Economic analysis of rapid multiplex polymerase chain reaction testing for meningitis/encephalitis in pediatric patients

Molecular diagnostics in cerebrospinal fluid for the diagnosis of central nervous system infections

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.

Advancing quantitative PCR with color cycle multiplex amplification

Quantitative PCR (qPCR) is the gold standard for detection and quantitation of known DNA targets, but the scarcity of spectrally distinct fluorophores and filter sets limits the number of detectable targets. Here, we introduce color cycle multiplex amplification (CCMA) to significantly increase the number of detectable DNA targets in a single qPCR reaction using standard instrumentation. In CCMA, presence of one DNA target species results in a pre-programmed pattern of fluorescence increases. This pattern is distinguished by cycle thresholds (Cts) through rationally designed delays in amplification. For example, we design an assay wherein Staphylococcus aureus sequentially induces FAM, then Cy5.5, then ROX fluorescence increases with more than 3 cycles between each signal. CCMA offers notably higher potential for multiplexing because it uses fluorescence permutation rather than combination. With 4 distinct fluorescence colors, CCMA theoretically allows the detection of up to 136 distinct DNA target sequences using fluorescence permutation. Experimentally, we demonstrated a single-tube qPCR assay screening 21 sepsis-related bacterial DNA targets in samples of blood, sputum, pleural effusion and bronchoalveolar lavage fluid, with 89% clinical sensitivity and 100% clinical specificity, showing its potential as a powerful tool for advanced quantitative screening in molecular diagnostics.

Exploring the Utility of Multiplex Infectious Disease Panel Testing for Diagnosis of Infection in Different Body Sites: A Joint Report of the Association for Molecular Pathology, American Society for Microbiology, Infectious Diseases Society of America, and Pan American Society for Clinical Virology

The use of clinical molecular diagnostic methods for detecting microbial pathogens continues to expand and, in some cases, supplant conventional identification methods in various scenarios. Analytical and clinical benefits of multiplex molecular panels for the detection of respiratory pathogens have been demonstrated in various studies. The use of these panels in managing different patient populations has been incorporated into clinical guidance documents. The Association for Molecular Pathology's Infectious Diseases Multiplex Working Group conducted a review of the current benefits and challenges to using multiplex PCR for the detection of pathogens from gastrointestinal tract, central nervous system, lower respiratory tract, and joint specimens. The Working Group also discusses future directions and novel approaches to detection of pathogens in alternate specimen types, and outlines challenges associated with implementation of these multiplex PCR panels.

BD MAX Enteric Bacterial, Bacterial Plus, and Virus Panels for Diagnosis of Acute Infectious Gastroenteritis: a Cost-Benefit Analysis

Economic assessment is required to gauge the value of implementing PCR syndromic platforms in the microbiology laboratory for the diagnosis of community-acquired acute gastroenteritis (AGE) in pediatric and adult in- and outpatients. A cost-benefit analysis was conducted from a health care system perspective using BD MAX Enteric Bacterial, Bacterial Plus, and Virus panels. Two 6-month periods were selected, in which either conventional procedures (in 2017) or BD MAX PCR multiplex panels (in 2018) were used. We retrospectively reviewed medical records of all patients with positive results and a representative sample of negative ones. A Markov model was used to represent transition probabilities between different health care states from time of stool microbiological study until completion of AGE-episode-associated health care. A total of 1,336 medical records were reviewed (829 in 2018 and 507 in 2017), showing overall a significantly higher positivity rate in 2018 than in 2017 (26% versus 6%, P < 0.001). The total cost per individual associated with health care for AGE was €314 in 2018 and €341 in 2017; when we only considered the pediatric cohort, the figures were €271 and €456, respectively. Using Tornado sensitivity analyses, we found that the three variables that most influenced the model in descending order of weight were the probability of longer hospital stays, the probability of returning to the emergency room (ER), and the probability of hospitalization from the ER. Use of BD MAX enteric PCR platforms for the diagnosis of community-acquired AGE instead of a non-PCR-based conventional approach results in an incremental benefit from a health care perspective in the general population, particularly children. IMPORTANCE The implementation of multiplex molecular panels allows microbiological laboratories to quickly, sensitively, and accurately diagnose acute infectious gastroenteritis. This methodology therefore allows faster decisions regarding treatment and infection control measures. Economic evaluations are required to gauge the value of implementing these syndromic PCR platforms in a community-based acute gastroenteritis setting. We studied the potential clinical and cost benefits, in terms of both their impact on laboratory costs and the subsequent costs of managing patients.

