Infectious Disease Diagnostics Research Articles

Performance comparison of three commercial multiplex molecular panels for respiratory viruses at a South African academic hospital.

Respiratory infections are a major contributor to hospital admissions. Identification of respiratory pathogens by means of conventional culture and serology methods remains challenging. Multiplex molecular assays are an appealing alternative that endeavours to be rapid, more accurate and less arduous. The study aimed to compare the clinical performance of three commercial multiplex molecular assays for respiratory viruses. Forty-eight respiratory specimens obtained from patients at Tygerberg Hospital in the Western Cape province of South Africa were studied. These specimens were collected between May 2020 and August 2020. The results of the Seegene Anyplex™ II RV16, FilmArray® Respiratory 2.1 plus Panel (FARP), and QIAstat-Dx® Respiratory SARS-CoV-2 Panel (QRP) were analysed based on the overlapping targets. A composite reference standard was applied to provide a standard reference for comparison. The overall sensitivity of the Seegene Anyplex™ II RV16 was 96.6% (57/59), the FARP 98.2% (56/57) and the QRP 80.7% (46/57). The overall specificities were 99.8% (660/661), 99.0% (704/711) and 99.7% (709/711), respectively. The QRP failed to detect coronaviruses and parainfluenza viruses in 41.7% (5/12) and 28.6% (4/14) of positive specimens, respectively, while the FARP produced the lowest target specificity of 88.4% (38/43) for rhinovirus/enterovirus. The overall specificity of all three platforms was comparable; however, the sensitivity of the QRP was inferior to that of the ARV and FARP. This study adds to the body of performance characteristics described for respiratory multiplex panels, especially in the African context where molecular diagnostics for infectious diseases are gaining momentum.

Rapid and simultaneous detection of common childhood diarrhea viruses by microfluidic-FEN1-assisted isothermal amplification with ultra-high specificity and sensitivity

Rapid and accurate diagnostic methods are crucial for managing viral gastroenteritis in children, a leading cause of global childhood morbidity and mortality. This study introduces a novel microfluidic-Flap endonuclease 1 (FEN1)-assisted isothermal amplification (MFIA) method for simultaneously detecting major viral pathogens associated with childhood diarrhea—rotavirus, norovirus, and adenovirus. Leveraging the specificity-enhancing properties of FEN1 with a universal dspacer-modified flap probe and the adaptability of microfluidic technology, MFIA demonstrated an exceptional detection limit (5 copies/μL) and specificity in the simultaneous detection of common diarrhea pathogens in clinical samples. Our approach addresses the limitations of current diagnostic techniques by offering a rapid (turn around time <1 h), cost-effective, easy design steps (universal flap design), and excellent detection performance method suitable for multiple applications. The validation of MFIA against the gold-standard PCR method using 150 actual clinical samples showed no statistical difference in the detection performance of the two methods, positioning it as a potential detection tool in pediatric diagnostic virology and public health surveillance. In conclusion, the MFIA method promises to transform pediatric infectious disease diagnostics and contribute significantly to global health efforts combating viral gastroenteritis.

Ultrafast and highly sensitive detection of SARS-CoV-2 spike protein by field-effect transistor graphene-based biosensors

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), etiological agent for the coronavirus disease 2019 (COVID-19), has resulted in over 775 million global infections. Early diagnosis remains pivotal for effective epidemiological surveillance despite the availability of vaccines. Antigen-based assays are advantageous for early COVID-19 detection due to their simplicity, cost-effectiveness, and suitability for point-of-care testing (PoCT). This study introduces a graphene field-effect transistor-based biosensor designed for high sensitivity and rapid response to the SARS-CoV-2 spike protein. By functionalizing graphene with monoclonal antibodies and applying short-duration gate voltage pulses, we achieve selective detection of the viral spike protein in human serum within 100 µs and at concentrations as low as 1 fg ml−1, equivalent to 8 antigen molecules per µl of blood. Furthermore, the biosensor estimates spike protein concentrations in serum from COVID-19 patients. Our platform demonstrates potential for next-generation PoCT antigen assays, promising fast and sensitive diagnostics for COVID-19 and other infectious diseases.

