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

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

GeneXpert: A Rapid and Supplementary Diagnostic Tool for Tuberculous Meningitis, Experience from Tertiary Neurocenter.

Background Tuberculous meningitis (TBM) is a highly lethal form of central nervous system tuberculosis (CNS TB) that causes high mortality and morbidity in children and adults. Nonspecific clinical presentation and fewer TB bacilli challenge clinicians resulting in delays in diagnosis and treatment. Aim This study aimed to evaluate the utility of GeneXpert alone and in combination with culture using 1 mL of cerebrospinal fluid (CSF) in a volume constraint situation. Methods A total of 125 clinically confirmed TBM and 110 non-TBM cases, comprised of both infectious and noninfectious diseases. were included in the study. Patient details including clinical signs and symptoms, CSF, and imaging data were collected from the case records. CSF samples were obtained from all the patients and were tested by the mycobacterial culture method and GeneXpert test. The performance of both the tests was statistically calculated and reported in the form of sensitivity and specificity. Results Out of 125 TBM cases, 40 were detected positive by culture and 26 by GeneXpert. All 110 non-TBM cases were identified negative by both methods. The sensitivity and specificity of GeneXpert in comparison with culture were 27 and 100%, respectively. The culture was found to be more sensitive (32%) than GeneXpert. But the assay was able to detect a considerable number of clinically confirmed culture-negative TBM cases. Conclusion GeneXpert is a rapid test and including this as an adjunctive test along with the culture in routine clinical practice can improve the diagnosis of TBM in volume constraint scenario.

Decision-making in the diagnosis of tuberculous meningitis.

Tuberculous meningitis (TBM) is the most devastating form of tuberculosis (TB) but diagnosis is difficult and delays in initiating therapy increase mortality. All currently available tests are imperfect; culture of Mycobacterium tuberculosis from the cerebrospinal fluid (CSF) is considered the most accurate test but is often negative, even when disease is present, and takes too long to be useful for immediate decision making. Rapid tests that are frequently used are conventional Ziehl-Neelsen staining and nucleic acid amplification tests such as Xpert MTB/RIF and Xpert MTB/RIF Ultra. While positive results will often confirm the diagnosis, negative tests frequently provide insufficient evidence to withhold therapy. The conventional diagnostic approach is to determine the probability of TBM using experience and intuition, based on prevalence of TB, history, examination, analysis of basic blood and CSF parameters, imaging, and rapid test results. Treatment decisions may therefore be both variable and inaccurate, depend on the experience of the clinician, and requests for tests may be inappropriate. In this article we discuss the use of Bayes' theorem and the threshold model of decision making as ways to improve testing and treatment decisions in TBM. Bayes' theorem describes the process of converting the pre-test probability of disease to the post-test probability based on test results and the threshold model guides clinicians to make rational test and treatment decisions. We discuss the advantages and limitations of using these methods and suggest that new diagnostic strategies should ultimately be tested in randomised trials.

Production of a latex agglutination reagent for the rapid diagnosis of cryptococcal meningitis / Producción de un reactivo de látex para el diagnóstico rápido de criptococosismeníngea

Abstract Cryptococcosis is a fungal disease affecting more than one million people per yearworldwide. Its main etiological agents are Cryptococcus neoformans species complex and Cryp-tococcus gattii species complex. Cryptococcal meningitis (CM) is considered an AIDS-definingcondition. Rapid diagnosis by cryptococcal antigen assays, either the latex agglutination test(LA) or the lateral flow assay, is key to decreasing mortality due to cryptococcal disease. Theaim of the study was to develop a latex agglutination reagent (LA-ANLIS) for the rapid and reliable diagnosis of cryptococcosis in Argentina. This reagent will be produced in order to supplythe NMLN (National Mycology Laboratory Network). The evaluation of LA-ANLIS performanceand its comparison with the Cryptococcus Antigen Latex Agglutination Test System (LA-IMMY)(Immuno-Mycologics, Inc., USA) were conducted in 94 samples of cerebrospinal fluid. LA-ANLISand LA-IMMY compared exhibited 100% positive agreement and 97% negative agreement. LA-ANLIS showed 94% sensitivity and 97% specificity with the positive and negative predictivevalues of 94% and 97%, respectively. The LA-ANLIS is a reliable, reproducible and cost-effectivereagent, especially useful in countries where the commercial kit is not generally available andmust be obtained at a high cost. National production of reagents is the best choice for a reliableaccess to the rapid diagnosis of CM in Argentina.

