Diagnostic performance of a multiplex PCR assay for meningitis in an HIV-infected population in Uganda

Fungal positivity and other laboratory parameters in HIV- and non-HIV-related cryptococcal meningitis patients upon antifungal treatment

The association between fungal positivity in cerebral spinal fluid (CSF) and other laboratory parameters in cryptococcal meningitis (CM) with or without HIV infection is unclear. India ink staining and culture were used to detect the Cryptococcus in the CSF during the treatment course. Hematology analysis and chemistry analysis of CSF were also performed. Flow cytometry was used to analyze the T lymphocyte subsets in the blood. The positivity of the culture reduced significantly faster than that of the ink staining in both HIV and non-HIV patients between treatment time points. The total protein in the CSF of the HIV-related patients was significantly lower than in the non-HIV-related patients at all time points of treatment (p = 0.009, 0.012, 0.001, and 0.037, respectively). The lactate dehydrogenase (LDH) in the CSF of the HIV-related patients at admission was significantly lower than in the non-HIV-related patients (p = 0.017). There were significant differences in glucose and LDH levels between different time points of treatment (p = 0.000 and 0.016, respectively) in the non-HIV-related patients. For Cryptococcus detection in CSF, the culture method appeared to be more sensitive and reliable than the ink staining method. HIV-related CM patients showed certain hematologic and CSF chemistry features which may help guide the management of patients.

Cryptococcal meningoencephalitis in a patient on immunomodulatory drug: A case report

BACKGROUND

Cryptococcus neoformans is an important fungal pathogen causing pneumonia and central nervous system infections mainly in immunocompromised hosts. Fingolimod is an immunomodulatory drug approved in the US and Europe for the treatment of multiple sclerosis.

CASE PRESENTATION

We herein report a case of cryptococcal meningoencephalitis in a 46-year-old male with a history of fingolimod for five years. He suffered from a progressive headache and visual impairment. These symptoms led to a suspicion of a central nervous system infection and C. neoformans was identified with nucleic acid-based PCR method. Subsequently, appropriate treatment was initiated, and the patient recovered.

CONCLUSIONS

Our case underlines the importance of active diagnostic measures such as cerebrospinal fluid analysis in patients under fingolimod treatment with central nervous symptoms. While multiple sclerosis may cause headache and vision impairment, similar symptoms may be caused by central nervous system infections. It has been suggested that fingolimod may subject one to infections and this may occur even years after initiation of the treatment. For our case patient Cerebrospinal fluid sample combined with PCR-based identification provided a rapid diagnosis.

Polymerase chain reaction negative cryptococcal meningitis

A 61-year-old male with subacute headache was found to have cryptococcal meningitis despite a negative BioFire FilmArray meningitis/encephalitis panel. This case underscores the importance of liberal cryptococcal antigen testing, and that a negative FilmArray panel is inadequate in excluding cryptococcal meningitis, particularly in a HIV-negative host.

HIV-associated disseminated cryptococcosis-An unusual clinical and diagnostic picture with successful cure by single dose liposomal amphotericin B treatment

BACKGROUND

Cryptococcosis is an invasive, opportunistic fungal infection seen especially in human immunodeficiency virus (HIV) infected patients. Cryptococcal meningitis (CM) is the second leading cause of mortality in HIV patients. We report a case of disseminated cryptococcosis presenting with altered mental status in a newly diagnosed HIV infection.

METHODS AND RESULTS

A 50-year-old with a short history of altered mental sensorium and a history of low-grade fever and weight loss for few months presented at a tertiary care hospital in North India. He was detected positive for HIV-1. Cryptococcal antigen (CRAG) was positive in Cerebrospinal fluid (CSF), and negative in serum. The fungal culture in CSF was sterile while the fungal blood culture grew Cryptococcus neoformans. The patient was treated with single high-dose Liposomal Amphotericin B (LAmB) therapy followed by Fluconazole and Flucytosine for the next two weeks followed by fluconazole daily for consolidation and maintenance therapy. Antiretroviral therapy (ART) was started 4 weeks after induction therapy. After 6 months, the patient is doing fine.

CONCLUSION

Single dose LAmB along with the backbone of fluconazole and flucytosine appears promising in disseminated cryptococcal infection in HIV-infected individuals.

Complex Decisions in HIV-Related Cryptococcosis: Addressing Second Episodes of Cryptococcal Meningitis

PURPOSE OF REVIEW

This review highlights the difficulties in diagnosing and treating persons with a prior history of cryptococcal meningitis who improve but suffer from a recurrence of symptoms. This scenario is well known to those who frequently care for patients with cryptococcal meningitis but is not well understood. We highlight major gaps in knowledge.

RECENT FINDINGS

We recently summarized our experience with 28 persons with paradoxical immune reconstitution inflammatory syndrome (IRIS) and 81 persons with microbiological relapse. CD4 count and cerebrospinal fluid white blood cell count were higher in IRIS than relapse but neither was reliable enough to routinely differentiate these conditions. Second-episode cryptococcal meningitis remains a difficult clinical scenario as cryptococcal antigen, while excellent for initial diagnosis has no value in differentiating relapse of infection from other causes of recurrent symptoms. Updated research definitions are proposed and rapid, accurate diagnostic tests are urgently needed.

The diagnosis of central nervous system infections in resource-limited settings and the use of novel and molecular diagnostic platforms to improve diagnosis

INTRODUCTION

Central nervous system infections (CNSI) disproportionately affect individuals in low-resource settings where diagnosis is challenging; large proportions of patients never receive a confirmed microbiological diagnosis resulting in inadequate management and high mortality. The epidemiology of CNSI varies globally and conventional diagnostics deployed in resource-limited settings have significant limitations, with an urgent need for improved diagnostic strategies.

AREAS COVERED

This review describes molecular platforms and other novel diagnostics used in the diagnosis of CNSI that are applicable to resource-limited settings. An extensive literature search of Medline and PubMed was performed. The emphasis is on investigations targeting infections of relevance to resource-limited settings either due to variation in regional CNSI epidemiology or due to increased prevalence in patients with immunosuppression. This includes commercially available multiplex PCR platforms, mycobacterial PCR platforms, and rapid diagnostics tests. To offer a framework for the optimal implementation in clinical settings, existing evidence highlighting the advantages and limitations of available platforms is reviewed.

EXPERT OPINION

The implementation of molecular platforms and other novel diagnostics has the potential to transform CNSI diagnosis in resource-limited settings, with several examples of successful rollout of novel diagnostics such as Xpert MTB/RIF Ultra and cryptococcal antigen testing.

