Performance evaluation of a combination Plasmodium dual-antigen CRP rapid diagnostic test in Lambaréné, Gabon.

PURPOSE: The consequent use of malaria rapid diagnostic tests (RDTs) preceding a treatment decision has improved the global management of malaria. A combination RDT, including an inflammation marker to potentially guide antibiotic prescription, could improve the management of acute febrile illness (AFI). METHODS: We performed a prospective, cross-sectional study in Gabon evaluating the STANDARD Malaria/CRP DUO (S-DUO) RDT. Participants aged 2 to 17 years with fever at presentation and/or a history of fever < 7 days were enrolled. Expert microscopy, SD Bioline Malaria Ag P.f/Pan test for malaria detection, and NycoCard CRP device for CRP were used as comparators. AFI cases were classified on a spectrum encompassing bacterial vs. non-bacterial infection. RESULTS: 415 participants with AFI were enrolled. S-DUO RDT sensitivity and specificity for malaria detection vs. microscopy were 99·1% (95·2-100%) and 72·7% (64·3-80·1%); and for CRP detection (20 mg/L and above) 86·9% (80-92%) and 87% (79·2-92·7%), respectively. The difference in CRP levels between bacterial infection (mean = 41·2 mg/L) and other causes of fever, measured from our study population using the Nycocard device, was statistically significant (p < 0·01); CRP precision-recall AUC to distinguish bacterial infection class vs. non-bacterial classifications was 0·79. CONCLUSION: S-DUO RDT is suitable for malaria detection in moderate-to-high malaria transmission settings such as in Lambaréné; however, a CRP band detection limit > 40 mg/L is more adequate for indication of antibiotic prescription for AFI cases in Gabon.

Toward the Development of a Circulating Free DNA-Based In Vitro Diagnostic Test for Infectious Diseases: a Review of Evidence for Tuberculosis.

The detection of circulating free DNA (cfDNA) has transformed the field of oncology and prenatal diagnostics. Clinical application of cfDNA for disease diagnosis and monitoring, however, is relatively recent in the field of infectious disease. The potential of cfDNA as a noninvasive diagnostic and monitoring tool is especially promising for tuberculosis (TB), as it enables the detection of both pulmonary and extrapulmonary TB from easily accessible urine and/or blood samples from any age group. However, despite the potential of cfDNA detection to identify TB, very few studies are described in the literature to date. A comprehensive search of the literature identified 15 studies that report detecting Mycobacterium tuberculosis DNA in the blood and urine of TB patients with nongenitourinary disease, but in only six of them were the methodological steps considered suitable for cfDNA isolation and detection. The sensitivities and specificities for the diagnosis of pulmonary and extrapulmonary TB cases reported in these six studies are highly variable, falling in the range of 29% to 79% and 67% to 100%, respectively. While most studies could not meet the performance requirements of the high-priority target product profiles (TPP) published by the World Health Organization (WHO), the study results nonetheless show promise for a point-of-care detection assay. Better designed prospective studies, using appropriate samples, will be required to validate cfDNA as a TB biomarker.

Continuous-flow, microfluidic, qRT-PCR system for RNA virus detection.

One of the main challenges in the diagnosis of infectious diseases is the need for rapid and accurate detection of the causative pathogen in any setting. Rapid diagnosis is key to avoiding the spread of the disease, to allow proper clinical decisions to be made in terms of patient treatment, and to mitigate the rise of drug-resistant pathogens. In the last decade, significant interest has been devoted to the development of point-of-care reverse transcription polymerase chain reaction (PCR) platforms for the detection of RNA-based viral pathogens. We present the development of a microfluidic, real-time, fluorescence-based, continuous-flow reverse transcription PCR system. The system incorporates a disposable microfluidic chip designed to be produced industrially with cost-effective roll-to-roll embossing methods. The chip has a long microfluidic channel that directs the PCR solution through areas heated to different temperatures. The solution first travels through a reverse transcription zone where RNA is converted to complementary DNA, which is later amplified and detected in real time as it travels through the thermal cycling area. As a proof of concept, the system was tested for Ebola virus detection. Two different master mixes were tested, and the limit of detection of the system was determined, as was the maximum speed at which amplification occurred. Our results and the versatility of our system suggest its promise for the detection of other RNA-based viruses such as Zika virus or chikungunya virus, which constitute global health threats worldwide. Graphical abstract Photograph of the RT-PCR thermoplastic chip.