Resumen La criptococosis es una enfermedad fúngica que afecta a más de un millón de personas por año en todo el mundo. Los principales agentes etiológicos pertenecen a los complejos de especies Cryptococcus neoformans y Cryptococcus gattii. La criptococosis meníngea (CM) se considera una enfermedad marcadora de sida. El diagnóstico rápido de esta enfermedad a través de la detección del antígeno de Cryptococcus, ya sea por aglutinación en partículas de látex o por inmunocromatografía, es clave para disminuir la mortalidad. El objetivo del presente estudio fue desarrollar un reactivo de aglutinación en partículas de látex para el diagnóstico rápido y certero de la CM en Argentina. Este reactivo (denominado en adelante LA-ANLIS) será producido para abastecer a la Red Nacional de Laboratorios de Micología. Se evaluó el desempeno del reactivo LA-ANLIS, y se realizó una comparación con el reactivo comercial Immuno-Mycologics, Inc. (en adelante, LA-IMMY) utilizando 94 muestras de líquido cefalorraquídeo. Hubo un 100% de acuerdo positivo y un 97% de acuerdo negativo entre los resultados obtenidos con los reactivos LA-ANLIS y LA-IMMY. El reactivo LA-ANLIS mostró una sensibilidad del 94% y una especificidad del 97%; los valores predictivos positivo y negativo fueron del 94 y del 97%, respectivamente. Se concluye que el LA-ANLIS es un reactivo confiable y rentable, que arroja resultados reproducibles, por lo que es especialmente útil en países donde los reactivos comerciales generalmente no están disponibles o sus costos son elevados. La producción nacional de reactivos es la mejor opción para asegurar el acceso de todos los hospitales al diagnóstico rápido de la CM en Argentina.

Production of a latex agglutination reagent for the rapid diagnosis of cryptococcal meningitis.

Cryptococcosis is a fungal disease affecting more than one million people per year worldwide. Its main etiological agents are Cryptococcus neoformans species complex and Cryptococcus gattii species complex. Cryptococcal meningitis (CM) is considered an AIDS-defining condition. Rapid diagnosis by cryptococcal antigen assays, either the latex agglutination test (LA) or the lateral flow assay, is key to decreasing mortality due to cryptococcal disease. The aim of the study was to develop a latex agglutination reagent (LA-ANLIS) for the rapid and reliable diagnosis of cryptococcosis in Argentina. This reagent will be produced in order to supply the NMLN (National Mycology Laboratory Network). The evaluation of LA-ANLIS performance and its comparison with the Cryptococcus Antigen Latex Agglutination Test System (LA-IMMY) (Immuno-Mycologics, Inc., USA) were conducted in 94 samples of cerebrospinal fluid. LA-ANLIS and LA-IMMY compared exhibited 100% positive agreement and 97% negative agreement. LA-ANLIS showed 94% sensitivity and 97% specificity with the positive and negative predictive values of 94% and 97%, respectively. The LA-ANLIS is a reliable, reproducible and cost-effective reagent, especially useful in countries where the commercial kit is not generally available and must be obtained at a high cost. National production of reagents is the best choice for a reliable access to the rapid diagnosis of CM in Argentina.

Cerebrospinal Fluid Lactate as a Prognostic Indicator in Postneurosurgical Bacterial Meningitis and Use of Intrathecal Colistin.

