of qPCR assays targeting the bacterial agents of meningitis by using an engineered Taq DNA polymerase. These qPCR-based assays can be used for direct detection and serogrouping / serotyping of S. pneumoniae, N. meningitidis and H. influenzae at concentrations close to the lower limit of medical decision point.

Pneumococcal sialidase promotes bacterial survival by fine-tuning of pneumolysin-mediated membrane disruption

Pneumolysin (Ply) is an indispensable cholesterol-dependent cytolysin for pneumococcal infection. Although Ply-induced disruption of pneumococci-containing endosomal vesicles is a prerequisite for the evasion of endolysosomal bacterial clearance, its potent activity can be a double-edged sword, having a detrimental effect on bacterial survivability by inducing severe endosomal disruption, bactericidal autophagy, and scaffold epithelial cell death. Thus, Ply activity must be maintained at optimal levels. We develop a highly sensitive assay to monitor endosomal disruption using NanoBiT-Nanobody, which shows that the pneumococcal sialidase NanA can fine-tune Ply activity by trimming sialic acid from cell-membrane-bound glycans. In addition, oseltamivir, an influenza A virus sialidase inhibitor, promotes Ply-induced endosomal disruption and cytotoxicity by inhibiting NanA activity in vitro and greater tissue damage and bacterial clearance in vivo. Our findings provide a foundation for innovative therapeutic strategies for severe pneumococcal infections by exploiting the duality of Ply activity.

Distinguishing community-acquired bacterial and viral meningitis: Microbes and biomarkers

Diagnostic tools to differentiate between community-acquired bacterial and viral meningitis are essential to target the potentially lifesaving antibiotic treatment to those at greatest risk and concurrently spare patients with viral meningitis from the disadvantages of antibiotics. In addition, excluding bacterial meningitis and thus decreasing antibiotic consumption would be important to help reduce antimicrobial resistance and healthcare expenses. The available diagnostic laboratory tests for differentiating bacterial and viral meningitis can be divided microbiological pathogen-focussed methods and biomarkers of the host response. Bacterial culture-independent microbiological methods, such as highly multiplexed nucleic acid amplification tests, are rapidly making their way into the clinical practice. At the same time, more conventional host protein biomarkers, such as procalcitonin and C-reactive protein, are supplemented by newer proteomic and transcriptomic signatures. This review aims to summarise the current state and the recent advances in diagnostic methods to differentiate bacterial from viral meningitis.

Manifestations of Myelinating Oligodendrocyte Glycoprotein Antibody-Associated Disease: A Rare Case of Suppurative Meningoencephalitis

Myelinating oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an inflammatory demyelinating disease of the central nervous system (CNS) mediated by MOG antibodies (MOG-IgG). It is associated with autoimmunity and encompasses various syndromes. However, manifestations presenting with symptoms of suppurative meningoencephalitis are rare. In this case, we admitted an 80-year-old male patient who presented with fever, headache, mental and behavioral abnormalities, and disturbance of consciousness. The cerebrospinal fluid (CSF) examination revealed elevated levels of leukocytes and protein, while magnetic resonance imaging (MRI) of the brain showed an abnormal signal in the parietal lobe surrounding the posterior horn of the right lateral ventricle. The patient tested positive for serum MOG-IgG, confirming the diagnosis of MOG-IgG-related meningoencephalitis. The treatment included intravenous immunoglobulin, glucocorticoids, third-generation cephalosporins, and immunosuppressants. Following the treatment, the patient experienced complete recovery.

Development and validation of a novel multiplex digital PCR assay for identification of pathogens in cerebrospinal fluid of children with bacterial meningitis

BACKGROUND AND AIMS

Identifying the pathogens of bacterial meningitis (BM) is crucial for its diagnosis and treatment. The aim of this study is to develop and validate a novel method for detecting pathogens in cerebrospinal fluid (CSF) of children with BM using a digital polymerase chain reaction (dPCR) assay.

MATERIALS AND METHODS

A novel multiplex dPCR assay method has been developed and validated. The diagnostic performance of the dPCR assay was compared with that of synchronous CSF culture, and the factors affecting its performance were analyzed.

RESULTS

A total of 69 children with BM were enrolled prospectively. The sensitivity of the dPCR assay was 94.44 %, specificity was 100 %, coincidence rate was 98.55 %, Kappa value was 0.959, and net reclassification improvement was 61.11 %. Compared with the CSF culture assay, the dPCR assay had higher sensitivity in different bacterial groups. Multiple factors affected its performance, including previous use of antibiotics, sampling time, BM complications, and levels of inflammatory biomarkers in CSF and blood (all P < 0.05). Patients who required intensive care and died had a higher bacterial DNA loads identified by dPCR assay (both P < 0.05).

CONCLUSION

This novel assay has better pathogen detection ability than CSF culture. Its performance was influenced by sampling time, previous use of antibiotics, and disease severity.

Recurrent bacterial meningitis in children in the Netherlands: a nationwide surveillance study

OBJECTIVES

This study aimed to estimate the recurrence rate of culture-positive bacterial meningitis in children in the Netherlands.

DESIGN

Nationwide surveillance study, using the database of the Netherlands Reference Laboratory for Bacterial Meningitis to identify patients with culture-positive bacterial meningitis during childhood.

SETTING

The study was based in the Netherlands.

PARTICIPANTS

A total of 9731 children with a first bacterial meningitis episode between 1 July 1987 and 30 June 2019 were identified.

