Progress and Challenges in Bacterial Meningitis: A Review

Unraveling the interplay between meningitis and mitochondria: Etiology, pathogenesis, and therapeutic insights

Meningitis, characterized by an inflammatory response affecting the membranes surrounding the brain and spinal cord, poses a formidable challenge to global public health. Its etiology spans a spectrum of infectious agents, ranging from bacteria, to viruses, fungi, and parasites. Concurrently, mitochondria-traditionally known as 'cellular powerhouses'-have emerged as critical players in various essential biological functions, including but not limited to, energy production, metabolic regulation, and cell fate determination. Emerging evidence suggests that mitochondria may play vital roles in the pathogenesis of meningitis. In this review, we delineated the definition, classification, etiology, pathogenesis, and clinical manifestations of meningitis, and elucidated the structure, dynamics and functions of mitochondria. We subsequently delved into the intricate interplay between meningitis and mitochondria, identifying potential therapeutic interventions targeting mitochondria for the first time. With clinical trials on the horizon, our review lays the foundation for a transformative era in meningitis therapeutics, where unraveling the intricate interplay between meningitis and mitochondria offers promise for mitigating neuroinflammation and improving patient outcomes.

Comparison of positive BioFire FilmArray meningitis/encephalitis (ME) panels, CSF cultures, CSF parameters, clinical presentation and in-patient mortality among patients with bacterial and fungal meningitis

The BioFire FilmArray meningitis/encephalitis panel (MEP) was brought to the University of Kentucky in 2016 to aid in the identification of community-acquired meningitis and encephalitis (ME). This panel has shown variable performance with some institutions showing high sensitivity and specificity for many pathogens but others seeing false positives during clinical use. We evaluated the panel's performance using retrospective chart review of patients at the University of Kentucky from October 2016 to September 2022, including 7,551 MEP results. Cerebrospinal fluid (CSF) samples with positive results for bacterial and fungal pathogens were compared with CSF and blood cultures, other laboratory parameters, and clinical presentations, to classify MEP results as true positive (TP), likely TP, or false positive (FP). Of 132 patients with positive bacterial or fungal MEP results, 48.9% of bacterial and 88.9% of cryptococcal analytes were classified as TP. The positive predictive value (PPV) varied by organism, with the highest being Listeria monocytogenes and Neisseria meningitidis. One-third of the FP results were Streptococcus agalactiae. Among patients with likely TP, 75.7% (28 out of 37) received oral or IV antibiotics before blood or CSF culture. MEP was 100% specific compared to culture. The PPV based on pathogen ranged from 78.6% to 100%. Interestingly, 27.4% (29 out of 106) cases (excluding FPs) would have no pathogen definitively identified if MEP had not been used. This study highlights the utility of MEP in rapidly diagnosing ME, particularly in patients pretreated with antibiotics. It also emphasizes the importance of correlating MEP results with clinical assessments and other diagnostic tests to assure accuracy.

IMPORTANCE

This study compares the performance of the meningitis/encephalitis panel (MEP) in detecting bacterial and fungal pathogens with cerebrospinal fluid cultures and other parameters. Almost half of bacterial analytes of MEP had positive cerebrospinal fluid (CSF) or blood cultures; the remaining 42% of bacterial analytes were correlated with clinical presentation and other CSF parameters. 27.4% (29 out of 106) cases would not have had a pathogen definitively identified if the MEP had not been used. This study highlights the importance of using MEP as a diagnostic tool, especially in patients who have already received antibiotics, where traditional culture-based methods may not be diagnostic. This research underscores the use of MEP in improving the speed of diagnosing meningitis. However, it emphasizes that MEP can produce false positive results in some patients. It is therefore necessary to interpret MEP results together with clinical assessments and other diagnostic tests to ensure the most accurate diagnosis.

Cerebrospinal fluid multiplex PCR cycle thresholds may predict ICU admission in community-acquired meningoencephalitis

OBJECTIVE

We investigated the relationship between cerebrospinal fluid (CSF) PCR cycle threshold (Ct) values, clinical characteristics, and outcomes in suspected CAM, while assessing QIAstat-Dx® ME Panel concordance with routine diagnostic methods.

METHODS

Frozen CSF from 30 individuals with suspected CAM were analyzed using the QIAstat-Dx® ME Panel. Ct values were categorized as low (≤ 30) or high (>30). Concordance with CSF FilmArray®/culture results was assessed using the Kappa coefficient.

RESULTS

Low Ct values were associated to CSF markers of meningitis and predicted ICU admissions (log-rank P = 0.025), particularly within the first two weeks of hospitalization (85 % for low Ct values versus 50 % for high Ct values, P = 0.041). Ct values were not associated with mortality in the survival analysis (log-rank P = 0.109). Substantial agreement was observed between QIAstat-Dx® and comparators (96.7 %, Kappa 0.839).

CONCLUSIONS

CSF Ct values can assist in risk stratification for timely ICU admission in individuals with CAM.

Stimuli-Responsive Nano Drug Delivery Systems for the Treatment of Neurological Diseases

Nanomaterials with unparalleled physical and chemical attributes have become a cornerstone in the field of nanomedicine delivery. These materials can be engineered into various functionalized nanocarriers, which have become the focus of research. Stimulus-responsive nanodrug delivery systems (SRDDS) stand out as a sophisticated class of nanocarriers that can release drugs in response to environmental cues. Due to the complex pathogenesis and the multifaceted pathological environment of the nervous system, developing accurate and effective drug therapy with low side-effects is a formidable task. In recent years, SRDDS have been widely used in the treatment of neurological diseases. By customizing SRDDS to align with the specific microenvironment of the nervous system tissues or external stimulation, the efficacy of drug delivery can be enhanced. This review provides an in-depth look at the characteristics of the microenvironment of neurological diseases and highlights case studies of SRDDS tailored to treat these disorders based on the unique stimulation criteria of nervous system tissues or external triggers. Additionally, this review provides a comprehensive overview of the progress and future prospects of SRDDS technology in the treatment of neurological diseases, providing valuable guidance for its transition from fundamental research to clinical application.

Interactions of the Pneumococcus with the Central Nervous System: Postnatal Meningitis Versus Fetal Neurodevelopment

In young children, pneumococcal meningitis epitomizes the paradigm of a destructive innate inflammatory response in the central nervous system: a five-alarm fire. In contrast, cell-free bacterial components reaching the fetal brain from an infected mother signal a quiet, noninflammatory immune response that drives abnormal neurodevelopment, changing brain architecture through neuroproliferation. This review addresses the difference between prenatal and postnatal bacterial-host signaling within the brain.

Determining causal pathogens and inflammatory state of mastitis in dairy cows via Gram staining of precipitates in milk

Early detection of bovine mastitis-causing pathogens is necessary for treatment. As culturing methods are time-consuming, a more rapid detection technique is required. This study investigated the sensitivity, specificity, and detection limit of Gram staining of milk precipitates (milk Gram stain, MGS) to detect bovine mastitis-causing pathogens in milk, as well as the potential of MGS to diagnose inflammation by counting polymorphonuclear leukocytes (PMN). MGS was performed on spontaneous mastitis cases. Culture methods were also used as reference standards to calculate the sensitivity, specificity, and bacterial load in milk to determine the detection limit of MGS. PMN in the mastitic milk were counted using Gram staining. Further, somatic cell counts (SCC), interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, IL-10 and serum amyloid A (SAA) concentrations in mastitic milk were measured using cell counting and enzyme-linked immunosorbent assay. The sensitivity and specificity for all pathogens were 0.62 and 0.90, for Gram-positive were 0.67 and 0.90, and for Gram-negative were 0.50 and 1.00, respectively. The detection limits for Gram-positive and Gram-negative bacteria were 1,560 and 4,680 cfu/mL, respectively. SCC were significantly positively correlated with PMN, milk IL-6, TNF-α, and SAA concentrations, whereas PMN were significantly negatively correlated with milk IL-10 concentration. Our results suggest that MGS may be applied as a rapid method to identify causal pathogens of mastitis before culture results are determined and may also estimate inflammatory status which cannot be detected with SCC. Further clinical trials are required to elucidate whether MGS is useful in clinical veterinary settings.

Cochlear Implant Infections

Cochlear implants (CIs) are associated with a range of infections. These infections present unique considerations because of their position relative to the respiratory tract and the central nervous system, as well as the propensity for biofilms to form on CIs. This article reviews infections related to CIs, including otitis media, mastoiditis, meningitis, and deep CI infection. High-quality evidence on the prevention and management of CI infections is lacking; however, best practices regarding prevention and management are provided.

