Identification of Human Adenovirus in Respiratory Samples with Luminex Respiratory Virus Panel Fast V2 Assay and Real-Time Polymerase Chain Reaction

Single-virus-sensitive barcode qPCR mediated by the aggregation of gold nanoparticle probes

Herein, we developed a gold nanoparticle (GNP)-mediated barcode qPCR strategy with a sensitivity for a single virus particle per reaction for the detection of influenza virus H3N2. The analysis of the results for pure virus and real virus samples show that GNP-mediated barcode qPCR is ∼16 times more sensitive than conventional qPCR, demonstrating the potential to reduce false negatives and improve early diagnosis of viral infections.

Respiratory virus detection among healthcare professionals in Brazil: work-related contact and episode recurrence during the COVID-19 pandemic

OBJECTIVES

Since the beginning of the COVID-19 pandemic, changes in the circulation of respiratory viruses have been observed after measures to control the spread of SARS-CoV-2 were implemented. In this sense, we aimed to understand the circulation of the respiratory virus and its impact in a controlled healthy population of healthcare professional (HCP) volunteers in phase III of the clinical trial of the ChadOx nCoV1 conducted in São Paulo, Brazil.

STUDY DESIGN

This was a nested observational cohort study within a clinical trial.

METHODS

We performed RT-qPCR to detect SARS-CoV-2, influenza virus A and B (IVA and IVB), respiratory syncytial virus (RSV), human rhinovirus (HRV), human metapneumovirus (hMPV), human coronaviruses (hCoVs: HKU-1, NL63, OC43, and 229-E), parainfluenza virus (PiV) I-IV, and q-PCR for adenovirus in nasopharyngeal and oropharyngeal samples obtained from HCP enrolled in the clinical trial to assess respiratory viruses infection among vaccinated and non-vaccinated.

RESULTS

From July 2020 to January 2022, 876 samples were included from 737 volunteers (median age: 33 years, 62.9% female). New episodes were registered for 119 individuals. We observed an overall positivity of 37.7% for SARS-CoV-2 and 16.4% for other respiratory viruses; HRV was the second most detected virus (8%), followed by RSV (2.4%). Fully vaccinated individuals accounted for 53.3% of collected samples, and 52.9% presented at least one respiratory virus infection, with SARS-CoV-2 being the most predominant etiologic agent (62.3%). Influenza and hMPV were not detected among the tested samples. Among the subjects that presented more than one episode, SARS-CoV-2 and HRV infections were related to direct contact with patients (P < 0.002).

CONCLUSIONS

Data show high infection rates among HCPs even under mask policies and contact precautions, highlighting the need for improvement in infection control measures in this population regardless of the vaccination program.

Respiratory Adenovirus Quantification with a Droplet Digital Polymerase Chain Reaction (ddPCR) Assay

Human adenoviruses (HAdVs) are double-stranded DNA viruses that can cause a wide spectrum of disease, including respiratory infections. Little is known about the value of respiratory HAdV quantification and its correlation with disease severity. In this study, we developed a quantitative HAdV droplet digital PCR (ddPCR) assay to study the association between viral loads, circulating types, and clinical outcomes. Remnant respiratory specimens positive for HAdV after the standard of care testing were collected from December 2020 to April 2022. A total of 129 samples were tested by a ddPCR method. Typing was performed using Nanopore sequencing of the hexon gene hypervariable region. Clinical chart reviews were performed to correlate the viral loads with the disease severity. The ddPCR assay showed an analytical sensitivity and a lower limit of quantification below 100 copies/mL. Of 129 positive clinical samples, 100 were quantified by ddPCR, 7 were too concentrated to be quantified, and 22 were negative. Of the 22 false negatives, only 3 were successfully typed; however, 99 of the 107 positive samples had a characterized genotype. The main HAdV types identified in this cohort were C1 (49.5%) followed by C2 (34.3%). No significant difference in HAdV loads was noted between patients who were admitted, those who required supplemental oxygen, and outpatients or between different HAdV types. HAdV ddPCR is a reliable absolute quantification approach for HAdV from respiratory samples. HAdV loads at initial presentation does not appear to differ between patients who require hospitalization versus outpatients. IMPORTANCE Measuring viral load using droplet digital PCR (ddPCR) is an absolute quantification approach that can facilitate comparability between different laboratories. This approach could prove valuable in studies that focus on the clinical utility of quantification. In this study, we evaluate a human adenovirus (HAdV) ddPCR assay and study the relationship between viral loads and outcomes after HAdV respiratory infections.

