Culture and Real-time Polymerase Chain reaction sensitivity in the diagnosis of invasive meningococcal disease: Does culture miss less severe cases?

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

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSIONS

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

4CMenB Vaccination to Prevent Meningococcal B Disease in Vietnam: Expert Review and Opinion

An advisory board meeting was held with experts in Vietnam (Hanoi, August 2022), to review the evidence on invasive meningococcal disease (IMD) epidemiology, clinical management, and meningococcal vaccines to reach a consensus on recommendations for meningococcal vaccination in Vietnam. IMD is a severe disease, with the highest burden in infants and children. IMD presents as meningitis and/or meningococcemia and can progress extremely rapidly. Almost 90% of deaths in children occur within the first 24 h, and disabling sequelae (e.g., limb amputations and neurological damage) occur in up to 20% of survivors. IMD patients are often hospitalized late, due to mild and nonspecific early symptoms and misdiagnosis. Difficulties related to diagnosis and antibiotic misuse mean that the number of reported IMD cases in Vietnam is likely to be underestimated. Serogroup B IMD is predominant in many regions of the world, including Vietnam, where 82% of IMD cases were due to serogroup B (surveillance data from 2012 to 2021). Four component meningococcal B vaccine (4CMenB) is used in many countries (and is part of the pediatric National Immunization Program in 13 countries), with infant vaccination starting from two months of age, and a 2 + 1 dosing schedule. Experts recommend 4CMenB vaccination as soon as possible in Vietnam, starting from two months of age, with a 2 + 1 dosing schedule, and at least completing one dose before 6 months of age.

Use of expanded Neisseria meningitidis serogroup B panels with the serum bactericidal antibody assay for the evaluation of meningococcal B vaccine effectiveness

INTRODUCTION

Neisseria meningitidis serogroup B (NmB) antigens are inherently diverse with variable expression among strains. Prediction of meningococcal B (MenB) vaccine effectiveness therefore requires an assay suitable for use against large panels of epidemiologically representative disease-causing NmB strains. Traditional serum bactericidal antibody assay using exogenous human complement (hSBA) is limited to the quantification of MenB vaccine immunogenicity on a small number of indicator strains.

AREAS COVERED

Additional and complementary methods for assessing strain coverage developed previously include the Meningococcal Antigen Typing System (MATS), Meningococcal Antigen Surface Expression (MEASURE) assay, and genotyping approaches, but these do not estimate vaccine effectiveness. We provide a narrative review of these methods, highlighting a more recent approach involving the hSBA assay in conjunction with expanded NmB strain panels: hSBA assay using endogenous complement in each vaccinated person's serum (enc-hSBA) against a 110-strain NmB panel and the traditional hSBA assay against 14 (4 + 10) NmB strains.

EXPERT OPINION

The enc-hSBA is a highly standardized, robust method that can be used in clinical trials to measure the immunological effectiveness of MenB vaccines under conditions that mimic real-world settings as closely as possible, through the use of endogenous complement and a diverse, epidemiologically representative panel of NmB strains.

Paper-Based Biosensors for the Detection of Nucleic Acids from Pathogens

Paper-based biosensors are microfluidic analytical devices used for the detection of biochemical substances. The unique properties of paper-based biosensors, including low cost, portability, disposability, and ease of use, make them an excellent tool for point-of-care testing. Among all analyte detection methods, nucleic acid-based pathogen detection offers versatility due to the ease of nucleic acid synthesis. In a point-of-care testing context, the combination of nucleic acid detection and a paper-based platform allows for accurate detection. This review offers an overview of contemporary paper-based biosensors for detecting nucleic acids from pathogens. The methods and limitations of implementing an integrated portable paper-based platform are discussed. The review concludes with potential directions for future research in the development of paper-based biosensors.

Diagnostic and treatment dilemmas in well children with petechial rash in the emergency department

This article presents a discussion based on a case study of an eight-month-old boy with petechial rash who presented at the emergency department (ED). Blood tests were obtained and intravenous antibiotics were administered. The patient was admitted to the children's ward and was discharged the next day. It was suspected that the rash was caused by a non-specific viral illness. Non-blanching rashes, such as petechial rash, in well children often lead to diagnostic and treatment dilemmas in the ED. Clinicians fear missing the diagnosis of invasive meningococcal disease, which results in blood tests, cannulation and early administration of antibiotics. Non-blanching rashes have many potential causes and extensive tests and antibiotic treatment may not always be necessary and have the potential to cause harm. A tailored approach to investigate, treat and discharge well children with petechial rash from the ED is advocated.

