Assessment of a rapid immunochromatographic test for the diagnosis of norovirus gastroenteritis

Electrochemical sensor for human norovirus based on covalent organic framework/pillararene heterosupramolecular nanocomposites

Noroviruses are the leading cause of acute gastroenteritis and food-borne diseases worldwide. Thus, a rapid, accurate, and easy-to-implement detection method for controlling infection and monitoring progression is urgently needed. In this study, we constructed a novel sandwich-type electrochemical biosensor integrated with two specific recognition elements (aptamer and peptide) for human norovirus (HuNoV). The electrochemical biosensor was fabricated using magnetic covalent organic framework/pillararene heterosupramolecular nanocomposites (MB@Apt@WP5A@Au@COF@Fe₃O₄) as the signal probes. The sensor showed high accuracy and selectivity. The detection method does not need the extraction and amplification of virus nucleic acid and has a short turn-around time. Intriguingly, the proposed biosensor had a limit of detection of 0.84 copy mL^-1 for HuNoV, which was the highest sensitivity among published assays. The proposed biosensor showed higher sensitivity and accuracy compared with immunochromatographic assay in the detection of 98 clinical specimens. The biosensor was capable of determining the predominant infection strain of GII.4 and also GII.3 and achieved 74% selectivity for HuNoV GII group. This study provides a potential method for point-of-care testing and highlights the integrated utilization of Apt and peptide in sensor construction.

Diagnostic Accuracy of Immunochromatographic Tests for the Detection of Norovirus in Stool Specimens: a Systematic Review and Meta-Analysis

Noroviruses are the leading cause of acute gastroenteritis in all age groups and constitute a major health and economic burden worldwide. This systematic review and meta-analysis aimed to determine the diagnostic accuracy of immunochromatographic tests (ICTs) for the detection of norovirus in stool specimens, which has not been performed previously. In this systematic review and meta-analysis (registered on PROSPERO, CRD42020186911), we searched Medline/PubMed, Embase, Cochrane Library, and Web of Science for all studies published up to 16 May 2020. The values for sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), and diagnostic odds ratio (DOR) of ICTs with 95% confidence interval (CI) were pooled using a bivariate random-effects model. The summary receiver operating characteristic curve and area under the curve were used to summarize overall test accuracy. We included 43 studies describing 7,428 samples. The overall estimates of sensitivity, specificity, LR+, LR-, DOR, and accuracy of ICT for diagnosing norovirus were 0.61 (95% CI, 0.54 to 0.67), 0.97 (95% CI, 0.95 to 0.98), 17.08 (95% CI, 11.15 to 26.18), 0.40 (95% CI, 0.34 to 0.46), 53.9 (95% CI, 31.32 to 92.78), and 0.928, respectively. Significant differences in pooled sensitivities were noted between age groups and in pooled DOR and LR+ between genogroups of included samples. ICT provides low sensitivity but high specificity and accuracy for detecting norovirus. Thus, an ICT for norovirus can be a rapid and convenient way for identifying patients early; however, a negative result cannot rule out norovirus infection and should be confirmed by a reference test.

Accuracy and Cross-Reactivity of Rapid Diagnostic Tests for Norovirus and Rotavirus in a Real Clinical Setting

Background

Rapid diagnostic test (RDT) of norovirus and rotavirus is commonly used for outbreak screening and patient management. Varying accuracy of the test and cross-reactivity has been reported and could affect the outcome of management. The primary purpose of this study is to provide the accuracy of norovirus and rotavirus rapid diagnostic tests and to analyze the cross-reactivity of both tests.

Materials and Methods

Stool samples collected from every acute diarrhea patient aged <15 years old who was admitted at Bhumibol Adulyadej Hospital, Bangkok, Thailand, from November 2014 to September 2016 underwent the following test: QuickNaviTM – Norovirus2 for norovirus, VIKIA^® Rota-Adeno for rotavirus, and aerobic bacterial culture. Real-time reverse transcription polymerase chain reaction was used as a gold standard for virus detection. False-positive results determined cross-reactivity.