Diagnosis and management of cryptococcal meningitis in HIV-infected adults

Cryptococcal meningitis is a leading cause of morbidity and mortality globally, especially in people with advanced HIV disease. Cryptococcal meningitis is responsible for nearly 20% of all deaths related to advanced HIV disease, with the burden of disease predominantly experienced by people in resource-limited countries. Major advancements in diagnostics have introduced low-cost, easy-to-use antigen tests with remarkably high sensitivity and specificity. These tests have led to improved diagnostic accuracy and are essential for screening campaigns to reduce the burden of cryptococcosis. In the last 5 years, several high-quality, multisite clinical trials have led to innovations in therapeutics that have allowed for simplified regimens, which are better tolerated and result in less intensive monitoring and management of medication adverse effects. One trial found that a shorter, 7-day course of deoxycholate amphotericin B is as effective as the longer 14-day course and that flucytosine is an essential partner drug for reducing mortality in the acute phase of disease. Single-dose liposomal amphotericin B has also been found to be as effective as a 7-day course of deoxycholate amphotericin B. These findings have allowed for simpler and safer treatment regimens that also reduce the burden on the healthcare system. This review provides a detailed discussion of the latest evidence guiding the clinical management and special circumstances that make cryptococcal meningitis uniquely difficult to treat.

Cryptococcal meningitis

Cryptococcus neoformans and Cryptococcus gattii species complexes cause meningoencephalitis with high fatality rates and considerable morbidity, particularly in persons with deficient T cell-mediated immunity, most commonly affecting people living with HIV. Whereas the global incidence of HIV-associated cryptococcal meningitis (HIV-CM) has decreased over the past decade, cryptococcosis still accounts for one in five AIDS-related deaths globally due to the persistent burden of advanced HIV disease. Moreover, mortality remains high (~50%) in low-resource settings. The armamentarium to decrease cryptococcosis-associated mortality is expanding: cryptococcal antigen screening in the serum and pre-emptive azole therapy for cryptococcal antigenaemia are well established, whereas enhanced pre-emptive combination treatment regimens to improve survival of persons with cryptococcal antigenaemia are in clinical trials. Short courses (≤7 days) of amphotericin-based therapy combined with flucytosine are currently the preferred options for induction therapy of cryptococcal meningitis. Whether short-course induction regimens improve long-term morbidity such as depression, reduced neurocognitive performance and physical disability among survivors is the subject of further study. Here, we discuss underlying immunology, changing epidemiology, and updates on the management of cryptococcal meningitis with emphasis on HIV-associated disease.

Advanced HIV disease: A review of diagnostic and prophylactic strategies

BACKGROUND

Despite expanded access to antiretroviral therapy (ART) and the rollout of the World Health Organization's (WHO) 'test-and-treat' strategy, the proportion of people with HIV (PWH) presenting with advanced HIV disease (AHD) remains unchanged at approximately 30%. Fifty percent of persons with AHD report prior engagement to care. ART failure and insufficient retention in HIV care are major causes of AHD. People living with AHD are at high risk for opportunistic infections and death. In 2017, the WHO published guidelines for the management of AHD that included a comprehensive package of care for screening and prophylaxis of major opportunistic infections (OIs). In the interim, ART regimens have evolved: integrase inhibitors are first-line therapy globally, and the diagnostic landscape is evolving. The objective of this review is to highlight novel point-of-care (POC) diagnostics and treatment strategies that can facilitate OI screening and prophylaxis for persons with AHD.

METHODS

We reviewed the WHO guidelines for recommendations for persons with AHD. We summarized the scientific literature on current and emerging diagnostics, along with emerging treatment strategies for persons with AHD. We also highlight the key research and implementation gaps together with potential solutions.

RESULTS

While POC CD4 testing is being rolled out in order to identify persons with AHD, this alone is insufficient; implementation of the Visitect CD4 platform has been challenging given operational and test interpretation issues. Numerous non-sputum POC TB diagnostics are being evaluated, many with limited sensitivity. Though imperfect, these tests are designed to provide rapid results (within hours) and are relatively affordable for resource-poor settings. While novel POC diagnostics are being developed for cryptococcal infection, histoplasmosis and talaromycosis, implementation science studies are urgently needed to understand the clinical benefit of these tests in the routine care.

CONCLUSIONS

Despite progress with HIV treatment and prevention, a persistent 20%-30% of PWH present to care with AHD. Unfortunately, these persons with AHD continue to carry the burden of HIV-related morbidity and mortality. Investment in the development of additional POC or near-bedside CD4 platforms is urgently needed. Implementation of POC diagnostics theoretically could improve HIV retention in care and thereby reduce mortality by overcoming delays in laboratory testing and providing patients and healthcare workers with timely same-day results. However, in real-world scenarios, people with AHD have multiple comorbidities and imperfect follow-up. Pragmatic clinical trials are needed to understand whether these POC diagnostics can facilitate timely diagnosis and treatment, thereby improving clinical outcomes such as HIV retention in care.

Recurrence of Symptoms Following Cryptococcal Meningitis: Characterizing a Diagnostic Conundrum With Multiple Etiologies

BACKGROUND

Cryptococcal meningitis is a common cause of AIDS-related mortality. Although symptom recurrence after initial treatment is common, the etiology is often difficult to decipher. We sought to summarize characteristics, etiologies, and outcomes among persons with second-episode symptomatic recurrence.

METHODS

We prospectively enrolled Ugandans with cryptococcal meningitis and obtained patient characteristics, antiretroviral therapy (ART) and cryptococcosis histories, clinical outcomes, and cerebrospinal fluid (CSF) analysis results. We independently adjudicated cases of second-episode meningitis to categorize patients as (1) microbiological relapse, (2) paradoxical immune reconstitution inflammatory syndrome (IRIS), (3) persistent elevated intracranial pressure (ICP) only, or (4) persistent symptoms only, along with controls of primary cryptococcal meningitis. We compared groups with chi-square or Kruskal-Wallis tests as appropriate.

RESULTS

724 participants were included (n = 607 primary episode, 81 relapse, 28 paradoxical IRIS, 2 persistently elevated ICP, 6 persistent symptoms). Participants with culture-positive relapse had lower CD4 (25 cells/μL; IQR: 9-76) and lower CSF white blood cell (WBC; 4 cells/μL; IQR: 4-85) counts than paradoxical IRIS (CD4: 78 cells/μL; IQR: 47-142; WBC: 45 cells/μL; IQR: 8-128). Among those with CSF WBC <5 cells/μL, 86% (43/50) had relapse. Among those with CD4 counts <50 cells/μL, 91% (39/43) had relapse. Eighteen-week mortality (from current symptom onset) was 47% among first episodes of cryptococcal meningitis, 31% in culture-positive relapses, and 14% in paradoxical IRIS.