Postneurosurgical bacterial meningitis (PNBM) is an emergency and requires early diagnosis and treatment with appropriate antibiotics. The cornerstone of diagnosis is microbiological analysis of the cerebrospinal fluid (CSF) cytochemical characteristics such as leucocyte count, CSF glucose, and protein concentration and CSF: Serum glucose ratio. However, this is often misleading in PNBM. The role of CSF lactate assay for diagnosis and prognosis has been debated. This case report looks into the serial measurement of CSF lactates in PNBM. It also looks into the role of intrathecal colistin. CSF lactate showed a steady decrease corresponding to improvement in clinical condition. Hence, CSF lactate could have a better prognostic value than other conventional markers in PNBM. Intrathecal colistin, in conjunction with the standard antibiotics, can contribute to a quick resolution of the condition.

A Statistical Classifier to Support Diagnose Meningitis in Less Developed Areas of Brazil.

This paper describes the development of statistical classifiers to help diagnose meningococcal meningitis, i.e. the most sever, infectious and deadliest type of this disease. The goal is to find a mechanism able to determine whether a patient has this type of meningitis from a set of symptoms that can be directly observed in the earliest stages of this pathology. Currently, in Brazil, a country that is heavily affected by meningitis, all suspected cases require immediate hospitalization and the beginning of a treatment with invasive tests and medicines. This procedure, therefore, entails expensive treatments unaffordable in less developed regions. For this purpose, we have gathered together a dataset of 22,602 records of suspected meningitis cases from the Brazilian state of Bahia. Seven classification techniques have been applied from input data of nine symptoms and other information about the patient such as age, sex and the area they live in, and a 10 cross-fold validation has been performed. Results show that the techniques applied are suitable for diagnosing the meningococcal meningitis. Several indexes, such as precision, recall or ROC area, have been computed to show the accuracy of the models. All of them provide good results, but the best corresponds to the J48 classifier with a precision of 0.942 and a ROC area over 0.95. These results indicate that our model can indeed help lead to a non-invasive and early diagnosis of this pathology. This is especially useful in less developed areas, where the epidemiologic risk is usually high and medical expenses, sometimes, unaffordable.

Comparison of enterovirus detection in cerebrospinal fluid with Bacterial Meningitis Score in children / Comparação da pesquisa de enterovírus no liquor com Escore de Meningite Bacteriana em crianças

ABSTRACT Objective To measure the role of enterovirus detection in cerebrospinal fluid compared with the Bacterial Meningitis Score in children with meningitis. Methods A retrospective cohort based on analysis of medical records of pediatric patients diagnosed as meningitis, seen at a private and tertiary hospital in São Paulo, Brazil, between 2011 and 2014. Excluded were patients with critical illness, purpura, ventricular shunt or recent neurosurgery, immunosuppression, concomitant bacterial infection requiring parenteral antibiotic therapy, and those who received antibiotics 72 hours before lumbar puncture. Results The study included 503 patients. Sixty-four patients were excluded and 94 were not submitted to all tests for analysis. Of the remaining 345 patients, 7 were in the Bacterial Meningitis Group and 338 in the Aseptic Meningitis Group. There was no statistical difference between the groups. In the Bacterial Meningitis Score analysis, of the 338 patients with possible aseptic meningitis (negative cultures), 121 of them had one or more points in the Bacterial Meningitis Score, with sensitivity of 100%, specificity of 64.2%, and negative predictive value of 100%. Of the 121 patients with positive Bacterial Meningitis Score, 71% (86 patients) had a positive enterovirus detection in cerebrospinal fluid. Conclusion Enterovirus detection in cerebrospinal fluid was effective to differentiate bacterial from viral meningitis. When the test was analyzed together with the Bacterial Meningitis Score, specificity was higher when compared to Bacterial Meningitis Score alone.