Detection of human adenovirus among Iranian pediatric hospitalized patients suspected of COVID-19: epidemiology and comparison of clinical features

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children typically results in similar symptoms with other viral respiratory agents including human adenoviruses (HAdVs). Mixed HAdV and SARS-CoV-2 infection (co-infection) in children might result in enhanced or reduced disease severity compared with single infections. The present study aims to investigate the rate of SARS-CoV2 and HAdV infection and also their coinfection and compare the two infections regarding their laboratory and clinical characteristics at hospital admission. A total of 360 combined oropharyngeal and nasopharyngeal swab samples from hospitalized children were examined by real-time PCR for the existence of the SARS-CoV-2 and HAdVs. The symptoms, the clinical characteristics and laboratory findings were retrieved and compared in SARS-CoV-2 and HAdVs positive cases. Of the total 360 suspected COVID-19 hospitalized children, 45 (12.5%) and 19 (5.3%) specimens were PCR-positive for SARS-CoV-2 and HAdV respectively. SARS-CoV-2 and HAdV co-infection was detected in 4 cases (1.1%). Regarding symptoms at hospital admission, fever in SARS-CoV-2 positive group was significantly higher than that in HAdV positive group [34 (85%) vs. 7 (46.7%), p = 0.012]. However, percentages of cases with sore throat, headache, fatigue, lymphadenopathy and conjunctivitis in HAdV positive group were significantly higher than those in SARS-CoV-2 positive group. SARS-CoV-2 and HAdV co-infected children showed mild respiratory symptoms. The present study revealed that SARS-CoV-2 positive children often appear to have a milder clinical course than children with respiratory HAdV infection and children co-infected with SARSCoV-2 and HAdV had less-severe disease on presentation.

Advanced Point-of-Care Testing Technologies for Human Acute Respiratory Virus Detection

The ever-growing global threats to human life caused by the human acute respiratory virus (RV) infections have cost billions of lives, created a significant economic burden, and shaped society for centuries. The timely response to emerging RVs could save human lives and reduce the medical care burden. The development of RV detection technologies is essential for potentially preventing RV pandemic and epidemics. However, commonly used detection technologies lack sensitivity, specificity, and speed, thus often failing to provide the rapid turnaround times. To address this problem, new technologies are devised to address the performance inadequacies of the traditional methods. These emerging technologies offer improvements in convenience, speed, flexibility, and portability of point-of-care test (POCT). Herein, recent developments in POCT are comprehensively reviewed for eight typical acute respiratory viruses. This review discusses the challenges and opportunities of various recognition and detection strategies and discusses these according to their detection principles, including nucleic acid amplification, optical POCT, electrochemistry, lateral flow assays, microfluidics, enzyme-linked immunosorbent assays, and microarrays. The importance of limits of detection, throughput, portability, and specificity when testing clinical samples in resource-limited settings is emphasized. Finally, the evaluation of commercial POCT kits for both essential RV diagnosis and clinical-oriented practices is included.

Meta-Analysis of the Diagnostic Efficacy of the Luminex xTAG Respiratory Viral Panel FAST v2 Assay for Respiratory Viral Infections

PURPOSE

Acute respiratory viral infections pose significant morbidity and mortality, making it essential to diagnose respiratory viral infections rapidly. In this study, the diagnostic efficacy of the Luminex xTAG Respiratory Virus Panel (RVP) FAST v2 test was evaluated on respiratory viral infections.

MATERIALS AND METHODS

Information was retrieved from electronic databases, including Embase, Web of Science, PubMed, and Cochrane Library, for systematic review. Studies that fulfilled predefined inclusion criteria were included. After the extraction of information, statistical software was utilized for quality evaluation, data analysis, and assessment of publication bias.

RESULTS

Eighty groups in fourfold tables from nine articles were included to perform statistical analyses. Therein, the mean specificity and mean sensitivity of Luminex xTAG RVP FAST v2 test for the detection of respiratory viral infections were 0.99 (0.98-0.99) and 0.88 (0.87-0.90), respectively. Additionally, the negative and positive likelihood ratios were 0.14 (0.11-0.19) and 87.42 (61.88-123.50), respectively. Moreover, the diagnostic odds ratio and area under the curve of summary receiver operating characteristic were 714.80 and 0.9886, respectively.

CONCLUSION

The Luminex xTAG RVP FAST v2 test could be a reliable and rapid diagnostic method for multiple respiratory viral infections.