PRIMARY AND SECONDARY OUTCOME MEASURES

Recurrence was defined as a subsequent episode >28 days, or caused by a different pathogen. Annual incidence and incidence rate ratios (IRRs) comparing the periods 1988-2003 and 2004-2019 were calculated. Predictors of recurrent meningitis were assessed using Cox proportional hazards regression.

RESULTS

Sixty-three (0.6%) of the 9731 children with a first bacterial meningitis episode contracted recurrent meningitis. Neisseria meningitidis was the leading pathogen for first meningitis episodes (52%) and Streptococcus pneumoniae for recurrent episodes (52%). The median annual incidence of first episodes per 100 000 children decreased from 11.81 (IQR 11.26-17.60) in 1988-2003 to 2.60 (IQR 2.37-4.07) in 2004-2019 (IRR 0.25, 95% CI 0.23 to 0.26). The incidence of recurrences did not change: 0.06 (IQR 0.02-0.11) in 1988-2003 to 0.03 (IQR 0.00-0.06) in 2004-2019 (IRR 0.65, 95% CI 0.39 to 1.1). Age above 5 years (OR 3.6 (95% CI 1.5 to 8.3)) and a first episode due to Escherichia coli (OR 25.7 (95% CI 7.2 to 92.0)) were associated with higher risks of recurrence.

CONCLUSION

The recurrence rate of childhood bacterial meningitis in the Netherlands was 0.6%. While the incidence rate of first episodes decreased substantially, this was not the case for recurrent episodes. Older age and a first episode due to E. coli were associated with higher recurrence risks.

Comparative proteomics reveals the antibiotic resistance and virulence of Cronobacter isolated from powdered infant formula and its processing environment

Cronobacter species are opportunistic foodborne pathogens that can cause neonatal meningitis, sepsis, and necrotizing enterocolitis. In this genus, certain level strains have high mortality to infant (Cronobacter sakazakii and Cronobacter malonaticus) and antibiotic tolerance. Cronobacter has strong environmental tolerance (acid resistance, high temperature resistance, UV resistance, antibiotic resistance, etc.) and can survive in a variety of environments. It has been isolated in various production environments and products in several countries. However, the relationships between Cronobacter antibiotic tolerance and virulence remain unclear, especially at the molecular level. In this study, 96 strains of Cronobacter were isolated from powdered infant formula and its processing environment and screened for antibiotic tolerance, and proteomic maps of the representative strains of Cronobacter with antibiotic tolerance were generated by analyzing proteomics data using multiple techniques to identify protein that are implicated in Cronobacter virulence and antibiotic resistance. The increase in antibiotic tolerance of Cronobacter had a certain increase in the production of enterotoxin and hemolysin. Only triple tolerated Cronobacter sakazakii decreased the utilization of sialic acid. A total of 16,131 intracellular proteins were detected in eight representative strains, and different proteomes were present in strains with different antibiotic tolerance, including 56 virulence-related proteins. Multiple virulence proteins regulated by unknown genes were also found in the eight isolated representative strains.

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.

Pericytes are protective in experimental pneumococcal meningitis through regulating leukocyte infiltration and blood-brain barrier function

BACKGROUND

Brain pericytes participate in the regulation of cerebral blood flow and the maintenance of blood-brain barrier integrity. Because of their perivascular localization, their receptor repertoire, and their potential ability to respond to inflammatory and infectious stimuli by producing various cytokines and chemokines, these cells are also thought to play an active role in the immune response to brain infections. This assumption is mainly supported by in vitro studies, investigations in in vivo disease models are largely missing. Here, we analysed the role of brain pericytes in pneumococcal meningitis, in vitro and in vivo in two animal models of pneumococcal meningitis.

METHODS

Primary murine and human pericytes were stimulated with increasing concentrations of different serotypes of Streptococcus pneumoniae in the presence or absence of Toll-like receptor inhibitors and their cell viability and cytokine production were monitored. To gain insight into the role of pericytes in brain infection in vivo, we performed studies in a zebrafish embryo model of pneumococcal meningitis in which pericytes were pharmacologically depleted. Furthermore, we analyzed the impact of genetically induced pericyte ablation on disease progression, intracranial complications, and brain inflammation in an adult mouse model of this disease.

RESULTS

Both murine and human pericytes reacted to pneumococcal exposure with the release of selected cytokines. This cytokine release is pneumolysin-dependent, TLR-dependent in murine (but not human) pericytes and can be significantly increased by macrophage-derived IL-1b. Pharmacological depletion of pericytes in zebrafish embryos resulted in increased cerebral edema and mortality due to pneumococcal meningitis. Correspondingly, in an adult mouse meningitis model, a more pronounced blood-brain barrier disruption and leukocyte infiltration, resulting in an unfavorable disease course, was observed following genetic pericyte ablation. The degree of leukocyte infiltration positively correlated with an upregulation of chemokine expression in the brains of pericyte-depleted mice.

CONCLUSIONS

Our findings show that pericytes play a protective role in pneumococcal meningitis by impeding leukocyte migration and preventing blood-brain barrier breaching. Thus, preserving the integrity of the pericyte population has the potential as a new therapeutic strategy in pneumococcal meningitis.

A Multicenter Epidemiological and Pathogenic Characteristics Study of Community-Acquired Bacterial Meningitis Children in China: Results from the Chinese Pediatric Bacterial Meningitis Surveillance (CPBMS) 2019-2020

Objective

To explore the epidemiological and pathogenic characteristics of children with community-acquired bacterial meningitis.

Methods

A multicenter, retrospective study was conducted among CABM patients under 15 years old from 33 hospitals in China from 2019 to 2020. The medical record, laboratory, and microbiological data were collected and analyzed.