Low-cost, real-time, continuous flow PCR system for pathogen detection.

In this paper, we present a portable and low cost point-of-care (POC) PCR system for quantitative detection of pathogens. Our system is based on continuous flow PCR which maintains fixed temperatures zones and pushes the PCR solution between two heated areas allowing for faster heat transfer and as a result, a faster PCR. The PCR system is built around a 46.0 mm × 30.9 mm × 0.4 mm disposable thermoplastic chip. In order to make the single-use chip economically viable, it was manufactured by hot embossing and was designed to be compatible with roll-to-roll embossing for large scale production. The prototype instrumentation surrounding the chip includes two heaters, thermal sensors, and an optical system. The optical system allows for pathogen detection via real time fluorescence measurements. FAM probes were used as fluorescent reporters of the amplicons generated during the PCR. To demonstrate the function of the chip, two infectious bacteria targets were selected: Chlamydia trachomatis and Escherichia coli O157:H7. For both bacteria, the limit of detection of the system was determined, PCR efficiencies were calculated, and different flow velocities were tested. We have demonstrated successful detection for these two bacterial pathogens highlighting the versatility and broad utility of our portable, low-cost, and rapid PCR diagnostic device.

Analytical performance of 17 commercially available point-of-care tests for CRP to support patient management at lower levels of the health system.

Accurate and precise point-of-care (POC) testing for C-reactive protein (CRP) can help support healthcare providers in the clinical management of patients. Here, we compared the analytical performance of 17 commercially available POC CRP tests to enable more decentralized use of the tool. The following CRP tests were evaluated. Eight quantitative tests: QuikRead go (Aidian), INCLIX (Sugentech), Spinit (Biosurfit), LS4000 (Lansionbio), GS 1200 (Gensure Biotech), Standard F200 (SD Biosensor), Epithod 616 (DxGen), IFP-3000 (Xincheng Biological); and nine semi-quantitative tests: Actim CRP (ACTIM), NADAL Dipstick (nal von minden), NADAL cassette (nal von minden), ALLTEST Dipstick (Hangzhou Alltest Biotech), ALLTEST Cassette cut-off 10-40-80 (Hangzhou Alltest Biotech), ALLTEST Cassette cut-off 10-30 (Hangzhou Alltest Biotech), Biotest (Hangzhou Biotest Biotech), BTNX Quad Line (BTNX), BTNX Tri Line (BTNX). Stored samples (n = 660) had previously been tested for CRP using Cobas 8000 Modular analyzer (Roche Diagnostics International AG, Rotkreuz, Switzerland (reference standards). CRP values represented the clinically relevant range (10-100 mg/L) and were grouped into four categories (<10 mg/L, 10-40 mg/L or 10-30 mg/L, 40-80 mg/L or 30-80 mg/L, and > 80mg/L) for majority of the semi-quantitative tests. Among the eight quantitative POC tests evaluated, QuikRead go and Spinit exhibited better agreement with the reference method, showing slopes of 0.963 and 0.921, respectively. Semi-quantitative tests with the four categories showed a poor percentage agreement for the intermediate categories and higher percentage agreement for the lower and upper limit categories. Analytical performance varied considerably for the semi-quantitative tests, especially among the different categories of CRP values. Our findings suggest that quantitative tests might represent the best choice for a variety of use cases, as they can be used across a broad range of CRP categories.

Physical and thermal strain of firefighters according to the firefighting tactics used to suppress wildfires.