Clinical and Laboratory Findings of 12 Children with Invasive Meningococcal Disease in Pediatric Intensive Care Unit

Introduction

Invasive meningococcal disease (IMD) is a serious infectious disease requiring stay in a pediatric intensive care unit (PICU) that continues to be associated with high morbidity and mortality rates. Prompt recognition, early antibiotic therapy, and aggressive supportive therapies can reduce mortality. We aimed to assess the clinical and laboratory characteristics of children with IMD. Patients and Methods. We retrospectively evaluated the medical records of 12 children with IMD requiring PICU stay between January 2018 and July 2019.

Results

We followed up 12 patients (five girls and seven boys, 5–168 months of age, and four below one year of age) with IMD (nine patients have meningococcemia with meningitis, and three patients have meningococcemia) in PICU. All children were previously healthy and have not received meningococcal vaccines. Their pediatric risk of mortality (PRISM) scores varies between 5 and 37, four of the patients required mechanical ventilation, and the predicted mortality was 39% at admission. Seven patients had catecholamine refractory septic shock and disseminated intravascular coagulation (DIC). Three of the patients required extracorporeal treatment. The predominant serogroup is Men B (5/12). The mortality rate was 16.6% with early use of antibiotics, fluids, and other interventions.

Conclusion

Mortality related to IMD is higher among children with severe meningococcemia despite early interventions in PICU. Routine use of meningococcal vaccines during childhood would be a better strategy for controlling IMD in both developing and developed countries.

The Role of Molecular Testing in Pediatric Meningitis Surveillance in Southern and East African Countries, 2008-2017

Background

As part of the global Invasive Bacterial Vaccine-Preventable Diseases Surveillance Network, 12 African countries referred cerebrospinal fluid (CSF) samples to South Africa’s regional reference laboratory. We evaluated the utility of real-time polymerase chain reaction (PCR) in detecting and serotyping/grouping Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae (HNS).

Methods

From 2008 to 2017, CSF samples collected from children <5 years old with suspected meningitis underwent routine microbiology testing in-country, and 11 680 samples were submitted for HNS PCR at the regional reference laboratory. Unconditional logistic regression, with adjustment for geographic location, was performed to identify factors associated with PCR positivity.

Results

The overall HNS PCR positivity rate for all countries was 10% (1195 of 11 626 samples). In samples with both PCR and culture results, HNS PCR positivity was 11% (744 of 6747 samples), and HNS culture positivity was 3% (207 of 6747). Molecular serotype/serogroup was assigned in 75% of PCR-positive specimens (762 of 1016). Compared with PCR-negative CSF samples, PCR-positive samples were more often turbid (adjusted odds ratio, 6.80; 95% confidence interval, 5.67–8.17) and xanthochromic (1.72; 1.29–2.28), had elevated white blood cell counts (6.13; 4.71–7.99) and high protein concentrations (5.80; 4.34–7.75), and were more often HNS culture positive (32.70; 23.18–46.12).

Conclusion

PCR increased detection of vaccine-preventable bacterial meningitis in countries where confirmation of suspected meningitis cases is impeded by limited culture capacity.

Time to positivity in bloodstream infection is not a prognostic marker for mortality: analysis of a prospective multicentre randomized control trial

OBJECTIVES

Time to positivity (TTP), calculated automatically in modern blood culture systems, is considered a proxy for microbial load and has been suggested as a potential prognostic marker in bloodstream infections. In this large, multicentre, prospectively collected cohort, our primary analysis aimed to quantify the relationship between the TTP of monomicrobial blood cultures and mortality.

METHODS

Data from a multicentre randomized controlled trial (RAPIDO) in bloodstream infection were analysed. Bloodstream infections were classified into 13 groups/subgroups. The relationship between mortality and TTP was assessed by logistic regression, adjusted for site, organism, and clinical variables, and linear regression was applied to examine the association between clinical variables and TTP. Robustness was assessed by sensitivity analysis.