The clinical impact of multiplex PCR panel diagnostics in paediatric meningitis/ encephalitis: a bicenter cohort study

PURPOSE

In infections of the Central Nervous System (iCNS), rapid identification of causing pathogens is crucial for survival and to avoid long-term sequelae. Targeted therapy may reduce side effects and development of antibiotic resistance. New molecular-based syndromic tests such as the "meningitis/encephalitis panel" (MEP) allow accelerated pathogen identification from cerebrospinal fluid. We conducted a clinical study to evaluate the MEP's efficacy in paediatric patients.

METHODS

Cohort study in a unique clinical setting by comparing the outcome data of two neighbouring Children's Hospitals in Germany which are comparable in size, catchment area and equipment but differ regarding availability of the MEP: study centre 1 (SC1): yes; SC2: no. The study population included 213 paediatric patients with a suspected iCNS (SC1: 106; SC2: 107), with comparable age, CRP at admission and frequency of intensive care. The primary outcome was total use of antibiotics.

RESULTS

Total antibiotic use per patient was numerically lower in SC1 than in SC2 (SC1: median 2.83 days; SC2 3.67 days; p = 0.671). Multiple linear regression analysis did not show a relevant association between MEP-availability and total antibiotic use (ß = 0.1, 95% confidence interval [-1.46; +1.67], p = 0.897). In the subcohort with suspected meningoencephalitis (SC1: 18, SC2: 17), duration of acyclovir treatment was shorter in SC1 than in SC2 (median 1.3 days vs. 2.7 days, descriptive p = 0.0397).

CONCLUSIONS

The add-on use of the MEP in paediatric patients with suspected iCNS was associated with a non-significant reduction in total antibiotic use, and with a reduced exposure to acyclovir in treated patients.

Clinical and Financial Impact of a Diagnostic Stewardship Program for Children with Suspected Central Nervous System Infection

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.

Evaluation of Discordant Results Between FilmArray Meningitis/Encephalitis Panel and Conventional Testing in Pediatric Patients: A Multisite Retrospective Cohort Study

BACKGROUND

The FilmArray Meningitis/Encephalitis panel (MEP) has an 11% false-positive and 2.2% false-negative rate compared with conventional testing. We describe clinical characteristics, treatment decisions, and outcomes in children with discordant results between MEP and conventional testing.

METHODS

We conducted a multisite review of patients ≤ 18 years with suspected central nervous system infection and positive results by MEP or conventional testing (cerebrospinal fluid [CSF] culture, herpes simplex virus [HSV] polymerase chain reaction (PCR), and enterovirus [EV] PCR). Descriptive results are provided for patients with discordant results. Comparison between group 1 (MEP and CSF culture positive) and group 2 (MEP positive, CSF culture negative, or showing a different pathogen) was made by Mann-Whitney test for continuous and Fisher's test for categorical variables.

RESULTS

A total of 355 patients had at least one pathogen identified. More than half of patients with bacterial pathogens identified that are included in the MEP had discordant results (30/52; 58%). There were 28 samples with bacterial pathogen identified on MEP only, 1 with different bacterial pathogens on MEP and culture, and 1 with Escherichia coli identified on CSF culture only. Patients in group 1 were more likely to have CSF pleocytosis, elevated CSF protein, and decreased CSF glucose than group 2 (P < .05). Two patients were HSV positive by MEP while HSV negative by PCR. Ten patients had discordant results between MEP and EV PCR.

CONCLUSIONS

Discordant results between MEP and conventional testing are common. Treatment decisions based on a positive MEP should be made in the appropriate clinical context.

Reassessing the Value of CSF Protein and Glucose Measurement in Pediatric Infectious Meningitis

OBJECTIVES

Infectious meningitis (IM) in US children is increasingly rare and new rapid multiplex PCR-based testing is increasingly available. We evaluated the added value of cerebrospinal fluid (CSF) protein and glucose tests to predict IM when compared with information provided by CSF white blood cell count (WBC) and multiplex polymerase chain reaction (PCR).

