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SUMMARYCentral nervous system (CNS) infections can be caused by various pathogens, including bacteria, viruses, fungi, and parasites. Molecular diagnostic methods are pivotal for identifying the different causative pathogens of these infections in clinical settings. The efficacy and specificity of these methods can vary per pathogen involved, and in a substantial part of patients, no pathogen is identified in the cerebrospinal fluid (CSF). Over recent decades, various molecular methodologies have been developed and applied to patients with CNS infections. This review provides an overview of the accuracy of nucleic acid amplification methods in CSF for a diverse range of pathogens, examines the potential value of multiplex PCR panels, and explores the broad-range bacterial and fungal PCR/sequencing panels. In addition, it evaluates innovative molecular approaches to enhance the diagnosis of CNS infections., Competing Interests: The authors declare no conflict of interest.

Severe central nervous system infections (CNSI), including community-acquired CNSI (CA-CNSI) and healthcare-associated ventriculitis and meningitis (HAVM), present high morbidity and mortality. Intraventricular antibiotic treatment (IVT) is advisable for these infections, though evidence is limited. We retrospectively analyzed data on 27 patients who received IVT for severe CA-CNSI and HAVM over 10 years, assessing clinical and paraclinical features, such as baseline severity and functional outcome, antibiotics, microbiological and laboratory data. Comparisons were made between patients affected by CNSI and HAVM and those with favorable and unfavorable outcomes, based on the modified Rankin scale. Gram-positive organisms dominated in CA-CNSI (64%), while gram-negative organisms were more frequent in HAVM (64%). Patients received a median of 30 days of intravenous antibiotics and 11 days of IVT, with no significant difference between CA-CNSI and HAVM. IVT-associated toxicity was rare. Patients with favorable outcomes (64%) had higher initial cerebrospinal fluid- white blood cell count (CSF-WBC), that decreased more rapidly than in patients with unfavorable outcomes. CSF-WBC dynamics did not differ between CA-CNSI and HAVM patients. Rapid decline in CSF-WBC after initiation of IVT was associated with favorable outcome. Despite severe neurological impairment at admission, most survivors achieved favorable long-term outcomes., Competing Interests: Declarations Competing interests The authors declare no competing interests. Ethics approval and consent to participate The study was approved by the local ethics committee (Kantonale Ethikkommission Zürich, BASEC- Nr2021-00631)., (© 2024. The Author(s).)

Human parechoviruses (HPeVs) are known to cause meningo-encephalitis among neonates and infants. We aimed to describe the epidemiology of HPeVs causing central nervous system infections in Alberta from 2014 to 2019 with comparison of known HPeV-3 and emerging HPeV-5. Genomic analysis was completed on a subset of HPeV-5 strains to understand genetic relatedness to other known strains. All cerebrospinal fluid (CSF) samples in Alberta with detection of HPeVs were identified and a case review of medical records was conducted, retrospectively, to gather demographic and clinical details. Descriptive and analytic statistics were used to describe and compare the characteristics of cases affected by HPeV-3 with HPeV-5. Genome amplification was completed on six HPeV-5 samples. During the study period, 18,882 CSF samples were tested; 56 were positive for HPeV-3 or HPeV-5, and 52 patients were included in this study (40 HPeV-3 cases and 12 HPeV-5). A total of 40% of cases occurred in 2016, and 64% of infections occurred in the months of August to October. The mean age of cases was 18 days for HPeV-5 compared with 26 days for HPeV-3 ( p = 0.045). Phylogenetic comparison showed similarity to a recombinant strain reported in Australia. HPeV meningo-encephalitis affected neonates/infants, mostly in late summer/early fall, and genomic sequencing of new strains can contribute to understanding the epidemiology of HPeV infections globally.

Background: Tuberculous meningitis (TBM) is a severe central nervous system (CNS) infection with a challenging diagnosis due to inadequate detection methods. This study evaluated current clinical detection methods and their applicability., Methods: A cohort of 514 CNS infection patients from 2018 to 2020 was studied. Data on general demographics, Cerebrospinal Fluid (CSF) analysis, epidemiology, and clinical outcomes were collected. TBM patients were identified, and the sensitivities of mmetagenomic next-generation sequencing (NGS), GeneXpert, and microbial culture were compared. Kappa statistic assessed the consistency between methods., Results: Among the patients involved, TBM (29%) and neurosyphilis (25%) were the two most prevalent CNS infections. CSF analysis indicated that 76% of patients had leukocytosis, suggesting a potential CNS inflammation. In TBM cases, 92.5% had elevated CSF protein and leukocyte counts. Moreover, the percentage of positive mNGS results was 55.6%. GeneXpert and MTB cultures alone had lower sensitivity, but combined use resulted in a 53.4% positive rate., Conclusions: This study highlights the high sensitivity of mNGS, comparable to GeneXpert and MTB culture. The combined methods are cost-effective and straightforward, and can partially substitute for mNGS, offering valuable alternatives for TBM diagnosis and providing insights into multiple diagnostic strategies in clinical practice., (© 2024. The Author(s).)

Objectives: We aimed to validate and refine the encephalitis criteria proposed by the International Encephalitis Consortium in a cohort of adults initially suspected of a central nervous system (CNS) infection., Methods: We included patients from two prospective cohort studies consisting of adults suspected of a CNS infection whom underwent a diagnostic lumbar puncture. We evaluated the test characteristics of the criteria for both possible and probable encephalitis. The reference standard was a final clinical diagnosis of encephalitis. Recalibration of the criteria was done by adjusting the weight of each criterion based on their respective odds., Results: In total 1446 episodes were evaluated, of whom 162 (11%) had a clinical diagnosis of encephalitis. Possible encephalitis had a sensitivity of 41% (95% CI 33-49) and a specificity of 88% (95% CI 86-90). Probable encephalitis had a sensitivity and specificity of respectively 27% (95% CI 20-34) and 95% (95% CI 94-96). Through odds-based weighting, we recalibrated the weight of each individual criterion, resulting in a model consisting of an altered mental status (weight of 2), seizures (weight of 3), elevated CSF leukocytes (weight of 5) and abnormalities on neuroimaging (weight of 9). We proposed a cut-off at 5 for possible encephalitis, (sensitivity 93% [95% CI 88-96]; specificity 51% [95% 49-54]), and at 8 for probable encephalitis (sensitivity 51% [95% CI 44-59]; specificity 91% [95% CI 89-92])., Conclusions: We validated and refined the existing diagnostic criteria for encephalitis, leading to a substantially enhanced sensitivity. These updated criteria hold promise to facilitate the accurate identification of encephalitis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Human Herpesviruses (HHVs) play a significant role in neurological diseases such as encephalitis and meningitis, adding significant morbidity. This study aims to retrospectively analyze the effect of HHVs on patients with neurological symptoms, focusing on the Herpesviridae family's contributions to central nervous system (CNS) infections., Methods: This retrospective cohort study included 895 patients suspected of viral CNS infections, utilizing molecular diagnosis via qPCR to identify HHVs in cerebrospinal fluid (CSF) samples. This was conducted at a reference tertiary care hospital for infectious diseases in the western Brazilian Amazon from January 2015 to December 2022, focusing on the Herpesviridae family's clinical repercussions and of Cytomegalovirus in CNS infections., Results: The findings revealed that 7.5% of the analyzed samples tested positive for HHVs, with Human Cytomegalovirus (HCMV) and Epstein-Barr Virus (EBV) being the most prevalent. A significant association was found between HHVs and neurological diseases such as encephalitis and meningitis, especially among people living with HIV/AIDS (PLWHA), highlighting the opportunistic nature of these viruses. The study underscores the critical role of CSF analysis in diagnosing CNS infections and the complexity of managing these infections in HIV patients due to their immunocompromised status., Conclusions: The results emphasize the need for comprehensive diagnostic approaches and tailored treatment strategies for CNS infections in immunocompromised individuals. The study calls for ongoing research and advancements in clinical practice to improve patient outcomes facing CNS infections, particularly those caused by HHVs.