CONCLUSIONS

Poor immune reconstitution was noted more often in relapse than IRIS as evidenced by lower CSF WBC and blood CD4 counts. These easily obtained laboratory values should prompt initiation of antifungal treatment while awaiting culture results.

CLINICAL TRIALS REGISTRATION

NCT01802385.

Human Herpesvirus-6 Detection in Cerebrospinal Fluid on the BioFire FilmArray Meningitis/Encephalitis Panel in a High HIV-prevalence African Setting

The prevalence and clinical relevance of human herpesvirus-6 (HHV-6) detection in cerebrospinal fluid (CSF) using multiplex polymerase chain reaction (PCR) testing in patients with suspected meningoencephalitis in high human immunodeficiency virus-prevalence African settings are not known. We describe the clinical and laboratory characteristics of 13 patients with HHV-6 CSF PCR positivity in Botswana.

Performance of Metagenomic Next-Generation Sequencing for the Diagnosis of Cryptococcal Meningitis in HIV-Negative Patients

Objectives

Metagenomic next-generation sequencing (mNGS) has been applied more and more widely for the diagnosis of infectious diseases, but its performance in the diagnosis of cryptococcal meningitis (CM) remains unclear.

Methods

Cerebrospinal fluid (CSF) samples from 197 HIV-negative patients with suspected central nervous system infections were tested simultaneously by mNGS and routine methods [India ink staining, fungal culture, or cryptococcal antigen (CrAg) tests]. The performance of mNGS was evaluated.

Results

Of the 197 enrolled cases, 46 (23.4%) cases were finally diagnosed with CM, including 43 (93.5%) Cryptococcus neoformans infections and 3 (6.5%) Cryptococcus gattii infections. The sensitivity, specificity, positive predictive value, negative predictive value, and concordance rate of mNGS were 93.5% [95% confidence interval (CI) at 86.4%~100.0%], 96.0% (95% CI at 92.9%~99.1%), 87.8%, 98.0%, and 95.4%, respectively. Comparing to the conventional diagnostic methods, the sensitivity and concordance rate of mNGS were slightly lower than those of CrAg tests (97.4%) but higher than those of India ink (63.0%) and culture (76.7%). Besides, mNGS had a sensitivity of 100.0% against culture. It should be noted that mNGS could identify Cryptococcus at species level; C. gattii of the 3 cases was only distinguished by mNGS.

Conclusions

CSF mNGS can be considered as a supplementary test to diagnose CM and directly distinguish C. gattii from C. neoformans in clinical specimens.

Molecular diagnosis of the central nervous system (CNS) infections

Central nervous system (CNS) infections such as meningitis and encephalitis are medical emergencies that require rapid diagnosis of the causative pathogen to guide early and adequate treatment since a delay in implementing an adequate antimicrobial therapy can lead to death. The current microbiological diagnostic methods based on culture or antigen detection have important limitations in their capacity to accurately identify the different potential pathogens causing CNS and, in the time, to obtaining results. Rapid syndromic molecular arrays have been developed. The main advantage of using a meningoencephalitis panel based in a multiplex test is that includes bacteria, viruses and fungi, covering the most prevalent microorganisms causing meningitis and encephalitis and the turn-around time is circa 1h. The use of these multiplex-PCR based tools is reviewed and the advantages and disadvantages of this technique are discussed.

Evaluation of the BioFire® FilmArray® Meningitis/Encephalitis panel in an adult and pediatric Ugandan population

BACKGROUND

Meningitis causes significant mortality in sub-Saharan Africa and limited diagnostics exist. We evaluated the utility of the BioFire® FilmArray® Meningitis/Encephalitis multiplex PCR panel (BioFire ME) in HIV-infected adults and HIV-infected and uninfected children presenting with suspected meningitis in Uganda.

METHODS

We tested cerebrospinal fluid (CSF) using a stepwise meningitis diagnostic algorithm including BioFire ME. We determined the diagnostic performance of BioFire ME for cryptococcal meningitis, using cryptococcal antigen (CrAg) and CSF culture as reference standards, and assessed other central nervous system (CNS) pathogens identified by the panel.

RESULTS

We evaluated 328 adult and 42 pediatric CSF specimens using BioFire ME. Of the adult CSF samples tested, 258 were obtained at baseline, and 70 were obtained from repeat lumbar punctures in cryptococcal meningitis. For Cryptococcus, sensitivity was 82%, specificity was 98%, PPV was 98%, and NPV was 79% in baseline specimens using CSF CrAg as the reference standard. Among follow-up specimens, a negative BioFire ME for Cryptococcus predicted CSF culture sterility with 84% NPV. Overall sensitivity was decreased at low fungal burdens: 29% for 0-99 Cryptococcus CFU/mL compared to 94% for ≥100 CFU/mL in baseline specimens. Other pathogens detected included E. Coli, H. influenzae, S. pneumoniae, CMV, enterovirus, HSV, HHV-6, and VZV. Two specimens tested positive for S. pneumoniae and one for Cryptococcus in the pediatric population.

CONCLUSIONS

Multiplex PCR is a promising rapid diagnostic test for meningitis in adults and children in resource-limited settings. Cryptococcus at low fungal burdens in CSF may be missed by BioFire ME.

Early diagnosis of Cryptococcus neoformans var. grubii meningitis using multiplex PCR assay in an immunocompetent patient

Cryptococcosis is an invasive fungal infection that mainly affects the lungs and central nervous system. While patients with cell-mediated immunodeficiency are at high risk of developing cryptococcosis, there have been increasing reports of cryptococcosis in immunocompetent individuals with no underlying conditions. Herein, we report a case of cryptococcal meningitis in a 55-year-old apparently immunocompetent man with a history of heavy alcohol consumption. Although the patient was initially treated for tuberculous meningitis and varicella-zoster virus induced vasculopathy due to a history of exposure to tuberculosis and a presence of stroke, a multiplex polymerase chain reaction (PCR) assay of cerebrospinal fluid (CSF) identified Cryptococcus species unexpectedly, enabling swift treatment and a favorable clinical outcome. The multiplex PCR assay, which can identify multiple pathogens simultaneously and instantly, may lead to early diagnosis and treatment by detecting unanticipated pathogens. Furthermore, the strain was identified through multilocus sequence typing (MLST) analysis as Cryptococcus neoformans var. grubii, Sequence Type 5, molecular type: VNI. Although simplified microbial identification techniques such as mass spectrometry have recently been developed, molecular biological assays are still essential for the accurate identification of infectious strains.