Viral etiology of acute gastroenteritis among Forcibly Displaced Myanmar Nationals and adjacent host population in Bangladesh

Background

Since August 2017, Myanmar nationals from Rakhine state have crossed the border into Bangladesh and settled in Cox’s Bazar, the World’s largest refugee camp. Due to overcrowding, poor sanitation, and hygienic practices they have been under significant health risks including diarrheal diseases. The objective of this study is to determine the viral etiology of acute gastroenteritis (AGE) among forcibly displaced Myanmar nationals (FDMN) and adjacent Bangladeshi local host population (AHP).

Methods

From April 2018 to April 2019, we collected stool specimens from 764 FDMN and 1159 AHP of all ages. We tested 100 randomly selected specimens from each group for the most common AGE viruses.

Results

Among 200 diarrhea patients, 55% and 64% of FDMN and AHP patients, respectively, had viral infections; the most common viruses were rotavirus (29% vs 44%), adenovirus (24% vs 31%), and norovirus (14% vs 10%). In both populations, viral infections were significantly higher in children less than 5 years of age, compared with bacterial infections that were higher in patients older than 5 years of age (P ≤ .05).

Conclusions

Disparities in viral and bacterial prevalence among various age groups warrant careful antibiotic usage, especially in children less than 5 years of age.

Adenovirus causing hepatic abscess formation and unexplained fever in adult liver transplant recipients

Adenovirus infection is commonly associated with self-limited respiratory and gastrointestinal illnesses. However, infection in immunocompromised individuals, such as transplant recipients, can cause severe life-threatening illness including pneumonitis, hemorrhagic cystitis, nephritis, hepatitis, and enterocolitis. In orthotopic liver transplant recipients, adenovirus viremia can cause hepatitis leading to marked transaminitis, allograft loss, and death. Although hepatic abscesses mediated by adenovirus have been described in other immunosuppressed patient populations, it has very rarely been described in liver transplant recipients. Here, we report two adult cases of hepatic abscesses following liver transplantation secondary to adenovirus infection and describe the successful treatment of these patients. Adenovirus should be considered as an uncommon etiology of hepatic abscess and unexplained fevers in adults following liver transplantation.

Critical evaluation of FDA-approved respiratory multiplex assays for public health surveillance

Introduction: Clinical management and identification of respiratory diseases has become more rapid and increasingly specific due to widespread use of PCR(polymerase chain reaction) multiplex technologies. Although significantly improving clinical diagnosis, multiplexed PCR assays could have a greater impact on local and global disease surveillance. The authors wish to propose methods of evaluating respiratory multiplex assays to maximize diagnostic yields specifically for surveillance efforts.

Areas covered: The authors review multiplexed assays and critically assess what barriers have limited these assays for disease surveillance and how these barriers might be addressed. The manuscript focuses specifically on the case study of using multiplexed assays for surveillance of respiratory pathogens. The authors also provide a method of validation of specific surveillance measures.

Expert commentary: Current commercially available respiratory multiplex PCR assays are widely used for clinical diagnosis; however, specific barriers have limited their use for surveillance. Key barriers include differences in testing phase requirements and diagnostic performance evaluation. In this work the authors clarify phase testing requirements and introduce unique diagnostic performance measures that simplify the use of these assays on a per target basis for disease surveillance.

Evaluation of monoclonal antibodies that detect conserved proteins from Respiratory Syncytial Virus, Metapneumovirus and Adenovirus in human samples

Human Respiratory Syncytial Virus (hRSV), human Metapneumovirus (hMPV) and Adenovirus (ADV), are three of the most prevalent viruses responsible for pneumonia and bronchiolitis in children and elderly worldwide, accounting for a high number of hospitalizations annually. Diagnosis of these viruses is required to take clinical actions that allow an appropriate patient management. Thereby, new strategies to design fast diagnostic methods are highly required. In the present work, six monoclonal antibodies (mAbs, two for each virus) specific for conserved proteins from hRSV, hMPV and ADV were generated and evaluated through different immunological techniques, based on detection of purified protein, viral particles and human samples. In vitro evaluation of these antibodies showed higher specificity and sensitivity than commercial antibodies tested in this study. These antibodies were used to design a sandwich ELISA tests that allowed the detection of hRSV, hMPV, and ADV in human nasopharyngeal swabs. We observed that hRSV and ADV were detected with sensitivity and specificity equivalent to a current Direct Fluorescence Assay (DFA) methodology. However, hMPV was detected with more sensitivity than DFA. Our data suggest that these new mAbs can efficiently identify infected samples and discriminate from patients infected with other respiratory pathogens.