Results

A total of 1610 children with CABM were identified and presented at a median onset age of 45 days of whom 955 (59.3%) were males. CABM occurred mostly in infants <1 year of age (84.0%, 1352/1610). In etiology-confirmed cases, the pathogens were isolated from CSF culture in 515 (32.0%), 400 (24.8%) in blood culture, and 186 (11.6%) both in CSF and blood culture. In total, 126 pathogens were identified through CSF mNGS in 330 CABM cases; 21 S. pneumoniae isolates were detected in 83 CABM cases by antigen detection method. Major pathogens were E. coli (195, 24.7%), GBS (170, 21.5%), and S. pneumoniae (157, 19.9%). GBS (29.3%, 22/75) was the first pathogen of CABM in neonates aged 0-6 days old, while E. coli (44.7%, 76/170) in 7 to 28 days of age; S. pneumoniae (96.2%, 151/157) was the most common pathogen in >3 months old cases. About 9.7% (19/195) strains of E. coli produced ultra‑broad‑spectrum β‑lactamases. The common intracranial imaging complications were subdural effusion and (or) empyema in 349 (21.7%), hydrocephalus in 233 (14.5%), and cerebral abscess in 178 (11.1%). A total of 389 (24.2%) cases were completely cured and 1088 (67.6%) cases improved. Among 166 patients (10.3%) with adverse outcomes, 32 cases (2.0%) died, and 37 cases (2.3%) relapsed.

Conclusion

The onset age of CABM in children is usually within 1 year of age, especially <3 months. The primary pathogens in infants less than 3 months old are E. coli and GBS, and the dominant pathogen in children older than 3 months old is S. pneumoniae. Subdural effusion and (or) empyema and hydrocephalus are common complications. CABM should not be excluded even if CSF leukocyte counts are within normal range. Due to the low detection rate of pathogens in children with CABM, standardized CSF bacteriological examination should be paid more attention to increase the pathogen detection rate. Non‑culture CSF detection methods may facilitate pathogenic diagnosis.

Accuracy of antigen tests for meningococcal meningitis in cerebrospinal fluid: A diagnostic meta-analysis

OBJECTIVES

Neisseria meningitidis is one of the major pathogens of meningitis in children worldwide and causes invasive meningococcal disease (IMD), which is a critical illness that mainly presents as meningitis and/or septicemia in children. Identification of N. meningitidis in cerebrospinal fluid (CSF) is the gold standard for the diagnosis of meningococcal meningitis, but antigen tests have advantages such as timely results, relatively low cost, and convenience. Yet, the diagnostic accuracy of antigen tests remains uncertain. Therefore, the aim of this meta-analysis was to evaluate the diagnostic accuracy of antigen tests for N. meningitidis in CSF.

METHODS

We searched the PubMed, Embase, and Cochrane Library databases for studies evaluating the diagnostic accuracy of antigen tests for N. meningitidis in CSF. We included studies that provided sufficient data to construct a 2 × 2 table on a per-sample basis. To determine the overall sensitivity and specificity of the antigen tests, we used polymerase chain reaction (PCR) as the reference standard and employed the hierarchical summary receiver operating characteristic model.

RESULTS

Nine studies with 4533 CSF samples were included. The meta-analysis yielded a pooled sensitivity of 91.2% (95% confidence interval [CI]: 80.0%-100.0%) and a pooled specificity of 93.8% (95% CI: 83.9%-100.0%). A subgroup analysis of 2 studies that reported the outcomes of MeningoSpeed yielded a pooled sensitivity of 93.4% (95% CI: 90.0%-95.8%) and a pooled specificity of 91.9% (95% CI: 88.6%-94.4%). Antigen testing for the N. meningitidis serogroup X had a pooled sensitivity of 92.4% (95% CI: 85.2%-96.2%) and a pooled specificity of 99.2% (95% CI: 78.7%-100.0%).

CONCLUSIONS

The studied antigen tests had high sensitivity and specificity for the diagnosis of meningococcal meningitis in CSF specimens. Antigen testing could serve as an accurate diagnostic method for assessing patients who have a suspected N. meningitidis infection.

The clinical utility of metagenomic next-generation sequencing for the diagnosis of central nervous system infectious diseases

BACKGROUND

To evaluate the clinical utility of metagenomic next-generation sequencing (mNGS) for the diagnosis of central nervous system infections (CNSI).

METHODS

Cerebrospinal fluid (CSF) from 54 patients who were high-level clinical suspicion of CNSI was collected and sent for mNGS and conventional tests from January 2019 to March 2022.

RESULTS

Twenty out of 54 patients were diagnosed with CNSI and 34 non-CNSI. Among the 34 non-CNSI, one was false positive by mNGS. Among the 20 CNSI, 11 had presumed viral encephalitis and/or meningitis, 5 had presumed bacterial meningitis, 2 had presumed TMB, 1 had Crytococcus meningitis and 1 had neurosyphilis. The sensitivity of viral encephalitis and/or meningitis was 0.73 (8/11); 10 virus were detected; 9/10 was dsDNA; 1/10 was ssRNA. SSRN ranged from 1 to 13. The accuracy rate was 0.4, the accuracy rate was positively correlated with SSRN (r = 0.738, P = 0.015), SSRN ≥ 1, the accuracy rate was 0.4; SSRN ≥ 3, the accuracy rate was 0.66; SSRN ≥ 4, the accuracy rate was 0.75; SSRN ≥ 6, the accuracy rate was 1. The sensitivity of bacterial meningitis was 1. Seven kinds of bacteria were detected, among which 3/7 were gram positive, 3/7 were gram negative, and 1/7 was infected NTM (nontuberculous mycobacteria). The accuracy rate was 0.43 (3/7). The sensitivity of TBM was 0.66 (2/3), the accuracy rate was 1. The sensitivity of Crytococcus meningitis was 1, the accuracy rate was 0.5. PPV (positive predictive value) of mNGS was 0.94, NPV (negative predictive value) of mNGS was 0.89, specificity was 0.97 and sensitivity was 0.8. The AUG for CSF mNGS diagnosis of CNSI was 0.89 (95% CI = 0.78-0.99) Headache, meningeal irritation sign and image of meninges abnormal were correlated with the sensitivity of mNGS (r = 0.451, 0.313, 0.446; p = 0.001, 0.021, 0.001); CSF Glucose and CSF Chloride were negatively correlated with sensitivity of mNGS (r = -0.395, -0.462; p = 0.003, ＜ 0.001).