Cryptococcus meningitis presented with multiple cerebral infarcts in an immunocompetent patient

Cryptococcus neoformans is generally observed with immunosuppressive conditions. Rarely, it may be seen in immunocompetent individuals and presented with non-specific conditions. We described an immunocompetent case of cryptococcal meningitis presented with multiple cerebral infarcts. Despite the late diagnosis and emergence of hydrocephalus during treatment, the patient was recovered without any sequelae. In immunocompetent patients, the conventional diagnostics tests may be negative because of the low fungal load. If it is available, the Biofire FilmArray meningitis panel has high sensitivity and specificity for diagnosis.

Diagnostic value of real-time PCR of brain mass lesion in HIV-associated toxoplasmic encephalitis: a case series

BACKGROUND

Toxoplasmic encephalitis (TE) is a leading cause of brain mass lesions (BML) in human immunodeficiency viruses (HIV)-infected patients. Yet, so far, no accurate diagnostic approach for TE has been developed. Herein, we presented a case series (9 HIV-infected patients with TG confirmed by RT-PCR of BML) to assess the diagnostic value of reverse transcription-polymerase chain reaction (RT-PCR) on TE.

METHODS

A total of 9 HIV-infected patients with TE confirmed by RT-PCR of BML were included in this study. Clinical data, including clinical symptoms, blood and CSF analysis, neuroimaging features, histopathological characteristics, treatment, and prognosis, were assessed in all patients. According to the results of RT-PCR of BML, all the patients received oral administration of trimethoprim-sulfamethoxazole combined with antiretroviral therapy (ART). Patients were followed up by telephone or outpatient service.

RESULTS

There were 8 male and 1 female patients; their age ranged from 26 to 56 years-old. The main symptom was intracranial hypertension (6/9). Six patients presented multiple brain lesions, which were mainly located in the supratentorial area (7/9). CD₄⁺ count ranged from 11 to 159 cells/μl (median 92 cells/μl), and serological HIV viral load 0-989190 copies/ml (median 192836 copies/ml). IgG and IgM against serum TG were positive in 7 and 1 patients, respectively. Moreover, regarding CSF, IgG against TG was positive in 3 patients, while all patients were negative for IgM. The neuroimaging features on MRI showed no specificity. Four patients were diagnosed with TE by histopathological findings. After receiving anti-Toxoplasma therapy, 8 (8/9) patients improved clinically to a considerable extent.

CONCLUSIONS

The application of RT-PCR of BML, together with conventional methods, may significantly improve the diagnostic efficiency of TE.

False negative diagnostic errors with polymerase chain reaction for the detection of cryptococcal meningoencephalitis

The accuracy of the BioFire FilmArray Meningitis/Encephalitis (ME) panel for the identification of Cryptococcus has recently been called into question. The primary objective of this study was to assess the agreement between the BioFire ME polymerase chain reaction (PCR) and other markers of cryptococcal infection. This retrospective review identified five patients with cryptococcal meningoencephalitis, 4 of whom had a negative ME panel for Cryptococcus. All five cases had positive serum cryptococcal antigens, and three of five had a positive cerebrospinal fluid (CSF) culture for Cryptococcus. The BioFire ME panel does not appear to be reliable for ruling out Cryptococcus meningoencephalitis; multiple testing methods are recommended.

Molecular diagnosis of meningitis and meningoencephalitis with an automated real-time multiplex polymerase chain reaction in a tertiary reference complex in Medellín, Colombia

Meningoencephalitis is a syndrome of multiple etiologies associated with important morbidity and mortality. It may be caused by various infectious agents (viruses, bacteria, parasites and fungi). Establishing the etiology of meningoencephalitis is crucial for early and specific treatment. Molecular assays such as the multiplex polymerase chain reaction (PCR) offer an alternative in diagnosing central nervous system infections. This study aimed to describe the performance of an automated multiplex molecular test from patients with suspected meningitis and meningoencephalitis in a tertiary referral complex in Medellin, Colombia. Thus, a prospective study was performed in 638 cerebrospinal fluid samples from January 2017 to July 2019. Molecular detections were carried out by means of the FilmArray^® Meningitis/Encephalitis (M/E) Panel from bioMérieux, France, and by conventional tests. Univariate analyses for microbiological and demographic characteristics were performed. Accuracy of the bacterial/fungal PCR assay compared to cultures was also performed. Among patients, 57.7% were male, the median age was 24 (IQR: 6 - 47) years old. The overall positivity was 15.2% (97 detections) and viruses were detected in 45.5% of the samples, bacteria in 43.5% and fungi in 10.8%. The most frequent etiological agents were: Streptococcus pneumoniae (16%), Cryptococcus neoformans/gatti (11.3%) and Herpes simplex virus (10.3%). Four double detections were found. Almost half of positive detections were in patients under 15 years old. This molecular approach is reliable and easily implantable into a laboratory routine, increasing the capacity of detection of bacterial and viral causative agents of meningitis, possibly playing a relevant role in the clinical context.

PCR past, present and future

PCR has become one of the most valuable techniques currently used in bioscience, diagnostics and forensic science. Here we review the history of PCR development and the technologies that have evolved from the original PCR method. Currently, there are two main areas of PCR utilization in bioscience: high-throughput PCR systems and microfluidics-based PCR devices for point-of-care (POC) applications. We also discuss the commercialization of these techniques and conclude with a look into their modifications and use in innovative areas of biomedicine. For example, real-time reverse transcription PCR is the gold standard for SARS-CoV-2 diagnoses. It could also be used for POC applications, being a key component of the sample-to-answer system.

Rapid Diagnostic Tests for Meningitis and Encephalitis-BioFire

Meningitis and encephalitis (ME) are important causes of morbidity and mortality worldwide. Patients suspected of having ME are often hospitalized and started on empiric antimicrobial treatment, because of the potential adverse consequences of delaying the diagnosis or treatment. Multiplexed polymerase chain reaction panels are one of several rapid diagnostic technologies that have the potential to overcome some of the limitations of conventional diagnostic methods for ME. The BioFire FilmArray Meningitis/Encephalitis Panel was the first Food and Drug Administration-cleared multiplex polymerase chain reaction for the evaluation of cerebrospinal fluid samples, able to identify 14 organisms in a single test reaction. This newer rapid diagnostic tool has an overall high sensitivity and specificity for the diagnosis of ME with a fast turnaround time and has the potential to improve resource utilization for patients presenting with suspicion of ME. However, further research is needed to determine its optimal use in the evaluation of patients with suspected ME.