Results

From 358 stool specimens, the sensitivity of RDTs for norovirus and rotavirus was 27.5% and 44.8%, respectively. The specificity of RDTs for norovirus and rotavirus was 97.7% and 91.6%, respectively. False positive results of RDT for norovirus occurred in 6 samples (1.7%) and 22 samples (6.1%) in RDT for rotavirus. Rotavirus RDT was found to have cross-reactivity with 11 norovirus infection and 3 bacterial infected stools.

Conclusion

We found that the RDTs for both rotavirus and norovirus have high specificity but low sensitivity. Cross-reactivity was observed in positive rotavirus RDT with half of it being norovirus.

Rapid detection of norovirus genogroup II in clinical and environmental samples using recombinase polymerase amplification

Norovirus is the leading cause of acute gastroenteritis all over the world, and the most genotype that causes its epidemic is norovirus genogroup II (NoVs GII). Rapid detection of NoVs is important because it can facilitate timely diagnosis. In this study, we designed universal specific primers and an Exo probe to hybridize to all genetic clusters of NoVs GII based on the conserved region at the ORF1-ORF2 junction of the genome. For the first time, we established a rapid and reliable reverse transcription recombinase polymerase amplification (RT-RPA) method for the detection of NoVs GII within 20 min. This method can specifically amplify NoVs GII, and the detection limit was as low as 1.66 × 10² copies/μL. The method was validated in terms of LOD, accuracy, and specificity. We tested 55 real samples including foods, water, and feces. The results showed a sensitivity of 96% and specificity of 100% to NoVs GII. The whole procedure can be operated by a mobile suitcase laboratory, which is useful for resource-limited diagnostic laboratories. This novel real-time RT-RPA assay is an accurate tool for point-of-care testing of NoVs, providing practical support for norovirus-caused disease diagnosis and prevention.

Development of a Nanobody-Based Lateral Flow Immunoassay for Detection of Human Norovirus

We previously identified a Nanobody (termed Nano-85) that bound to a highly conserved region on the norovirus capsid. In this study, the Nanobody was biotinylated and gold conjugated for a lateral flow immunoassay (termed Nano-IC). We showed that the Nano-IC assay was capable of detecting at least four antigenically distinct GII genotypes, including the newly emerging GII.17. In the clinical setting, the Nano-IC assay had sensitivities equivalent to other commercially available lateral flow systems. The Nano-IC method was capable of producing results in ~5 min, which makes this method useful in settings that require rapid diagnosis, such as cruise ship outbreaks and elder care facilities. The Nano-IC assay has several advantages over antibody-based IC methods: for example, Nanobodies can be readily produced in large quantities, they are generally more stable than conventional antibodies, and the Nanobody binding sites can be easily obtained by X-ray crystallography.

Human noroviruses are the dominant cause of outbreaks of acute gastroenteritis. These viruses are usually detected by molecular methods, including reverse transcriptase PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Human noroviruses are genetically and antigenically diverse, with two main genogroups that are further subdivided into over 40 different genotypes. During the past decade, genogroup 2 genotype 4 (GII.4) has dominated in most countries, but recently, viruses belonging to GII.17 have increased in prevalence in a number of countries. A number of commercially available ELISAs and lateral flow immunoassays were found to have lower sensitivities to the GII.17 viruses, indicating that the antibodies used in these methods may not have a high level of cross-reactivity. In this study, we developed a rapid Nanobody-based lateral flow immunoassay (Nano-immunochromatography [Nano-IC]) for the detection of human norovirus in clinical specimens. The Nano-IC assay detected virions from two GII.4 norovirus clusters, which included the current dominant strain and a novel variant strain. The Nano-IC method had a sensitivity of 80% and specificity of 86% for outbreak specimens. Norovirus virus-like particles (VLPs) representing four genotypes (GII.4, GII.10, GII.12, and GII.17) could be detected by this method, demonstrating the potential in clinical screening. However, further modifications to the Nano-IC method are needed in order to improve this sensitivity, which may be achieved by the addition of other broadly reactive Nanobodies to the system.