CONCLUSION

mNGS is a detection means with high sensitivity, wide coverage and strong timeliness, which can help clinicians to identify the pathogen diagnosis quickly, conduct targeted anti-infection treatment early and reduce antibiotic abuse. The pathogen which causing low CSF Glucose, low CSF Chloride or meninges infections was more likely to be detected by mNGS. It may be related to growth and structural characteristics of the pathogen and blood-brain barrier damage.

Effect of Follow-Up Cerebrospinal Fluid Cultures in Post-Neurosurgical Patients' Outcome with Gram-Negative Bacterial Meningitis/Encephalitis

Background

To investigate the factors associated with follow-up CSF cultures (FUCCs) in post-neurosurgical patients with gram-negative bacterial meningitis/encephalitis and the effect of FUCCs on treatment management and patient outcomes.

Methods

This single-centered retrospective cohort study enrolled post-neurosurgical patients with gram-negative bacterial meningitis/encephalitis at a tertiary-care university hospital between 2012 and 2022. The risk factors for 28-day mortality were evaluated using multivariate Cox analysis. FUCC-related risk factors were also analyzed.

Results

Among the 844 enrolled patients, 504 (59.7%) underwent FUCC, and FUCC was found to be associated with lower rates of both all-cause (hazard ratio (HR) 0.391; 95% confidence interval (CI), 0.235-0.651; p<0.001) and attributable mortality (HR 0.463; 95% CI, 0.239-0.897; p=0.023) in Post-neurosurgical patients diagnosed with Gram-negative bacterial meningitis/encephalitis. Moreover, the results of the study underscored that patients with persistent gram-negative bacterial meningitis/encephalitis had a lower all-cause/attributable short-term survival rate according to 28-day mortality Kaplan-Meier analysis (P=0.001/0.006).

Conclusion

Performing FUCC has been demonstrated to lower mortality rates in Post-neurosurgical patients suffering from Gram-negative bacterial meningitis/encephalitis. The higher mortality rate observed in patients with persistent gram-negative bacterial meningitis/encephalitis suggests that performing FUCC is a crucial component of proper patient care and management, and is therefore recommended for use by clinicians as a standard practice. This finding underscores the significance of consistent implementation of FUCC in the management and prognosis of patients with Post-neurosurgical infections.

Factors associated with afebrile presentation and delayed defervescence of bacterial meningitis in children under 3 years of age: a multi-centre retrospective analysis

BACKGROUND

This multi-center study aimed to identify factors affecting fever and delayed defervescence in bacterial meningitis (BM) patients under 3 years of age because of the variability of fever in this patient population.

METHODS

Only BM patients under 3 years treated at 49 centers in China from November 2018 to end-April 2021 were included in the study. Univariate and multivariate logistic regression analyses were performed to determine factors associated with afebrile presentation and fever of delayed defervescence.

RESULTS

A total of 863 BM patients under 3 years were included in the study. Coagulase negative staphylococcus was associated with afebrile presentation (OR = 1.176), while septicaemia and ear-nose-throat infections were associated with fever (P < 0.05). The patients with fever were assigned into early and delayed defervescence groups based on defervescence time (less than and more than or equal to one week). Furthermore, Streptococcus agalactiae meningitis (OR = 1.124), concomitant gastrointestinal infection (OR = 1.276), encephalomalacia (or = 1.339), and subdural effusion (OR = 1.454) were independently associated with delayed defervescence (all P < 0.05).

CONCLUSIONS

The findings can aid in the efficient utilization of fever in auxiliary diagnosis and evaluating the condition of the disease.

[A case of community-acquired Listeria monocytogenes meningitis]

Meningitis caused by Listeria monocytogenes is a rare disease in immunocompetent individuals, however, in the presence of certain risk factors with clinical signs indicating infection of the central nervous system it should not be ignored. In this case report, we present the medical history of a 72-year-old man, suffering from hypertension and liver cirrhosis, who was diagnosed with meningitis caused by L. monocytogenes. The patient was admitted to our Department with the symptoms of weakness, dizziness, high fever and urinary incontinence. Laboratory tests showed elevated inflammatory and liver enzyme values as well as low white blood cell and platelet counts were confirmed. Imaging tests did not prove any abnormalities. Due to septic parameters, after microbiological samples were collected, empiric ceftriaxon and metronidazol treatment was started. Despite our therapeutic efforts, the condition of the patient had not improved significantly. The patient still suffered from high fever; increasing agitation and tremor, coordination disorder appeared, raising the possibility of a bacterial infection of the central nervous system. Examination of the cerebrospinal fluid confirmed the diagnosis of bacterial meningitis. In the meantime, findings of microbiological cultures verified the infection of L. monocytogenes, however, cerebrospinal fluid culture did not detect any pathogen. Following that, the therapy continued with targeted ampicillin which resulted in rapid improvement of the patient's condition; fevers and neurological symptoms have ceased to exist. We considered the case worthy of presentation because of the pitfalls of the diagnosis, the emerging differential diagnostic difficulties and the favorable outcome due to the effectiveness of targeted antibiotic treatment. Orv Hetil. 2023; 164(36): 1437-1441.