Impact of the Film Array Meningitis/Encephalitis panel in adults with meningitis and encephalitis in Colombia

The Biofire® Film Array Meningitis Encephalitis (FAME) panel can rapidly diagnose common aetiologies but its impact in Colombia is unknown. A retrospective study of adults with CNS infections in one tertiary hospital in Colombia. The cohort was divided into two time periods: before and after the implementation of the Biofire® FAME panel in May 2016. A total of 98 patients were enrolled, 52 and 46 were enrolled in the Standard of Care (SOC) group and in the FAME group, respectively. The most common comorbidity was human immunodeficiency virus infection (47.4%). The median time to a change in therapy was significantly shorter in the FAME group than in the SOC group (3 vs. 137.3 h, P < 0.001). This difference was driven by the timing to appropriate therapy (2.1 vs. 195 h, P < 0.001) by identifying viral aetiologies. Overall outcomes and length of stay were no different between both groups (P > 0.2). The FAME panel detected six aetiologies that had negative cultures but missed identifying one patient with Cryptococcus neoformans. The introduction of the Biofire FAME panel in Colombia has facilitated the identification of viral pathogens and has significantly reduced the time to the adjustment of empirical antimicrobial therapy.

Impact of cerebrospinal fluid syndromic testing in the management of children with suspected central nervous system infection

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/mm³). 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.

Molecular diagnosis of the central nervous system (CNS) infections

Central nervous system (CNS) infections such as meningitis and encephalitis are medical emergencies that require rapid diagnosis of the causative pathogen to guide early and adequate treatment since a delay in implementing an adequate antimicrobial therapy can lead to death. The current microbiological diagnostic methods based on culture or antigen detection have important limitations in their capacity to accurately identify the different potential pathogens causing CNS and, in the time, to obtaining results. Rapid syndromic molecular arrays have been developed. The main advantage of using a meningoencephalitis panel based in a multiplex test is that includes bacteria, viruses and fungi, covering the most prevalent microorganisms causing meningitis and encephalitis and the turn-around time is circa 1h. The use of these multiplex-PCR based tools is reviewed and the advantages and disadvantages of this technique are discussed.

Methods for rapid diagnosis of meningitis etiology in adults

Infectious meningitis can be caused by viral, bacterial or fungal pathogens. Despite widely available treatments, many types of infectious meningitis are still associated with significant morbidity and mortality. Delay in diagnosis contributes to poor outcomes. Cerebrospinal fluid cultures have been used traditionally but are time intensive and sensitivity is decreased by empiric treatment prior to culture. More rapid techniques such as the cryptococcal lateral flow assay (IMMY), GeneXpert MTB/Rif Ultra (Cepheid) and FilmArray multiplex-PCR (Biofire) are three examples that have drastically changed meningitis diagnostics. This review will discuss a holistic approach to diagnosing bacterial, mycobacterial, viral and fungal meningitis.

Etiology of Central Nervous System Infections in a Rural Area of Nepal Using Molecular Approaches

The etiology of infections of the central nervous system (CNS) in Nepal often remains unrecognized because of underdeveloped laboratory facilities. The aim of this study was to investigate the etiology of CNS infections in a rural area of Nepal using molecular methods. From November 2014 to February 2016, cerebrospinal fluid (CSF) was collected from 176 consecutive patients presenting at United Mission Hospital in Tansen, Nepal, with symptoms of possible CNS infection. After the CSF samples were stored and transported frozen, polymerase chain reaction (PCR) was performed in Sweden, targeting a total of 26 pathogens using the FilmArray^® ME panel (BioFire, bioMerieux, Salt Lake City, UT), the MeningoFinder^® 2SMART (PathoFinder, Maastricht, The Netherlands), and an in-house PCR test for dengue virus (DENV), Japanese encephalitis virus (JEV), and Nipah virus (NiV). The etiology could be determined in 23%. The bacteria detected were Haemophilus influenzae (n = 5), Streptococcus pneumoniae (n = 4), and Neisseria meningitidis (n = 1). The most common virus was enterovirus detected in eight samples, all during the monsoon season. Other viruses detected were cytomegalovirus (n = 6), varicella zoster virus (n = 5), Epstein–Barr virus (n = 3), herpes simplex virus (HSV) type 1 (HSV-1) (n = 3), HSV-2 (n = 3), human herpes virus (HHV) type 6 (HHV-6) (n = 3), and HHV-7 (n = 2). Cryptococcus neoformans/gatti was found in four samples. None of the samples were positive for DENV, JEV, or NiV. Of the patients, 67% had been exposed to antibiotics before lumbar puncture. In conclusion, the etiology could not be found in 77% of the samples, indicating that the commercial PCR panels used are not suitable in this setting. Future studies on the etiology of CNS infections in Nepal could include metagenomic techniques.

Evaluation of the Biofire FilmArray meningitis/encephalitis assay for the detection of Cryptococcus neoformans/gattii

OBJECTIVES

Cryptococcal meningitis (CM) remains an important cause of morbidity and mortality among immunocompromised patients. Laboratory diagnostics for CM includes antigen detection, staining and culture. Data on the performance of the Biofire® FilmArray® meningitis/encephalitis (ME) panel for detecting Cryptococcus neoformans/gattii is limited, with several reports describing false negativity for this target.

METHODS

A retrospective analysis of 1384 physician-ordered ME panel tests ordered between January 2017 to October 2018 was performed. ME panel results were compared to cerebrospinal fluid (CSF) cryptococcal antigen (CrAg) and CSF culture testing and clinical significance of cryptococcal detection was determined.

RESULTS

There were 34 patients positive for cryptococcal detection by either ME panel, CSF CrAg or CSF culture in 2.7% of CSF specimens tested (38/1384). Of the 34 patients positive for cryptococcal detection, 85.3% were human immunodeficiency virus positive (29/34). The ME panel detected 32/38 (84.2%) cryptococcal-positive specimens, culture detected 28/38 (73.7%) and CSF CrAg was positive in 37/38 specimens (97.4%). The ME panel had a sensitivity and specificity of 96.4% (95% CI 81.7-99.9%) and 99.6% (95% CI 99.2-99.9%) compared with culture, and 83.8% (95% CI 68.0-93.8%) and 99.9% (95% CI 99.6-100.0%) compared to CSF CrAg testing, respectively. CrAg titres were lower among ME panel-negative, culture-negative specimens compared with ME panel-positive, culture-negative specimens (reciprocal median end-point titres of 128 ± 60 vs. 1920 ± 1730, p 0.04). All five CrAg-positive, ME panel- and culture-negative specimens were obtained from previously treated CM patients.