Innovative approaches to microbial identification enhancing accuracy and speed in infectious disease diagnostics

The rapid and accurate identification of microbial pathogens is crucial for effective management of infectious diseases. Traditional methods, though reliable, are often time-consuming. Recent advancements in molecular diagnostics, mass spectrometry, and next-generation sequencing (NGS) have revolutionized the field by enhancing both the speed and accuracy of microbial identification. Polymerase chain reaction (PCR) and its derivatives, such as real-time PCR, enable rapid amplification of genetic material, significantly reducing diagnostic times. Techniques like nucleic acid sequence-based amplification (NASBA) and loop-mediated isothermal amplification (LAMP) further extend these capabilities to resource-limited settings by operating at constant temperatures. Mass spectrometry, particularly matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), provides rapid and accurate microbial identification by analyzing protein profiles. This method has high throughput, is cost-effective, and offers the ability to detect antimicrobial resistance, significantly impacting clinical decision-making and patient management. NGS technologies offer comprehensive pathogen detection by sequencing entire microbial genomes. This approach is invaluable in diagnosing complex infections, tracking outbreaks, and identifying antibiotic resistance genes, though its high cost and complexity limit widespread use. The integration of these innovative technologies into clinical practice enhances the ability to diagnose and manage infectious diseases effectively. Molecular diagnostics, mass spectrometry, and NGS each bring unique strengths, from rapid and precise pathogen detection to comprehensive genetic analysis and resistance profiling. These advancements contribute to improved patient outcomes and more effective public health strategies. The continued development and implementation of these technologies are essential to address the evolving challenges in microbial diagnostics, paving the way for more precise and personalized approaches in infectious disease management.

A Label-free Optical Biosensor-Based Point-of-Care Test for the Rapid Detection of Monkeypox Virus.

Diagnostic approaches that combine the high sensitivity and specificity of laboratory-based digital detection with the ease of use and affordability of point-of-care (POC) technologies could revolutionize disease diagnostics. This is especially true in infectious disease diagnostics, where rapid and accurate pathogen detection is critical to curbing the spread of disease. We have pioneered an innovative label-free digital detection platform that utilizes Interferometric Reflectance Imaging Sensor (IRIS) technology. IRIS leverages light interference from an optically transparent thin film, eliminating the need for complex optical resonances to enhance the signal by harnessing light interference and the power of signal averaging in shot-noise-limited operation to achieve virtually unlimited sensitivity. In our latest work, we have further improved our previous 'Single-Particle' IRIS (SP-IRIS) technology by allowing the construction of the optical signature of target nanoparticles (whole virus) from a single image. This new platform, 'Pixel-Diversity' IRIS (PD-IRIS), eliminated the need for z-scan acquisition, required in SP-IRIS, a time-consuming and expensive process, and made our technology more applicable to POC settings. Using PD-IRIS, we quantitatively detected the Monkeypox virus (MPXV), the etiological agent for Monkeypox (Mpox) infection. MPXV was captured by anti-A29 monoclonal antibody (mAb 69-126-3) on Protein G spots on the sensor chips and were detected at a limit-of-detection (LOD) - of 200 PFU/ml (~3.3 attomolar). PD-IRIS was superior to the laboratory-based ELISA (LOD - 1800 PFU/mL) used as a comparator. The specificity of PD-IRIS in MPXV detection was demonstrated using Herpes simplex virus, type 1 (HSV-1), and Cowpox virus (CPXV). This work establishes the effectiveness of PD-IRIS and opens possibilities for its advancement in clinical diagnostics of Mpox at POC. Moreover, PD-IRIS is a modular technology that can be adapted for the multiplex detection of pathogens for which high-affinity ligands are available that can bind their surface antigens to capture them on the sensor surface.