Purpose: Enteroviruses (EV) comprises many different types and are the most common cause of aseptic meningitis. How the virus affects the brain including potential differences between types are largely unknown. Measuring biomarkers in CSF is a tool to estimate brain damage caused by CNS infections., Methods: A retrospective study was performed in samples from 38 patients with acute neurological manifestations and positive CSF-EV RNA ( n  = 37) or serum-IgM ( n  = 1). The EV in 17 samples were typed by sequencing. The biomarkers neurofilament light (NFL), glial fibrillary acidic protein (GFAP), S-100B protein, amyloid-β (Aβ) 40 and Aβ42, total-tau (T-tau) and phosphorylated tau (P-tau) were measured and compared with data derived from a control group ( n  = 19)., Results: There were no increased levels of GFAP ( p  ≤ 0.1) nor NFL ( p  ≤ 0.1) in the CSF of patients with EV meningitis ( n  = 38) compared with controls. However, we found decreased levels of Aβ42 ( p  < 0.001), Aβ40 ( p  < 0.001), T-tau ( p  ≥ 0.01), P-tau ( p  ≤ 0.001) and S-100B ( p  ≤ 0.001). E30 ( n  = 9) and CVB5 ( n  = 6) were the most frequent EV-types identified, but no differences in biomarker levels or other clinical parameters were found between the infecting virus type. Seven patients who were followed for longer than one month reported remaining cognitive impairment, although no correlations with biomarker concentrations were observed., Conclusion: There are no indication of neuronal or astrocyte damage in patients with EV meningitis. Yet, decreased concentrations of Aβ40, Aβ42, P-tau and T-tau were shown, a finding of unknown importance. Cognitive impairment after acute disease occurs, but with only a limited number of patients analysed, no conclusion can be drawn concerning any association with biomarker levels or EV types.

Central nervous system (CNS) infections carry a substantial burden of morbidity and mortality worldwide, and accurate and timely diagnosis is required to optimize management. Metagenomic next-generation sequencing (mNGS) has proven to be a valuable tool in detecting pathogens in patients with suspected CNS infection. By sequencing microbial nucleic acids present in a patient's cerebrospinal fluid, brain tissue, or samples collected outside of the CNS, such as plasma, mNGS can detect a wide range of pathogens, including rare, unexpected, and/or fastidious organisms. Furthermore, its target-agnostic approach allows for the identification of both known and novel pathogens. This is particularly useful in cases where conventional diagnostic methods fail to provide an answer. In addition, mNGS can detect multiple microorganisms simultaneously, which is crucial in cases of mixed infections without a clear predominant pathogen. Overall, clinical mNGS testing can help expedite the diagnostic process for CNS infections, guide appropriate management decisions, and ultimately improve clinical outcomes. However, there are key challenges surrounding its use that need to be considered to fully leverage its clinical impact. For example, only a few specialized laboratories offer clinical mNGS due to the complexity of both the laboratory methods and analysis pipelines. Clinicians interpreting mNGS results must be aware of both false negatives-as mNGS is a direct detection modality and requires a sufficient amount of microbial nucleic acid to be present in the sample tested-and false positives-as mNGS detects environmental microbes and their nucleic acids, despite best practices to minimize contamination. Additionally, current costs and turnaround times limit broader implementation of clinical mNGS. Finally, there is uncertainty regarding the best practices for clinical utilization of mNGS, and further work is needed to define the optimal patient population(s), syndrome(s), and time of testing to implement clinical mNGS., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Objectives: Central nervous system (CNS) infections caused by carbapenem-resistant Gram-negative bacteria (CR-GNB) present a major health and economic burden worldwide. This multicentre prospective study aimed to assess the feasibility and usefulness of CSF therapeutic drug monitoring (TDM) after intrathecal/intraventricular administration of polymyxin B in patients with CNS infections., Methods: Forty-two patients treated with intrathecal/intraventricular administration of polymyxin B against CR-GNB-induced CNS infections were enrolled. CSF trough level (Cmin) was collected beginning on Day 2 post-polymyxin B initiation and thereafter. The primary outcomes were clinical cure and 28-day all-cause mortality., Results: All patients started with intrathecal/intraventricular administration of polymyxin B at a dose of 5 g/day, corresponding to a median CSF Cmin of 2.93 mg/L (range, 0.21-25.74 mg/L). Clinical cure was 71.4%, and the median CSF Cmin of this group was higher than that of clinical failure group [3.31 (IQR, 1.73-5.62) mg/L versus 2.25 (IQR, 1.09-4.12) mg/L; P = 0.011]. In addition, with MICs ≤ 0.5 mg/L, maintaining polymyxin B CSF Cmin above 2.0 mg/L showed a higher clinical cure rate (P = 0.041). The 28-day all-cause mortality rate was 31.0% and had no association with CSF Cmin., Conclusions: After intrathecal/intraventricular administration of polymyxin B, CSF concentrations fluctuated considerably inter- and intra-individual. Polymyxin B CSF Cmin above 2.0 mg/L was associated with clinical cure when MICs were ≤ 0.5 mg/L, and the feasibility of TDM warrants additional clinical studies., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Purpose: Cerebrospinal fluid (CSF) granulocytes are associated with bacterial meningitis, but information on its diagnostic value is limited and primarily based on retrospective studies. Therefore, we assessed the diagnostic accuracy of CSF granulocytes., Methods: We analyzed CSF granulocytes (index test) from all consecutive patients in two prospective cohort studies in the Netherlands. Both studies included patients ≥ 16 years, suspected of a central nervous system (CNS) infection, who underwent a diagnostic lumbar puncture. All episodes with elevated CSF leukocytes (≥ 5 cells per mm 3 ) were selected and categorized by clinical diagnosis (reference standard)., Results: Of 1261 episodes, 625 (50%) had elevated CSF leukocytes and 541 (87%) were included. 117 of 541 (22%) were diagnosed with bacterial meningitis, 144 (27%) with viral meningoencephalitis, 49 (9%) with other CNS infections, 76 (14%) with CNS autoimmune disorders, 93 (17%) with other neurological diseases and 62 (11%) with systemic diseases. The area under the curve to discriminate bacterial meningitis from other diagnoses was 0.97 (95% confidence interval [CI] 0.95-0.98) for CSF granulocyte count and 0.93 (95% CI 0.91-0.96) for CSF granulocyte percentage. CSF granulocyte predominance occurred in all diagnostic categories. A cutoff at 50% CSF granulocytes gave a sensitivity of 94% (95% CI 90-98), specificity of 80% (95% CI 76-84), negative predictive value of 98% (95% CI 97-99) and positive predictive value of 57% (95% CI 52-62)., Conclusion: CSF granulocytes have a high diagnostic accuracy for bacterial meningitis in patients suspected of a CNS infection. CSF granulocyte predominance occurred in all diagnostic categories, limiting its value in clinical practice., (© 2024. The Author(s).)

The application of metagenomic next-generation sequencing (mNGS) in pathogens detection of cerebrospinal fluid (CSF) is limited because clinical, microbiological, and biological information are not well connected. We analyzed the 428 enrolled patients' clinical features, pathogens diagnostic efficiency of mNGS in CSF, microbial community structure and composition in CSF, and correlation of microbial and clinical biomarkers in CSF. General characteristics were unspecific but helpful in formulating a differential diagnosis. CSF mNGS has a higher detection rate (34.6%) compared to traditional methods (5.4%). mNGS detection rate was higher when the time from onset to CSF collection was ≤20 days, the CSF leukocytes count was >200 × 10 6 /L, the CSF protein concentration was >1.3 g/L, or CSF glucose concentration was ≤2.5 mmol/L in non-postoperative bacterial CNS infections (CNSi). CSF was not strictly a sterile environment, and the potential pathogens may contribute to the dysbiosis of CSF microbiome. Furthermore, clinical biomarkers were significantly relevant to CNS pathogens. Clinical data are helpful in choosing a proper opportunity to obtain an accurate result of mNGS, and can speculate whether the mNGS results are correct or not. Our study is a pioneering study exploring the CSF microbiome in different CNSIs., (© 2024 The Author(s). The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: COVID-19 is primarily considered a respiratory tract infection, but it can also affect the central nervous system (CNS), which can result in long-term sequelae. In contrast to CNS infections by classic neurotropic viruses, SARS-CoV-2 is usually not detected in cerebrospinal fluid (CSF) from patients with COVID-19 with neurological involvement (neuro-COVID), suggesting fundamental differences in pathogenesis., Methods: To assess differences in CNS metabolism in neuro-COVID compared to CNS infections with classic neurotropic viruses, we applied a targeted metabolomic analysis of 630 metabolites to CSF from patients with (i) COVID-19 with neurological involvement [n = 16, comprising acute (n = 13) and post-COVID-19 (n = 3)], (ii) viral meningitis, encephalitis, or myelitis (n = 10) due to herpes simplex virus (n = 2), varicella zoster virus (n = 6), enterovirus (n = 1) and tick-borne encephalitis virus (n = 1), and (iii) aseptic neuroinflammation (meningitis, encephalitis, or myelitis) of unknown etiology (n = 21) as additional disease controls., Results: Standard CSF parameters indicated absent or low neuroinflammation in neuro-COVID. Indeed, CSF cell count was low in neuro-COVID (median 1 cell/µL, range 0-12) and discriminated it accurately from viral CNS infections (AUC = 0.99) and aseptic neuroinflammation (AUC = 0.98). 32 CSF metabolites passed quality assessment and were included in the analysis. Concentrations of differentially abundant (fold change ≥|1.5|, FDR ≤ 0.05) metabolites were both higher (9 and 5 metabolites) and lower (2 metabolites) in neuro-COVID than in the other two groups. Concentrations of citrulline, ceramide (d18:1/18:0), and methionine were most significantly elevated in neuro-COVID. Remarkably, triglyceride TG(20:1&#95;32:3) was much lower (mean fold change = 0.09 and 0.11) in neuro-COVID than in all viral CNS infections and most aseptic neuroinflammation samples, identifying it as highly accurate biomarker with AUC = 1 and 0.93, respectively. Across all samples, TG(20:1&#95;32:3) concentration correlated only moderately with CSF cell count (ρ = 0.65), protein concentration (ρ = 0.64), and Q-albumin (ρ = 0.48), suggesting that its low levels in neuro-COVID CSF are only partially explained by less pronounced neuroinflammation., Conclusions: The results suggest that CNS metabolite responses in neuro-COVID differ fundamentally from viral CNS infections and aseptic neuroinflammation and may be used to discover accurate diagnostic biomarkers in CSF and to gain insights into differences in pathophysiology between neuro-COVID, viral CNS infections and aseptic neuroinflammation., (© 2024. The Author(s).)