RESULTS

In total 4468 participants were included in the RAPIDO. After exclusions, 3462 were analysed, with the most common organisms being coagulase-negative staphylococci (1072 patients) and Escherichia coli (861 patients); 785 patients (22.7%) died within 28 days. We found no relationship between TTP and mortality for any groups except for streptococci (odds ratio (OR) with each hour 0.98, 95%CI 0.96-1.00) and Candida (OR 1.03, 95%CI 1.00-1.05). There was large variability between organisms and sites in TTP. Fever (geometric mean ratio (GMR) 0.95, 95%CI 0.92-0.99), age (GMR per 10 years 1.01, 95%CI 1.00-1.02), and neutrophilia were associated with TTP (GMR 1.03, 95%CI 1.02-1.04).

CONCLUSIONS

Time to positivity is not associated with mortality, except in the case of Candida spp. (longer times associated with worse outcomes) and possibly streptococci (shorter times associated with worse outcomes). There was a large variation between median times across centres, limiting external validity.

Etiology of acute meningitis and encephalitis from hospital-based surveillance in South Kazakhstan oblast, February 2017-January 2018

Encephalitis and meningitis (EM) are severe infections of the central nervous system associated with high morbidity and mortality. The etiology of EM in Kazakhstan is not clearly defined, so from February 1, 2017 to January 31, 2018 we conducted hospital-based syndromic surveillance for EM at the Shymkent City Hospital, in the South Kazakhstan region. All consenting inpatients meeting a standard case definition were enrolled. Blood and cerebrospinal fluid (CSF) samples were collected for bacterial culture, and CSF samples were additionally tested by PCR for four bacterial species and three viruses using a cascading algorithm. We enrolled 556 patients. Of these, 494 were of viral etiology (including 4 probable rabies cases), 37 were of bacterial etiology, 19 were of unknown etiology and 6 were not tested. The most commonly identified pathogens included enterovirus (73%, n = 406 cases), herpes simplex virus (12.8%, n = 71), and Neisseria meningitidis (3.8%, n = 21). The incidence rates (IRs) for enteroviral and meningococcal EM were found to be 14.5 and 0.7 per 100,000 persons, respectively. The IR for bacterial EM using both PCR and culture results was 3–5 times higher compared to culture-only results. Antibacterial medicines were used to treat 97.2% (480/494) of virus-associated EM. Incorporation of PCR into routine laboratory diagnostics of EM improves diagnosis, pathogen identification, ensures IRs are not underestimated, and can help avoid unnecessary antibacterial treatment.

Increased nasal Streptococcus pneumoniae presence in Western environment associated with allergic conditions in Chinese immigrants

BACKGROUND

Chinese immigrants living in Australia experience increased allergic conditions: asthma, eczema, hay fever and wheeze. Recently we reported diminished innate cytokine responses in long-term immigrants, potentially increasing their pathogenic viral load and microbial carriage. We hypothesise that a Western environment changes the nasal microbiome profile, and this altered profile may be associated with the development of allergic conditions. In this cross-sectional study, we aimed to examine the loading of viral and microbial respiratory pathogens in the upper airway.

METHODS

Adult Chinese immigrants were grouped depending on time spent in Australia: short-term (<6 years) or long-term (≥6 years). First, age- and gender-matched immigrants were selected for an initial screen using quantitative polymerase chain reaction (qPCR) micro-array panels. Then based on initial results the viruses, human parainfluenza 3 and rhinovirus, and the bacteria, Burkholderia spp., Staphylococcus aureus and Streptococcus pneumoniae, were validated using qPCR in the population. Associations for bacterial prevalence with atopic phenotypes were investigated.

RESULTS

Pooling the initial screen and validation subjects, S. aureus and S. pneumoniae had higher prevalence in long-term compared with short-term subjects (25.0% vs 8.1%, P = 0.012; and 76.8% vs 48.4%, P = 0.002). Those immigrants with nasal S. pneumoniae presence resided longer (average time 90.4 months) in Australia than immigrants without S. pneumoniae (52.7 months; P = 0.001). After adjusting for confounders, Chinese immigrants with S. pneumoniae carriage have a five-fold increased risk of doctor-diagnosed eczema (odds ratio, OR 5.36, 95% CI: 1.10-26.14; P = 0.038) compared to immigrants without S. pneumoniae carriage. There was a trend of S. pneumoniae abundance correlating with reduced host Toll-like receptor gene expression.