Hybrid interfacial cryosoret nano-engineering in photonic resonator interferometric scattering microscopy: Insights from nanoparticles and nano-assemblies

The requirements of augmented signal contrast provided by nanoparticle tags in biosensor microscopy-based point-of-care technologies for cancer and infectious disease diagnostics can be addressed through metallo-dielectric nanoarchitectures that enhance optical scattering and absorption to provide digital resolution detection of single tags with simple instrumentation. Photonic Resonator Interferometric Scattering Microscopy (PRISM) enables label-free visualization of nanometer-scale analytes such as extracellular vesicles and virions, and its applicability can be extended to biomolecular analyte counting through nanoparticle tags. Here, we present template-free, linker-less cryosoret nano-assemblies fabricated via adiabatic cooling (−196 °C) as plasmonic nano-antennas that provide high scattering contrast in PRISM. Plasmonic Ag and Au nanomaterials and their cryosorets are evaluated through imaging experiments and simulations based on the finite element method to understand the photo-plasmonic coupling effect at the surface of a photonic crystal (PC) interface. The Ag and Au cryosorets provide at most 8.29-fold and 6.77-fold higher signal contrast compared to their singlet counterpart. Through the simulations, the averaged field magnitude enhancements of 2.77-fold and 3.68-fold are observed for Ag and Au cryosorets when interfacing with PCs compared to bare glass substrates. The hybrid coupling between the localized Mie and delocalized Bragg plasmons of cryosorets and the underlying PC's guided mode resonance provides insights for developing nano-assembly-based nano-tags for biosensing applications.

Challenges of Diphtheria Toxin Detection.

Diphtheria toxin (DT) is the main virulence factor of Corynebacterium diphtheriae, C. ulcerans and C. pseudotuberculosis. Moreover, new Corynebacterium species with the potential to produce diphtheria toxin have also been described. Therefore, the detection of the toxin is the most important test in the microbiological diagnosis of diphtheria and other corynebacteria infections. Since the first demonstration in 1888 that DT is a major virulence factor of C. diphtheriae, responsible for the systemic manifestation of the disease, various methods for DT detection have been developed, but the diagnostic usefulness of most of them has not been confirmed on a sufficiently large group of samples. Despite substantial progress in the science and diagnostics of infectious diseases, the Elek test is still the basic recommended diagnostic test for DT detection. The challenge here is the poor availability of an antitoxin and declining experience even in reference laboratories due to the low prevalence of diphtheria in developed countries. However, recent and very promising assays have been developed with the potential for use as rapid point-of-care testing (POCT), such as ICS and LFIA for toxin detection, LAMP for tox gene detection, and biosensors for both.

Metagenomic next-generation sequencing as a diagnostic tool in the clinical routine of an infectious diseases department: a retrospective cohort study.

Metagenomic next-generation sequencing (mNGS) of circulating cell-free DNA from plasma is a hypothesis-independent broadband diagnostic method for identification of potential pathogens. So far, it has only been investigated in special risk populations (e.g. patients with neutropenic fever). To investigate the extent to which mNGS (DISQVER® platform) can be used in routine clinical practice. We collected whole blood specimens for mNGS testing, blood cultures (BC), and pathogen-specific PCR diagnostics. Clinical data and pathogen diagnostics were retrospectively reviewed by an infectious disease expert panel regarding the adjustment of anti-infective therapy. In 55 selected patients (median age 53years, 67% male) with heterogeneous diagnoses, a total of 66 different microorganisms and viruses were detected using mNGS (51% viruses, 38% bacteria, 8% fungi, 3% parasites). The overall positivity rate of mNGS was 53% (29/55). Fifty-two out of 66 (79%) potential pathogens detected by mNGS were found in patients with primary or secondary immunodeficiency. The concordance rates of BC and pathogen-specific PCR diagnostics with mNGS testing were 14% (4/28) and 36% (10/28), respectively (p < 0.001). An additional bacterial pathogen (Streptococcus agalactiae) could only be detected by BC. Therapeutic consequences regarding anti-infective therapy were drawn from 23 pathogens (35% of detections), with 18 of these detections occurring in patients with immunodeficiency. We conclude that mNGS is a useful diagnostic tool, but should only be performed selectively in addition to routine diagnostics of infectious diseases. The limited number of patients and the retrospective study design do not allow any further conclusions.