Clinical value of heparin-binding protein in adult bacterial intracranial infection

Background

The accurate and sensitive diagnosis of intracranial infection continues to pose a critical challenge. This study aimed to probe into the clinical value of heparin binding protein (HBP) in bacterial intracranial infection.

Methods

Patients suspected of having bacterial intracranial infection and admitted to Shanghai General Hospital from November 2021 to November 2023 were selected as study subjects and divided into an infected group and a non-infected group. The receiver operating characteristic (ROC) curve was constructed to compare the diagnostic accuracy of HBP, procalcitonin (PCT), and C-reactive protein (CRP), as well as their value in differentiating Gram-positive bacteria and Gram-negative bacterial infections.

Results

According to the results of bacterial identification, the infected groups were divided into a Gram-negative bacteria group (n = 142) and a Gram-positive bacteria group (n = 128), while the non-infected group comprised 120 patients after neurosurgery involving dura opening. Statistically significant differences were observed in the levels of HBP, PCT, and CRP between the infected group and the non-infected group (all p< 0.05). Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) of HBP was 0.935, and the AUCs of PCT and CRP were 0.931 and 0.863, respectively. In the comparison of HBP, PCT, and CRP levels in the Gram-negative bacteria and Gram-positive bacteria groups, the AUCs were 0.816, 0.602, and 0.591, respectively. When the cutoff value of HBP was 72.34 ng/mL, its specificity reached 96.1% and its sensitivity was 57.8%. When PCT and CRP levels were less than 1.67 ng/mL and 23.12 ng/mL, respectively, both the sensitivity (52.3%, 53.1%) and specificity (66.9%, 59.9%) were relatively low.

Conclusion

HBP, PCT, and CRP can be employed as diagnostic indicators for bacterial intracranial infection. HBP (>72.34 ng/mL) can act as an important index for the diagnosis of Gram-negative bacteria in patients with intracranial infection.

Impact of fever on the outcome non-anoxic acute brain injury patients: a systematic review and meta-analysis

BACKGROUND

Fever is a common condition in intensive care unit (ICU) patients, with an incidence between 30 and 50% in non-neurological ICU patients and up to 70-90% in neurological ICU patients. We aim to perform systematic review and meta-analysis of current literature to assess impact of fever on neurological outcomes and mortality of acute brain injury patients.

METHODS

We searched PubMed/Medline, Scopus and Embase databases following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, and we included both retrospective and prospective observational studies, interventional studies, and randomized clinical trials that had data on body temperature and fever during ICU admission. The primary endpoints were neurological outcome and mortality at any time. Secondary outcomes included: early neurological deterioration, delayed cerebral ischemia (DCI, only for patients with subarachnoid hemorrhage), large infarct or hemorrhage size, hemorrhagic transformation (only for patients with ischemic stroke). This study was registered in PROSPERO (CRD42020155903).

RESULTS

180 studies from 14692 records identified after the initial search were included in the final analysis, for a total of 460,825 patients. Fever was associated with an increased probability of unfavorable neurological outcome (pooled OR 2.37 [95% CI 2.08-2.71], I2:92%), death (pooled OR 1.31 [95% CI 1.28-1.34], I2:93%), neurological deterioration (pooled OR 1.10 [95% CI 1.05-1.15]), risk of DCI (pooled OR 1.96 [95% CI 1.73-2.22]), large infarct size (pooled OR 2.94 [95% CI 2.90-2.98]) and hemorrhagic transformation (pooled OR 1.63 [95% CI 1.34-1.97]) and large hemorrhagic volume (pooled OR 2.38 [95% CI 1.94-2.93]).

CONCLUSION

Fever was associated with poor neurological outcomes and mortality in patients with acute brain injury. Whether normothermia should be targeted in the management of all neuro critically ill patients warrants specific research.

Population pharmacokinetic modeling of ceftriaxone in cerebrospinal fluid in children: should we be using once- or twice-daily dosing for meningitis?

Guidelines for bacterial meningitis in children recommend intravenous ceftriaxone 50 mg/kg (max 2 g) twice daily (BD) or 100 mg/kg (max 4 g) once daily (OD), leaving the decision regarding the dose frequency to the prescriber. We investigated the cerebrospinal fluid (CSF) penetration of ceftriaxone to evaluate whether one dosing regimen is superior. Unbound ceftriaxone concentrations were measured in serum and CSF samples from children aged 0-18 years treated with ceftriaxone if there was a sample remaining after clinical tests were performed. A serum-CSF population pharmacokinetic model was developed using non-linear mixed-effects modeling. The once- and twice-daily dosing regimens were simulated, and the probability of target attainment (PTA) was determined for maintaining a CSF concentration above a minimum inhibitory concentration (MIC) of 1 mg/L for common meningitis pathogens and 4 mg/L for Staphylococcus aureus for 100% of the dosing interval. Sixteen serum and 87 CSF samples were collected from 98 children (age range 0.1-18.5 years). The final two-compartment serum-CSF model included a renal maturation function with weight scaling on clearance and volume of distribution. The estimated serum:CSF uptake was 20.1%. For MIC 1 mg/L, the 24 h PTA was higher for OD (88%) compared with BD (53%) dosing, although both achieved a 100% PTA at steady state. For S. aureus (MIC 4 mg/L), neither dosing regimen was sufficient. Our findings support the use of a 100 mg/kg once daily regimen for empirical treatment of bacterial meningitis due to earlier achievement of the pharmacodynamic target. Neither dosing regimen was adequate for S. aureus meningitis.

Exploring the appropriate situation of performing CSF mNGS in patients with proposed intracranial infections

BACKGROUND

Identifying the responsible pathogen is crucial for precision medicine in intracranial infections, and Cerebrospinal Fluid (CSF) Metagenomic Next-Generation Sequencing (mNGS) is a reliable method for this detection. However, the indiscriminate utilization of this approach may impose a financial burden on both patients and society. The study aims to investigate the optimal conditions for applying CSF mNGS in patients with suspected intracranial infections, offering valuable references for precision medicine of intracranial infections.

METHODS

A total of 175 hospitalized patients presenting with suspected intracranial infections were selected for retrospective analysis. Base on the detection of responsible pathogens using CSF mNGS, the patients were categorized into two groups, responsible pathogens in Group A were detected but not in Group B. The types of responsible pathogens in group A and the final diagnosis of patients in group B were analyzed. Demographic data, clinical presentation, CSF analysis, imaging results, and electroencephalography (EEG) findings were analyzed for both groups. Finally, a scoring system was established to promptly assess the appropriateness of CSF mNGS for patients with suspected intracranial infections. Each independent predictor was assigned a score of 1, and the patients were subsequently scored. We advocate sending patients' CSF for mNGS when the cumulative score is ≥ 2.

RESULTS

In Group A, the predominant responsible pathogen was the varicella-zoster virus (VZV), while Group B exhibited the highest proportion of final diagnoses related to epilepsy. The logistic regression model indicates that headache [OR = 2.982, 95% CI (1.204-7.383), p = 0.018], increased cerebrospinal fluid white cell count [OR = 4.022, 95% CI (1.331-12.156), p = 0.014], and decreased cerebrospinal fluid glucose levels [OR = 9.006, 95% CI (2.778-29.194), P < 0.001] are independent predictive factors for intracranial infection pathogens detected by CSF mNGS. Under this scoring system, the sensitivity for detecting the responsible pathogen was 57.5%, and the specificity was 87.4%.

CONCLUSION

The likelihood of detecting the responsible pathogen through CSF mNGS in patients with suspected intracranial infections can be evaluated using the scoring system. Furthermore, it is crucial to consider the possibility of another condition, such as epilepsy, when the responsible pathogen is not detected using cerebrospinal fluid mNGS.

Insights into the role of Streptococcus oralis as an opportunistic pathogen in infectious diseases

Streptococcus oralis, belonging to the viridans group streptococci (VGS), has been considered a member of normal flora mainly inhabiting the oral cavity. However, more recently, there has been growing recognition of its role as a causative agent in various life-threatening infectious diseases such as infective endocarditis (IE) and meningitis. Additionally, the differences in the prevalence, clinical features, and prognosis of opportunistic infections between S. oralis and other VGS species have been addressed. Particularly the predominance of S. oralis in IE has drawn critical attention. In potentially fatal infections, clinical neglect of S. oralis as an instigating agent might significantly impede early diagnosis and treatment. Nevertheless, to date, the infectious diseases associated with S. oralis have not yet been comprehensively described. Therefore, this review will give an overview of infectious diseases caused by S. oralis to uncover its hidden role as an opportunistic pathogen.