IMPORTANCE We previously identified a Nanobody (termed Nano-85) that bound to a highly conserved region on the norovirus capsid. In this study, the Nanobody was biotinylated and gold conjugated for a lateral flow immunoassay (termed Nano-IC). We showed that the Nano-IC assay was capable of detecting at least four antigenically distinct GII genotypes, including the newly emerging GII.17. In the clinical setting, the Nano-IC assay had sensitivities equivalent to other commercially available lateral flow systems. The Nano-IC method was capable of producing results in ~5 min, which makes this method useful in settings that require rapid diagnosis, such as cruise ship outbreaks and elder care facilities. The Nano-IC assay has several advantages over antibody-based IC methods: for example, Nanobodies can be readily produced in large quantities, they are generally more stable than conventional antibodies, and the Nanobody binding sites can be easily obtained by X-ray crystallography.

High sensitive and selective electrochemical biosensor: Label-free detection of human norovirus using affinity peptide as molecular binder

Norovirus is known as the major cause of highly infection for gastrointestinal tracts. In this study, robust and highly sensitive biosensors for detecting human norovirus by employing a recognition affinity peptide-based electrochemical platform were described. A series of amino acid-substituted and cysteine-incorporated recognition peptides isolated from evolutionary phage display technique was chemically synthesized and immobilized to a gold sensor layer, the detection performance of the gold-immobilized synthetic peptide-based sensor system was assessed using QCM, CV and EIS. Using EIS, the limit of detection with Noro-1 as a molecular binder was found to be 99.8nM for recombinant noroviral capsid proteins (rP2) and 7.8copies/mL for human norovirus, thereby demonstrating a high degree of sensitivity for their corresponding targets. These results suggest that a biosensor which consists of affinity peptides as a molecular binder and miniaturized microdevices as diagnostic tool could be served as a new type of biosensing platform for point-of-care testing.

Three-dimensional paper-based slip device for one-step point-of-care testing

In this study, we developed a new type of paper-based analytical device (PAD), the three-dimensional (3D) slip-PAD, to detect infectious human norovirus for global healthcare. The 3D configuration of the papers combined with a slip design provides unique features and versatility that overcome the limitations of fluidic manipulation and sensitivity in point-of-care (POC) tests. The assay can be carried out in a single step based on a moveable slip design, making it suitable for unskilled users. The 3D fluidic network developed by layered construction of wax-patterned papers provides different fluidic paths for the sequential delivery of multiple fluids without the need for peripheral equipment. The release and mixing of enhancement reagents on the device improved the sensitivity and detection limit. The assay results could be visualized by naked eye within 10 min, with subsequent amplification of the signal over time (<60 min). The device showed a broad dynamic range of detection and high sensitivity, with a detection limit of 9.5 × 10⁴ copies ml⁻¹ for human norovirus. These results demonstrate that the 3D slip-PAD is a sensitive diagnostic assay for detecting human norovirus infection that is particularly suitable for POC testing in regions where resources are scarce.

Evaluation of the updated RIDA®QUICK (Version N1402) immunochromatographic assay for the detection of norovirus in clinical specimens

The sensitivity and specificity of the R-Biopharm RIDA(®)QUICK (N1402) immunochromatography assay for norovirus detection was examined using fecal material from Australian gastroenteritis incidents. The study involved the analysis of 3 groups of specimens; group 1 comprised 100 norovirus open reading frame (ORF) 1 RT-PCR positive specimens; group 2 comprised 100 ORF 1 RT-PCR norovirus negative specimens and group 3 comprised 12 specimens containing common gastroenteritis viruses other than norovirus. The RIDA(®)QUICK (N1402) assay detected both GI and GII norovirus and had an overall sensitivity of 87%. Genotype analysis of the capsid region of the genome (ORF 2) indicated the RIDA(®)QUICK (N1402) assay could detect a range of genotypes including GI.1, GI.2, GI.3, GI.4, GI.5, GII.3, GII.4 (including variants GII.4 (2009-like), GII.4 (2012), GII.4 (2012-like) and GII.4 (unknown)), GII.6, GII.13 and GII.21. The assay had good sensitivity for both GI and GII norovirus. The assay had a specificity of 97% and did not cross react with a number of common fecal viruses. However, one of eight rotavirus positive, norovirus negative specimens gave a positive result; rotavirus cannot be taken as the cause of such a false positive but cannot be excluded either. The kit was quick and easy to use and would be valuable in point-of-care testing.