Advances in Nucleic Acid Assays for Infectious Disease: The Role of Microfluidic Technology.

Within the fields of infectious disease diagnostics, microfluidic-based integrated technology systems have become a vital technology in enhancing the rapidity, accuracy, and portability of pathogen detection. These systems synergize microfluidic techniques with advanced molecular biology methods, including reverse transcription polymerase chain reaction (RT-PCR), loop-mediated isothermal amplification (LAMP), and clustered regularly interspaced short palindromic repeats (CRISPR), have been successfully used to identify a diverse array of pathogens, including COVID-19, Ebola, Zika, and dengue fever. This review outlines the advances in pathogen detection, attributing them to the integration of microfluidic technology with traditional molecular biology methods and smartphone- and paper-based diagnostic assays. The cutting-edge diagnostic technologies are of critical importance for disease prevention and epidemic surveillance. Looking ahead, research is expected to focus on increasing detection sensitivity, streamlining testing processes, reducing costs, and enhancing the capability for remote data sharing. These improvements aim to achieve broader coverage and quicker response mechanisms, thereby constructing a more robust defense for global public health security.

Molecular Diagnostics for Infectious Diseases: Implications for Diagnosis and Management

Molecular Diagnostics for Infectious Diseases: Implications for Diagnosis and Management

Recombinase polymerase amplification: method’s characteristics and applications in diagnostics of infectious diseases

Isothermal amplification techniques have been actively developed in recent years and are gradually introduced into the range of methods for infectious disease diagnostics. One of the fastest isothermal methods is recombinase polymerase amplification (RPA). This review contains information about the principle of RPA, the role of individual reaction components and primer design considerations. It provides information on characteristics of various methods of RPA results detection, effects of inhibitors, temperature and agitation on the efficiency of reaction. Approaches to quantitative and multiplex RPA are described, as well as some variants of portable devices designed to identify infectious agents. The conclusion summarizes advantages and disadvantages of RPA in comparison with other amplification methods.

Metagenomics to improve infectious disease diagnostics in low- and middle-income countries.

Metagenomics to improve infectious disease diagnostics in low- and middle-income countries.

Palm-Sized Lab-In-A-Magnetofluidic Tube Platform for Rapid and Sensitive Virus Detection.

Simple, sensitive, and accurate molecular diagnostics are critical for preventing rapid spread of infection and initiating early treatment of diseases. However, current molecular detection methods typically rely on extensive nucleic acid sample preparation and expensive instrumentation. Here, a simple, fully integrated, lab-in-a-magnetofluidic tube (LIAMT) platform is presented for "sample-to-result" molecular detection of virus. By leveraging magnetofluidic transport of micro/nano magnetic beads, the LIAMT device integrates viral lysis, nucleic acid extraction, isothermal amplification, and CRISPR detection within a single engineered microcentrifuge tube. To enable point-of-care molecular diagnostics, a palm-sized processor is developed for magnetofluidic separation, nucleic acid amplification, and visual fluorescence detection. The LIAMT platform is applied to detect SARS-CoV-2 and HIV viruses, achieving a detection sensitivity of 73.4 and 63.9 copiesµL-1, respectively. Its clinical utility is further demonstrated by detecting SARS-CoV-2 and HIV in clinical samples. This simple, affordable, and portable LIAMT platform holds promise for rapid and sensitive molecular diagnostics of infectious diseases at the point-of-care.

Breaking Boundaries in Pneumonia Diagnostics: Transitioning from Tradition to Molecular Frontiers with Multiplex PCR.