METHODS

We retrospectively reviewed CSF results from October 2015 to August 2017 in patients 0 to 18 years at a US children's hospital. Noninfectious evaluations were excluded. Test characteristics were calculated for CSF WBC, protein, and glucose in isolation and in parallel for prediction of microbiologically confirmed IM. Chart review was performed to identify consideration of protein and glucose in medical decision-making (MDM).

RESULTS

We identified 735 patients including 446 <2 months; 45 (6.1%) had microbiologically-confirmed IM, including 23 (5.2%) age <2 months. Multiplex PCR and/or CSF WBC identified all IM patients. When added to CSF WBC, measurement of glucose made no contribution to sensitivity, specificity, positive predictive value (PPV) or negative predictive value (NPV), and protein had no impact on sensitivity and decreased the specificity, PPV, and NPV compared with CSF WBC alone. Abnormal protein was documented in MDM in 6 (0.8%) patients, all of whom had elevated WBC counts also cited. Glucose was not mentioned in MDM.

CONCLUSIONS

Multiplex PCR testing and WBC may be sufficient to predict meningitis in children in low incidence settings. Protein and glucose did not contribute significant additional information. More intentional use of protein and glucose testing in patients with suspected IM may achieve higher value care.

Impact of a 24/7 multiplex-PCR on the management of patients with confirmed viral meningitis

Objectives

The relevance of syndromic multiplex-PCR for the etiological diagnosis of meningitis or meningoencephalitis is still a matter of debate. Here, we studied the impact of a 24/7 multiplex-PCR on the management of patients consulting in the emergency department for suspicion of community-acquired meningitis.

Methods

We conducted a single-center retrospective study at the Emergency department of Lariboisière University Hospital (Paris, France) including all patients suspected of meningitis. During period 1 (April 2014-March 2017), the molecular assays used for the detection of infectious agents in the cerebrospinal fluid (CSF) were performed during the daytime. During period 2 (April 2017-March 2019), multiplex-PCR (BioFire® Filmarray® Meningitis/Encephalitis Panel [ME], bioMérieux) was performed 24/7.

Results

During the periods 1 and 2, 4 100 and 3 574 patients were included and 284 (6.9%) and 308 (8.6%) meningitis were diagnosed, respectively. During the periods 1 and 2, the most common causes of meningitis were enterovirus (23.9% and 29.5%), varicella zoster virus (10.2% and 6.8%) and herpes simplex virus-2 (4.2% and 8.1%). For patients with confirmed viral meningitis, a significant decrease was found between period 1 and period 2, respectively for the rate of hospitalization (73.9% vs 42.0%; p < 0.05), the length of stay (3[2–5] vs 2[1–3] days; p < 0.05), the empirical antiviral (26.1% vs 14.5%) and antibacterial administrations (29.3% vs 14.5%; p < 0.05).

Conclusions

Multiplex-PCR is an important tool in the diagnosis of infectious meningitis in the emergency department and is relevant in the management of meningitis by screening for patients who do not require hospitalization and antibacterial therapy.

Multiplex Molecular Point-of-Care Test for Syndromic Infectious Diseases

Point-of-care (POC) molecular diagnostics for clinical microbiology and virology has primarily focused on the detection of a single pathogen. More recently, it has transitioned into a comprehensive syndromic approach that employs multiplex capabilities, including the simultaneous detection of two or more pathogens. Multiplex POC tests provide higher accuracy to for actionable decisionmaking in critical care, which leads to pathogen-specific treatment and standardized usages of antibiotics that help prevent unnecessary processes. In addition, these tests can be simple enough to operate at the primary care level and in remote settings where there is no laboratory infrastructure. This review focuses on state-of-the-art multiplexed molecular point-of-care tests (POCT) for infectious diseases and efforts to overcome their limitations, especially related to inadequate throughput for the identification of syndromic diseases. We also discuss promising and imperative clinical POC approaches, as well as the possible hurdles of their practical applications as front-line diagnostic tests.