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.

Role of lumbar puncture in clinical outcome of suspected acute bacterial meningitis

BACKGROUND

Meningitis remains a significant source of mortality and morbidity, with an incidence of 1 per 100000 persons in the United States. Guidelines recommend obtaining blood cultures and cerebrospinal fluid (CSF) studies in patients presenting with acute meningitis syndrome, and beginning treatment with broad spectrum antibiotics based on the age and certain predisposing conditions. In some patients however, the diagnostic lumbar puncture (LP) is not performed due to a multitude of reasons, ranging from increased intracranial pressure to failed attempt. In such situations, appropriate therapy is initiated empirically and often continued without establishment of a definitive diagnosis.

AIM

To determine whether a diagnostic LP in acute meningitis syndrome was associated with a better outcome and less duration of antibiotic therapy, along with potential causes for deferral of procedure.

METHODS

A retrospective study was conducted amongst the patients presenting to a 360 bedded community hospital in central Massachusetts with a diagnosis of acute meningitis syndrome between January 2010 – September 2022. The electronic health records were accessed to collect necessary demographic and clinical data, including etiology of meningitis, lumbar puncture results, reason for procedure deferral, duration of antibiotic therapy and clinical outcome. The patients were subsequently divided into two groups based on whether they received a LP or not, and data was analyzed.

RESULTS

A total of 169 patients admitted with acute meningitis syndrome between September 2010-2022 were included in the study. The mean age of the participants was 54.3 years (SD +/- 19.2 years). LP was performed for 130 (76.9%) participants, out of which, 28 (21.5%) showed some growth in CSF culture. The most commonly identified organism was streptococcus pneumoniae. Amongst the 39 patients in whom LP was deferred, the major reasons recorded were: Body habitus (n = 6, 15.4%), and unsuccessful attempt (n = 4, 10.3%). While 93 (71.5%) patients with LP received antibiotic therapy, only 19 (48.7%) patients without LP received the antibiotics, with the principal reason being spontaneous improvement in sensorium without any diagnosed source of infection. The mean duration of antibiotic use was 12.3 days (SD +/- 5.6) in the LP group and 11.5 days (SD +/- 7.0) in the non-LP group (P = 0.56; statistically not significant). We observed higher long term sequalae in the non-LP group (n = 6, 15.4%) compared to the LP group (n = 9, 6.9%). Similarly, the death rate was higher in the non-LP group (n = 7, 18.0%) compared to the LP group (n = 9, 6.9%).

CONCLUSION

LP remains the cornerstone for diagnosing meningitis, but often CSF results are unavailable, leading to empiric treatment. Our study identified that body habitus and unsuccessful attempts were the most common reasons for LP not being performed, leading to empiric antibiotic coverage. There was no difference between the duration of antibiotics received by the two groups, but a lower proportion of patients without LP received antibiotics, attributed to a spontaneous improvement in sensorium. However, the residual neurological sequelae and death rates were higher in patients without LP, signifying a potential under-treatment. A LP remains crucial to diagnose meningitis, and a lack of CSF analysis predisposes to under-treatment, leading to higher neurological sequelae and increased chances of death.

Epidemiology, clinical features and outcome of adults with meningococcal meningitis: a 15-year prospective nationwide cohort study

Background

We describe the epidemiology, clinical features and outcome of adult meningococcal meningitis in the Netherlands over a 15-year period.

Methods

We studied adults (age ≥ 16 years) who were listed by the Netherlands Reference Laboratory for Bacterial Meningitis and/or included in the prospective nationwide cohort study (MeninGene) between January 2006 and July 2021. Incidences were calculated per epidemiological year (July-June).

Findings

We identified 442 episodes of adult meningococcal meningitis. The median patient age was 32 years (IQR 18-55) and 226 episodes (51%) occurred in female patients. The annual incidence per 100,000 adults fluctuated, from 0.33 in 2006-2007 to 0.05 in 2020-2021, with a temporal increase up to 0.30 from 2016 to 2018, driven by an outbreak of serogroup W (MenW). Of 442 episodes, 274 episodes (62%) in 273 patients were included in the clinical cohort study. The overall case fatality rate was 4% (10 of 274) and 16% (43 of 274) had an unfavourable outcome (Glasgow Outcome Scale score 1-4). Compared to other serogroups, MenW was associated with higher rates of unfavourable outcome (6 of 16 [38%] vs. 37 of 251 [15%], P = 0.03) and death (4 of 16 [25%] vs. 6 of 251 [2%], P = 0.001).

Interpretation

The overall incidence of adult meningococcal meningitis in the Netherlands is low and outcome is generally favourable. An increase of MenW meningitis occurred from 2016 to 2018, which was associated with more unfavourable outcome and death.

Funding

Netherlands Organisation for Health Research and Development, European Research Council, National Institute of Public Health and Environmental protection.