The advent of rapid molecular microbiology testing has revolutionized infectious disease diagnostics and is now impacting pneumonia diagnosis and management. Molecular platforms offer highly multiplexed assays for diverse viral and bacterial detection, alongside antimicrobial resistance markers, providing the potential to significantly shape patient care. Despite the superiority in sensitivity and speed, debates continue regarding the clinical role of multiplex molecular testing, notably in comparison to standard methods and distinguishing colonization from infection. Recent guidelines endorse molecular pneumonia panels for enhanced sensitivity and rapidity, but implementation requires addressing methodological differences and ensuring clinical relevance. Diagnostic stewardship should be leveraged to optimize pneumonia testing, emphasizing pre- and post-analytical strategies. Collaboration between clinical microbiologists and bedside providers is essential in developing implementation strategies to maximize the clinical utility of multiplex molecular diagnostics in pneumonia. This narrative review explores these multifaceted issues, examining the current evidence on the clinical performance of multiplex molecular assays in pneumonia, and reflects on lessons learned from previous microbiological advances. Additionally, given the complexity of pneumonia and the sensitivity of molecular diagnostics, diagnostic stewardship is discussed within the context of current literature, including implementation strategies that consider pre-analytical and post-analytical modifications to optimize the clinical utility of advanced technologies like multiplex PCR.

Large-volume RT-LAMP enables extraction-free amplification of HIV RNA from fingerstick plasma

BackgroundPoint-of-care (POC) nucleic acid amplification tests (NAAT) can significantly expand testing coverage, which is critical for infectious disease diagnostics and monitoring. The development of various isothermal amplification techniques greatly simplifies NAATs, but the cumbersome nucleic acid extraction step remains a bottleneck for the POC. Alternatively, extraction-free amplification, where crude samples are directly added into the assay, substantially simplifies the workflow. However, sample dilution is often needed in extraction-free amplification to reduce assay inhibition from sample matrices. Since NAATs are typically run at small volumes around 20 μL, the input sample quantity is therefore limited, resulting in an inevitable sensitivity loss. ResultsHere we explore the potential to perform isothermal amplification in larger reaction volumes to accommodate larger sample quantities, thereby improving sensitivity in extraction-free amplification. We demonstrated the approach by developing large-volume reverse transcription loop-mediated isothermal amplification (RT-LAMP) for HIV RNA detection from fingerstick plasma. We found that LAMP at reaction volumes up to 1 mL maintained the same performance. We then identified plasma dilution conditions needed to maintain the limit of detection in RT-LAMP. Subsequently, using inactivated HIV virus, we showed the successful detection of 24 HIV RNA copies in a 500 μL RT-LAMP reaction in the presence of 20 μL plasma (fingerstick volumes), translating to a viral load of 1200 copies per mL. To reduce the increased reagent cost with expanded reaction volumes, we further identified lower-cost reagents with maintained assay performance. Moreover, we showed that large-volume LAMP, compared to 20 μL reactions, could tolerate higher concentrations of various inhibitors in the sample, such as albumin and GuSCN. Significance and noveltyNAATs are conventionally conducted at small reaction volumes. Here we demonstrated that LAMP can be run at large reaction volumes (over 100 μL) with maintained assay performance, allowing sample inhibition to be mitigated while accommodating larger sample quantities. The same strategy of expanding reaction volumes could be applied to other isothermal amplification methods and various POC applications, to streamline test workflows and/or improve assay sensitivity.

IMPLICATION OF NANOPORE SEQUENCING TECHNOLOGY FOR PATHOGENIC DIAGNOSTICS: A MINI-REVIEW

DNA sequencing is the most critical technique to explore and study genomic data of human beings and surrounding environments. The history of DNA sequencing has rapidly grown since the first-generation DNA sequencing in 1977. Until now, emerging high-throughput sequencing technology has recently revolutionized omics areas, including genomics, transcriptomics, metagenomics, and metabolomics for the development of modern molecular biology. Besides the short-read sequencing method (Illumina platforms), the long-read sequencing technologies (including Pacific Biosciences and Oxford Nanopore Technologies) have been developed with the advantages of larger read sizes, portable devices, and diverse preparation kits. Consequently, the number of biological databases and study-related nanopore sequencing technologies has grown fast. This review paper summarized the principle and fundament of nanopore sequencing regarding their advanced applications in pathogenic diagnostics of different hosts. The most recent application of nanopore sequencing in the diagnostics of infectious diseases is highlighted and discussed to provide insights into the novelty of nanopore sequencing technology and its future perspectives.