DISCUSSION

The ME panel had high correlation with CSF culture and a somewhat lower correlation with CSF CrAg testing. The potential utility of using negative ME panel test results to predict culture sterility among patients undergoing treatment for CM warrants further study.

Diagnostic challenges of central nervous system infection: extensive multiplex panels versus stepwise guided approach

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.

Diagnostic test accuracy of the BioFire® FilmArray® meningitis/encephalitis panel: a systematic review and meta-analysis

BACKGROUND

The FilmArray® meningitis/encephalitis (ME) panel is a multiplex PCR assay which can detect the most commonly identified pathogens in central nervous system infections. It significantly decreases the time to diagnosis of ME and data has yielded several positive outcomes. However, in part, reports of both false positive and false negative detections have resulted in concerns about adoption.

OBJECTIVES

The aim was to evaluate the ME panel in a diagnostic test accuracy review.

DATA SOURCES

The PubMed and EMBASE databases were systematically searched through May 2019.

STUDY ELIGIBILITY CRITERIA

Eligible studies were those providing sensitivity and specificity data for the ME panel compared with a reference standard. Studies providing details on false positive and false negative results of the panel as well as further investigation (adjudication) of the discordant results between the panel and comparator assays were included and assessed separately.

PARTICIPANTS

Patients with suspected ME for whom a panel was ordered were included.

METHODS

The ME panel was compared to reference standard methods for diagnosing community-acquired ME. We performed a meta-analysis and calculated the summary sensitivity and specificity of the ME panel. Moreover, we evaluated the false positive and false negative results of the panel.

RESULTS

Thirteen studies (3764 patients) were included in the review and 8 of them (3059 patients) were pooled in a meta-analysis. The summary estimates of sensitivity and specificity with 95% confidence intervals (CI) was 90% (95% CI 86-93%) and 97% (95% CI 94-99%), respectively. When we looked specifically at studies that assessed further the false positive and false negative results, false positive detections were 11.4% and 4% before and after adjudication, respectively. The highest proportion of false positive was observed for Streptococcus pneumoniae followed by Streptococcus agalactiae. False negative isolates were 2.2% and 1.5% before and after adjudication, respectively. Herpes simplex virus 1 and 2, enterovirus and Cryptococcus neoformans/gattii had the highest proportions of false negative determinations. False negative C. neoformans/gattii were mostly patients with positive antigen titres, on treatment or cleared disease.

CONCLUSIONS

The currently available literature suggests that the ME panel has high diagnostic accuracy. However, the decision for implementation should be individualized based on the needs of the patient population, the capabilities of the laboratory, and the knowledge of the healthcare providers that will utilize the test.

A review of a 13-month period of FilmArray Meningitis/Encephalitis panel implementation as a first-line diagnosis tool at a university hospital

Early diagnosis and treatment of meningitis and encephalitis is essential for reducing both their morbidity and mortality. The FilmArray® Meningitis/Encephalitis (FA-M/E) panel is a recently available molecular tool allowing the simultaneous detection of 14 pathogens in about one hour. We evaluated its routine use over a 13-month period at Nîmes University Hospital, France. Cerebrospinal fluid (CSF) specimens were prospectively analyzed, independently of cell count; results were retrospectively analyzed and positive results compared to clinical and microbiological data. Among the 708 patients included (734 CSF samples), 89 (12.6%) had a positive FA-M/E panel, 71 (80%) for a viral pathogen and 18 (20%) for a bacterial pathogen. Enterovirus and HHV-6 were the main detected pathogens. Mean time-to-results was 1h46mn. Four non-clinically relevant results were detected (3 HHV-6 and 1 Haemophilus influenzae) on the basis of inconsistent clinical and/or biological data, and/or after visualization of melting curves. No CSF pleocytosis was observed in 11% of the patients with a positive FA-M/E panel. For the 18 patients with a positive FA-M/E panel for a bacterial pathogen, five (28%) had CSF samples showing a positive Gram stain allowing an early diagnosis of bacterial infection and 67% had CSF displaying a positive culture. Altogether the panel detected 5 cases of bacterial M/E (29%) not diagnosed by culture. Despite undeniable advantages, mainly ease of use, quick result availability, and an extremely low rate of invalid results, measures should be implemented to limit false-positive results due to contamination and a careful interpretation based on the overall data for each patient is required.

Association of the FilmArray Meningitis/Encephalitis Panel With Clinical Management

OBJECTIVES

To determine the association of the use of the multiplex assay meningitis/encephalitis panel with clinical management of suspected meningitis.

METHODS

A cross-sectional study was conducted with children 0 to 18 years of age who received a lumbar puncture within 48 hours of admission for an infectious workup. Patient demographic and presenting information, laboratory studies, and medication administration were collected. The primary measure was length of stay (LOS) with secondary measures: time on antibiotics, time to narrowing antibiotics, and acyclovir doses. LOS and antibiotic times were stratified for outcomes occurring before 36 hours. Logistic regression analysis was used to account for potential confounding factors associated with both the primary and secondary outcomes. A value of P < .05 was considered statistically significant.

RESULTS

Meningitis panel use was associated with a higher likelihood of a patient LOS <36 hours (P = .04; odds ratio = 1.7; 95% confidence interval [CI]: 1.03-2.87), a time to narrowing antibiotics <36 hours (P = .008; odds ratio = 1.89; 95% CI: 1.18-2.87), and doses of acyclovir (P < .001; incidence rate ratio = 0.37; 95% CI: 0.26-0.53). When controlling for potential confounding factors, these associations persisted.

CONCLUSIONS

Use of the meningitis panel was associated with a decreased LOS, time to narrowing of antibiotics, and fewer acyclovir doses. This likely is a result of the rapid turnaround time as compared with cerebrospinal fluid cultures. Additional studies to examine the outcomes related to this change in management are warranted.

Diagnostic Testing in Central Nervous System Infection

Patients with central nervous system (CNS) infection experience very high levels of morbidity and mortality, in part because of the many challenges inherent to the diagnosis of CNS infection and identification of a causative pathogen. The clinical presentation of CNS infection is nonspecific, so clinicians must often order and interpret many diagnostic tests in parallel. This can be a daunting task given the large number of potential pathogens and the availability of different testing modalities. Here, we review traditional diagnostic techniques including Gram stain and culture, serology, and polymerase chain reaction (PCR). We highlight which of these are recommended for the pathogens most commonly tested among U.S. patients with suspected CNS infection. Finally, we describe the newer broad-range diagnostic approaches, multiplex PCR and metagenomic sequencing, which are increasingly used in clinical practice.