Impact of COVID-19 on the Prevalence and Drug Resistance of Bacteria Isolated From Bacterial Meningitis Cerebrospinal Fluid in Shandong Province: A Multicenter Retrospective Study

Our objective was to evaluate the ramifications of the 2019 coronavirus disease (COVID-19) pandemic on the microbial profile and antimicrobial resistance patterns of bacteria isolated from cerebrospinal fluid (CSF) specimens of patients with bacterial meningitis. We conducted a retrospective analysis of laboratory results and clinical records about positive CSF cultures reported by the SPARSS network from 2017 to 2023. The study covered three distinct periods: January 2017 to December 2019 (before the COVID-19 pandemic), January 2020 to December 2022 (during the COVID-19 pandemic), and January 2023 to December 2023 (after the COVID-19 pandemic), with a total of 5793 CSF isolates collected. Notably, the proportion of male patients (61.3%) was higher than that of females. After COVID-19, we observed a notable shift in the seasonal peak of CSF pathogens, with a delay of approximately 3 months. Remarkable alterations were evident in both pediatric and adult CSF isolate profiles. In children, the predominant pathogens included coagulase-negative Staphylococcus (CoNS), Streptococcus pneumonia, and Escherichia coli. Notably. After COVID-19, there was a significant decrease in the proportion of CoNS (p = 0.0039) and a notable increase in E. coli (p = 0.0067). In adults, the top three pathogens were CoNS, Acinetobacter baumannii, and Klebsiella pneumoniae. After the pandemic, we observed a significant reduction in the prevalence of A. baumannii (p = 0.0059), while the proportions of K. pneumoniae, Pseudomonas aeruginosa, Enterobacter cloacae, and Enterococcus faecalis increased significantly (p < 0.05). Additionally, among multidrug-resistant bacteria, the detection rate of carbapenem-resistant E. coli escalated (p = 0.0375). Antimicrobial susceptibility analysis indicated a declining trend in resistance rates for CoNS and A. baumannii to certain antibiotics following the pandemic. Conversely, resistance to imipenem in A. baumannii increased. In conclusion, the COVID-19 pandemic has significantly influenced the composition, antimicrobial resistance patterns, and epidemiological dynamics of CSF-isolated bacteria in Shandong province. To effectively address these changes, ongoing and dynamic surveillance of pathogen trends and antimicrobial resistance rate is essential.

Positive Predictive Value of Contrast-Enhanced Fluid-Attenuated Inversion Recovery (FLAIR) Magnetic Resonance Imaging in Diagnosis of Meningitis Among Pediatrics Taking Cerebrospinal Fluid Analysis as Gold Standard

BACKGROUND AND OBJECTIVE

Cerebrospinal fluid (CSF) analysis is the gold standard for meningitis diagnosis. It is invasive, time-consuming, and can inoculate infection. CSF analysis is not appropriate for many children without significant clinical suspicion, and delaying decision-making can have negative consequences. Therefore, medical research has long focused on speedy, non-invasive meningitis diagnosis. This study aimed to examine the positive predictive value (PPV) of contrast-enhanced fluid-attenuated inversion recovery magnetic resonance imaging (CE-FLAIR MRI) in meningitis diagnosis.

MATERIALS AND METHODS

It was a cross-sectional study that was conducted in the Department of Radiology, The Children's Hospital in Lahore, from December 29, 2017, to June 28, 2018. The 198 patients were included of either gender with an age of 1 to 15 years and underwent CE-FLAIR MRI due to suspicion of meningitis. The gold standard for meningitis diagnosis was cerebrospinal fluid analysis, while CE-FLAIR MRI results were graded as true positives and false positives. The chi-square test was used. The p-value less than 0.05 was taken as statistically significant.

RESULTS

The mean age of the patients was 4.18±2.48 years. The majority, 116 (58.6%), of the patients were aged below 5 years. There were 125 (63.1%) male and 73 (36.9%) female patients with a male-to-female ratio of 1.7:1. The diagnosis of meningitis using CE-FLAIR MRI was made in 187 (94.4%) patients with a PPV of 94.4%, which was further confirmed on CSF analysis. The PPV of CE-FLAIR-MRI across various subgroups based on the patient's age and gender were statistically insignificant, which showed consistency across all included age and gender groups (p > 0.05).

CONCLUSION

The contrast-enhanced FLAIR magnetic resonance imaging was found to have a high positive predictive value of 94.4% in the diagnosis of meningitis, taking cerebrospinal fluid analysis as the gold standard. CE-FLAIR MRI's noninvasive and ionizing radiation-free characteristics advocate its preferred use in future clinical practice.

Post-Meningitic Syndrome: Pathophysiology and Consequences of Streptococcal Infections on the Central Nervous System

Streptococcus species represent a significant global cause of meningitis, leading to brain damage through bacterial virulence factors and the host inflammatory response. Upon entering the central nervous system (CNS), excessive inflammation leads to various neurological and psychological complications. This review explores the pathophysiological mechanisms and associated outcomes of streptococcal meningitis, particularly its short- and long-term neurological sequelae. Neurological symptoms, such as cognitive impairment, motor deficits, and sensory loss, are shown to vary in severity, with children being particularly susceptible to lasting complications. Among survivors, hearing loss, cognitive decline, and cranial nerve palsies emerge as the most frequently reported complications. The findings highlight the need for timely intervention, including neurorehabilitation strategies that focus on optimizing recovery and mitigating long-term disabilities. Future recommendations emphasize improving early diagnosis, expanding vaccine access, and personalizing rehabilitation protocols to enhance patient outcomes. As a novel contribution, this review proposes the term "post-meningitic syndrome" to showcase the broad spectrum of CNS complications that persist following streptococcal meningitis, providing a framework for a future clinical and research focus.

Energy Expenditure in Critically Ill Patients with Aneurysmal Subarachnoid Hemorrhage, Intracerebral Hemorrhage, and Traumatic Brain Injury-A Prospective Observational Study

BACKGROUND

Energy expenditure (EE) in patients with aneurysmal subarachnoid hemorrhage (SAH) may differ from other intracranial pathologies, such as intracerebral hemorrhage (ICH) or traumatic brain injury (TBI), due to an activation of the sympathetic nervous system. Indirect calorimetry (IC) is recommended, but is not always available. We study EE, catabolism, and metabolic stress in patients with SAH, TBI, ICH, and sepsis as controls.

METHODS

A prospective observational study was conducted in the intensive care units of the University Medical Center Hamburg-Eppendorf, Germany. IC was used to measure EE on days 2-3, 5-7, and 10-15 post-admission. Urinary catecholamines, metabolites, and urine urea were also measured. Statistical analysis included t-tests, Chi-square tests, and generalized mixed models.

RESULTS

We included 110 patients-43 SAH patients (13 with the surgical securing of the aneurysm and 30 with coil embolization of the aneurysm), 22 TBI patients, 23 ICH patients, and 22 controls. The generalized linear mixed model analysis for groups and timepoints including age, height, and weight as covariates revealed a significantly lower EE at timepoint 1 for ICH versus SAH-interventional (p = 0.003) and versus the control (p = 0.004), as well as at timepoint 2 for ICH versus SAH-interventional (p = 0.002) and versus SAH-surgical (p = 0.013) with a lower EE in ICH patients. No significant differences between groups were found for EE at the other timepoints, or concerning urine urea and measurements of catecholamines in urine.

CONCLUSIONS

In patients with SAH, ICH, and TBI, no meaningful differences in EE were detected compared to septic critically ill patients, except for a lower EE in ICH patients in the early phase.

PCR-positive meningococcal CSF infection without pleocytosis but high IL-6 and IL-8

BACKGROUND

Meningococcal meningitis is still a severe disease causing high mortality and morbidity rates. Early diagnosis is crucial to ensure prompt antibiotic therapy. However, identification of the pathogen can be challenging.

CASE PRESENTATION

A 32-year-old male patient with systemic lupus erythematosus (SLE) presented to the emergency room with fever, nausea, vomiting, headache and lower back pain as well as multiple petechial bleedings. On suspicion of meningococcal infection, the emergency doctor had already administered one dose of ceftriaxone before arrival to the clinic. Blood works showed massive inflammation due to bacterial infection. Cerebrospinal fluid (CSF) analysis showed normal cell count, protein and glucose levels but PCR was positive for Neisseria meningitis and IL-6 as well as IL-8 were elevated. On antibiotic therapy with ceftriaxone, the patient's condition improved quickly.