Impact of a Rapid Diagnostic Meningitis/Encephalitis Panel on Antimicrobial Use and Clinical Outcomes in Children

Rapid molecular diagnostic assays are increasingly used to guide effective antimicrobial therapy. Data on their effectiveness to decrease antimicrobial use in children have been limited and varied. We aimed to assess the impact of the implementation of the FilmArray Meningitis Encephalitis Panel (MEP) on antimicrobial use and outcomes in children. In an observational retrospective study performed at Atlantic Health System (NJ), we sought to evaluate the duration of intravenous antibiotic treatment (days of therapy (DoT)) for patients <21 years of age hospitalized and evaluated for presumptive meningitis or encephalitis before and after the introduction of the MEP. A secondary analysis was performed to determine if recovery of a respiratory pathogen influenced DoT. The median duration of antibiotic therapy prior to the implementation of the MEP was 5 DoT (interquartile range (IQR): 3-6) versus 3 DoT (IQR: 1-5) (p < 0.001) when MEP was performed. The impact was greatest on intravenous third-generation cephalosporin and ampicillin use. We found a reduction in the number of inpatient days associated with the MEP. In the regression analysis, a positive respiratory pathogen panel (RPP) was not a significant predictor of DoT (p = 0.08). Furthermore, we found no significant difference between DoT among patients with negative and positive RPP (p = 0.12). Our study supports the implementation of rapid diagnostics to decrease the utilization of antibiotic therapy among pediatric patients admitted with concerns related to meningitis or encephalitis.

Burden of Pediatric Central Nervous System Infection and Cost-Benefit Simulation of Multiplex Polymerase Chain Reaction in Japan

To investigate the clinical use of multiplex polymerase chain reaction (mPCR) in Japan, epidemiological and clinical data for central nervous infections are needed. Here, we report on the epidemiology and economic burden of central nervous system infections and a simulation of the cost-benefit analysis of the Filmarray® Meningitis/Encephalitis (FAME) test for possible clinical use in Japan. We performed FAME tests on samples from 27 patients with pleocytosis aged between 0 and 20 years seen in six community hospitals in Nara and Osaka prefectures. All clinical management procedures were performed without knowledge of the mPCR test results. We analyzed the clinical data and calculated the required reduction in average length of stay for the FAME test to be cost-beneficial. Among the 27 cases, the FAME test revealed causal pathogens in 13 cases (48.1%). The average medical and social costs per case were ¥299,118 ($2,719.2) and ¥171,768 ($1,561.5), respectively. The minimal needed reduction in average length of stay for the FAME test to be cost-beneficial was 0.32- 0.86 days per meningitis case. The result can be informative for evaluating the cost-effectiveness of the clinical use of the FAME test in Japan.

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 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.

Implementation of the FilmArray ME panel in laboratory routine using a simple sample selection strategy for diagnosis of meningitis and encephalitis

Background

Infectious meningitis is a serious disease and patient outcome relies on fast and reliable diagnostics. A syndromic panel testing approach like the FilmArray ME can accelerate diagnosis and therefore decrease the time to pathogen specific therapy. Yet, its clinical utility is controversial, mainly because of a remaining uncertainty in correct interpretation of results, limited data on its performance on clinical specimens and its relatively high costs. The aim of this study was to analyze clinical performance of the assay in a real life setting at a tertiary university hospital using a pragmatic and simple sample selection strategy to reduce the overall cost burden.

Methods

Over a period of 18 months we received 4623 CSF samples (2338 hospitalizations, 1601 individuals). FilmArray ME analysis was restricted to CSF-samples with a high pretest probability of infectious meningitis, e.g. positive Gram-stain, samples in which leukocytes and/or bacteria were evident or urgent suspicion of infection was communicated by clinicians. N = 171 samples matched to our risk criteria and were subjected to FilmArray ME analysis. Those samples were also analyzed by reference methods: culture only (n = 45), PCR only (n = 20) or both methods (n = 106).

Results

56/171 (32.75%) were FilmArray ME positive. Bacterial pathogens were detected in 30/56 (53.57%), viral pathogens were detected in 27/56 (48.21%) and yeast DNA was detected in 1/56 (1.79%) of positive samples. Double detection occurred in 2/56 samples. In 52/56 (92.86%) FilmArray ME positive samples, results could be confirmed by the reference assays (sensitivity = 96.30%, specificity =96.58%).