Diagnosis and Management of Central Nervous System Cryptococcal Infections in HIV-Infected Adults

Cryptococcal meningitis persists as a significant source of morbidity and mortality in persons with HIV/AIDS, particularly in sub-Saharan Africa. Despite increasing access to antiretrovirals, persons presenting with advanced HIV disease remains common, and Cryptococcus remains the most frequent etiology of adult meningitis. We performed a literature review and herein present the most up-to-date information on the diagnosis and management of cryptococcosis. Recent advances have dramatically improved the accessibility of timely and affordable diagnostics. The optimal initial antifungal management has been newly updated after the completion of a landmark clinical trial. Beyond antifungals, the control of intracranial pressure and mitigation of toxicities remain hallmarks of effective treatment. Cryptococcal meningitis continues to present challenging complications and continued research is needed.

Mortality in adult patients with culture-positive and culture-negative meningitis in the Botswana national meningitis survey: a prevalent cohort study

BACKGROUND

CNS infections are a leading cause of HIV-related deaths in sub-Saharan Africa, but causes and outcomes are poorly defined. We aimed to determine mortality and predictors of mortality in adults evaluated for meningitis in Botswana, which has an estimated 23% HIV prevalence among adults.

METHODS

In this prevalent cohort study, patient records from 2004-15 were sampled from the Botswana national meningitis survey, a nationwide audit of all cerebrospinal fluid (CSF) laboratory records from patients receiving a lumbar puncture for evaluation of meningitis. Data from all patients with culture-confirmed pneumococcal and tuberculous meningitis, and all patients with culture-negative meningitis with CSF white cell count (WCC) above 20 cells per μL were included in our analyses, in addition to a random selection of patients with culture-negative CSF and CSF WCC of up to 20 cells per μL. We used patient national identification numbers to link CSF laboratory records from the national meningitis survey to patient vital registry and HIV databases. Univariable and multivariable Cox proportional hazards models were used to evaluate clinical and laboratory predictors of mortality.

FINDINGS

We included data from 238 patients with culture-confirmed pneumococcal meningitis, 48 with culture-confirmed tuberculous meningitis, and 2900 with culture-negative CSF (including 1691 with CSF WCC of up to 20 cells per μL and 1209 with CSF WCC above 20 cells per μL). Median age was 37 years (IQR 31-46), 1605 (50%) of 3184 patients were male, 2188 (72%) of 3023 patients with registry linkage had documentation of HIV infection, and median CD4 count was 139 cells per μL (IQR 63-271). 10-week and 1-year mortality was 47% (112 of 238) and 49% (117 of 238) for pneumococcal meningitis, 46% (22 of 48) and 56% (27 of 48) for tuberculous meningitis, and 41% (1181 of 2900) and 49% (1408 of 2900) for culture-negative patients. When the analysis of patients with culture-negative CSF was restricted to those with known HIV infection, WCC (0-20 cells per μL vs >20 cells per μL) was not predictive of mortality (average hazard ratio 0·93, 95% CI 0·80-1·09).

INTERPRETATION

Mortality from pneumococcal, tuberculous, and culture-negative meningitis was high in this setting of high HIV prevalence. There is an urgent need for improved access to diagnostics, to better define aetiologies and develop novel diagnostic tools and treatment algorithms.

FUNDING

National Institutes of Health, President's Emergency Plan for AIDS Relief, National Institute for Health Research.

Approche syndromique multiplexe en réanimation

Le développement récent des nouveaux tests de diagnostic rapide par PCR multiplexe à visée syndromique, capables de détecter plusieurs dizaines de pathogènes en quelques heures, a entraîné un changement de paradigme en microbiologie et en pratique clinique. Plusieurs d’entre eux, comme les panels pour détecter les germes en cause dans les bactériémies, les infections respiratoires hautes ou basses et les méningoencéphalites, sont déjà disponibles et peuvent apporter une aide dans le diagnostic des infections chez les patients de réanimation. Bien que ces nouvelles techniques présentent des avantages évidents pour le dénombrement de micro-organismes et parfois pour la détection simultanée de gènes de résistance, pour les délais d’exécution et de rendus de résultats, elles présentent cependant certains défis, comme l’évaluation de leurs performances réelles, leur coût très élevé, le choix des stratégies d’utilisation et l’interprétation clinicobiologique des résultats. Dans cet article, nous avons passé en revue les différents tests qui peuvent ou pourront aider les réanimateurs dans leur pratique quotidienne, relevé leurs limites et leur impact bénéfique potentiel sur le soin des patients.

Symptomatic Cryptococcal Antigenemia Presenting as Early Cryptococcal Meningitis With Negative Cerebral Spinal Fluid Analysis

BACKGROUND

Individuals with cryptococcal antigenemia are at high risk of developing cryptococcal meningitis if untreated. The progression and timing from asymptomatic infection to cryptococcal meningitis is unclear. We describe a subpopulation of individuals with neurologic symptomatic cryptococcal antigenemia but negative cerebral spinal fluid (CSF) studies.

METHODS

We evaluated 1201 human immunodeficiency virus-seropositive individuals hospitalized with suspected meningitis in Kampala and Mbarara, Uganda. Baseline characteristics and clinical outcomes of participants with neurologic-symptomatic cryptococcal antigenemia and negative CSF cryptococcal antigen (CrAg) were compared to participants with confirmed CSF CrAg+ cryptococcal meningitis. Additional CSF testing included microscopy, fungal culture, bacterial culture, tuberculosis culture, multiplex FilmArray polymerase chain reaction (PCR; Biofire), and Xpert MTB/Rif.

RESULTS

We found 56% (671/1201) of participants had confirmed CSF CrAg+ cryptococcal meningitis and 4% (54/1201) had neurologic symptomatic cryptococcal antigenemia with negative CSF CrAg. Of those with negative CSF CrAg, 9% (5/54) had Cryptococcus isolated on CSF culture (n = 3) or PCR (n = 2) and 11% (6/54) had confirmed tuberculous meningitis. CSF CrAg-negative patients had lower proportions with CSF pleocytosis (16% vs 26% with ≥5 white cells/μL) and CSF opening pressure >200 mmH2O (16% vs 71%) compared with CSF CrAg-positive patients. No cases of bacterial or viral meningitis were detected by CSF PCR or culture. In-hospital mortality was similar between symptomatic cryptococcal antigenemia (32%) and cryptococcal meningitis (31%; P = .91).

CONCLUSIONS

Cryptococcal antigenemia with meningitis symptoms was the third most common meningitis etiology. We postulate this is early cryptococcal meningoencephalitis. Fluconazole monotherapy was suboptimal despite Cryptococcus-negative CSF. Further studies are warranted to understand the clinical course and optimal management of this distinct entity.