Recombinase Polymerase and Loop-Mediated Isothermal Amplification in the DNA Diagnostics of Infectious Diseases

Recombinase Polymerase and Loop-Mediated Isothermal Amplification in the DNA Diagnostics of Infectious Diseases

Status check: next-generation sequencing for infectious-disease diagnostics.

Next-generation sequencing (NGS) applications for the diagnostics of infectious diseases has demonstrated great potential with three distinct approaches: whole-genome sequencing (WGS), targeted NGS (tNGS), and metagenomic NGS (mNGS, also known as clinical metagenomics). These approaches provide several advantages over traditional microbiologic methods, though challenges still exist.

Progress in Treatment and Diagnostics of Infectious Disease with Polymers.

In this era of advanced technology and innovation, infectious diseases still cause significant morbidity and mortality, which need to be addressed. Despite overwhelming success in the development of vaccines, transmittable diseases such as tuberculosis and AIDS remain unprotected, and the treatment is challenging due to frequent mutations of the pathogens. Formulations of new or existing drugs with polymeric materials have been explored as a promising new approach. Variations in shape, size, surface charge, internal morphology, and functionalization position polymer particles as a revolutionary material in healthcare. Here, an overview is provided of major diseases along with statistics on infection and death rates, focusing on polymer-based treatments and modes of action. Key issues are discussed in this review pertaining to current challenges and future perspectives.

Clinical and laboratory aspects of infectious mononucleosis in different age groups

Infectious mononucleosis is an acute anthroponotic disease that develops as a result of human infection with viruses of the Herpesviridae family: Epstein – Barr virus (EBV), cytomegalovirus (CMV), herpes viruses of the 6th (HHV-6) and 7th types.The aim of our work was to study the clinical features and laboratory parameters of the course of infectious mononucleosis in patients of three age groups.Material and methods. A retrospective analysis of 156 medical records of patients who were on outpatient treatment by an infectious disease specialist at Clinical Medicine Center MedMix was carried out. Patients were divided into three categories according to the age criterion: the first group from 0 to 5 years consisted of 58 (37.2 %) children, the second group was represented by persons from 5 to 18 years old – 58 (37.2 %), the third group was formed by patients from 18 to 53 years old – 40 (25.6 %) people.Results and its discussion. Among children aged 0 to 5 years, boys (67.2 %) more frequently fell sick, and in the group from 18 to 53 years, females (70 %) were more likely to have the disease. Clinical symptoms such as generalized lymphadenopathy (82.7 %), nasopharyngeal lesions (79.3 %) and changes in the general blood test (86.2 %) were most frequently detected in children aged up to 5 years, while fever (81 %) and oropharyngeal lesions (74.1 %) were most frequently detected in patients aged from 5 to 18 years. Liver damage with the development of acute induced viral hepatitis was recorded in all age groups (24.1, 27.6 and 30 %). EBV infection was most frequently diagnosed among children aged from 5 to 18 years and persons aged from 18 to 53 years (in 62.1 and 70 % of cases, respectively, p &lt; 0.05). Mixed infection with the combination of VEB + CMV + HHV-6 was significantly more frequent in children under 5 years of age (34.5 %; p &lt; 0.05).Conclusions. In childhood, the clinical manifestations of infectious mononucleosis were more pronounced. Such intense course of the disease caused frequent visits to an infectious disease specialist and diagnostics with the establishment of an etiological agent. The dominance of EBV infection in the development of infectious mononucleosis in all groups was established. However, at the age up to 5 years, the most common mixed infections were the following combinations: EBV + CMV, EBV + HHV-6, EBV + CMV + HHV-6 and CMV + HHV-6.