CONCLUSIONS

We present a rare case of meningococcal infection of the CSF in a SLE patient without further CSF abnormalities. We discuss the involvement of early antibiotic treatment and the role of the patient's immune status in the normal CSF findings of this case. Moreover, this case demonstrates the importance of early antibiotic therapy in bacterial meningitis for the clinical outcome.

Invasive Group A Streptococcal Meningitis Following COVID-19 Infection Complicated by Multisystem Inflammatory Syndrome: A Case Report

We present a case of a 60-year-old woman who developed invasive group A streptococcal (GAS) meningitis following a COVID-19 infection, complicated by multisystem inflammatory syndrome (MIS). Initially diagnosed with COVID-19 based on fever, nasal obstruction, cough, and sore throat, her symptoms improved with symptomatic treatment, except for a persistent sore throat. She later presented with hematemesis and was found to have bacterial pneumonia and dehydration. Despite treatment with ceftriaxone, her condition worsened with the development of a headache, shivering, and worsening respiratory and circulatory symptoms. Cerebrospinal fluid analysis confirmed bacterial meningitis, and treatment was escalated to include ceftriaxone, ampicillin, and vancomycin. An MRI revealed a parapharyngeal space abscess, and subsequent blood cultures identified GAS as the causative organism. The patient was treated with ampicillin for 14 days, followed by oral amoxicillin. Her condition improved, and she was discharged with no neurological deficits. This case underscores the need for vigilance in detecting secondary bacterial infections in post-COVID-19 patients, especially in MIS, where atypical presentations can delay diagnosis. Early recognition and aggressive treatment are vital to preventing complications and ensuring favorable outcomes.

Global patterns of syphilis, gonococcal infection, typhoid fever, paratyphoid fever, diphtheria, pertussis, tetanus, and leprosy from 1990 to 2021: findings from the Global Burden of Disease Study 2021

BACKGROUND

Certain infectious diseases are caused by specific bacterial pathogens, including syphilis, gonorrhea, typhoid and paratyphoid fever, diphtheria, pertussis, tetanus, leprosy, and tuberculosis. These diseases significantly impact global health, contributing heavily to the disease burden. The study aims to thoroughly evaluate the global burden of syphilis, gonorrhea, typhoid and paratyphoid fever, diphtheria, pertussis, tetanus, and leprosy.

METHODS

Leveraging the Global Burden of Disease (GBD) study 2021, age-specific and Socio-demographic Index (SDI)-specific incidence, disability-adjusted life-years (DALYs), and death for eight specific bacterial infections across 204 countries and territories from 1990 to 2021 were analyzed. Percentage changes in age-standardized incidence rate (ASIR), DALY rate, and mortality rate (ASMR) were also examined, with a focus on disease distribution across different regions, age groups, genders, and SDI.

RESULTS

By 2021, among the eight diseases, gonococcal infection had the highest global ASIR [1096.58 per 100,000 population, 95% uncertainty interval (UI): 838.70, 1385.47 per 100,000 population], and syphilis had the highest global age-standardized DALY rate (107.13 per 100,000 population, 95% UI: 41.77, 212.12 per 100,000 population). Except for syphilis and gonococcal infection, the age-standardized DALY rate of the remaining diseases decreased by at least 55% compared to 1990, with tetanus showing the largest decrease by at least 90%. Globally, significant declines in the ASIR, age-standardized DALY rate, and ASMR for these eight bacterial infections have been observed in association with increases in the SDI. Regions with lower SDI, such as sub-Saharan Africa, experienced a relatively higher burden of these eight bacterial infections.

CONCLUSIONS

Although there has been an overall decline in these eight diseases, they continue to pose significant public health challenges, particularly in low SDI regions. To further reduce this burden in these areas, targeted intervention strategies are essential, including multi-sectoral collaboration, policy support, improved WASH management, and enhanced research efforts.

Pasteurella multocida infection induces blood-brain barrier disruption by decreasing tight junctions and adherens junctions between neighbored brain microvascular endothelial cells

Meningitis induced by Pasteurella multocida has been substantially described in clinical practice in both human and veterinary medicine, but the underlying mechanisms have not been previously reported. In this study, we investigated the influence of P. multocida infection on the permeability of the blood-brain barrier (BBB) using different models. Our in vivo tests in a mouse model and in vitro tests using human brain microvascular endothelial cell (hBMEC) model showed that P. multocida infection increased murine BBB permeability in mice and hBMEC monolayer permeability. Furthermore, we observed that P. multocida infection resulted in decreased expression of tight junctions (ZO1, claudin-5, occludin) and adherens junctions (E-cadherin) between neighboring hBMECs. Subsequent experiments revealed that P. multocida infection promoted the activation of hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor A (VEGFA) signaling and NF-κB signaling, and suppressed the HIF-1α/VEGFA significantly remitted the decrease in ZO1/E-cadherin induced by P. multocida infection (P < 0.001). NF-κB signaling was found to contribute to the production of chemokines such as TNF-1α, IL-β, and IL-6. Additionally, transmission electron microscopy revealed that paracellular migration might be the strategy employed by P. multocida to cross the BBB. This study provides the first evidence of the migration strategy used by P. multocida to traverse the mammalian BBB. The data presented herein will contribute to a better understanding of the pathogenesis of the zoonotic pathogen P. multocida.

Use of Metagenomic Next-Generation Sequencing to Identify Pathogens Involved in Central Nervous System Infections

Purpose

Application of metagenomic next-generation sequencing (mNGS) in identifying nosocomial central nervous system (CNS) infections in critical care units remains understudied.

Methods

We conducted a retrospective analysis of microbiological results through both mNGS and routine examination of cerebrospinal fluid (CSF) samples from patients with nosocomial CNS infections. The aim of this study was to assess the clinical diagnostic effect of nosocomial mNGS in this population.

Results

The study included 26 cases of nosocomial CNS infections in total. A total of 69.2% (18/26) of the samples tested positive for mNGS, which is substantially greater than the 7.7% (2/26; p<0.05) detected through conventional techniques. Administration of antibiotics before culture is most likely the cause of the low CSF culture rate. Twenty-five pathogenic strains that were missed by standard testing. Three pathogens that were consistent with the mNGS results were positive by routine tests. Eight cases were negative by mNGS due to low pathogen CSF titres. Compared to traditional testing, mNGS demonstrated 100% sensitivity and 33.3% specificity in diagnosing CNS infections. The thirty-day mortality rate was 26.9% (7/26).

Conclusion

Routine microbiologic testing frequently falls short of detecting all neuroinvasive pathogens. Our research suggests that mNGS offers an alternative means of detecting nosocomial CNS infections. By applying mNGS to CSF samples from patients with meningitis or encephalitis, we were able to improve the ability to diagnose nosocomial neurologic infections.

Identifying Clinical and Biochemical Predictors of Seizures in Children with Acute Bacterial Meningitis: Insights from a Cross-Sectional Study

Background: The occurrence of seizures in bacterial meningitis is important, as it has been reported to increase the risk of complications; however, its frequency and predictors are not well studied yet. Objective: To assess the frequency, clinical, and biochemical predictors of seizures in children with acute bacterial meningitis. Method: A cross-sectional study recruited confirmed acute bacterial meningitis cases based on positive CSF culture and sensitivity among children aged 2 months to 15 years admitted to the Central Child Teaching Hospital emergency department in Iraq. Patients were divided into two groups based on seizure at presentation time. Demographic characteristics [age, gender, residence, duration of fever and disease, presenting complaints and antibiotic intake]; hematological [WBC, neutrophils] Lymphocyte, N/L ratio, packed cell volume, platelets, blood sugar, and cerebrospinal fluid (CSF) indices were compared between groups. Results: Seizures had a frequency of 18% among the 122 children and were significantly higher in younger cases with female predominance. By multivariate analysis and odds ratio (OR), predictors for seizure were as follows: CSF lymphocytes (OR=0.25, 95%CI=0.08–0.26), lethargy (OR=8.15, 95%CI=1.03-68.65), headache (OR=0.09, 95%CI=0.02-0.45), neck stiffness (OR=0.07, 95% CI=0.01-0.61) and poor feeding (OR=4.8, 95%CI=1.21–18.97). Conclusions: CSF lymphocytes reliably predicted seizures with good sensitivity and specificity of 75% and 73%. Lethargy and poor feeding had the highest odds as clinical predictors of seizures. Together, those results can help with risk stratification and allocate resources for high-risk cases to improve patient outcomes.