The aim of this study was to analyse the physiological strain of firefighters, using heart rate (HR) and core temperature, during real wildfire suppression according to the type of attack performed (direct, indirect or mixed). Three intensity zones were established according to the HR corresponding to the ventilatory threshold (VT) and respiratory compensation threshold (RCT): zone 1, RCT. The exercise workload (training impulse (TRIMP)), the physiological strain index (PSI) and the cumulative heat strain index(CHSI) were calculated using the time spent in each zone, and the HR and core temperature, respectively. Significantly higher mean HR, time spent in Z2 and Z3 and TRIMP h(-1) were found in direct and mixed versus indirect attacks. The highest PSI and CHSI were observed in the direct attack. In conclusion, exercise strain and combined thermal strain, but not core temperature during wildfire suppression, are related to the type of attack performed. STATEMENT OF RELEVANCE: Our findings demonstrated that wildfire firefighting is associated with high physiological demands, which vary significantly depending on the tactics chosen for performing the task. These results should be kept in mind when planning programmes to improve wildland firefighters' physical fitness, which will allow improvement in their performance.

Distinguishing bacterial versus non-bacterial causes of febrile illness - A systematic review of host biomarkers.

BACKGROUND: Acute febrile illnesses (AFIs) represent a major disease burden globally; however, the paucity of reliable, rapid point-of-care testing makes their diagnosis difficult. A simple tool for distinguishing bacterial versus non-bacterial infections would radically improve patient management and reduce indiscriminate antibiotic use. Diagnostic tests based on host biomarkers can play an important role here, and a target product profile (TPP) was developed to guide development. OBJECTIVES: To qualitatively evaluate host biomarkers that can distinguish bacterial from non-bacterial causes of AFI. DATA SOURCES: The PubMed database was systematically searched for relevant studies published between 2015 and 2019. STUDY ELIGIBILITY CRITERIA: Studies comparing diagnostic performances of host biomarkers in patients with bacterial versus non-bacterial infections were included. PARTICIPANTS: Studies involving human participants and/or human samples were included. METHODS: We collected information following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A risk of bias assessment was performed, based on a modified QUADAS-2 (Quality Assessment of Diagnostic Accuracy Score 2). RESULTS: We identified 1107 publications. Following screening, 55 publications were included, with 265 biomarker entries. Entries mostly comprised protein biomarkers (58.9%), followed by haematological, RNA, and metabolite biomarkers (15.5%, 8.7%, 12.5%). Sensitivity/specificity was reported for 45.7% of biomarker entries. We assessed a high overall risk of bias for most entries (75.8%). In studies with low/medium risk of bias, four biomarker entries tested in blood samples had sensitivity/specificity of more than 0.90/0.80. Only 12 additional biomarker entries were identified with sensitivity/specificity of more than 0.65/0.65. CONCLUSIONS: Most recently assessed biomarkers represent well-known biomarkers, e.g. C-reactive protein and procalcitonin. Some protein biomarkers with the highest reported performances include a combined biomarker signature (CRP, IP-10, and TRAIL) and human neutrophil lipocalin (HNL). Few new biomarkers are in the pipeline; however, some RNA signatures show promise. Further high-quality studies are needed to confirm these findings.

Anticipating the future: prognostic tools as a complementary strategy to improve care for patients with febrile illnesses in resource-limited settings.

In low-income and middle-income countries, most patients with febrile illnesses present to peripheral levels of the health system where diagnostic capacity is very limited. In these contexts, accurate risk stratification can be particularly impactful, helping to guide allocation of scarce resources to ensure timely and tailored care. However, reporting of prognostic research is often imprecise and few prognostic tests or algorithms are translated into clinical practice.Here, we review the often-conflated concepts of prognosis and diagnosis, with a focus on patients with febrile illnesses. Drawing on a recent global stakeholder consultation, we apply these concepts to propose three use-cases for prognostic tools in the management of febrile illnesses in resource-limited settings: (1) guiding referrals from the community to higher-level care; (2) informing resource allocation for patients admitted to hospital and (3) identifying patients who may benefit from closer follow-up post-hospital discharge. We explore the practical implications for new technologies and reflect on the challenges and knowledge gaps that must be addressed before this approach could be incorporated into routine care settings.Our intention is that these use-cases, alongside other recent initiatives, will help to promote a harmonised yet contextualised approach for prognostic research in febrile illness. We argue that this is especially important given the heterogeneous settings in which care is often provided for patients with febrile illnesses living in low-income and middle-income countries.