Klebsiella pneumoniae invasive syndrome with liver abscess and purulent meningitis presenting as acute hemiplegia: a case report

BACKGROUND

Klebsiella pneumoniae can infect a variety of sites, with the risk of infection being higher in the immunocompromised state such as diabetes mellitus. A distinct invasive syndrome has been detected mostly in Southeast Asia in the past two decades. A common destructive complication is pyogenic liver abscess that can be complicated by metastatic endophthalmitis as well as the involvement of the central nervous system, causing purulent meningitis or brain abscess.

CASE PRESENTATION

We report a rare case of an invasive liver abscess caused by K. pneumoniae, with metastatic infections of meninges. A 68-year-old man with type 2 diabetes mellitus presented to our emergency department as sepsis. Sudden disturbed consciousness was noticed with presentation of acute hemiplegia and gaze preference mimicking a cerebrovascular accident.

CONCLUSIONS

The above case adds to the scarce literature on K. pneumoniae invasive syndrome with liver abscess and purulent meningitis. K. pneumoniae is a rare cause of meningitis and should raise suspicions about the disease in febrile individuals. In particular, Asian patients with diabetes presenting with sepsis and hemiplegia prompt a more thorough evaluation with aggressive treatment.

Neonatal Meningitis-Causing Escherichia coli Induces Microglia Activation which Acts as a Double-Edged Sword in Bacterial Meningitis

Bacterial meningitis is a devastating disease occurring worldwide, with up to half of survivors left with permanent neurological sequelae. Neonatal meningitis-causing Escherichia coli (NMEC) is the most common Gram-negative bacillary organism that causes meningitis, particularly during the neonatal period. Here, RNA-seq transcriptional profiles of microglia in response to NMEC infection show that microglia are activated to produce inflammatory factors. In addition, we found that the secretion of inflammatory factors is a double-edged sword that promotes polymorphonuclear neutrophil (PMN) recruitment to the brain to clear the pathogens but, at the same time, induces neuronal damage, which may be related to the neurological sequelae. New neuroprotective therapeutic strategies must be developed for the treatment of acute bacterial meningitis. We found that transforming growth factor-β (TGF-β) may be a strong candidate in the treatment of acute bacterial meningitis, as it shows a therapeutic effect on bacterial-meningitis-induced brain damage. Prevention of disease and early initiation of the appropriate treatment in patients with suspected or proven bacterial meningitis are the key factors in reducing morbidity and mortality. Novel antibiotic and adjuvant treatment strategies must be developed, and the main goal for new therapies will be dampening the inflammatory response. Based on this view, our findings may help develop novel strategies for bacterial meningitis treatment.

Nanotechnology-based photo-immunotherapy: a new hope for inhibition of melanoma growth and metastasis

Melanoma is the most aggressive form of skin cancer and there is a need for the development of effective anti-melanoma therapies as it shows high metastatic ability and low response rate. In addition, it has been identified that traditional phototherapy could trigger immunogenic cell death (ICD) to activate antitumor immune response, which could not only effectively arrest primary tumor growth, but also exhibit superior effects in terms of anti-metastasis, anti-recurrence for metastatic melanoma treatment However, the limited tumor accumulation of photosensitizers/photothermal agents and immunosuppressive tumor microenvironment severely weaken the immune effects. The application of nanotechnology facilitates a higher accumulation of photosensitizers/photothermal agents at the tumor site, which can thus improve the antitumor effects of photo-immunotherapy (PIT). In this review, we summarize the basic principles of nanotechnology-based PIT and highlight novel nanotechnologies that are expected to enhance the antitumor immune response for improved therapeutic efficacy.

A Prospective Observational Study of Children with FS-Associated Hospitalization: The Implication and Outcomes of Pathogen Detection in Cerebrospinal Fluid

Background

Febrile seizures (FS) are a common cause of paediatric emergencies, but research on their aetiology and epidemiology are limited. The aim of this study was to investigate the prevalence of central nervous system (CNS) pathogenic infections in patients with FS-associated hospitalization.

Methods

A prospective observational study was conducted in children under 16 years of age with FS-associated hospitalization. Demographic, clinical and laboratory data were recorded. Multiplex-PCR was performed on cerebrospinal fluid (CSF) samples for nine viruses, nine bacteria and one fungus.

Results

A total of 119 children were enrolled between June 2021 and June 2022. Of these, 83.2% had a final diagnosis of FS (69.7%) or FS plus (13.4%). In addition, epilepsy and encephalitis/meningitis were also found in 16.8% (20/119). Seven pathogens were identified from 9 CSF samples (7.6%), including viruses (EV, EBV, HHV-6) and bacteria (H. influenzae, S. pneumoniae, M. tuberculosis, S. putrefaciens). There were no significant clinical or laboratory differences between children who tested positive or negative for pathogens in the CSF, except for the presentation of herpes pharyngitis. Children with encephalitis/meningitis had longer hospital stays compared with those diagnosed with FS at discharge; abnormal EEG findings were significantly more common in patients with epilepsy.

Conclusion

FS-associated hospitalized children may have viral or bacterial intracranial infections. Pathogen testing of CSF is an important basis for timely antibiotic or antiviral therapy when clinical and laboratory findings make FS indistinguishable from other CNS disorders.

Taste vs. pain: A sensory feast in bacterial meningitis

During meningitis, sensory neurons detect bacterial toxins and metabolites. Early activation of pain receptors suppresses host defense in the meninges while, later, taste receptors amplify inflammation in the spinal cord. Is a neuroimmune axis a clue to new treatments?