Loratadine Derivative Lo-7: A Weapon against Drug-Resistant Enterococcus and Streptococcal Infections

The primary obstacles in the management of Enterococcus and Streptococcal infections are drug resistance and biofilm formation. Our study revealed that loratadine at a concentration of ≥25 μM exhibited significant inhibitory effects on biofilm formation in 167 clinical strains of Enterococcus faecalis and 15 clinical isolates of Streptococcus agalactiae, Streptococcus pyogenes, and Streptococcus pneumoniae. Additionally, the antibiofilm activity against E. faecalis and Streptococcal was demonstrated by several loratadine derivatives with altered side-chain carbamate moieties. This study investigated the antibacterial activity of the loratadine derivative Lo-7 against clinical strains of S. agalactiae and S. pyogenes, with minimum inhibitory concentrations ranging from 12.5 to 25 μM. The findings revealed that a low concentration of loratadine derivative Lo-7 (3.125 μM) significantly augmented the bactericidal efficacy of vancomycin against multidrug-resistant (MDR) S. agalactiae, both in vitro and in vivo. The loratadine derivative Lo-7, even at low concentrations, demonstrated significant efficacy in eliminating intracellular MDR S. agalactiae within macrophages, potentially indicating a unique advantage over vancomycin, linezolid, and loratadine. Mechanistically, exposure to the loratadine derivative Lo-7 resulted in membrane depolarization without affecting membrane permeability in S. agalactiae. The potential targeting of the SecG subunit of the SecYEG membrane-embedded channel by the loratadine derivative Lo-7 in S. agalactiae was identified through quantitative proteomics, a drug affinity responsive target stability assay, and molecular docking.

LC-MS metabolomics and lipidomics in cerebrospinal fluid from viral and bacterial CNS infections: a review

There is compelling evidence that a dysregulated immune inflammatory response in neuroinfectious diseases results in modifications in metabolic processes and altered metabolites, directly or indirectly influencing lipid metabolism within the central nervous system (CNS). The challenges in differential diagnosis and the provision of effective treatment in many neuroinfectious diseases are, in part, due to limited understanding of the pathophysiology underlying the disease. Although there are numerous metabolomics studies, there remains a deficit in neurolipidomics research to provide a comprehensive understanding of the connection between altered metabolites and changes in lipid metabolism. The brain is an inherently high-lipid organ; hence, understanding neurolipidomics is the key to future breakthroughs. This review aims to provide an integrative summary of altered cerebrospinal fluid (CSF) metabolites associated with neurolipid metabolism in bacterial and viral CNS infections, with a particular focus on studies that used liquid chromatography-mass spectrometry (LC-MS). Lipid components (phospholipids) and metabolites (carnitine and tryptophan) appear to be the most significant indicators in both bacterial and viral infections. On the basis of our analysis of the literature, we recommend employing neurolipidomics in conjunction with existing neurometabolomics data as a prospective method to enhance our understanding of the cross link between dysregulated metabolites and lipid metabolism in neuroinfectious diseases.

A 48-year-old man with fever, nauseous, vomiting, and dizzy: A CARE case report

RATIONALE

Listeria monocytogenes (LM) is an important foodborne bacterium, and LM meningoencephalitis is rare in clinical practice, with poor prognosis in severe patients. It is prone to misdiagnosis in clinical practice. We first reported a case of severe LM meningoencephalitis with muscle lesions and evaluated the comprehensive condition.

PATIENT CONCERNS

A 48-year-old man had a fever and was admitted to the neurology department due to dizziness, nausea, and vomiting for 20 days.

DIAGNOSES

LM meningoencephalitis complicated with muscle lesions.

INTERVENTIONS

We used moxifloxacin 0.4 g, qd, meropenem 2 g, q8h, and dexamethasone 10 mg, qd to reduce exudation and adhesion. Then due to consideration of side effects, we increased the dose of ampicillin by 2 g, q4h, stopped using meropenem and moxifloxacin, and turned to maintenance treatment with dexamethasone and ampicillin. We comprehensively managed his vital signs and physical organ functions, we also controlled some comorbidities. During the hospitalization period thereafter, we used intravenous anti-infection treatment with moxifloxacin 0.4 g, qd, ampicillin 0.5 g, q4h.

OUTCOMES

Half a year later, the reexamination showed only protein elevation in cerebrospinal fluid and hydrocephalus in MRI. Afterward, the symptoms did not recur again. The patient recovered well after discharge.

LESSONS

LM meningoencephalitis complicated with lower limb muscle lesions is clinically rare. This report focuses on relevant treatment plans, which provide value for the examination and comprehensive management of patients with LM infection in the future.

Acute infections of the central nervous system in children and adults: diagnosis and management

Central nervous system infections are due to different microorganisms such as viruses, bacteria, mycobacteria, fungi, amoebas, and other parasites. The etiology depends on multiple risk factors, and it defines the infection location because some microorganisms prefer meninges, brain tissue, cerebellum, brain stem or spinal cord. The microorganisms induce diseases in the nervous system through direct invasion, neurotoxin production, and the triggered immune response. To determine the infection etiology, there are several diagnostic tests which may be conducted with cerebrospinal fluid, blood, respiratory and stool samples. These tests include but are not limited to direct microscopic examination of the sample, stains, cultures, antigenic tests, nucleic acid amplification tests, metagenomic next-generation sequencing, immunologic biomarker and neuroimaging, especially contrast-enhanced magnetic resonance imaging. The treatment may consist of specific antimicrobial treatment and supportive standard care. Since viruses have no specific antiviral treatment, antimicrobial treatment is mainly targeted at non-viral infections. This article will focus on diagnosis and treatment of acute acquired infections of the central nervous system beyond the neonatal period. The discussion defines the disease, provides the clinical presentation, explains the etiology and risk factors, and briefly mentions potential complications. This updated review aims to provide the reader with all the elements needed to adequately approach a patient with a central nervous system infection. Mycobacterium tuberculosis infection, Cryptococcus spp. infection and vaccines are not within the scope of this article.

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.

Postencephalitic syndrome with immune-mediated psychosis in an adult with meningitis due to Streptococcus pneumoniae: A case report

Introduction

A first psychotic episode may be related to neurological diseases, especially encephalitis of infectious or autoimmune origin. It is remarkable that an immune-mediated encephalitis triggered by a confirmed subacute bacterial meningitis is documented, and this is the case we will present.

Clinical case

A 22-year-old woman with no previous medical history, immunocompetent, with three months of behavioral, affective and cognitive symptoms with subsequent compromise of sensory perception and psychosis. Examination of cerebrospinal fluid showed inflammatory signs with positive FilmArray© for Streptococcus pneumoniae. She received anti-psychotic and antibiotic treatment for 2 weeks without clinical improvement. Postencephalitic syndrome with immune-mediated psychosis was considered as a diagnosis, and immunosuppressive management with corticosteroid and plasmapheresis was initiated with complete resolution of symptoms. After one year of follow-up no neurological relapse has been identified.

Discussion

Encephalitis is a neurological syndrome due to brain parenchymal damage that can result in psychiatric symptoms including psychosis and behavioral changes. Its causes are usually infectious (usually viral) or autoimmune (Anti NMDA, AMPA, LGI1 or others). A psychiatric condition in bacterial meningitis without improvement with antibiotic treatment is remarkable, its presence should suggest an immune-mediated post-infectious syndrome that may respond to the use of immunomodulators even in the absence of identification of autoimmune encephalitis-associated antibodies. No similar cases have been reported in the literature.

Conclusion

Immune-mediated psychosis may be a manifestation of post-encephalitic syndrome associated with bacterial meningitis and its treatment with immunosuppressants may offer benefit in cases where the use of antipsychotics and antibiotics shows no improvement.

The impact of the FilmArray meningitis/encephalitis panel on empiric antibiotic prescriptions in patients with suspected community-acquired meningitis

The BioFire® FilmArray® meningitis/encephalitis (FA/ME) panel provides rapid testing for common cerebrospinal fluid pathogens. We compared empiric antibiotic utilization between patients with suspected community-acquired meningitis with and without an FA/ME panel ordered. No significant differences in antibiotic use were found.

Predictive role of PAR and LAR in refractory suppurative meningitis in infants

BACKGROUND

Meningitis can be caused by a variety of pathogenic microorganisms, which can lead to higher mortality and disability rates. However, the clinical manifestations of suppurative meningitis are often atypical in infants and young children, which makes early clinical diagnosis difficult.PAR and LAR are considered as a novel inflammatory biomarker and have been applied in tumors, IgA nephropathy, sepsis.

OBJECTIVE

To investigate the application of platelet/albumin (PAR) and lactate dehydrogenase/albumin (LAR) in refractory suppurative meningitis in infants.