Background: Opportunistic infections in the central nervous system (CNS) can be a serious threat to people living with HIV. Early aetiological diagnosis and targeted treatment are crucial but difficult. Metagenomic next-generation sequencing (mNGS) has significant advantages over traditional detection methods. However, differences in the cerebrospinal fluid (CSF) microbiome profiles of patients living with and without HIV with suspected CNS infections using mNGS and conventional testing methods have not yet been adequately evaluated., Methods: We conducted a retrospective cohort study in the first hospital of Changsha between January 2019 and June 2022 to investigate the microbiomes detected using mNGS of the CSF of patients living with and without HIV with suspected CNS infections. The pathogens causing CNS infections were concurrently identified using both mNGS and traditional detection methods. The spectrum of pathogens identified was compared between the two groups., Results: Overall, 173 patients (140 with and 33 without HIV) with suspected CNS infection were enrolled in our study. In total, 106 (75.7%) patients with and 16 (48.5%) patients without HIV tested positive with mNGS (p = 0.002). Among the enrolled patients, 71 (50.7%) with HIV and five (15.2%) without HIV tested positive for two or more pathogens (p < 0.001). Patients with HIV had significantly higher proportions of fungus (20.7% vs. 3.0%, p = 0.016) and DNA virus (59.3% vs. 21.2%, p < 0.001) than those without HIV. Epstein-Barr virus (33.6%) was the most commonly identified potential pathogen in the CSF of patients living with HIV using mNGS, followed by cytomegalovirus (20.7%) and torque teno virus (13.8%). The top three causative pathogens identified in patients without HIV were Streptococcus (18.2%), Epstein-Barr virus (12.1%), and Mycobacterium tuberculosis (9.1%). In total, 113 patients living with HIV were diagnosed as having CNS infections. The rate of pathogen detection in people living with HIV with a CNS infection was significantly higher with mNGS than with conventional methods (93.8% vs. 15.0%, p < 0.001)., Conclusion: CSF microbiome profiles differ between patients living with and without HIV with suspected CNS infection. mNGS is a powerful tool for the diagnosis of CNS infection among people living with HIV, especially in those with mixed infections., (© 2024 British HIV Association.)

Infections of the central nervous system (CNS) can lead to severe outcomes if not accurately diagnosed and treated. The broad spectrum of pathogens involved in CNS infections can make diagnosis challenging. Polymerase chain reaction (PCR) -based multiplex molecular diagnostic panels can rapidly and simultaneously detect multiple neuropathogens in cerebrospinal fluid (CSF). This study was aimed to assess the Bio-Speedy Meningitis/Encephalitis RT-PCR MX-17 panel (Bioeksen, İstanbul, Türkiye), a novel multiplex PCR test, in diagnosing CNS infections. The panel can detect a range of pathogens, including Escherichia coli K1, Haemophilus influenzae, Listeria monocytogenes, Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus agalactiae, enterovirus (EV), herpes simplex virus (HSV) 1 and 2, HHV-6, HHV-7, HHV-8, human parechovirus (HPeV), varicella zoster virus (VZV), cytomegalovirus (CMV) and Cryptococcus gatti/neoformans in CSF samples. This retrospective study included 128 CSF samples from 128 patients sent to Bursa Uludağ University Health Application and Research Center Microbiology Laboratory between June 2022 and July 2023 to search for CNS infectious agents. Patient clinical, radiological and laboratory data were collected from the Hospital Information Record System (HIRS). Bacterial pathogens were identified through culture, while viral pathogens were detected in CSF samples using the Fast Track Diagnostics (FTD) multiplex RT-PCR panel (Fast Track Diagnostics Ltd., Luxembourg) for HSV-1, HSV-2, VZV, EV, mumps virus and HPeV. The stored CSF samples were then tested using the BioSpeedy panel and the results were compared with those of the culture and the FTD panel. Pathogens that were detected were considered positive if they were consistent with the patient's symptoms and CSF characteristics according to infectious disease and pediatric infectious disease specialists. Pathogens detected but not supported by the patient's symptoms and CSF characteristics were classified as uncertain clinical relevance (UCR). Out of the 128 patients tested for CNS infectious agents, 44 (34.4%) were diagnosed with a CNS infection. The overall pathogen detection rate with all methods was 43.2% (19/44). The Bio-Speedy panel identified pathogens in 29.5% (13/44) of the patients, followed by the FTD panel (20.5%, 9/44) and culture (9.1%, 4/44). Four bacteria were identified with culture, three of which were also detected by the Bio-Speedy panel. Additionally, six bacteria were identified with Bio-Speedy panel, that were not identified by culture. The FTD panel identified nine viruses, four of which were also identified by Bio-Speedy. In total, the Bio-Speedy panel detected 13 of the 19 positive pathogens (nine bacteria and four viruses: [S.pneumoniae (n= 3), VZV (n= 3), N.meningitidis (n= 2), H.influenzae (n= 2), L.monocytogenes (n= 1), E.coli (n= 1) ve EV (n= 1)]. However, the Bio-Speedy panel identified 15 pathogens [S.pneumoniae (n= 1), E.coli (n= 1), C.gatti/neoformans (n= 1), CMV (n= 8), HHV-6 (n= 3) ve HHV-7 (n= 1)] considered as UCR. The Bio-Speedy identified the causative pathogens in the highest percentage (29.5%) of patients with confirmed CNS infections. Nevertheless, test results should be interpreted based on patient characteristics to ensure appropriate patient management. Using multiple methods and multiplex tests may improve diagnostic accuracy for CNS infections.