CONCLUSION

Our findings suggest that nasal S. pneumoniae may play a role in the development of allergic conditions in Chinese immigrants in a Western environment.

Molecular typing of group B Neisseria meningitidis'subcapsular antigens directly on biological samples demonstrates epidemiological congruence between culture-positive and -negative cases: A surveillance study of invasive disease over a 13-year period

BACKGROUND

Surveillance of serogroup B Neisseria meningitidis (MenB) subcapsular antigen variant distribution in invasive disease (IMD) is fundamental for multicomponent vaccine coverage prediction. IMD incidence in Tuscany in 2018 was 0.37/100,000 inhabitants, with MenB representing 57% of cases. More than 50% of MenB responsible for IMD cannot be grown in culture, and molecular characterization of these cases is often lacking. The aim of the present study was to describe the distribution of MenB subcapsular antigens, comparing their distribution in culture-positive and culture-negative cases.

METHODS

Molecular data regarding clonal complexes and subcapsular antigen variants of the 55 MenB-IMD occurring in Tuscany from 2007 to 2019 were made available, and their distribution between culture-positive and culture-negative cases was compared. Genetic-MATS and MenDeVAR prediction systems were used to assess multicomponent vaccine coverage predictions.

RESULTS

Culture-positive and culture-negative cases presented a similar percentage representation of fHbp subfamilies. Clonal complex 162 was almost constantly associated with fHbp B231/v1.390, Neisserial-heparin-binding-antigen (NHBA) peptide 20, and PorinA P1.22,14 (BAST-3033): these were the most represented antigenic variants, both in culture-positive and culture-negative groups. Point-estimate 4CMenB coverage prediction was 88.5% (84.6%-92.3%).

CONCLUSIONS

Our data demonstrate that non-cultivable meningococci, responsible for IMD, possess genetic variants of subcapsular antigens that are representative of what has been observed in culture. The vaccine-related antigenic epidemiology of MenB is thus similar in both groups. One of the first on-field applications of gMATS and MenDeVAR identifies their major advantage in their accessibility and in the possibility of dynamic data implementation that must be pursued continuously in the future.

Acute Febrile Illness Among Children in Butajira, South-Central Ethiopia During the Typhoid Fever Surveillance in Africa Program

Background

Clearly differentiating causes of fever is challenging where diagnostic capacities are limited, resulting in poor patient management. We investigated acute febrile illness in children aged ≤15 years enrolled at healthcare facilities in Butajira, Ethiopia, during January 2012 to January 2014 for the Typhoid Fever Surveillance in Africa Program.

Methods

Blood culture, malaria microscopy, and blood analyses followed by microbiological, biochemical, and antimicrobial susceptibility testing of isolates were performed. We applied a retrospectively developed scheme to classify children as malaria or acute respiratory, gastrointestinal or urinary tract infection, or other febrile infections and syndromes. Incidence rates per 100 000 population derived from the classification scheme and multivariate logistic regression to determine fever predictors were performed.

Results

We rarely observed stunting (4/513, 0.8%), underweight (1/513, 0.2%), wasting (1/513, 0.2%), and hospitalization (21/513, 4.1%) among 513 children with mild transient fever and a mean disease severity score of 12 (95% confidence interval [CI], 11–13). Blood cultures yielded 1.6% (8/513) growth of pathogenic agents; microscopy detected 13.5% (69/513) malaria with 20 611/µL blood (95% CI, 15 352–25 870) mean parasite density. Incidences were generally higher in children aged ≤5 years than >5 to ≤15 years; annual incidences in young children were 301.3 (95% CI, 269.2–337.2) for malaria and 1860.1 (95% CI, 1778.0–1946.0) for acute respiratory and 379.9 (95% CI, 343.6–420.0) for gastrointestinal tract infections.

Conclusions

We could not detect the etiological agents in all febrile children. Our findings may prompt further investigations and the reconsideration of policies and frameworks for the management of acute febrile illness.