METHODS

The relevant clinical data of 107 children with suppurative meningitis were retrospectively analyzed, and were divided into common group (82 cases) and refractory group (25 cases) according to the severity of the disease according to the relevant clinical consensus. The relevant clinical data and laboratory examination of the children in the two groups were compared. The diagnostic value of PAR and LAR in children with refractory suppurative meningitis was analyzed and multivariate Logistic regression analysis was performed.

RESULT

The PAR of children with suppurative meningitis in refractory group was lower than that in common group (P < 0.05), while LAR was higher than that in common group (P < 0.05). Meanwhile, multivariate Logistic regression analysis showed that LAR and cerebrospinal fluid glucose ≤ 1.5mmo/L were risk factors for poor prognosis (OR > 1, P < 0.05). PAR was a protective factor (OR < 1, P < 0.05).

CONCLUSION

PAR and LAR can be used for early diagnosis of refractory suppurative meningitis in children as protective and risk factors, respectively.

Severe CSF immune cell alterations in cryptococcal meningitis gradually resolve during antifungal therapy

Cryptococcal meningitis (CM) is a severe fungal disease in immunocompromised patients affecting the central nervous system (CNS). Host response and immunological alterations in the cerebrospinal fluid (CSF) after invasion of Cryptococcus neoformans to the central nervous system have been investigated before but rigorous and comprehensive studies examining cellular changes in the CSF of patients with cryptococccal meningitis are still rare. We retrospectively collected CSF analysis and flow cytometry data of CSF and blood in patients with CM (n = 7) and compared them to HIV positive patients without meningitis (n = 13) and HIV negative healthy controls (n = 7). Within the group of patients with CM we compared those with HIV infection (n = 3) or other immunocompromised conditions (n = 4). Flow cytometry analysis revealed an elevation of natural killer cells and natural killer T cells in the CSF and blood of HIV negative patients with CM, pointing to innate immune activation in early stages after fungal invasion. HIV positive patients with CM exhibited stronger blood-CSF-barrier disruption. Follow-up CSF analysis over up to 150 days showed heterogeneous cellular courses in CM patients with slow normalization of CSF after induction of antifungal therapy.

Epidemiology and Clinical Outcomes of Bacterial Meningitis in Children and Adults in Low- and Middle-Income Countries

Purpose of Review

Despite the availability of effective vaccines against the three primary pathogens (Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis) that cause bacterial meningitis, this condition remains a significant cause of morbidity, neurologic sequelae, and mortality among children and adults living in low-income and middle-income countries.

Recent Findings

Bacterial meningitis represents a significant public health challenge for national and global health systems. Since vaccine-preventable meningitis remains highly prevalent in low-income and middle-income countries, the World Health Organization (WHO) recently developed a global roadmap to defeating meningitis by 2030 and ameliorating its associated neurological sequelae.

Summary

There is a need for a global approach to surveillance and prevention of bacterial meningitis. Increasing vaccination coverage with conjugate vaccines against pneumococcus and meningococcus with optimal immunization schedules are high-value healthcare interventions. Additionally, overcoming diagnostic challenges and the early institution of empirical antibiotic therapy and, when feasible, adjunctive steroid therapy constitutes the pillars of reducing the disease burden of bacterial meningitis in resource-limited settings.

Recurrent community-acquired pneumococcal meningitis in adults with and without identified predisposing factors

Bacterial meningitis is still a significant public health concern, with high morbidity and mortality rates. Despite this, it is still a rare event that requires the bacterial invasion of the meninges. However, some predisposing factors can trigger recurrent episodes of meningitis. This study is aimed at determining the clinical characteristics and the molecular epidemiology of episodes of recurrent community-acquired meningitis with and without predisposing factors. For this purpose, we performed a retrospective study of our laboratory database during the period of 2010 to 2020. Additionally, using molecular tools developed in our previous works, the epidemiology of the pathogens causing these episodes was analyzed using cerebrospinal fluid samples, especially in the absence of isolated strains. We observed a total of 1,779 meningitis cases and 230 were caused by Streptococcus pneumoniae. Of those, 16 were recurrent meningitis episodes (16/1,779; 0.9%) from seven patients. Pneumococcus was the main agent responsible in these recurrent episodes and only two episodes were caused by Haemophilus influenzae. The mean age of these patients was 20 years old and three had predisposing factors which could have led to contracting meningitis. The samples presented different pneumococcal serotypes. Most of them were non-vaccine-covered serotypes and antibiotic susceptible strains. Therefore, it was demonstrated how the practical employment of molecular tools, developed for research, when applied in the routine of diagnosis, can provide important information for epidemiological surveillance. Furthermore, it was shown how pneumococcus was the leading cause of recurrent community-acquired meningitis without predisposing factors, suggesting that pneumococcal vaccination may be necessary, even in those groups of individuals considered to be less susceptible.

Neuroinfectious Emergencies

OBJECTIVE

This article describes nervous system infections and complications that lead to neurologic emergencies.

LATEST DEVELOPMENTS

New research on the use of dexamethasone in viral and fungal infections is reviewed. The use of advanced MRI techniques to evaluate nervous system infections is discussed.

ESSENTIAL POINTS

Neurologic infections become emergencies when they lead to a rapid decline in a patient's function. Emergent complications may result from neurologic infections that, if not identified promptly, can lead to permanent deficits or death. These complications include cerebral edema and herniation, spinal cord compression, hydrocephalus, vasculopathy resulting in ischemic stroke, venous thrombosis, intracerebral hemorrhage, status epilepticus, and neuromuscular respiratory weakness.

Clinical research progress on intrathecal glucocorticoids in the treatment of infections: A review

In some infectious diseases, pathogenic microorganisms can directly or indirectly cause significant inflammatory reactions in the central nervous system, leading to severe neurological dysfunction, such as suppurative meningitis, tuberculous meningitis, and febrile infections. related epilepsy syndrome, etc. In these diseases, adjuvant administration of glucocorticoids is necessary to inhibit the release of proinflammatory cytokines, and intrathecal administration can deliver the drug more directly to the target. In this article, the authors studied intrathecal glucocorticoids for the treatment of infectious inflammatory reactions in terms of pharmacological effects and mechanisms, pharmacokinetics, clinical application, and safety. The authors concluded that the article could help provide new treatment strategies for infectious diseases.

A Reduction in the Number of Hospitalized Cases of Acute Meningitis during the COVID-19 Pandemic in Japan

Objective The changes in the prevalence of acute meningitis during the coronavirus disease 2019 (COVID-19) pandemic remain unclear. This study aimed to compare the prevalence of acute meningitis before and during the COVID-19 pandemic in Japan. Methods We retrospectively reviewed the Japanese nationwide administrative medical payment system database, Diagnosis Procedure Combination (DPC), from 2016 to 2022. A total of 547 hospitals consistently and seamlessly offered DPC data during this period. The study period was divided into the following three periods: April 2016 to March 2018 (fiscal years 2016-2017), April 2018-March 2020 (2018-2019), and April 2020-March 2022 (2020-2021). Results Among the 28,161,806 patients hospitalized during the study period, 28,399 were hospitalized for acute meningitis: 16,678 for viral/aseptic type, 6,189 for bacterial type, 655 for fungal type, 429 for tuberculous, 2,310 for carcinomatous type, and 2,138 for other or unknown types of meningitis. A significant decrease during the pandemic was confirmed in viral (n=7,032, n=5,775, and n=3,871 in each period; p<0.0001) and bacterial meningitis (n=2,291, n=2,239, and n=1,659; p<0.0001) cases. Meanwhile, no decrease was observed in fungal meningitis (n=212, n=246, and n=197; p=0.056) or carcinomatous meningitis (n=781, n=795, and n=734; p=0.27). The decrease in the number of tuberculous meningitis cases was equivocal (n=166, n=146, and n=117; p=0.014). The decrease during the pandemic was more remarkable in younger populations aged <50 years than in older populations, both for viral and bacterial meningitis. Conclusion The number of hospitalized cases of acute meningitis clearly decreased during the COVID-19 pandemic, especially for viral and bacterial meningitis in younger populations aged <50 years.

Streptococcus suis meningitis in China: a case report

Introduction

Streptococcus suis is one of the porcine pathogens that have recently emerged as a pathogen capable of causing zoonoses in some humans. Patients infected with S. suis can present with sepsis, meningitis, or arthritis. Compared to common pathogens, such as Meningococcus, Streptococcus pneumoniae, and Haemophilus influenzae, S. suis infections in humans have been reported only rarely.