Parechovirus (HpEV) and Enterovirus (EV) infections in children mostly have a mild course but are particularly fearsome in newborns in whom they may cause aseptic meningitis, encephalitis, and myocarditis. Our study aimed to describe the clinical presentations and peculiarities of CNS infection by HpEV and EV in neonates. This is a single-center retrospective study at Istituto Gaslini, Genoa, Italy. Infants aged ≤ 30 days with a CSF RTq-PCR positive for EV or HpEV from January 1, 2022, to December 1, 2023, were enrolled. Each patient's record included demographic data, blood and CSF tests, brain MRI, therapies, length of stay, ICU admission, complications, and mortality. The two groups were compared to identify any differences and similarities. Twenty-five patients (15 EV and 10 HpEV) with a median age of 15 days were included. EV patients had a more frequent history of prematurity/neonatal respiratory distress syndrome (p = 0.021), more respiratory symptoms on admission (p = 0.012), and higher C-reactive protein (CRP) levels (p = 0.027), whereas ferritin values were significantly increased in HpEV patients (p = 0.001). Eight patients had a pathological brain MRI, equally distributed between the two groups. Three EV patients developed myocarditis and one HpEV necrotizing enterocolitis with HLH-like. No deaths occurred.  Conclusion: EV and HpEV CNS infections are not easily distinguishable by clinical features. In both cases, brain MRI abnormalities are not uncommon, and a severe course of the disease is possible. Hyper-ferritinemia may represent an additional diagnostic clue for HpEV infection, and its monitoring is recommended to intercept HLH early and initiate immunomodulatory treatment. Larger studies are needed to confirm our findings. What is Known: • Parechovirus and Enteroviruses are the most common viral pathogens responsible for sepsis and meningoencephalitis in neonates and young infants. • The clinical course and distinguishing features of Parechovirus and Enterovirus central nervous system infections are not well described. What is New: • Severe disease course, brain MRI abnormalities, and complications are not uncommon in newborns with Parechovirus and Enteroviruses central nervous system infections. • Hyper-ferritinemia may represent an additional diagnostic clue for Parechovirus infection and its monitoring is recommended., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Post-operative central nervous system infections (PCNSIs) are serious complications of craniotomy. Many factors, including patient-related, surgical, and postoperative factors, affect the survival of patients with PCNSIs. Timely and effective implementation of antibiotics targeting pathogenic bacteria is crucial to reduce mortality. Metagenomic next-generation sequencing (mNGS) has been used successfully to detect pathogens associated with infectious diseases. This study was designed to evaluate the factors influencing mortality and to explore the application value of mNGS in patients with PCNSIs. We conducted a retrospective study of patients with PCNSIs in our unit from 1/12/2019 to 28/2/2021. Clinical data, cerebrospinal fluid (CSF) parameters, surgical information, and mNGS results were collected. Follow-up telephone calls were made in June 2021 for 90 days survival after discharge. 99 patients were enrolled, and the overall mortality rate was 36.4% (36/99). Kaplan-Meier survival analysis suggested that the risk factors for poor prognosis included age ≥ 53 years, Glasgow Coma scale (GCS) score ≤ 8, CSF/blood glucose ratio (C/B-Glu) ≤ 0.23, 2 or more operations, mechanical ventilation (MV), and non-mNGS test. MV and poor wound healing were independent risk factors for 90 day mortality according to the multivariate Cox proportional hazards model (OR = 6.136, P = .017, OR = 2.260, P = .035, respectively). Among the enrolled patients, causative pathogens were identified in 37. Gram-negative pathogens were found in 22 (59.5%) patients, and the remaining 15 (40.5%) were Gram-positive pathogens. Univariate analysis showed that white cell count and protein and lactate levels in the CSF of the Gram-negative group were higher than those of the Gram-positive group (P < .05). mNGS and conventional microbiological culture were tested in 34 patients, and the positive detection rate of mNGS was 52.9%, which was significantly higher than that of microbiological culture (52.9% vs 26.5%, χ2 = 4.54, P = .033). The mortality rate of PCNSIs is high, and patients with MV and poor wound healing have a higher mortality risk. Gram-negative pathogens were the predominant pathogens in the patients with PCNSIs. mNGS testing has higher sensitivity and has the potential to reduce the risk of mortality in patients with PCNSIs., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Knowledge of the clinical presentation of central nervous system (CNS) infections and the causative pathogens is crucial for appropriate diagnosis and rapid initiation of appropriate treatment to prevent severe neurological sequelae. The aim of this study is to understand the aetiology of CNS infections based on the clinical presentation of Vietnamese patients. A prospective hospital-based cohort study was conducted between May 2014 and May 2017. We screened 137 patients with clinically suspected CNS infection for fungal, bacterial and viral pathogens using their cerebrospinal fluid (CSF) and blood cultures. In addition, DNA or RNA extracted from CSF samples were subjected to nucleic acid testing (NAT) with a selective panel of bacterial, viral and fungal pathogens. At least one pathogen could be detected in 41% (n = 56) of the patients. The main pathogens causing CNS infections were Streptococcus suis (n = 16; 12%) and Neisseria meningitidis (n = 9; 7%), followed by Herpes simplex virus 1/2 (n = 4; 3%) and Klebsiella pneumoniae (n = 4; 3%). Other pathogens were only identified in a few cases. Patients with bacterial CNS infections were significantly older, had a worse outcome, a lower Glasgow Coma Scale (GCS), a higher rate of speech impairment and neck stiffness than patients with viral or tuberculous CNS infections. In northern Vietnam, adults are mostly affected by bacterial CNS infections, which have a severe clinical course and worse outcomes compared to viral or tuberculous CNS infections. Clinicians should be aware of the regional occurrence of pathogens to initiate rapid and appropriate diagnosis and treatment., (© 2022. The Author(s).)

Background: Community-acquired central nervous system infections (CA-CNS infections) have the characteristics of acute onset and rapid progression, and are associated with high levels of morbidity and mortality worldwide. However, there have been only limited studies on the etiology of this infections. Here, metagenomic next-generation sequencing (mNGS), a comprehensive diagnosis method, facilitated us to better understand the etiology of CA-CNS infections., Methods: We conducted a single-center retrospective study between September 2018 and July 2021 in which 606 cerebrospinal fluid (CSF) samples were collected from suspected CNS infectious patients for mNGS testing, and all positive samples were included in this analysis., Results: After the exclusion criteria, a total of 131 mNGS-positive samples were finally enrolled. Bacterial, viral, fungal, parasitic, specific pathogen and mixed infections were accounted for 32.82% (43/131), 13.74% (18/131), 0.76% (1/131), 2.29% (3/131) and 6.87% (9/131), respectively. A total of 41 different pathogens were identified, including 16 bacteria, 12 viruses, 10 fungi, and 1 parasite and 3 specific pathogens. The most frequent infecting pathogens are Epstein-Barr virus (n = 14), Herpes simplex virus 1 (n = 14), Mycobacterium tuberculosis (n = 13), Streptococcus pneumoniae (n = 13), and Cryptococcus neoformans (n = 8). Some difficult-to-diagnose pathogen infections were also detected by mNGS, such as Streptococcus suis , Pseudorabies virus , Bunyavirus , Orientia tsutsugamushi and Toxoplasma gondii ., Conclusion: In this study, mNGS identified a wide variety of pathogens of CA-CNS infections and many of which could not be detected by conventional methods. Our data provide a better understanding of the etiology of CA-CNS infections and show that mNGS represents a comparative screening of CSF in an unbiased manner for a broad range of human pathogens., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhang, Wu, Shi, Liu, Xu, Dai, Chang and Ma.)

The cerebrospinal fluid (CSF) space is convoluted. CSF flow oscillates with a net flow from the ventricles towards the cerebral and spinal subarachnoid space. This flow is influenced by heartbeats, breath, head or body movements as well as the activity of the ciliated epithelium of the plexus and ventricular ependyma. The shape of the CSF space and the CSF flow preclude rapid equilibration of cells, proteins and smaller compounds between the different parts of the compartment. In this review including reinterpretation of previously published data we illustrate, how anatomical and (patho)physiological conditions can influence routine CSF analysis. Equilibration of the components of the CSF depends on the size of the molecule or particle, e.g., lactate is distributed in the CSF more homogeneously than proteins or cells. The concentrations of blood-derived compounds usually increase from the ventricles to the lumbar CSF space, whereas the concentrations of brain-derived compounds usually decrease. Under special conditions, in particular when distribution is impaired, the rostro-caudal gradient of blood-derived compounds can be reversed. In the last century, several researchers attempted to define typical CSF findings for the diagnosis of several inflammatory diseases based on routine parameters. Because of the high spatial and temporal variations, findings considered typical of certain CNS diseases often are absent in parts of or even in the entire CSF compartment. In CNS infections, identification of the pathogen by culture, antigen detection or molecular methods is essential for diagnosis., (© 2022. The Author(s).)

Cerebrospinal fluid (CSF) analysis is an important diagnostic tool for many conditions affecting the central nervous system (CNS), especially CNS infectious diseases. Despite its low specificity, CSF white blood cell counts, CSF protein levels, CSF serum glucose ratio and CSF lactate measurement are useful in differentiating infections caused by distinct groups of pathogens. CSF direct examination and cultures can identify causative organisms and antibiotic sensitivities as well. Adjunctive tests such as latex agglutination, different immunological assays and molecular reactions have great specificities and increasing sensitivities. In this article, some recent diagnostic methods applied to CSF analysis for frequent CNS infections are presented.

Objective: To investigate the optimal implementation and clinical and financial impacts of the FilmArray Meningitis Encephalitis Panel (MEP) multiplex polymerase chain reaction testing of cerebrospinal fluid (CSF) in children with suspected central nervous system infection., Study Design: A pre-post quasiexperimental cohort study to investigate the impact of implementing MEP using a rapid CSF diagnostic stewardship program was conducted at Children's Hospital Colorado (CHCO). MEP was implemented with electronic medical record indication selection to guide testing to children meeting approved use criteria: infants <2 months, immunocompromised, encephalitis, and ≥5 white blood cells/μL of CSF. Positive results were communicated with antimicrobial stewardship real-time decision support. All cases with CSF obtained by lumbar puncture sent to the CHCO microbiology laboratory meeting any of the 4 aforementioned criteria were included with preimplementation controls (2015-2016) compared with postimplementation cases (2017-2018). Primary outcome was time-to-optimal antimicrobials compared using log-rank test with Kaplan-Meier analysis., Results: Time-to-optimal antimicrobials decreased from 28 hours among 1124 preimplementation controls to 18 hours (P < .0001) among 1127 postimplementation cases (72% with MEP testing conducted). Postimplementation, time-to-positive CSF results was faster (4.8 vs 9.6 hours, P < .0001), intravenous antimicrobial duration was shorter (24 vs 36 hours, P = .004), with infectious neurologic diagnoses more frequently identified (15% vs 10%, P = .03). There were no differences in time-to-effective antimicrobials, hospital admissions, antimicrobial starts, or length of stay. Costs of microbiologic testing increased, but total hospital costs were unchanged., Conclusions: Implementation of MEP with a rapid central nervous system diagnostic stewardship program improved antimicrobial use with faster results shortening empiric therapy. Routine MEP testing for high-yield indications enables antimicrobial optimization with unchanged overall costs., (Copyright © 2022 Elsevier Inc. All rights reserved.)