Effectiveness and Impact of the 4CMenB Vaccine against Group B Meningococcal Disease in Two Italian Regions Using Different Vaccination Schedules: A Five-Year Retrospective Observational Study (2014-2018)

Background: A few years after the introduction in Italy of a four-component anti-meningococcal B vaccine (4CMenB), we evaluated the effectiveness and impact of vaccination in two regions using different schedules (2, 4, 6, 12 months in Tuscany vs. 7, 9, 15 months in Veneto) through an observational retrospective study. Methods: Vaccination started in 2014 in Tuscany and in 2015 in Veneto; the data collected referred to the period 2006–2018 for Tuscany and 2007–2018 for Veneto. Cases of invasive meningococcal disease due to N. Meningitidis B were identified by culture and/or real-time PCR. Results: In Tuscany, pre-vaccine incidence was 1.96 (95% CL 1.52; 2.40) and dropped to 0.62 (95% CL 0.60; 0.64) in the post-4CMenB era. Evaluating only vaccinated children, post-4CMenB incidence was 0.12 (95% CL 0.08; 0.15). In Veneto pre-vaccine incidence was 1.94 (95% CL 1.92; 1.96) and dropped to 1.34 (95% CL 1.31; 1.38) in the post-4CMenB era. In the vaccinated population, MenB incidence was 0.53 (95% CL 0.50; 0.56). Vaccine effectiveness was 93.6% (95% CL 55.4; 99.1) in Tuscany and 91.0% (95% CL 59.9; 97.9) in Veneto, with mean vaccine coverages of 83.9% and 81.7%, respectively. The overall impact (evaluating both vaccinated and unvaccinated children) was 0.68 (95% CL 0.10; 0.89) in Tuscany and 0.31 (95% CL −0.56; 0.69) in Veneto; the total impact (evaluating only vaccinated children) was 0.94 (95% CL 0.56; 0.99) and 0.90 (95% CL 0.57; 0.97), respectively. The relative case reduction (RCR) was 65% in Tuscany and 31% in Veneto. Considering the vaccinated population, the RCR was equal to 91% and 80%, respectively. Conclusion: In conclusion, 4CMenB appears to have a very high effectiveness in Italy; the impact of vaccination appears greater where the immunization program is started early.

Invasive meningococcal disease in Italy: from analysis of national data to an evidence-based vaccination strategy

Introduction

Invasive meningococcal disease (IMD) is one of the most severe vaccine-preventable disease not yet under control. In Italy, although different anti-meningococcal vaccines are available, their offer among regions is heterogeneous. The aim of this study is to describe the epidemiology of IMD in Italy based on analysis of national surveillance data for 2011-2017 to optimize the vaccination strategy.

Methods

IMD surveillance data from the Italian National Health Institute were analysed. Microsoft Excel was used to present trend analysis, stratifying by age and serogroups.

Results

In Italy, during the period 2011-2017, the incidence of IMD increased from 0.25 cases/100,000 inhabitants in 2011 to 0.33 cases/100,000 in 2017. Most cases after 2012 were caused by non-B serogroups. The number of cases in subjects aged 25-64 years increased steadily after 2012 (36 cases in 2011, 79 in 2017), mostly due to non-B serogroups, representing more than 65% of cases in those aged 25+ years.

Conclusions

In the period from 2011 to 2017, the incidence of IMDs increased in Italy. The increase, probably due also to a better surveillance, highlights the importance of the disease in the adult population and the high level of circulation of non-B serogroups in particular after 2012. Our analysis supports an anti-meningococcal vaccination plan in Italy that should include the highest number of preventable serogroups and be aimed at vaccinating a wider population through a multicohort strategy.

A pooled analysis of the LAMP assay for the detection of Neisseria meningitidis

Background

Neisseria meningitidis is a major cause of bacterial meningitis, and these infections are associated with a high mortality rate. Rapid and reliable diagnosis of bacterial meningitis is critical in clinical practice. However, this disease often occurs in economically depressed areas, so an inexpensive, easy to use, and accurate technology is needed. We performed a pooled-analysis to assess the potential of the recently developed loop-mediated isothermal amplification (LAMP) assay for detection of meningococcus.

Methods

Pubmed, Embase, and Web of Science were searched to identify original studies that used the LAMP assay to detect meningococcus. After pooling of data, the sensitivity and specificity were calculated, a summary receiver operating characteristic (SROC) curve was determined, and the area under the SROC curve was computed to determine diagnostic accuracy. Publication bias was assessed using Deek’s funnel plot.

Results

We examined 14 studies within 6 publications. The LAMP assay had high sensitivity (94%) and specificity (100%) in the detection of meningococcus in all studies. The area under the SROC curve (0.980) indicated high overall accuracy of the LAMP assay. There was no evidence of publication bias.