RESUMO Objetivo Avaliar o papel da pesquisa de enterovírus no líquido cefalorraquidiano em comparação com o Escore de Meningite Bacteriana em crianças com meningite. Métodos Coorte retrospectiva, realizada pela análise de prontuários, incluindo pacientes pediátricos, com diagnóstico de meningite e atendidos em um hospital privado e terciário, localizado em São Paulo, entre 2011 e 2014. Foram excluídos os pacientes com doença crítica, púrpura, derivação ventricular ou neurocirurgia recente, imunossupressão, outra infecção bacteriana concomitante que necessitasse de antibioticoterapia parenteral e aqueles que receberam antibiótico 72 horas antes da punção lombar. Resultados Foram incluídos no estudo 503 pacientes. Destes, 64 foram excluídos e 94 não realizaram todos os exames para análise. Dos 345 pacientes restantes, 7 ficaram no Grupo de Meningite Bacteriana e 338 no Grupo de Meningite Asséptica. Não houve diferença estatística entre os grupos. Na análise do Escore de Meningite Bacteriana, dos 338 pacientes com possível meningite asséptica (culturas negativas), 121 deles tiveram um ou mais pontos para o Escore de Meningite Bacteriana, com valor de sensibilidade de 100%, especificidade de 64,2% e valor preditivo negativo de 100%. Dos 121 pacientes com Escore de Meningite Bacteriana positivo, 71% (86 pacientes) tiveram a pesquisa de enterovírus positiva no líquido cefalorraquidiano. Conclusão A pesquisa de enterovírus no líquido cefalorraquidiano mostrou-se eficaz em diferenciar a meningite bacteriana da viral. Analisada junto com o Escore de Meningite Bacteriana, a especificidade foi maior em comparação ao Escore de Meningite Bacteriana isolado.

Multiplexed instrument-free meningitis diagnosis on a polymer/paper hybrid microfluidic biochip.

Neisseria meningitidis (N. meningitidis), Streptococcus pneumoniae (S. pneumoniae), and Haemophilus influenzae type b (Hib) are three most common pathogens accounting for most bacterial meningitis, a serious global infectious disease with high fatality, especially in developing nations. Because the treatment and antibiotics differ among each type, the identification of the exact bacteria causing the disease is vital. Herein, we report a polymer/paper hybrid microfluidic biochip integrated with loop-mediated isothermal amplification (LAMP) for multiplexed instrument-free diagnosis of these three major types of bacterial meningitis, with high sensitivity and specificity. Results can be visually observed by the naked eye or imaged by a smartphone camera under a portable UV light source. Without using any specialized laboratory instrument, the limits of detection of a few DNA copies per LAMP zone for N. meningitidis, S. pneumoniae and Hib were achieved within 1h. In addition, these three types of microorganisms spiked in artificial cerebrospinal fluid (ACSF) were directly detected simultaneously, avoiding cumbersome sample preparation procedures in conventional methods. Compared with the paper-free non-hybrid microfluidic biochip over a period of three months, the hybrid microfluidic biochip was found to have a much longer shelf life. Hence, this rapid, instrument-free and highly sensitive microfluidic approach has great potential for point-of-care (POC) diagnosis of multiple infectious diseases simultaneously, especially in resource-limited settings.

Some techniques of detection of type B Haemophilus influenza in the diagnosis of meningitis due to type B H. influenza

Some techniques of detection of Hib were compared, including classic techniques such as bacterial culture and modern techniques such as PCR method. The results were as follows: 21% (+) culture with Hib compared to the total of clinically diagnosed cases, Hib-latex agglutination with 95% sensitivity and 99.6% specificity, counter immunophoresis assay to detect Hib by 97% sensitivity and 100% specificity. PCR increased the number of positive cases of Hib meningitis by 42.8% compared to culture alone. Blood culture gave a highly significant value to diagnose (51% Hib-possitive culture)