Cerebrospinal fluid cytokines and chemokines exhibit distinct profiles in bacterial meningitis and viral meningitis

Differential diagnosis of bacterial meningitis (BM) and viral meningitis (VM) is a critical clinical challenge, as the early and accurate identification of the causative agent determines the appropriate treatment regimen and markedly improves patient outcomes. Clinical and experimental studies have demonstrated that the pathogen and the host immune response contribute to mortality and neurological sequelae. As BM is associated with the activation of an inflammatory cascade, the patterns of pro- and anti-inflammatory cytokines/chemokines (CTs/CKs) present in the cerebrospinal fluid (CSF) in response to the immune assault may be useful as sensitive markers for differentiating BM from VM. In the present study, the ability of CTs/CKs in the CSF to differentiate between BM and VM was investigated. For this, biochemical markers and CT/CK profiles were analysed in 145 CSF samples, divided into three groups: BM (n=61), VM (n=58) and the control group (C; n=26) comprising patients with meningism. The CSF concentrations of monocyte chemoattractant protein-1, interleukin (IL)-8, IL-1β, IL-6, macrophage inflammatory protein-1α (MIP-1α), epithelial-neutrophil activating peptide, IL-10, tumour necrosis factor-α (TNF-α), proteins and white blood cells were significantly higher and the CSF glucose level was significantly lower in the BM group compared with the VM and C groups (P<0.01). Correlation analysis identified 28 significant correlations between various CTs/CKs in the BM group (P<0.01), with the strongest positive correlations being for TNF-α/IL-6 (r=0.75), TNF-α/MIP-1α (r=0.69), TNF-α/IL-1β (r=0.64) and IL-1β/MIP-1α (r=0.64). To identify the optimum CT/CK patterns for predicting and classifying BM and VM, a dataset of 119 BM and VM samples was divided into training (n=90) and testing (n=29) subsets for use as input for a Random Forest (RF) machine learning algorithm. For the 29 test samples (15 BM and 14 VM), the RF algorithm correctly classified 28 samples, with 92% sensitivity and 93% specificity. The results show that the patterns of CT/CK levels in the CSF can be used to aid discrimination of BM and VM.

Development of subdural empyema from subdural effusion after suppurative encephalitis: A case report

BACKGROUND

Chronic subdural effusion is very common in the cranial imaging of middle-aged and older people. Herein, we report a patient misdiagnosed with subdural effusion, who was eventually diagnosed with chronic subdural empyema (SDE) caused by Streptococcus pneumoniae.

CASE SUMMARY

A 63-year-old man was brought to our emergency room with a headache, vomiting, and disturbed consciousness. Computed tomography (CT) revealed a bilateral subdural effusion at the top left side of the frontal lobe. Cerebrospinal fluid examination after lumbar puncture indicated suppurative meningitis, which improved after anti-infective therapy. However, the patient then presented with acute cognitive dysfunction and right limb paralysis. Repeat CT showed an increase in left frontoparietal subdural effusion, disappearance of the left lateral ventricle, and a shift of the midline to the right. Urgent burr hole drainage showed SDE that was culture-positive for Streptococcus pneumoniae. His condition improved after adequate drainage and antibiotic treatment.

CONCLUSION

Patients with unexplained subdural effusion, especially asymmetric subdural effusion with intracranial infection, should be assessed for chronic SDE. Early surgical treatment may be beneficial.

Adjunctive dexamethasone treatment in adults with listeria monocytogenes meningitis: a prospective nationwide cohort study

Background

A French cohort study described a detrimental effect of adjunctive dexamethasone treatment in listeria meningitis. Based on these results guidelines recommend not to use dexamethasone if L. monocytogenes is suspected or stop dexamethasone when the pathogen is detected. We studied clinical characteristics, treatment regimens and outcome of adults with Listeria monocytogenes meningitis in a nationwide cohort study on bacterial meningitis.

Methods

We prospectively assessed adults with community-acquired L. monocytogenes meningitis in the Netherlands between Jan 1, 2006, and July 1, 2022. We identified independent predictors for an unfavourable outcome (Glasgow Outcome Scale score 1 to 4) and mortality by logistic regression.

Findings

162 out of 2664 episodes (6%) of community-acquired bacterial meningitis episode were caused by L. monocytogenes in 162 patients. Adjunctive dexamethasone 10 mg QID was started with the first dose of antibiotics in 93 of 161 patients (58%) and continued for the full four days in 83 (52%) patients. Different doses, duration or timing of dexamethasone were recorded in 11 patients (7%) and 57 patients (35%) did not receive dexamethasone. The case fatality rate was 51 of 162 (31%) and an unfavourable outcome occurred in 91 of 162 patients (56%). Age and the standard regimen of adjunctive dexamethasone were independent predictors for an unfavourable outcome and mortality. The adjusted odds ratio of dexamethasone treatment for unfavourable outcome was 0.40 (95% confidence interval 0.19-0.81).

Interpretation

Adjunctive dexamethasone is associated with an improved outcome in patients with L. monocytogenes meningitis and should not be withheld if L. monocytogenes is suspected or detected as causative pathogen.

Funding

European Research Council and Netherlands Organisation for Health Research and Development.

The Diagnostic Value of Cerebrospinal Fluid Lactate for Detection of Sepsis in Community-Acquired Bacterial Meningitis

Community-acquired bacterial meningitis conveys significant morbidity and mortality due to intracranial and systemic complications, and sepsis is a major contributor to the latter. While cerebrospinal fluid (CSF) analysis is essential in the diagnosis of bacterial meningitis, its predictive utility for detection of sepsis is unknown. We investigated the diagnostic performance of CSF parameters for sepsis defined by the Sepsis-3 criteria in a retrospective cohort of patients with community-acquired bacterial meningitis. Among 103 patients, 69.5% developed sepsis. CSF lactate was associated with sepsis with an odds ratio of 1.11 (p = 0.022), while CSF cell counts, glucose and protein levels were not (all p > 0.4). Employing the optimal cutoff of 8.2 mmol/L, elevated CSF lactate resulted in a sensitivity of 81.5% and specificity of 61.5% for sepsis. In exploratory analyses, CSF lactate was also associated with in-hospital mortality with an odds ratio of 1.21 (p = 0.011). Elevated CSF lactate might contribute to early diagnosis of sepsis as well as prognostication in patients with community-acquired bacterial meningitis.