A child presented to the emergency department with fever, reduced consciousness, irritability and reduced oral intake. Infective meningitis and encephalitis were within the differential diagnoses. Is a lumbar puncture (LP) indicated and, if so, what is the optimal timing of LP? Will antimicrobial pretreatment affect the cerebrospinal fluid (CSF) results? How can clinicians optimise diagnostic stewardship to benefit individual patients and society at large? Interpretation of rapidly available CSF biochemical tests (protein, glucose and lactate levels) and microscopy can provide a prompt insight into the infective aetiology and inform treatment and further diagnostic testing strategies. Diagnosis of an aetiological pathogen in a patient presenting with central nervous system (CNS) infection has clinical, infection control and public health implications. A plethora of tests are available to enable CSF analysis in patients with possible CNS infection. We aimed to summarise current evidence and guidance to ensure the best possible use of the diagnostics available., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The Old world Alphavirus, Middelburg virus (MIDV), is not well known and although a few cases associated with animal illness have previously been described from Southern Africa, there has been no investigation into the association of the virus with human illness. The current study aimed to investigate possible association of MIDV infection with febrile or neurological manifestations in hospitalized or symptomatic patients fromGauteng, South Africa., Methods: This study is a descriptive retrospective and prospective laboratory based study. Archived cerebrospinal fluid (CSF) samples submitted to the National Health Laboratory Service (NHLS), Tshwane Academic division for viral investigation from public sector hospitals in Gauteng as well as EDTA (ethylenediaminetetraacetic acid) whole blood samples from ad hoc cases of veterinary students, presenting with neurological and febrile illness, were selected and screened for the presence of alphaviruses using real-time reverse transcription(rtRT) PCR.Virus isolations from rtRT-PCR positive samples were conducted in Vero cell culture and used to obtain full genome sequences. Basic descriptive statistical analysis was conducted using EpiInfo., Results: MIDV was detected by rtRT-PCR in 3/187 retrospective CSF specimens obtained from the NHLS from hospitalised patients in the Tshwane region of Gauteng and 1/2 EDTA samples submitted in the same year (2017) from ad hoc query arbovirus cases from veterinary students from the Faculty of Veterinary Science University of Pretoria.Full genome sequences were obtained for virus isolates from two cases; one from an EDTA whole blood sample (ad hoc case) and another from a CSF sample (NHLS sample).Two of the four Middelburg virus positive cases,for which clinical information was available, had other comorbidities or infections at the time of infection., Conclusion: Detection of MIDV in CSF of patients with neurological manifestations suggests that the virus should be investigated as a human pathogen with the potential of causing or contributing to neurological signs in children and adults., Competing Interests: The authors have declared that no competing interests exist. Author Anton Stoltz was unable to confirm their authorship contributions. On their behalf, the corresponding author has reported their contribution to the best of their knowledge.

This study was undertaken to assess whether SARS-CoV-2 causes a persistent central nervous system infection. SARS-CoV-2-specific antibody index and SARS-CoV-2 RNA were studied in cerebrospinal fluid following COVID-19. Cerebrospinal fluid was assessed between days 1 and 30 (n = 12), between days 31 and 90 (n = 8), or later than 90 days (post-COVID-19, n = 20) after COVID-19 diagnosis. SARS-CoV-2 RNA was absent in all patients, and in none of the 20 patients with post-COVID-19 syndrome were intrathecally produced anti-SARS-CoV-2 antibodies detected. The absence of evidence of SARS-CoV-2 in cerebrospinal fluid argues against a persistent central nervous system infection as a cause of neurological or neuropsychiatric post-COVID-19 syndrome. ANN NEUROL 2022;91:150-157., (© 2021 The Authors. Annals of Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Objectives: In central nervous system infections, early and correct management is of utmost importance. Rapid syndromic panel testing can potentially provide valuable guidance. The FilmArray meningitis/encephalitis (ME) panel detects 14 pathogens through multiplex PCR. Our study objectives were to assess its performance compared with established diagnostic procedures, especially real-time quantitative PCR for detection of viruses, and to determine the diagnostic and clinical significance of discrepant results., Methods: All cerebrospinal fluid samples sent for viral diagnostics to our microbiological laboratory over 34 months were analysed with the ME panel and in-house real-time PCR for herpes simplex virus type 1 (HSV-1), HSV-2, varicella zoster virus and enteroviruses. Other pathogens detected by the panel were confirmed by routine diagnostic procedures. Discrepant results were analysed through interpretation of biological and clinical data, and performance data were calculated for individual pathogens., Results: Altogether, 315 pathogens were detected by the ME panel in 4199 cerebrospinal fluid samples (7.5%) and an additional 21 viral targets were identified using real-time PCR. Thirty-four ME panel detections were not confirmed, totalling 55 discrepant results. After discrepancy analysis, 20 false-positive and 21 false-negative ME panel results remained. Performance varied between pathogens. Sensitivity for HSV-1 was calculated at 82.4% (59.0%-93.8%) with three false-negative results. Also noteworthy were 13 false-negative enterovirus and eight false-positive Streptococcus pneumoniae results., Conclusions: Our analysis shows good performance for the ME panel in diagnosing central nervous system infection. The risk of false-negative HSV-1 results, however, warrants additional testing when encephalitis is suspected. Uncertainties in interpretation of enterovirus and S. pneumoniae results represent other limitations., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Purpose: Multiple sclerosis (MS) is the most common immune-mediated CNS disease, characterised by demyelination and progressive neurological disability. The B-cell activating factor BAFF has been described as one important factor in the pathophysiology of different autoimmune diseases., Methods: We measured BAFF levels in the serum and cerebrospinal fluid (CSF) in 50 consecutive patients with MS and 35 patients with infectious CNS disease (ID). 52 patients with other, non-inflammatory disorders (OND), served as controls., Results: BAFF-serum levels in ID patients were higher than in patients diagnosed with MS (ID 0.55 ± 0.24 ng/ml, MS 0.43 ± 0.14 ng/ml, OND 0.45 ± 0.24 ng/ml; p  = 0.09). Interestingly, MS patients had lower BAFF CSF levels compared to the controls and ID patients, and the CSF levels in the latter were elevated compared to those of the controls (MS 0.17 ± 0.11 ng/ml, OND 0.25 ± 0.14 ng/ml, ID 0.97 ± 0.78 ng/ml; p  < 0.001)., Conclusions: The ID patients' having higher absolute BAFF levels in the CSF than in the serum indicates that the increased BAFF CSF levels were caused by intrathecal synthesis rather than passive transfer via a disturbed blood-brain-barrier. The significantly decreased BAFF CSF levels in MS patients were a surprising result of our study. Although it has been reported that astrocytes in active MS lesions can express BAFF, the soluble form was not increased in the CSF of MS patients. It remains unclear whether the inflammatory features of active MS plaques are truly represented by the CSF compartment.

We retrospectively examined the yield of a cerebrospinal fluid (CSF) multiplex real-time PCR assay of febrile young infants undergoing a full sepsis work-up. Eighty infants were included in the study: Forty-nine (61%) neonates and 31 (39%) 29-90 day-old patients were included in the study. A viral pathogen was detected in 59% (47/80) of the samples, human enterovirus in 53% (42/80) and Human parechovirus in 6% (5/80). The CSF of nearly half of the subjects with CNS infection was without pleocytosis; all CSF cultures were negative. Multiplex PCR CSF testing enhances the diagnosis of pathogen-specific viral CNS infection among febrile young infants.