Characteristics and outcomes of patients diagnosed with norovirus gastroenteritis after allogeneic hematopoietic stem cell transplantation based on immunochromatography

Norovirus gastroenteritis (NV-GE) is a highly transmittable disease that can lead to fatal outcomes in vulnerable populations including patients after hematopoietic stem cell transplantation (HSCT). Prompt detection of NV is therefore important for HSCT recipients. Immunochromatography (IC) can be used to easily and rapidly diagnose NV-GE by detecting NV antigens. In this study, we examined 642 stool specimens in patients who developed diarrhea after allogeneic HSCT between January 2007 and June 2011. NV was detected in 10 of 350 (2.9 %) HSCT recipients. The median onset of symptoms was 36 days (range 3-93) after HSCT. The median duration of symptoms was 42 days (3-135). A second or subsequent allogeneic HSCT was associated with a higher incidence of NV-GE (P = 0.034). Of four patients who underwent colonoscopy, two showed intestinal graft-versus-host disease (GVHD) histopathology, whereas the other two showed no evidence of GVHD, and thus no need for intensified immunosuppression. None of the patients died of NV-GE. In conclusion, IC may be useful in the differential diagnosis of diarrhea after allogeneic HSCT, and could enable the appropriate adjustment of immunosuppressive drugs and prompt preventive measures.

Norovirus

Norovirus, an RNA virus of the family Caliciviridae, is a human enteric pathogen that causes substantial morbidity across both health care and community settings. Several factors enhance the transmissibility of norovirus, including the small inoculum required to produce infection (<100 viral particles), prolonged viral shedding, and its ability to survive in the environment. In this review, we describe the basic virology and immunology of noroviruses, the clinical disease resulting from infection and its diagnosis and management, as well as host and pathogen factors that complicate vaccine development. Additionally, we discuss overall epidemiology, infection control strategies, and global reporting efforts aimed at controlling this worldwide cause of acute gastroenteritis. Prompt implementation of infection control measures remains the mainstay of norovirus outbreak management.

Pediatric norovirus infection

Noroviruses (NoVs) are among the most frequent causes of acute pediatric gastroenteritis. Although the disease is often self-limiting and recovery is the rule, it constitutes an important health problem because of its highly contagious nature and the high rate of morbidity. NoVs are responsible for 47-96 % of outbreaks of acute pediatric gastroenteritis, and 5-36 % of sporadic cases. NoV-induced gastroenteritis is a frequent cause of hospitalization, and severe and sometimes fatal cases have been reported in immunocompromised children. The increasing recognition of NoVs as the cause of pediatric disease and the limited success in preventing outbreaks have led to consideration of vaccines. However, while awaiting the development of a vaccine, there is an urgent need for more epidemiological data concerning childhood NoV infection, including the impact of NoVs on different age groups, the possible etiological role of NoVs in infections other than gastroenteritis, and the socioeconomic impact of NoVs on households.

Point-of-care tests for infection control: should rapid testing be in the laboratory or at the front line?

BACKGROUND

A point-of-care test (POCT) offers a rapid result to manage a patient immediately. The presumed simplicity of such tests belies observed variation between personnel in performing and interpreting results when not appropriately trained. The number of point-of-care devices being developed for the diagnosis of infectious diseases is increasing; by understanding the limitations associated with their use, such tests for infection control purposes may be possible.

AIM

To review the expanding repertoire of POCTs for the diagnosis of infectious diseases and to assess their utility as tools to aid in the reduction of hospital-acquired infection and outbreak management.

METHODS

A systematic review using PubMed and Scopus of published literature on the subject of POCTs for the diagnosis of infectious diseases.

FINDINGS

Although the number of publications describing POCTs is increasing, there remains a paucity of literature describing their use in a clinical setting. Of the literature reviewed, POCTs for the diagnosis of respiratory syncytial virus and norovirus have the greatest utility in an infection control setting, although the data suggest that sensitivity and training issues might be a problem. The future generation of POCT devices is likely to be molecular-based, improving sensitivity but at a significant cost to the user.

CONCLUSIONS

POCTs have a role in infection control but currently the lack of good, consistent clinical data surrounding their use outside of the laboratory is a limiting factor in their implementation.