Conclusion

The FilmArray ME assay is a fast and reliable diagnostic tool for the management of infectious meningitis and can easily be implemented in routine diagnostic workflows. However, correlation of test results and underlying clinical symptoms requires experienced users and the awareness of potentially false negative or false positive results. Moreover, considering the need for antimicrobial susceptibility testing, the use of molecular tests as a stand-alone diagnostic cannot be recommended.

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.

FilmArray Meningitis/Encephalitis (ME) panel in the diagnosis of bacterial meningitis

The precise diagnosis of bacterial meningitis is essential. Cytological and biochemical examination of cerebrospinal fluid (CSF) are not specific. Conventional methods for bacterial meningitis lack sensitivity or take too long for a final result. Therefore, other methods for rapid and accurate diagnosis of central nervous system infections are required. FilmArray meningitis/encephalitis (ME) panel is a PCR multiplex for simultaneous and rapid identification of 14 pathogens, including 6 bacteria, 7 viruses, and Cryptococcus. We evaluated 436 CSF samples submitted to FilmArray ME Panel. Among them, 25 cases were positive for bacteria, being Streptococcus pneumonia the most frequent (48 %). Among positive cases for bacteria, 60 % were positive only with FilmArray. All the bacterial meningitis cases in which the only positive test was FilmArray had CSF findings suggestive of bacterial meningitis, including neutrophilic pleocytosis, increased CSF protein and lactate, and decreased CSF glucose. These findings suggest that FilmArray may increase the diagnostic sensitivity for bacterial meningitis.

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.

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.

Economic analysis of rapid multiplex polymerase chain reaction testing for meningitis/encephalitis in adult patients

PURPOSE

Many patients with suspected meningitis do not require hospitalization yet are admitted, often resulting in unnecessary care and additional cost. We assessed the possible economic impact of a rapid multiplex test for suspected adult community-acquired meningitis/encephalitis.

METHODS

A model simulated diagnosis, clinical decisions, resource use/costs of standard of care (SOC) and two cerebrospinal fluid (CSF) testing strategies using the FDA-cleared BioFire® FilmArray® System (FA) which provides results in approximately one hour.

RESULTS

Pathogens detected by FA caused approximately 74% of cases, 97% of which would be accurately diagnosed with FA. False positives and false negatives more often led to extended/unnecessary admission than inappropriate discharge/missed admission. Mean cost per case ranged from 16829 to 20791. A strategy of testing all suspected cases yielded greater savings (2213/case) than testing only those with abnormal CSF (812/case) and both were less expensive than SOC.

CONCLUSION

This economic analysis demonstrates that FA can inform more appropriate clinician decisions resulting in cost savings with greater economic benefits achievable with syndromic testing of all cases, rather than SOC or targeted syndromic testing.

Cerebrospinal Fluid Analysis With the BioFire FilmArray Meningitis/Encephalitis Molecular Panel Reduces Length of Hospital Stay in Patients With Suspected Central Nervous System Infections

The Meningitis/Encephalitis Panel (MEP) is a sensitive and specific Food and Drug Administration–approved molecular diagnostic test for the 14 most common infectious etiologies of meningoencephalitis. Using a before–after controlled study design, MEP reduced length of hospital stay by 1.5 days, and this effect was mediated by the reduced time to final microbiology reporting.

Cost of managing meningitis and encephalitis among infants and children in the United States

A retrospective cohort study design was used to assess the use and costs of diagnostic tests, medication, and total hospitalization costs for pediatric patients with suspected meningitis/encephalitis who received a lumbar puncture (LP) procedure. Related costs were calculated by timing of LP performed and infectious etiology for infants (<1 year) and children (1-17 years). A total of 3030 infants and 3635 children with suspected ME diagnosed between 2011 and 2014 were included in the study. The mean hospitalization cost for infants and children was $12,759 and $11,119, respectively, with medication and laboratory test costs of $834 and $1771 for infants and $825 and $855 for children, respectively. Total visit cost increased with delayed LP procedure, ICU stay, and if the etiology was viral (other than enterovirus or arbovirus) or bacterial. Higher diagnostic and treatment costs were associated with delayed LP procedure, etiologic agent, and ICU stay.