CLINICAL TRIALS REGISTRATION

NCT01802385.

Usefulness of the FilmArray meningitis/encephalitis (M/E) panel for the diagnosis of infectious meningitis and encephalitis in Taiwan

BACKGROUND/PURPOSE

Early recognition of causative pathogens is critical for the appropriate management of central nervous system infection and improved outcomes. The BioFire^® FilmArray^® Meningitis/Encephalitis Panel (BioFire^® ME Panel, BioFire Diagnostics) is the first U.S. Food and Drug Administration (FDA)-approved multiplex PCR assay that allows the rapid detection of 14 pathogens, including bacteria (n = 6), viruses (n = 7), and fungi (n = 1), from cerebrospinal fluid (CSF). The performance of the panel is expected to be dependent on the epidemiology of M/E in different geographical regions.

METHODS

In this preliminary study, we used the BioFire^® ME Panel in 42 subjects who presented to the emergency department with symptoms of M/E in our hospital. The results were compared to conventional culture, antigen detection, PCR, and various laboratory findings.

RESULTS

The panel detected six positive samples, of which five were viral and one bacterial. We observed an overall agreement rate of 88% between the BioFire^® ME Panel results and the conventional methods. There were no false-positive findings, but five discordant results were observed for enterovirus, herpes simplex virus type 1, Escherichia coli, and Cryptococcus species.

CONCLUSIONS

The BioFire^® ME Panel performed equivalently to the traditional PCR methods for virus detection, and better than bacterial cultures. This revolutionary system represents a paradigm shift in the diagnosis of M/E and may aid in the rapid identification of community-acquired M/E. However, the usefulness of this tool is limited in regions with a high prevalence of infectious M/E caused by microorganisms not included in the panel.

Sensitivity of Cerebrospinal Fluid Cytology for the Diagnosis of Cryptococcal Infections: A 21-Year Single-Institution Retrospective Review

Objectives

Cryptococcal meningoencephalitis is the most common fungal infection of the central nervous system diagnosed by cerebrospinal fluid cytology (CSF) studies. Existing literature suggests that routine CSF cytomorphologic evaluations are exquisitely specific; however, less is known about their sensitivity.

Methods

An electronic record review of the cytopathology and microbiology files was conducted for the 21-year interval from January 1, 1995, through December 31, 2015.

Results

In 21 years, 12,584 CSF samples were processed in the laboratory. Of these, 24 (0.2%) were reported positive for cryptococcal organisms by light microscopy, and 129 CSF fungal cultures were positive for Cryptococcus species. All cotested specimens with positive cytology results were positive on culture (15 specimens, 100% specificity). Twenty-four samples with positive culture results were negative by CSF cytology (sensitivity 39%).

Conclusions

When culture is used as a gold standard, CSF cytology is 100% specific and 39% sensitive, with a positive predictive value of 100% and a negative predictive value of 99.8%.

Cryptococcal Meningitis Diagnostics and Screening in the Era of Point-of-Care Laboratory Testing

Over the past ten years, standard diagnostics for cryptococcal meningitis in HIV-infected persons have evolved from culture to India ink to detection of cryptococcal antigen (CrAg), with the recent development and distribution of a point-of-care lateral flow assay. This assay is highly sensitive and specific in cerebrospinal fluid (CSF), but is also sensitive in the blood to detect CrAg prior to meningitis symptoms. CrAg screening of HIV-infected persons in the blood prior to development of fulminant meningitis and preemptive treatment for CrAg-positive persons are recommended by the World Health Organization and many national HIV guidelines. Thus, CrAg testing is occurring more widely, especially in resource-limited laboratory settings. CrAg titer predicts meningitis and death and could be used in the future to customize therapy according to burden of infection.

[Meningitis/Encephalitis diagnosis in ICU using Multiplex PCR system: Is it time of change?]

OBJECTIVE

To evaluate the clinical impact of Meningitis/Encephalitis FilmArray® panel for the diagnosis of cerebral nervous system infection and to compare the results (including time for diagnosis) with those obtained by conventional microbiological techniques.

METHODS

A prospective observational study in an Intensive Care Unit of adults from a tertiary hospital was carried out. Cerebrospinal fluid from all patients was taken by lumbar puncture and assessed by the meningitis/encephalitis FilmArray® panel ME, cytochemical study, Gram, and conventional microbiological cultures.

RESULTS

A total of 21 patients admitted with suspicion of Meningitis/Encephalitis. Median age of patients was 58.4 years (RIQ 38.1-67.3), median APACHE II 18 (RIQ 12-24). Median stay in ICU and median hospital stay was 4 (RIQ 2-6) and 17 days (RIQ 14-28), respectively. The overall mortality was 14.3%. A final clinical diagnosis of meningitis or encephalitis was established in 16 patients, obtaining the etiological diagnosis in 12 of them (75%). The most frequent etiology was Streptococcus pneumoniae (8 cases). FilmArray® allowed etiological diagnosis in 3 cases in which the culture had been negative, and the results led to changes in the empirical antimicrobial therapy in 7 of 16 cases (43.8%). FilmArray® yielded a global sensitivity and specificity of 100% and 90%, respectively. The median time to obtain results from the latter and conventional culture (including antibiogram) was 2.9 hours (RIQ 2.1-3.8) and 45.1 hours (RIQ 38.9-58.7), respectively.

CONCLUSIONS

The Meningitis/Encephalitis FilmArray® panel was able to establish the etiologic diagnosis faster than conventional methods. Also, it achieved a better sensitivity and led to prompt targeted antimicrobial therapy.

Understanding Pathogenesis and Care Challenges of Immune Reconstitution Inflammatory Syndrome in Fungal Infections

Immune deficiency of diverse etiology, including human immunodeficiency virus (HIV), antineoplastic agents, immunosuppressive agents used in solid organ recipients, immunomodulatory therapy, and other biologics, all promote invasive fungal infections. Subsequent voluntary or unintended immune recovery may induce an exaggerated inflammatory response defining immune reconstitution inflammatory syndrome (IRIS), which causes significant mortality and morbidity. Fungal-associated IRIS raises several diagnostic and management issues. Mostly studied with Cryptococcus, it has also been described with other major fungi implicated in human invasive fungal infections, such as Pneumocystis, Aspergillus, Candida, and Histoplasma. Furthermore, the understanding of IRIS pathogenesis remains in its infancy. This review summarizes current knowledge regarding the clinical characteristics of IRIS depending on fungal species and existing strategies to predict, prevent, and treat IRIS in this patient population, and tries to propose a common immunological background to fungal IRIS.