The good and the bad: using C reactive protein to distinguish bacterial from non-bacterial infection among febrile patients in low-resource settings.

C reactive protein (CRP), a marker for the presence of an inflammatory process, is the most extensively studied marker for distinguishing bacterial from non-bacterial infections in febrile patients. A point-of-care test for bacterial infections would be of particular use in low-resource settings where other laboratory diagnostics are not always available, antimicrobial resistance rates are high and bacterial infections such as pneumonia are a leading cause of death. This document summarises evidence on CRP testing for bacterial infections in low-income and middle-income countries (LMICs). With a push for universal health coverage and prevention of antimicrobial resistance, it is important to understand if CRP might be able to do the job. The use of CRP polarised the global health community and the aim of this document is to summarise the 'good and the bad' of CRP in multiple settings in LMICs. In brief, the literature that was reviewed suggests that CRP testing may be beneficial in low-resource settings to improve rational antibiotic use for febrile patients, but the positive predictive value is insufficient to allow it to be used alone as a single tool. CRP testing may be best used as part of a panel of diagnostic tests and algorithms. Further studies in low-resource settings, particularly with regard to impact on antibiotic prescribing and cost-effectiveness of CRP testing, are warranted.

Bacterial versus non-bacterial infections: a methodology to support use-case-driven product development of diagnostics.

Acute febrile illness (AFI) is one of the most common reasons for seeking medical care in low-income and middle-income countries. Bacterial infections account for a relatively small proportion of AFIs; however, in the absence of a simple diagnostic test to guide clinical decisions, healthcare professionals often presume that a non-malarial febrile illness is bacterial in origin, potentially resulting in inappropriate antibiotic use. An accurate differential diagnostic tool for AFIs is thus essential, to both limit antibiotic use to bacterial infections and address the antimicrobial resistance crisis that is emerging globally, without resorting to multiple or complex pathogen-specific assays. The Biomarker for Fever-Diagnostic (BFF-Dx) study is one of the largest fever biomarker studies ever undertaken. We collected samples and classified disease aetiology in more than 1900 individuals, distributed among enrolment centres in three countries on two continents. Identical protocols were followed at each study site, and the same analyses were conducted in each setting, enabling like-with-like comparisons to be made among the large sample set generated. The BFF-Dx methodology can act as a model for other researchers, facilitating wider utility of the work in the future. The established sample collection is now accessible to researchers and companies and will facilitate the development of future fever-related diagnostic tests. Here, we outline the methodology used to determine the sample populations and to differentiate bacterial versus non-bacterial AFIs. Future publications will set out in more detail the study's demographics, the causes of fever identified and the performance of selected biomarkers.

Efficacy of environmental friendly disinfectants against the major postharvest pathogens of stone fruits on plastic and wood surfaces.

Disinfection of surface facilities during postharvest handling operation is an important practice to avoid secondary fruit infections at stone fruit packinghouses. The aim of this work was to evaluate the effect of six environmental friendly disinfectants against Monilinia fructicola, Penicillium expansum, Rhizopus spp., and Alternaria spp. on plastic and wood surfaces. Hydrogen peroxide, peracetic acid, sodium hypochlorite, Mico-E-pro®, Proallium FRD-N®, and DMC Clean-CNS® were used as the disinfectants. Untreated and surfaces treated with water were used as controls. Plastic and wood surfaces were sampled with Rodac plates at 2 and 24 h after treatments and the number of colonies were counted. In general, all disinfectants reduce the number of viable conidia from all studied surfaces. Hydrogen peroxide used in a concentration of 150 mg L-1 was the less effective disinfectant in all studied pathogens. The commercial product Mico-E-pro® composed of oregano, onion, and orange extract at a dose of 10 mg L-1 was the most effective disinfectant. Rhizopus spp. was the pathogen more resistant to the disinfectants followed by P. expansum, M. fructicola, and Alternaria spp. Water decreased the number of conidia adhered to the surface. In addition, the untreated control showed substantial conidia reduction after 24 h of artificial inoculation.