Evaluation of the Bioline Standard Diagnostics SD immunochromatographic norovirus detection kit using fecal specimens from Australian gastroenteritis incidents

Human norovirus is a major cause of both sporadic cases and outbreaks of gastroenteritis and comprises two main genogroups (GI and GII) which, in turn, comprise a variety of genotypes. The current study examined the efficacy of the Bioline SD kit using fecal material from Australian gastroenteritis incidents. At best, the SD kit had a sensitivity of 62%. Freezing and thawing specimens before testing significantly improved sensitivity. The SD kit had a specificity of 98.6%. Genotype analysis (Open Reading Frame 2) indicated the SD kit could detect a range of genotypes and genotype variants including GI.1, GI.3, GI.4, GII.1, GII.3, GII.4 (unclassified), GII.4 (2006b), GII.4 (2009), GII.4 (2012) and GII.6 but the kit failed to detect GI.2 and GII.2 norovirus. The kit did not cross-react with a number of common fecal viruses including astrovirus, sapovirus, rotavirus or adenovirus. The kit was very easy to use and would be valuable in point-of-care testing.

Molecular detection and genotyping of noroviruses

Noroviruses (NoVs) are a major cause of gastroenteritis worldwide in humans and animals and are known as very infectious viral agents. They are spread through feces and vomit via several transmission routes involving person-to-person contact, food, and water. Investigation of these transmission routes requires sensitive methods for detection of NoVs. As NoVs cannot be cultivated to date, detection of these viruses relies on the use of molecular methods such as (real-time) reverse transcriptase polymerase chain reaction (RT-PCR). Regardless of the matrix, detection of NoVs generally requires three subsequent steps: a virus extraction step, RNA purification, and molecular detection of the purified RNA, occasionally followed by molecular genotyping. The current review mainly focused on the molecular detection and genotyping of NoVs. The most conserved region in the genome of human infective NoVs is the ORF1/ORF2 junction and has been used as a preferred target region for molecular detection of NoVs by methods such as (real-time) RT-PCR, NASBA, and LAMP. In case of animal NoVs, broad range molecular assays have most frequently been applied for molecular detection. Regarding genotyping of NoVs, five regions situated in the polymerase and capsid genes have been used for conventional RT-PCR amplification and sequencing. As the expected levels of NoVs on food and in water are very low and inhibition of molecular methods can occur in these matrices, quality control including adequate positive and negative controls is an essential part of NoV detection. Although the development of molecular methods for NoV detection has certainly aided in the understanding of NoV transmission, it has also led to new problems such as the question whether low levels of human NoV detected on fresh produce and shellfish could pose a threat to public health.

Evaluation of 4 immunochromatographic tests for rapid detection of norovirus in faecal samples

BACKGROUND

The rapid detection of noroviruses is essential to implement measures to reduce the rapid spread of gastroenteritis infections they cause, notably in institutions.

OBJECTIVES

To evaluate 4 rapid immunochromatographic tests: RIDA(®)QUICK Norovirus, ImmunoCardSTAT!(®) Norovirus, NOROTOP(®) and SD BIOLINE NOROVIRUS by determining their sensitivity and specificity on a large panel of samples representing 11 genotypes of norovirus genogroup I and 14 of genogroup II, and their cross-reactivity with other enteric viruses.

STUDY DESIGN

Thawed stool samples containing norovirus genogroup I or II or other enteric viruses, and negative samples, were tested by the 4 assays and compared to the reference standard RT-PCR. Fresh stool samples were also tested by RIDA(®)QUICK.

RESULTS

The sensitivity of RIDA(®)QUICK, ImmunoCardSTAT!(®), NOROTOP(®) and SD BIOLINE for the detection of norovirus genogroup I on thawed samples was 17%, 26%, 52% and 23%, respectively. For genogroup II, the sensitivity was 64%, 39%, 50% and 54%, respectively. For GII.4, the main circulating genotype, the sensitivity was 78%, 59%, 61% and 67%, respectively. For all tests, the specificity was 100% and no cross-reactivity with other enteric viruses was observed. The sensitivity of RIDA(®)QUICK on fresh stool samples positive for GII.4 was 71%.

CONCLUSIONS

Knowing that most gastroenteritis cases are due to GII.4, the immunochromatographic tests may be useful for preliminary screening, notably in outbreaks. However, negative samples need to be tested using RT-PCR methods.