Enterovirus (EV) is commonly associated with central nervous system (CNS) syndromes. Recently, gastroenteric viruses, including rotavirus (RVA), human astrovirus (HAstV), and norovirus (NoV), have also been associated with CNS neurological disorders. The aim of the present study was to investigate the presence of EV, RVA, HAst, and NoV associated to CNS infections with undiagnosed etiology in Northwest region of São Paulo State, Brazil, and to conduct the molecular characterization of the positive samples detected. A total of 288 cerebrospinal fluid samples collected from July to December 2017 were tested for EV and NoV by quantitative real-time polymerase chain reaction (RT-qPCR), HAstV by conventional RT-PCR, and RVA by enzyme-linked immunosorbent assay. Positive-EV samples were inoculated in cells lines, amplified by RT-PCR and sequenced. RVA, NoV, and HAstV were not detected. EV infection was detected in 5.5% (16/288), and five samples successful genotyped: echovirus 3 (E3) (1/5), coxsackie virus A6 (CVA6) (1/5), and coxsackie virus B4 (CVB4) (3/5). Meningitis was the main syndrome observed (12/16; 75%). CVA6, CVB4, and E3 were identified associated with aseptic meningitis. Reports of CVA6 associated with aseptic meningitis are rare, E3 had not been previously reported in Brazil, and epidemiological data on CVB4 in the country is virtually unknown. The present investigation illustrates the circulation of diverse EV types in a small regional sample set and in a short period of time, highlighting the importance of an active EV surveillance system in CNS infections. Enhanced understanding of undiagnosed CNS infections will assist in public health and health care planning., (© 2020 Wiley Periodicals LLC.)

Cerebrospinal fluid (CSF) analysis is a diagnostic tool for many conditions affecting the central nervous system. Urgent indications for lumbar puncture include suspected central nervous system infection or subarachnoid hemorrhage. CSF analysis is not necessarily diagnostic but can be useful in the evaluation of other neurologic conditions, such as spontaneous intracranial hypotension, idiopathic intracranial hypertension, multiple sclerosis, Guillain-Barré syndrome, and malignancy. Bacterial meningitis has a high mortality rate and characteristic effects on CSF white blood cell counts, CSF protein levels, and the CSF:serum glucose ratio. CSF culture can identify causative organisms and antibiotic sensitivities. Viral meningitis can present similarly to bacterial meningitis but usually has a low mortality rate. Adjunctive tests such as CSF lactate measurement, latex agglutination, and polymerase chain reaction testing can help differentiate between bacterial and viral causes of meningitis. Immunocompromised patients may have meningitis caused by tuberculosis, neurosyphilis, or fungal or parasitic infections. Subarachnoid hemorrhage has a high mortality rate, and rapid diagnosis is key to improve outcomes. Computed tomography of the head is nearly 100% sensitive for subarachnoid hemorrhage in the first six hours after symptom onset, but CSF analysis may be required if there is a delay in presentation or if imaging findings are equivocal. Xanthochromia and an elevated red blood cell count are characteristic CSF findings in patients with subarachnoid hemorrhage. Leptomeningeal carcinomatosis can mimic central nervous system infection. It has a poor prognosis, and large-volume CSF cytology is diagnostic.

Cutibacterium acnes is the third most common cause of cerebrospinal fluid (CSF) shunt infection and is likely underdiagnosed due to the difficulty in culturing this pathogen. Shunt infections lead to grave neurologic morbidity for patients especially when there is a delay in diagnosis. Currently, the gold standard for identifying CSF shunt infections is microbiologic culture. However, C. acnes infection often results in falsely negative cultures; therefore, new diagnostic methods are needed. To investigate potential CSF biomarkers of C. acnes CSF shunt infection we adapted a rat model of CSF catheter infection to C. acnes. We found elevated levels of interleukin-1β (IL-1β), IL-6, chemokine ligand 2, and IL-10 in the CSF and brain tissues of animals implanted with C. acnes- infected catheters compared to sterile controls at day 1 postinfection. This coincided with modest increases in neutrophils in the CSF and, to a greater extent, in the brain tissues of animals with C. acnes infection, which closely mirrors the clinical findings in patients with C. acnes shunt infection. Mass spectrometry revealed that the CSF proteome is altered during C. acnes shunt infection and changes over the course of disease, typified at day 1 postinfection by an acute-phase and pathogen neutralization response evolving to a response consistent with wound resolution at day 28 compared to a sterile catheter placement. Collectively, these results demonstrate that it is possible to distinguish C. acnes infection from sterile postoperative inflammation and that CSF proteins could be useful in a diagnostic strategy for this pathogen that is difficult to diagnose., (Copyright © 2021 American Society for Microbiology.)

Background: Central nervous system infections cause substantial morbidity and mortality in pediatric patients. However, in approximately half of the clinical cases, the etiology is unidentified. As an unbiased molecular diagnostic technology, next-generation sequencing is gradually being applied to investigate central nervous system infections. This review summarizes and critiques the literature on this new technology for etiologic identification of unexplained central nervous system infections in pediatric patients and discusses the future prospects for development of this technology in pediatrics., Methods: A comprehensive PubMed search was conducted of articles published from January 1, 2008, to June 26, 2020 in order to retrieve all available studies on this topic. Other relevant articles were identified from recent reviews and the bibliographies of the retrieved full-text articles., Results: Among the 441 studies retrieved, 26 pediatric studies, comprising 15 case reports and 11 case series, used next-generation sequencing as a diagnostic tool. In these 26 studies, next-generation sequencing was performed on cerebrospinal fluid samples from 529 pediatric patients, and potential causal pathogens were identified in 22.1% of the cases., Conclusion: There is increasing evidence that next-generation sequencing can play a role in identifying the causes of unexplained encephalitis, meningoencephalitis, and meningitis in pediatric patients, although the diagnostic value of next-generation sequencing is difficult to quantify. There is an increasing need for close collaboration between laboratory scientists and clinicians. We believe that further clinical studies should be performed to evaluate the performance of next-generation sequencing for individual targets and in high-risk populations., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The aim of the study was to evaluate the impact of the use of BioFire® FilmArray® meningitis/encephalitis(FA-ME) panel which enables rapid automated CSF testing for 14 common viral, bacterial, and yeast pathogens that cause CNS infections, in the management of children with suspected CNS infection. A prospective cohort study was performed on children admitted to a tertiary pediatric hospital, over a period of 1 year, with possible CNS infection and CSF pleocytosis (> 15 cells/mm 3 ). Children were randomized 1:1, either to use FA-ME or separate molecular CSF microbiological tests according to usual pediatric practice in the hospital. Length of hospital stay, duration of antimicrobials, and total cost of hospitalization were compared between groups. A total of 142 children were included in the study (71 cases). A pathogen was detected in 37/71(52.1%) children with the use of FA-ME and in 16/71(22.5%) in the control group (P value < 0.001). In aseptic meningitis cases a virus was detected in 27/61(44.2%) and in 11/66(16.7%) controls (P value < 0.001). Median (IQR) length of stay in cases and controls with aseptic meningitis was 5(4-8) and 8(6-10) days, respectively (P value < 0. 001). The median (IQR) duration of antimicrobials in cases and controls was 4(2-5.7) and 7(5-10) days, respectively (P value < 0.001). The hospitalization cost was calculated in cases and controls 1042€ (932-1372) and 1522€ (1302-1742), respectively (P value < 0.001). The use of FA-ME was able to reduce significantly the use of antimicrobials, the hospitalization days, and the total cost comparing to the control group in children with suspected CNS infection.

A 48-year-old man who worked in mining in remote, northern Australia was transferred from a rural hospital 5 days after the onset of headaches, subjective fevers and flaccid paralysis of the left upper limb. Initial investigations demonstrated inflammatory cerebrospinal fluid (CSF) changes and a longitudinally extensive cervical cord lesion. Given two serial negative blood and CSF cultures, he was treated as inflammatory myelitis with intravenous methylprednisolone. Despite the initial improvement in pain and left arm power, the patient's neurological deficit plateaued and then deteriorated with worsening neck pain, diaphragmatic dysfunction and dysphagia requiring intubation and respiratory support. A third CSF culture isolated Burkholderia pseudomallei confirming a diagnosis of neuro-melioidosis. Repeat imaging revealed the rostral extension of the original spinal cord lesion into the medulla and pons. Over the next 4 weeks, the patient's neurological deficits slowly improved with continued intravenous antibiotic therapy with meropenem and oral trimethoprim/sulfamethoxazole., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

To investigate whether and how cerebrospinal fluid (CSF) findings can contribute to distinguish tick-borne encephalitis (TBE) from herpes simplex virus (HSV) and varicella zoster virus (VZV) induced central nervous system (CNS) infections (HSV-I, VZV-I). Chart review and identification of TBE, HSV- I, and VZV-I was carried out, fulfilling the following criteria: (1) clinical signs of encephalitis and/or meningitis, (2) complete CSF analysis and confirmed viral etiology by either PCR or antibody testing in CSF, (3) hospitalized patients, and (4) available brain magnetic resonance imaging (MRI). Fifty-nine patients with 118 CSF/serum pairs were included. These comprised 21 with TBE (35 CSF/serum pairs), 20 (40 CSF/serum pairs) with HSV-I, and 18 (43 CSF/serum pairs) with VZV-I. In contrast to HSV-I and VZV-I, CSF cell differentiation in TBE showed more often an increased (>20%) proportion of granulocytes ( p < 0.01) and a more frequent quantitative intrathecal IgM synthesis ( p = 0.001 and p < 0.01, respectively), while the second was even more pronounced when follow-up CSF analyses were included ( p < 0.001). CSF findings help to distinguish TBE from other viral infections. In cases with CSF pleocytosis and a positive history for a stay in or near an endemic area, TBE antibodies in CSF and serum should be determined, especially if granulocytes in CSF cell differentiation and/or an intrathecal IgM synthesis is present.