The role of the NxTAG® respiratory pathogen panel assay and other multiplex platforms in clinical practice

INTRODUCTION

The advent of nucleic acid amplification tests has significantly improved the aetiologic diagnosis of respiratory infections. However, multiplex real-time polymerase chain reaction (PCR) can be technologically challenging. Areas covered: This paper reports the results of the main published studies on the NxTAG Respiratory Pathogen Panel (RPP) and discusses the advantages and disadvantages of extensive use of multiplex assays in clinical practice. Expert commentary: Currently available data seem to indicate that routine use of multiplex assays, including NxTAG RPP Assay, should be recommended only when epidemiological data concerning circulation of viruses and bacteria have to be collected. Their use in clinical practice seems debatable. They have limited sensitivity and specificity at least in the identification of some infectious agents or, as in the case of NxTAG RPP, they have not been evaluated in a sufficient number of patients to allow definitive conclusions. In the future, the clinical relevance of multiplex assays, including NxTAG RPP, could significantly increase, mainly because a number of new antiviral agents effective against several respiratory viruses for which no drug is presently available will be marketed. In addition, it is highly likely that the efficiency of multiplex assays will be significantly improved.

Comparison of NxTAG Respiratory Pathogen Panel and Anyplex II RV16 Tests for Multiplex Detection of Respiratory Pathogens in Hospitalized Children

Multiplex molecular techniques can detect a diversity of respiratory viruses and bacteria that cause childhood acute respiratory infection rapidly and conveniently. However, currently available techniques show high variation in performance. We sought to compare the diagnostic accuracy of the novel multiplex NxTAG respiratory pathogen panel (RPP) RUO test versus a routine multiplex Anyplex II RV16 assay in respiratory specimens collected from children <18 years of age hospitalized with nonspecific symptoms of acute lower respiratory infection. Parallel testing was performed on nasopharyngeal aspirates prospectively collected at referral Children's Hospital Sant Joan de Déu (Barcelona, Spain) between June and November 2015. Agreement values between the two tests and kappa coefficients were assessed. Bidirectional sequencing was performed for the resolution of discordant results. A total of 319 samples were analyzed by both techniques. A total of 268 (84.0%) of them yielded concordant results. Positive percent agreement values ranged from 83.3 to 100%, while the negative percent agreement was more than 99% for all targets except for enterovirus/rhinovirus (EV/RV; 94.4%). Kappa coefficients ranged from 0.83 to 1.00. Discrepancy analysis confirmed 66.0% of NxTAG RPP RUO results. A total of 260 viruses were detected, with EV/RV (n = 105, 40.4%) being the most prevalent target. Viral coinfections were found in 44 (14.2%) samples. In addition, NxTAG RPP RUO detected single bacterial and mixed viral-bacterial infections in seven samples. NxTAG RPP RUO showed high positive and negative agreement with Anyplex II RV16 for main viruses that cause acute respiratory infections in children, coupled with an additional capability to detect some respiratory bacteria.

Partial comparison of the NxTAG Respiratory Pathogen Panel Assay with the Luminex xTAG Respiratory Panel Fast Assay V2 and singleplex real-time polymerase chain reaction for detection of respiratory pathogens

In this study, 185 nasopharyngeal swabs were tested to compare the sensitivity and specificity of the Luminex NxTAG (NxTAG) Respiratory Pathogen Panel (RPP) Assay with those of the Luminex Respiratory Virus Panel (RVP) Fast Assay v2 and singleplex real-time polymerase chain reaction (PCR). The NxTAG Assay identified at least one infectious agent in 164 (88.7%) of the swabs. In 91 (6.2%) tests with negative results with the RVP Fast Assay v2, a virus was identified by the NxTAG (P < 0.001). With the NxTAG Assay, the detection rates were significantly higher for respiratory syncytial virus (P = 0.003), human metapneumovirus (P < 0.001), human rhinovirus/human enterovirus (P = 0.009) and human adenovirus (P < 0.001). Finally, the NxTAG Assay identified M. pneumoniae in 32 of 44 (72.7%) PCR-positive samples. However, the concordance with real-time PCR results was low for both assays. In conclusion, the results indicate that the NxTAG Assay overcomes some of the limitations of previous Luminex assays, although further studies are needed for a more complete evaluation of the new assay.

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NxTAG Respiratory Pathogen Panel Assay was developed to improve viral detection and to simultaneously identify atypical bacteria.

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NxTAG Assay has overcome some of the limitations of the previous Luminex assays.

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NxTAG Assay remains generally less sensitive and specific than singleplex real-time polymerase chain reaction.

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Further studies on more samples collected during the whole year are needed for a complete evaluation of the NxTAG Assay.