Human Listeriosis

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that can cause severe invasive infections upon ingestion with contaminated food. Clinically, listerial disease, or listeriosis, most often presents as bacteremia, meningitis or meningoencephalitis, and pregnancy-associated infections manifesting as miscarriage or neonatal sepsis. Invasive listeriosis is life-threatening and a main cause of foodborne illness leading to hospital admissions in Western countries. Sources of contamination can be identified through international surveillance systems for foodborne bacteria and strains' genetic data sharing. Large-scale whole genome studies have increased our knowledge on the diversity and evolution of L. monocytogenes, while recent pathophysiological investigations have improved our mechanistic understanding of listeriosis. In this article, we present an overview of human listeriosis with particular focus on relevant features of the causative bacterium, epidemiology, risk groups, pathogenesis, clinical manifestations, and treatment and prevention.

Neisseria meningitidis Sibling Small Regulatory RNAs Connect Metabolism with Colonization by Controlling Propionate Use

Neisseria meningitidis (meningococcus) colonizes the human nasopharynx, primarily as a commensal, but sporadically causing septicemia and meningitis. During colonization and invasion, it encounters different niches with specific nutrient compositions. Small noncoding RNAs (sRNAs) are used to fine-tune expression of genes, allowing adaptation to their physiological differences. We have previously characterized sRNAs (Neisseria metabolic switch regulators [NmsRs]) controlling switches between cataplerotic and anaplerotic metabolism. Here, we extend the NmsR regulon by studying methylcitrate lyase (PrpF) and propionate kinase (AckA-1) involved in the methylcitrate cycle and serine hydroxymethyltransferase (GlyA) and 3-hydroxyacid dehydrogenase (MmsB) involved in protein degradation. These proteins were previously shown to be dysregulated in a ΔnmsRs strain. Levels of transcription of target genes and NmsRs were assessed by reverse transcriptase quantitative PCR (RT-qPCR). We also used a novel gene reporter system in which the 5' untranslated region (5' UTR) of the target gene is fused to mcherry to study NmsRs-target gene interaction in the meningococcus. Under nutrient-rich conditions, NmsRs downregulate expression of PrpF and AckA-1 by direct interaction with the 5' UTR of their mRNA. Overexpression of NmsRs impaired growth under nutrient-limiting growth conditions with pyruvate and propionic acid as the only carbon sources. Our data strongly suggest that NmsRs downregulate propionate metabolism by lowering methylcitrate enzyme activity under nutrient-rich conditions. Under nutrient-poor conditions, NmsRs are downregulated, increasing propionate metabolism, resulting in higher tricarboxylic acid (TCA) activities. IMPORTANCE Neisseria meningitidis colonizes the human nasopharynx, forming a reservoir for the sporadic occurrence of epidemic invasive meningococcal disease like septicemia and meningitis. Propionic acid generated by other bacteria that coinhabit the human nasopharynx can be utilized by meningococci for replication in this environment. Here, we showed that sibling small RNAs, designated NmsRs, riboregulate propionic acid utilization by meningococci and, thus, colonization. Under conditions mimicking the nasopharyngeal environment, NmsRs are downregulated. This leads to the conversion of propionic acid to pyruvate and succinate, resulting in higher tricarboxylic acid cycle activity, allowing colonization of the nasopharynx. NmsRs link metabolic state with colonization, which is a crucial step on the trajectory to invasive meningococcal disease.

CSF-contacting neurons respond to Streptococcus pneumoniae and promote host survival during central nervous system infection

The pathogenic bacterium Streptococcus pneumoniae (S. pneumoniae) can invade the cerebrospinal fluid (CSF) and cause meningitis with devastating consequences. Whether and how sensory cells in the central nervous system (CNS) become activated during bacterial infection, as recently reported for the peripheral nervous system, is not known. We find that CSF infection by S. pneumoniae in larval zebrafish leads to changes in posture and behavior that are reminiscent of pneumococcal meningitis, including dorsal arching and epileptic-like seizures. We show that during infection, invasion of the CSF by S. pneumoniae massively activates in vivo sensory neurons contacting the CSF, referred to as "CSF-cNs" and previously shown to detect spinal curvature and to control posture, locomotion, and spine morphogenesis. We find that CSF-cNs express orphan bitter taste receptors and respond in vitro to bacterial supernatant and metabolites via massive calcium transients, similar to the ones observed in vivo during infection. Upon infection, CSF-cNs also upregulate the expression of numerous cytokines and complement components involved in innate immunity. Accordingly, we demonstrate, using cell-specific ablation and blockade of neurotransmission, that CSF-cN neurosecretion enhances survival of the host during S. pneumoniae infection. Finally, we show that CSF-cNs respond to various pathogenic bacteria causing meningitis in humans, as well as to the supernatant of cells infected by a neurotropic virus. Altogether, our work uncovers that central sensory neurons in the spinal cord, previously involved in postural control and morphogenesis, contribute as well to host survival by responding to the invasion of the CSF by pathogenic bacteria during meningitis.

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.