Introduction : Central nervous system (CNS) infections can be life-threatening and are often associated with disabling sequelae. One important factor in most CNS infections is a timely pathogen-specific treatment. The diagnostic methods available, however, do not always reach a satisfying sensitivity and specificity. In these cases, there is need for additional diagnostic biomarkers. Chemokines represent potential candidates as biomarkers, since they are an important pillar of the host immune response. The aim of this review is to discuss the diagnostic potential of cerebrospinal fluid (CSF) CXCL13 in patients with CNS infections. Areas covered : Data were obtained from a literature search in PubMed up to October 2019. This review focusses on articles on the potential of CXCL13 as a diagnostic tool. The majority of identified studies aimed to characterize its role in two diseases, namely Lyme neuroborreliosis and neurosyphilis. Expert opinion : CSF CXCL13 has a significant potential as a diagnostic and monitoring add-on marker in Lyme neuroborreliosis. Differences in study design, control groups and clinical parameters between studies, however, affect sensitivity, specificity and cutoff values, underlining the need of further studies to address these issues and pave the way for a generalized clinical practice.

Following implementation of the FilmArray meningitis and encephalitis panel, which enables rapid syndromic cerebrospinal fluid testing, HSV testing doubled in children >60 days with suspected central nervous system infection at Children's Hospital Colorado. Acyclovir initiation was unchanged, but duration decreased. Diagnostic and antimicrobial stewardship is needed for MEP optimization., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Lactate is produced from anaerobic glycolysis, which occurs in most tissues in the human body. Blood lactate is tested in most physiologically unwell patients in the Emergency Department and helps to guide treatment and prognosis. Cerebrospinal fluid (CSF) lactate, however, is not often measured. Various central nervous system (CNS) conditions lead to a rise in CSF lactate, including acute neurological infection, stroke, seizures and mitochondrial pathologies. This article discusses the utility and limitations of CSF lactate, highlighting specific clinical situations where it can help in the diagnosis of CNS infections and unexplained encephalopathy., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

The etiology of central nervous system (CNS) infections such as meningitis and encephalitis remains unknown in a large proportion of cases partly because the diversity of pathogens that may cause CNS infections greatly outnumber available test methods. We developed a metagenomic next generation sequencing (mNGS)-based approach for broad-range detection of pathogens associated with CNS infections suitable for application in the acute care hospital setting. The analytical sensitivity of mNGS performed on an Illumina MiSeq was assessed using simulated cerebrospinal fluid (CSF) specimens (n = 9). mNGS data were then used as a training dataset to optimize a bioinformatics workflow based on the IDseq pipeline. For clinical validation, residual CSF specimens (n = 74) from patients with suspected CNS infections previously tested by culture and/or PCR, were analyzed by mNGS. In simulated specimens, the NGS reads aligned to pathogen genomes in IDseq were correlated to qPCR C T values for the respective pathogens (R = 0.96; p < 0.0001), and the results were highly specific for the spiked pathogens. In clinical samples, the diagnostic accuracy, sensitivity and specificity of the mNGS with reference to conventional methods were 100%, 95% and 96%, respectively. The clinical application of mNGS holds promise to benefit patients with CNS infections of unknown etiology.

Introduction: In an attempt to identify a wide spectrum of viral infections, cerebrospinal fluid (CSF) specimens were collected from pediatric cases with the preliminary diagnosis of viral encephalitis/meningoencephalitis in two reference hospitals, from October 2011 to December 2015., Methodology: A combination of nucleic acid-based assays, including in house generic polymerase chain reaction (PCR) assays for enteroviruses, flaviviruses and phleboviruses, a commercial real-time PCR assay for herpesviruses and a commercial real time multiplex PCR, enabling detection of frequently-observed viral, bacterial and fungal agents were employed for screening., Results: The microbial agent could be characterized in 10 (10%) of the 100 specimens. Viral etiology could be demonstrated in 7 (70%) specimens, which comprises Human Herpesvirus 6 (4/7), Herpes Simplex virus type1 (2/7) and Enteroviruses (1/7). In 3 specimens (30%), Streptococcus pneumoniae, Listeria monocytogenes and Staphylococcus aureus were detected via the multiplex PCR, which were also isolated in bacteriological media. All specimens with detectable viral nucleic acids, as well as unreactive specimens via nucleic acid testing remained negative in bacteriological cultures., Conclusions: Herpes and enteroviruses were identified as the primary causative agents of central nervous system infections in children. Enterovirus testing must be included in the diagnostic work-up of relevant cases., Competing Interests: No Conflict of Interest is declared, (Copyright (c) 2020 Aylin Altay-Kocak, Gulendam Bozdayi, Janine Michel , Meltem Polat, Saliha Kanik-Yuksek , Hasan Tezer, Aykut Ozkul, Kamruddin Ahmed, Andreas Nitsche, Koray Ergunay.)

Background: Central nervous system (CNS) may be infected by several agents, resulting in different presentations and outcomes. Analysis of cerebrospinal fluid (CSF) markers could be helpful to differentiate specific conditions and setting an appropriate therapy., Methods: Patients presenting with signs and symptoms were enrolled if, before receiving a diagnostic lumbar puncture, signed a written informed consent. We analyzed CSF indexes of blood-brain barrier permeability (CSF to serum albumin ratio or CSAR), inflammation (CSF to serum IgG ratio, neopterin), amyloid deposition (1-42 β-amyloid), neuronal damage (Total tau (T-tau), Phosphorylated tau (P-tau), and 14.3.3 protein) and astrocyte damage (S-100β)., Results: Two hundred and eighty-one patients were included: they were mainly affected by herpesvirus encephalitis, enterovirus meningoencephalitis, bacterial meningitis (Neisseria meningitidis and Streptococcus pneumoniae), and infection by other etiological agents or unknown pathogen. Their CSF features were compared with HIV-negative patients and native HIV-positive individuals without CNS involvement. 14.3.3 protein was found in bacterial and HSV infections while T-tau and neopterin were abnormally high in the herpesvirus group. P-tau, instead, was elevated in enterovirus meningitis. S-100β was found to be high in patients with HSV-1 and HSV-2 infections but not in those with Varicella Zoster Virus (VZV). Thirty-day mortality was unexpectedly low (2.7%): patients who died had higher levels of T-tau and, significantly, lower levels of Aβ1-42., Conclusion: This work demonstrates that CSF biomarkers of neuronal damage or inflammation may vary during CNS infections according to different causative agents. The prognostic value of these biomarkers needs to be assessed in prospective studies.