A systematic review of biomarkers to detect active tuberculosis.

Millions of cases of tuberculosis (TB) go undiagnosed each year. Better diagnostic tools are urgently needed. Biomarker-based or multiple marker biosignature-based tests, ideally performed on blood or urine, for the detection of active TB might help to meet target product profiles proposed by the World Health Organization for point-of-care testing. We conducted a systematic review to summarize evidence on proposed biomarkers and biosignatures and evaluate their quality and level of evidence. We screened the titles and abstracts of 7,631 citations and included 443 publications that fulfilled the inclusion criteria and were published in 2010-2017. The types of biomarkers identified included antibodies, cytokines, metabolic activity markers, mycobacterial antigens and volatile organic compounds. Only 47% of studies reported a culture-based reference standard and diagnostic sensitivity and specificity. Forty-four biomarkers (4%) were identified in high-quality studies and met the target product profile minimum criteria, of which two have been incorporated into commercial assays. Of the 44 highest-quality biomarkers, 24 (55%) were multiple marker biosignatures. No meta-analyses were performed owing to between-study heterogeneity. In conclusion, TB biomarker discovery studies are often poorly designed and findings are rarely confirmed in independent studies. Few markers progress to a further developmental stage. More validation studies that consider the intended diagnostic use cases and apply rigorous design are needed. The extracted data from this review are currently being used by FIND as the foundation of a dynamic database in which biomarker data and developmental status will be presented.

Author Correction: A systematic review of biomarkers to detect active tuberculosis.

In the original version of this Analysis, author Seda Yerlikaya was mistakenly spelled as Seda Yerliyaka. This has now been amended.

Preparation and metabolic characterization of isolated rat lung cells.

Collagenase digestion of minced lung tissue yielded isolated cells, functionally viable as judged by several metabolic and morphological criteria, representative of all the cell species normally present in the tissue. The efficiency of the isolation procedure was about 25 per cent. Aerobic metabolism was not affected by most of the substrates tested except by succinate which increased oxygen utilization, and glucose, fructose and octanoate which significantly decreased oxygen uptake. Since no significant changes have been observed in the cellular adenine nucleotide content during glucose depression of aerobic metabolism it is concluded that the glycolytic flux had to be sufficient as to account for the decrease in the mitochondrial energy production. The mechanism responsible for these effects as well as their physiological significance are discussed herewith.

[Current status of the degree of malnutrition in hospitalized patients of the Community of La Rioja]. / Estado actual del grado de desnutrición en los pacientes hospitalizados de la Comunidad de La Rioja.

UNLABELLED: Recent studies have reflected the prevalence of malnutrition within the hospital sphere. The high incidence of malnutrition in hospitals and the negative effect this has on the evolution of patients, since complications are significantly greater in undernourished patients, make it important to find out the nutritional status of patients when they are admitted to hospital and to follow their progress. In the La Rioja region, there have been no prior studies establishing the nutritional status of patients in hospital, so this study was undertaken. It is important to know whether malnutrition is present, the degree of any malnutrition found, and, where necessary, to make the medical and nursing staff aware of the importance of proper nutritional care during a hospital stay. MATERIALS AND METHODS: In a sample of 240 patients selected at random, a nutritional assessment was made on admission. If the patients were still hospitalized one week later, the nutritional assessment was repeated. RESULTS: After the initial assessment, only 12.5% of the 240 patients showed normal nutritional status; mild malnutrition was seen in 55% of cases while moderate and severe cases represented 28.3% and 0.8%, with the most prevalent types of malnutrition being kwasiorkor and mixed (31.6% and 29.6%, respectively). There was no statistical association between the sex of the patient and the degree of malnutrition (p > 0.05). On analysis of the cases by age group, those patients aged less than 65 years mainly presented a marasmus-like and mixed malnutrition, both to a slight degree, whereas the most prevalent malnutrition in patients over the age of 65 was the kwashiorkor type. Among patients with slight and moderate degrees of malnutrition, most of them were diagnosed as suffering from digestive-system related pathologies. After one week, 37.5% of them continued in hospital and approximately half of those presenting normal nutritional status on admission were found to have a status of slight malnutrition.