Methods

This case report described a 57-year-old man who presented with impaired consciousness and fever following several days of backache. He was a butcher who worked in an abattoir and had wounded his hands 2 weeks prior. The patient was dependent on alcohol for almost 40 years. S. suis was detected in the cerebrospinal fluid by metagenomic next-generation sequencing. Although he received adequate meropenem and low-dose steroid therapy, the patient suffered from bilateral sudden deafness after 5 days of the infection. The final diagnosis was S. suis meningitis and sepsis.

Results

The patient survived with hearing loss in both ears and dizziness at the 60-day follow-up.

Discussion

We reported a case of S. suis infection manifested as purulent meningitis and sepsis. Based on literature published worldwide, human S. suis meningitis shows an acute onset and rapid progression in the nervous system. Similar to bacterial meningitis, effective antibiotics, and low-dose steroids play important roles in the treatment of human S. suis meningitis.

Coagulase-negative staphylococci are the main causes of bacterial meningitis in duck

Since September 2018, serious meningitis has been found on some breeding-duck farms in Shandong Province, China. A large number of ducks exhibit severe neurological symptoms. The ducks were randomly selected for laboratory testing. Duck brain samples were collected using standard sterile techniques, and the staphylococci isolates were detected in 404 (70.14%) out of 576 brain samples. A total of 525 coagulase-negative staphylococci (CoNS) strains were isolated, including 6 species: Staphylococcus sciuri (S. sciuri) (67.24%, 353/525), Staphylococcus epidermidis (S. epidermidis) (9.71%, 51/525), Staphylococcus saprophyticus (S. saprophyticus) (8.38%, 44/525), Staphylococcus lentus (S. lentus) (7.62%, 40/525), Staphylococcus haemolyticus (S. haemolyticus) (2.48%, 13/525), and Staphylococcus xylosus (S. xylosus) (4.57%, 24/525). Mixed strain infections were detected in 121 (29.95%) infected presentations. The antimicrobial susceptibility testing indicated that 40.38% of the isolates exhibited multi-drug resistance, and 53.90% of the strains were methicillin-resistant strains by amplification of the methicillin resistance gene (mecA) gene. Through experimental reproduction of the disease, we determined that the CoNS strains were the leading pathogens causing bacterial meningitis in ducks. Although these CoNS strains does not directly cause the death of sick ducks, they still cause large economic losses due to the retarded growth and development of the sick ducks, lower feed returns, and lower grades of processed duck products. The results of this study will contribute to our understanding of the epidemiology and pathogenesis of CoNS and be helpful in the prevention and treatment of the infection.

Bacterial and Viral Infectious Disease of the Spine

Spinal infections are a diverse group of diseases affecting different compartments of the spine with variable clinical and imaging presentations. Diagnosis of spinal infections is based on a combination of clinical features, laboratory markers, and imaging studies. Imaging plays a pivotal role in the diagnosis and management of spinal infections. The characteristic imaging manifestations of bacterial and viral infections in the spine are discussed with key teaching points emphasized.

Cochlear Implants after Meningitis and Otosclerosis: A Comparison between Cochlear Ossification and Speech Perception Tests

(1) Background: Performance after Cochlear Implantation (CI) can vary depending on numerous factors. This study aims to investigate how meningitis or otosclerosis can influence CI performance. (2) Methods: Retrospective analysis of CI performance in patients with etiological diagnosis of meningitis or otosclerosis, comparing the etiologies and analyzing the image findings, along with electrode array insertion status and technique. (3) Results: Speech recognition in CI patients with otosclerosis improves faster than in patients with meningitis. Other features such as radiological findings, degree of cochlear ossification, surgical technique used and total or partial insertion of electrodes do not seem to be directly related to speech recognition test performance. (4) Conclusions: Patients should be warned that their postoperative results have a strong correlation with the disease that caused their hearing loss and that, in cases of meningitis, a longer duration of speech-language training may be necessary to reach satisfactory results.

Clinical characteristics and prognosis of Klebsiella pneumoniae meningitis in adults

Background

Klebsiella pneumoniae is a causative agent of bacterial meningitis in adults. However, there is little information regarding this infection. Therefore, this study comprehensively analyzed the clinical characteristics and prognosis of Klebsiella pneumoniae meningitis (KPM) patients.

Methods

The clinical data of adult hospitalized patients with KPM were retrospectively collected from January 2015 to December 2022. The clinical characteristics and antibiotic resistance of KPM were evaluated. Meanwhile, a set of logistic regression models was constructed to identify prognostic factors for death. These prognostic factors were subsequently combined to develop a nomogram for predicting the risk of in-hospital mortality in individual patients. Finally, the receiver operating characteristic curve and calibrate plot were utilized to verify the performance of the nomogram.

Results

This study included 80 adult patients with KPM, 58 (72.5%) of whom were males. The mortality rate was 45%. Among them, 74 (92.5%) were diagnosed with healthcare-associated meningitis. Thirty-seven carbapenem-resistant Klebsiella pneumoniae (CRKP) strains were susceptible to tigecycline, polymyxin, and ceftazidime/avibactam. CRKP (OR = 9.825, 95%CI = 2.757-35.011, P < 0.001), length of stay (OR = 0.953, 95%CI = 0.921-0.986, P = 0.005), and C-reactive protein-to-prealbumin ratio (CRP/PA, OR = 3.053, 95%CI = 1.329-7.016, P = 0.009) were identified as predictive factors for mortality using multivariate logistic regression. Finally, a nomogram for death prediction was established. The area under the curve of this nomogram was 0.900 (95% CI = 0.828-0.971).

Conclusions

KPM is a fatal disease associated with high incidence of healthcare-associated infections and carbapenem resistance. Moreover, CRKP, length of stay, and CRP/PA were found to be independent predictors of mortality.

From Text to Insight: A Natural Language Processing-Based Analysis of Topics and Trends in Neurosurgery

BACKGROUND AND OBJECTIVES

Neurosurgical research is a rapidly evolving field, with new research topics emerging continually. To provide a clearer understanding of the evolving research landscape, our study aimed to identify and analyze the prevalent research topics and trends in Neurosurgery.

METHODS

We used BERTopic, an advanced natural language processing-based topic modeling approach, to analyze papers published in the journal Neurosurgery . Using this method, topics were identified based on unique sets of keywords that encapsulated the core themes of each article. Linear regression models were then trained on the topic probabilities to identify trends over time, allowing us to identify "hot" (growing in prominence) and "cold" (decreasing in prominence) topics. We also performed a focused analysis of the trends in the current decade.

RESULTS

Our analysis led to the categorization of 12 438 documents into 49 distinct topics. The topics covered a wide range of themes, with the most commonly identified topics being "Spinal Neurosurgery" and "Treatment of Cerebral Ischemia." The hottest topics of the current decade were "Peripheral Nerve Surgery," "Unruptured Aneurysms," and "Endovascular Treatments" while the cold topics were "Chiari Malformations," "Thromboembolism Prophylaxis," and "Infections."

CONCLUSION

Our study underscores the dynamic nature of neurosurgical research and the evolving focus of the field. The insights derived from the analysis can guide future research directions, inform policy decisions, and identify emerging areas of interest. The use of natural language processing in synthesizing and analyzing large volumes of academic literature demonstrates the potential of advanced analytical techniques in understanding the research landscape, paving the way for similar analyses across other medical disciplines.

Neuropeptide Calcitonin Gene-Related Peptide Promotes Immune Homeostasis of Bacterial Meningitis by Inducing Major Histocompatibility Complex Class II Ubiquitination

BACKGROUND

Calcitonin gene-related peptide (CGRP), an immunomodulatory neuropeptide, is important for regulating pain transmission, vasodilation, and the inflammatory response. However, the molecular mechanisms of the CGRP-mediated immune response remain unknown.

METHODS

The effects of CGRP on bacterial meningitis (BM) and its underlying mechanisms were investigated in BM mice in vivo and macrophages in vitro.

RESULTS

Peripheral injection of CGRP attenuated cytokine storms and protected mice from fatal pneumococcal meningitis, marked by increased bacterial clearance, improved neuroethology, and reduced mortality. When the underlying mechanisms were investigated, we found that CGRP induces proteasome-dependent degradation of major histocompatibility complex class II (MHC-II) in macrophages and then inhibits CD4+ T-cell activation. MARCH1 was identified as an E3 ligase that can be induced by CGRP engagement and promote K48-linked ubiquitination and degradation of MHC-II in macrophages. These results provide new insights into neuropeptide CGRP-mediated immune regulation mechanisms.

CONCLUSIONS

We conclude that targeting the nervous system and manipulating neuroimmune communication is a promising strategy for treating intracranial infections like BM.