Discussion

The LAMP assay has accuracy comparable to bacterial culture and PCR for detection of meningococcus, but is less expensive and easier to use. We suggest the adoption of the LAMP assay to detect meningococcus, especially in economically depressed areas.

Neisseria meningitidis serogroup C causing primary polyarthritis in an octogenarian

A man in his 80s presented to the hospital with a 36-hour history of fever, myalgia, bilateral shoulder and right knee pain. Joint fluid aspirates from his shoulders and right knee isolated Gram-negative diplococci. After failing to grow on standard and selective media, Neisseria meningitidis was identified by 16s PCR and subsequently typed as serogroup C. He had no clinical features of meningitis or meningococcaemia. Blood cultures were negative and an EDTA blood sample was negative for meningococcal ctrA gene. Urine PCR was negative for Neisseria gonorrhoeae He was treated successfully with two arthroscopic joint washouts of his right knee, aspirates of both shoulders, 40 days of intravenous ceftriaxone and intensive physiotherapy as both an inpatient and outpatient. In the literature, we have not found any previously documented cases of serogroup C meningococcus causing polyarticular primary septic arthritis in this age group or guidance on duration of antibiotic treatment. Literature on the impact of rehabilitation to baseline function was also found to be lacking. Although rare, primary meningococcal arthritis (PMA) should be considered as a differential diagnosis in cases of acute polyarticular septic arthritis. Polyarticular PMA in older adults may require prolonged rehabilitation before one might expect to return to premorbid function.

Neisseria meningitidis with H552Y substitution on rpoB gene shows attenuated behavior in vivo: report of a rifampicin-resistant case following chemoprophylaxis

We present the first Italian reported case of an invasive meningococcal disease with rifampicin-resistance (Rif-R)secondary to chemoprophylaxis. The case is entered in a cluster of two IMDs registered in Tuscany, Italy, in November 2019 caused by two non-differentiable group-C Neisseria meningitidis belonging to ST-11 clonal-complex. The contact case, differently from the index, harbored H552Y mutation on rpoB gene which is known to confer Rif-R putting a high-cost fee on bacterial fitness. The extremely mild clinical presentation in the contact can constitute an in vivo demonstration of the virulence attenuation observed in vitro for H552Ymutants. Clinicians should be aware of the possibility of secondary cases with induced Rif-R and keep a high level of suspicion on contacts who received rifampicin-chemoprophylaxis. Molecular characterization of Rif-R should be performed routinely directly on biological samples and not only on isolates, in order to rapidly detect rare cases of resistance and consequently modify chemoprophylaxis for contacts.

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.

Spatiotemporal Analysis of Serogroup C Meningococcal Meningitis Spread in Niger and Nigeria and Implications for Epidemic Response

BACKGROUND

After the re-emergence of serogroup C meningococcal meningitis (MM) in Nigeria and Niger, we aimed to re-evaluate the vaccination policy used to respond to outbreaks of MM in the African meningitis belt by investigating alternative strategies using a lower incidence threshold and information about neighboring districts.

METHODS

We used data on suspected and laboratory-confirmed cases in Niger and Nigeria from 2013 to 2017. We calculated global and local Moran's I-statistics to identify spatial clustering of districts with high MM incidence. We used a Pinner model to estimate the impact of vaccination campaigns occurring between 2015 and 2017 and to evaluate the impact of 3 alternative district-level vaccination strategies, compared with that currently used.

RESULTS

We found significant clustering of high incidence districts in every year, with local clusters around Tambuwal, Nigeria in 2013 and 2014, Niamey, Niger in 2016, and in Sokoto and Zamfara States in Nigeria in 2017.We estimate that the vaccination campaigns implemented in 2015, 2016, and 2017 prevented 6% of MM cases. Using the current strategy but with high coverage (85%) and timely distribution (4 weeks), these campaigns could have prevented 10% of cases. This strategy required the fewest doses of vaccine to prevent a case. None of the alternative strategies we evaluated were more efficient, but they would have prevented the occurrence of more cases overall.

CONCLUSIONS

Although we observed significant spatial clustering in MM in Nigeria and Niger between 2013 and 2017, there is no strong evidence to support a change in methods for epidemic response in terms of lowering the intervention threshold or targeting neighboring districts for reactive vaccination.