Estado actual del grado de desnutrición en los pacientes hospitalizados de la Comunidad de La Rioja / Current status of the degree of malnutrition in institutionalized patients in the region of La Rioja

Estudios recientes reflejan una importante prevalencia de malnutrición en el ámbito hospitalario. La elevada incidencia de desnutrición en este ámbito y el efecto negativo que ésta tiene sobre la evolución de los pacientes, ya que las complicaciones en pacientes malnutridos son significativamente mayores, hace que sea importante conocer cuál es el estado nutricional de los pacientes en el momento que ingresan en el hospital y hacer un seguimiento de su evolución. En la Comunidad Autónoma de La Rioja no se ha realizado ningún estudio que establezca el estado nutritivo de los pacientes hospitalizados, lo que motivó este trabajo. Es importante conocer si hay desnutrición, cuál es su grado y, si fuese necesario, concienciar al personal médico y de enfermería de la importancia del cuidado nutricional durante la estancia hospitalaria. Material y métodos: Sobre una muestra de 240 pacientes seleccionados de forma aleatoria, se realizó una valoración nutricional en el momento del ingreso. Al cabo de una semana, si continuaban ingresados se les repitió la valoración nutricional. Resultados: Tras la valoración inicial, de los 240 pacientes sólo el 12,5 por ciento presentó un estado nutricional normal, la desnutrición de grado leve se reflejó en un 55 por ciento de los casos y las de grado moderado y grave aparecieron en un 28,3 por ciento y 0,8 por ciento, siendo los tipos de desnutrición kwashiorkor y mixto los más prevalentes (31,6 por ciento y 29,6 por ciento respectivamente). No hubo asociación estadística entre el sexo y el grado de desnutrición (P > 0,05).Analizando los casos por grupos de edades, aquellos pacientes con edades inferiores a 65 años presentaban principalmente una desnutrición de tipo marasmo y mixta, ambas de grado leve, mientras que en pacientes mayores de 65 años la desnutrición más prevalente fue la de tipo kwashiorkor. La mayoría de los pacientes con grado de desnutrición leve y moderado, habían sido diagnosticados de patología diagnosticadas con el aparado digestivo. Tras una semana continuaban ingresados el 37,5 por ciento y entre los que presentaron un estado nutricional normal al ingreso, se dio la circunstancia que en aproximadamente la mitad de ellos, el estado nutricional pasó a grado leve (AU)

Recent studies have reflected the prevalence of malnutrition within the hospital sphere. The high incidence of malnutrition in hospitals and the negative effect this has on the evolution of patients, since complications are significantly greater in undernourished patients, make it important to find out the nutritional status of patients when they are admitted to hospital and to follow their progress. In the La Rioja region, there have been no prior studies establishing the nutritional status of patients in hospital, so this study was undertaken. It is important to know whether malnutrition is present, the degree of any malnutrition found, and, where necessary, to make the medical and nursing staff aware of the importance of proper nutritional care during a hospital stay. Materials and Methods: In a sample of 240 patients selected at random, a nutritional assessment was made on admission. If the patients were still hospitalized one week later, the nutritional assessment was repeated. Results: After the initial assessment, only 12.5% of the 240 patients showed normal nutritional status; mild malnutrition was seen in 55% of cases while mo-derate and severe cases represented 28.3% and 0.8%, with the most prevalent types of malnutrition being kwasiorkor and mixed (31.6% and 29.6%, respectively). There was no statistical association between the sex of the patient and the degree of malnutrition (p > 0.05). On analysis of the cases by age group, those patients aged less than 65 years mainly presented a marasmus-li-ke and mixed malnutrition, both to a slight degree, whereas the most prevalent malnutrition in patients over the age of 65 was the kwashiorkor type. Among patients with slight and moderate degrees of malnutrition, most of them were diagnosed as suffering from digestive-system related pathologies. After one week, 37’%% of them continued in hospital and approximately half of those presenting normal nutritional status on admission were found to have a status of slight malnutrition (AU)