Ominous Causes of Headache

PURPOSE OF REVIEW

While primary headaches like migraines or cluster headaches are prevalent and often debilitating, it's the secondary headaches-those resulting from underlying pathologies-that can be particularly ominous. This article delves into the sinister causes of headaches, underscoring the importance of a meticulous clinical approach, especially when presented with red flags.

RECENT FINDINGS

Headaches, one of the most common complaints in clinical practice, span a spectrum from benign tension-type episodes to harbingers of life-threatening conditions. For the seasoned physician, differentiating between these extremes is paramount. Headache etiologies covered in this article will include subarachnoid hemorrhage (SAH), cervical artery dissection, cerebral venous thrombosis, meningitis, obstructive hydrocephalus, and brain tumor.

An unusual imaging presentation of pediatric bacterial meningoencephalitis: a case-report study

Background

Bacterial meningoencephalitis is a serious infection affecting the brain and its surrounding membranes. While imaging studies play a crucial role in diagnosing this condition, the typical radiological findings are well-documented. However, this case report describes an unusual imaging presentation that deviates from the expected patterns, emphasizing the need for awareness of such variations.

Case presentation

A 7-year-old female with no prior medical history was referred to our hospital with fever, seizure, and loss of Consciousness. She had mild flu a week before admission. The duration of seizure episodes were 2-3 min, with tonic-clonic uncontrollable jerky movements. Brudzinski and Kernig signs were positive and plantar reflex was upward bilaterally in the physical examination. The computed tomography (CT) scan showed brain ventriculomegaly/hydrocephalus, and MRI findings indicated multiple foci located at cerebellum, basal ganglia, and thalamus alongside intensely restricted diffusion of the layering debris, suggesting pyogenic ventriculitis. Cerebrospinal fluid (CSF) analysis showed severe hypoglycorrhachia, despite non-significant increase of protein. The patient was undergone antibiotic therapy with ceftriaxone, vancomycin and rifampin, resulting in normalization of CSF values.

Conclusion

This case report highlights the importance of recognizing and interpreting unusual imaging presentations of bacterial meningoencephalitis in paediatric patients. It emphasizes the need for a comprehensive diagnostic approach, including clinical evaluation, laboratory tests, and imaging studies, to ensure accurate diagnosis and appropriate management of this potentially life-threatening condition. Further research and awareness of atypical imaging findings are warranted to enhance our understanding and improve patient outcomes.

Rare Cases of Pseudomonas aeruginosa Meningitis in Children: 10-Year Experience in a Single Center

OBJECTIVE

The primary objective was to elucidate the epidemiologic characteristics, risk determinants, and clinical outcomes associated with Pseudomonas aeruginosa-induced meningitis.

METHODS

All cases of meningitis caused by Pseudomonas aeruginosa that were treated at the hospital between 2012 and 2022 were retrospectively analyzed and detailed.

RESULTS

During a 10-year period, only 10 patients satisfied the inclusion criteria. Three patients had previously undergone neurosurgical procedures and 4 patients had leukemia.

CONCLUSIONS

Although Pseudomonas aeruginosa meningitis possesses a low incidence rate, the rate of mortality is high. Patients with leukemia or those who have undergone neurosurgery are the most susceptible to diagnosis. Cases of severe neutropenia present only mild or no cerebrospinal fluid pleocytosis. In patients with sensitive Pseudomonas aeruginosa meningitis, the timely use of anti-Pseudomonas carbapenems for intravenous treatment is highly effective. For drug-resistant Pseudomonas aeruginosa meningitis, intrathecal polymyxins administration can be an effective treatment option.

Maintenance of brain health: The role of social determinants of health and other non-traditional cardiovascular risks

Brain health is the complete functioning of the brain across the life course to support the full physical, mental, social, and spiritual well-being and quality of life of an individual towards attaining and maintaining the epitome of a meaningful, impactful, purposeful, and productive life. The determinants of brain health are complex and include at least in part, non-traditional risks such as interactions among social, economic, physical, and internal factors (e.g., emotions and adaptations to changing life experiences), and external factors such as environment, geography, and climate change. Thus, social determinants of health (e.g., where we work, live, and play) are those non-medical factors that influence health outcomes, and as non-traditional cardiovascular factors, may influence the development of traditional cardiovascular risks. Examples of the non-traditional cardiovascular factors include environmental stressors (e.g., climate change, air pollution), and psychological and physical abuse. In this article, we provide a discussion of social determinants of health and other non-traditional cardiovascular risks as they relate to brain health.

Diagnostic Accuracy of Cerebrospinal Fluid Multiplex Polymerase Chain Reaction Panel Testing in Patients With Suspected Central Nervous System Infections: A Multi-Center Study in the United Arab Emirates

Background Delays in diagnosis and treatment of central nervous system (CNS) infections can lead to significant morbidity and mortality among children and adults. Prior antibiotic treatment is a major hurdle to accurate diagnosis due to falsely negative cerebrospinal fluid (CSF) cultures in partially treated patients. Increasingly, molecular diagnostic methods using multiplex polymerase chain reaction (mPCR) testing on CSF samples are being utilized in clinical practice for timely and accurate diagnosis. However, there is no data regarding the diagnostic accuracy or clinical impact of CSF mPCR testing in the Middle East region. We sought to compare the diagnostic accuracy of an automated mPCR CSF panel with routine CSF culture, the current gold standard, in the United Arab Emirates (UAE).  Methods This single-gated, multi-center, diagnostic accuracy study included patients from birth onwards who were admitted to any of the three participating hospitals with an initial diagnosis of meningitis or encephalitis, between January 2017 and March 2021, and had CSF samples collected for mPCR and culture. Sociodemographic, clinical, and molecular data were collected for all. Results A total of 353 CSF samples were collected from patients from 0-90 years old hospitalized for suspected CNS infection. Children constituted 51% of the study population, and males were slightly over-represented (55.2%). Pathogens were detected by mPCR in 78 (22%) CSF samples, of which 19 (24%) were bacteria and 59 (76%) were viruses. No fungal pathogens were detected. Enteroviruses were the most prevalent CNS pathogen among our cohort (40%), followed by herpes simplex virus type 2 (HSV-2) (12.5%). Children constituted 69% of positive samples for enterovirus, while HSV-2 was exclusively detected among adults. Using CSF culture as the diagnostic gold standard, the mPCR panel demonstrated high specificity (100%) and sensitivity (96.3%) in diagnosing CNS infection among all age groups. mPCR testing demonstrated a high overall percentage of agreement (OPA) with CSF culture (98.9%). Patients with bacterial meningitis had a significantly longer hospitalization (p=0.004) and duration of antibiotic therapy (p=0.001) compared to those with viral meningitis. Three CSF samples were negative on mPCR testing but positive on culture. These pathogens included: methicillin-sensitive Staphylococcus aureus(MSSA), Bacillus cereus, and Mycobacterium Tuberculosis (MTB). In addition, 13 patients had negative CSF cultures but tested positive on CSF mPCR. These pathogens included Streptococcus pneumoniae (seven patients), Haemophilus influenzae (three patients), Streptococcus agalactiae (two patients), and Escherichia coli (one patient). All discordant results were confirmed by reviewing the patient's clinical presentation, CSF analysis, clinical course, and final diagnosis. Conclusion CSF mPCR panel is a highly sensitive and specific diagnostic tool for the diagnosis of CNS infections among all age groups in the UAE. Routine use of CSF mPCR panels can decrease healthcare costs by reducing the length of stay and can also aid antibiotic stewardship efforts by reducing antibiotic overuse in patients with viral CSF infections. CSF culture and mPCR complement each other by identifying CNS pathogens in patients with prior antibiotic exposure who would otherwise be missed if relying on CSF culture alone. However, concomitant CSF culture samples should be sent to avoid missing unusual CNS pathogens.

Therapeutic advances in neuroinfectious diseases

There have been several major advances in therapeutic options for the treatment of neurological infections over the past two decades. These advances encompass both the development of new antimicrobial therapies and the repurposing of existing agents for new indications. In addition, advances in our understanding of the host immune response have allowed for the development of new immunomodulatory strategies in the treatment of neurological infections. This review focuses on the key advances in the treatment of neurological infections, including viral, bacterial, fungal, and prion diseases, with a particular focus on immunomodulatory treatment options. This review also highlights the process by which clinicians can request access to therapeutic agents on a compassionate or emergency basis when they may not be commercially available. While many therapeutic advances have been achieved in the past several years, there remains a pressing need for the continued development of additional therapeutic agents in the treatment of neurological infections.