Background: Patients harboring an external ventricular drain (EVD) who develop signs of infection require screening for infection in the central nervous system (CNS). The cerebrospinal fluid (CSF) can be collected by the EVD or by lumbar puncture (LP). If only one sample is analyzed, the diagnosis might be dubious or false-negative. The objective of this study was to compare the diagnosis accuracy of CNS infection of CSF samples collected from EVD and LP., Methods: We conducted a transversal study where data were prospectively collected from 2016 to 2019. Patients harboring EVD with signs of infection were submitted to the CSF analysis collected by LP and EVD. Diagnosis sensibility and results correlation were analyzed using the kappa index., Results: The 141 samples from LP and 141 samples from EVD were collected from 108 patients. Among the 282 samples, a total of 77 had infection. Seventy CSF samples from LP fulfilled infection criteria. However, only 32 EVD samples demonstrated infection. Among the 70 cases of infection based on the LP sample, 25 CSF samples collected from the EVD were also suggestive of infection; but in 45 patients only the CSF samples from LP met infection criteria. Seven patients had diagnosis of infection only in the EVD sample. The kappa correlation index of the results obtained from LP and EVD was 0.260 and the McNemar χ 2 test was <0.01., Conclusions: The CSF analysis exclusive from the EVD has a low sensibility and negative predictive value. CSF collected from LP has a sensibility 2.18 times higher than EVD., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Cerebrospinal fluid (CSF) testing is a key component for the diagnosis of central nervous system (CNS) infections. Current meningitis and encephalitis management guidelines agree on the need for CSF molecular testing in combination with other direct and indirect biological testing, both in CSF and blood. Multiplex molecular tests have been developed to reduce turnaround times and facilitate the diagnostic approach., Objectives: We aim to discuss the role of multiplex molecular panels in the management of CNS infections., Sources: The MEDLINE database and the grey literature have been searched for relevant articles., Content: New molecular multiplex panels are being developed to simultaneously detect a large array of neuropathogens in CSF. Although one of these assays has been US Food and Drug Administration-approved, extensive analytical and clinical validation is still missing, and suboptimal performance related issues have been raised. Its use has been associated with decreased costs, reduced length of hospital stay and reduced antiviral therapy administration in retrospective, industry-sponsored studies. The pros and cons of this multiplex syndromic approach are discussed in this narrative review., Implications: Molecular multiplex CNS infection diagnosis panels have been developed and present several attractive features, including ease of use and low turnaround time. However, suboptimal analytical performances render these tests difficult to use without additional confirmatory tests. Such panels are not comprehensive nor adapted to all situations, depending on the epidemiological or clinical context. Overall, available data in the literature currently do not support the use of a multiplex PCR panel in clinical routine as a 'stand-alone' molecular assay. Except in restricted laboratory capacity settings where such easy-to-use multiplex panels offer the diagnostic means that would otherwise not be available, the stepwise testing approach remains a more rational option. Serological testing both in blood and CSF should not be neglected, but it represents essential complementary tools regarding some neuropathogens., (Copyright © 2020 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Pentraxin 3 (PTX3) is an acute phase protein; its plasmatic levels significantly rise during severe infections. Data on PTX3 levels in cerebrospinal fluid (CSF) of patients with central nervous system (CNS) infections are lacking. We aimed (a) to assess the diagnostic potential of measuring CSF PTX3 levels in patients with CNS infections and (b) to establish CSF PTX3 cutoffs to distinguish between bacterial and aseptic meningoencephalitis (ROC curve). PTX3 levels were measured in CSF from 19 patients admitted to Trieste Hospital, Italy, with CNS infection. A diagnosis of bacterial infection and aseptic meningoencephalitis was made in 7 (37%) and 12 (63%) patients, respectively. Subjects with bacterial infections showed significantly higher PTX3 levels (13.5 vs 1.27 ng/mL in aseptic meningoencephalitis, p = 0.010). We identified two different CSF PTX3 levels cutoffs. (1) The best cutoff to maximise Youden's J was 9.6 ng/mL with a sensitivity, specificity, positive predictive value and negative predictive value (NPV) of 71.4%, 91.4%, 83.3%, 84.6%, respectively. (2) The cutoff with higher NPV (100%) was 3.6 ng/mL; a diagnosis of bacterial infections was obtained in 0% patients with CSF PTX3 levels < 3.6 ng/mL vs 58% of those with CSF PTX3 levels ≥ 3.6 ng/mL (p = 0.017). CSF PTX3 levels are higher in bacterial meningitis than aseptic meningoencephalitis. A cutoff of 3.6 ng/mL of CSF PTX3 has a high NPV and can be used to exclude bacterial CNS infections.

Purpose: We assessed the performance of metagenomic next-generation sequencing (mNGS) in the diagnosis of infectious encephalitis and meningitis. Methods: This was a prospective multicenter study. Cerebrospinal fluid samples from patients with viral encephalitis and/or meningitis, tuberculous meningitis, bacterial meningitis, fungal meningitis, and non-central nervous system (CNS) infections were subjected to mNGS. Results: In total, 213 patients with infectious and non-infectious CNS diseases were finally enrolled from November 2016 to May 2019; the mNGS-positive detection rate of definite CNS infections was 57.0%. At a species-specific read number (SSRN) ≥2, mNGS performance in the diagnosis of definite viral encephalitis and/or meningitis was optimal (area under the curve [AUC] = 0.659, 95% confidence interval [CI] = 0.566-0.751); the positivity rate was 42.6%. At a genus-specific read number ≥1, mNGS performance in the diagnosis of tuberculous meningitis (definite or probable) was optimal (AUC=0.619, 95% CI=0.516-0.721); the positivity rate was 27.3%. At SSRNs ≥5 or 10, the diagnostic performance was optimal for definite bacterial meningitis (AUC=0.846, 95% CI = 0.711-0.981); the sensitivity was 73.3%. The sensitivities of mNGS (at SSRN ≥2) in the diagnosis of cryptococcal meningitis and cerebral aspergillosis were 76.92 and 80%, respectively. Conclusion: mNGS of cerebrospinal fluid effectively identifies pathogens causing infectious CNS diseases. mNGS should be used in conjunction with conventional microbiological testing. Trial Registration: Chinese Clinical Trial Registry, ChiCTR1800020442., (Copyright © 2020 Xing, Zhang, Ma, He, Yao, Wang, Qi, Chen, Wu, Wang, Huang, Du, Wang, Wang, Yang and Yu.)

Central nervous system infection (CNSI) is a significant type of infection that plagues the fields of neurology and neurosurgical science. Prompt and accurate diagnosis of CNSI is a major challenge in clinical and laboratory assessments; however, developing new methods may help improve diagnostic protocols. This study evaluated the second-generation micro/nanofluidic chip platform (MNCP-II), which overcomes the difficulties of diagnosing bacterial and fungal infections in the CNS. The MNCP-II is simple to operate, and can identify 44 genus or species targets and 35 genetic resistance determinants in 50 minutes. To evaluate the diagnostic accuracy of the second-generation micro/nanofluidic chip platform for CNSI in a multicenter study. The limit of detection (LOD) using the second-generation micro/nanofluidic chip platform was first determined using six different microbial standards. A total of 180 bacterium/fungi-containing cerebrospinal fluid (CSF) cultures and 26 CSF samples collected from CNSI patients with negative microbial cultures were evaluated using the MNCP-II platform for the identification of microorganism and determinants of genetic resistance. The results were compared to those obtained with conventional identification and antimicrobial susceptibility testing methods. The LOD of the various microbes tested with the MNCP-II was found to be in the range of 250-500 copies of DNA. For the 180 CSF microbe-positive cultures, the concordance rate between the platform and the conventional identification method was 90.00%; eight species attained 100% consistency. In the detection of 9 kinds of antibiotic resistance genes, including carbapenemases, ESBLs, aminoglycoside, vancomycin-related genes, and mecA, concordance rates with the conventional antimicrobial susceptibility testing methods exceeded 80.00%. For carbapenemases and ESBLs-related genes, both the sensitivity and positive predictive values of the platform tests were high (>90.0%) and could fully meet the requirements of clinical diagnosis. MNCP-II is a very effective molecular detection platform that can assist in the diagnosis of CNSI and can significantly improve diagnostic efficiency.

Determining the etiological basis of central nervous system (CNS) infections is inherently challenging, primarily due to the multi-etiological nature. Using RNA sequencing, we aimed to identify microbes present in cerebrospinal fluid (CSF) of two patients suffering CNS infection, previously diagnosed with Cryptococcus sp. and Streptococcus pneumoniae infection, respectively. After meta-transcriptomic analysis, and confirmation with real-time PCR, hepatitis B virus (HBV) was detected in the CSF of two patients diagnosed with CNS syndrome. Phylogenetic analysis of the partial HBV genomes from these patients showed that they belonged to genotypes B and C and clustered with other viruses of Asian origin. In countries with high levels of HBV endemicity, the virus is likely to be found in patients diagnosed with CNS infections, although whether it contributes to symptoms and pathology, or is simply a coincidental infection, is unknown and merits further investigation., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to analyze the clinical and laboratory characteristics of children with peripheral facial nerve palsy (pFP) with a focus on identifying infectious etiology and long-term outcome. We conducted an ICD-10-based retrospective chart review on children hospitalized with pFP between January 1, 2006, and December 31, 2016. Furthermore, a telephone-based follow-up survey was performed. A total of 158 patients were identified, with a median age of 10.9 years (interquartile range 6.4-13.7). An infectious disease was associated with pFP in 82 patients (51.9%); 73 cases were classified as idiopathic pFP (46.2%). Three cases occurred postoperatively or due to a peripheral tumor. Among the infectious diseases, we identified 33 cases of neuroborreliosis and 12 viral infections of the central nervous system (CNS), caused by the varicella-zoster virus, human herpesvirus 6, herpes simplex virus, enterovirus, and Epstein-Barr virus. Other infections were mainly respiratory tract infections (RTIs; 37 cases). Children with an associated CNS infection had more often headache and nuchal rigidity, a higher cerebrospinal fluid cell count, and a longer length of hospital stay. Long-term follow-up revealed an associated lower risk of relapse in CNS infection-associated pFP. Among all groups, permanent sequelae were associated with female sex, a shorter length of hospitalization, and a lower white blood cell count at presentation. pFP is frequently caused by an CNS infection or is associated with concurrent RTIs, with a potential impact on the short- and long-term clinical course.