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BACKGROUND: Pregnant women are vulnerable against COVID-19 infection due to physiological and immunological changes. COVID-19 in pregnancy affects fetal well-being with a potential for vertical infection. AIM: This study aims to determine the incidence of vertical infection and anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in infants born to mothers with positive COVID-19 infection. MATERIALS AND METHODS: Amniotic fluid, swabs of the newborn's nasopharynx and oropharynx, and swabs of the placenta were examined using reverse transcription polymerase chain reaction (RT-PCR) for SARS-CoV-2. Serological examination was performed by Electro-Chemiluminescence Immunoassay on infant's blood. RESULT(S): Four of 33 pregnant women gave birth to infants positive SARS-CoV-2 infection. RT-PCR examination of all amniotic fluid and placental swabs was negative for SARS-CoV-2. Four of 33 infants (12.1%) showed negative polymerase chain reaction (PCR) results but positive SARS-CoV-2 antibodies, another 4 newborns (12.1%) showed positive PCR results, but no SARS-CoV-2 antibodies detected. The remaining 25 babies (75.8%) showed both negative PCR and serologic results. CONCLUSION(S): No evidence of vertical transmission found in this study.Copyright © 2023 Cut Meurah Yeni, Zinatul Hayati, Sarjani M. Ali, Hasanuddin Hasanuddin, Rusnaidi Rusnaidi, Cut Rika Maharani.
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The aim of the study is to describe a case of COVID-19 and myocardial infarction in an elderly patient. Material and methods. The analysis of medical documentation (outpatient card of the patient, medical history, postmortem report) was carried out. Studied macro- and micropreparations (staining with hematoxylin and eosin). Results. A 67-year-old patient, from 23.04.2020 to 26.04.2020, was hospitalized with a diagnosis of suspected coronavirus infection (COVID-19). On the background of the treatment, the patient's biological death occurred (26.04.2020). The sectional study revealed signs of bilateral total hemorrhagic pneumonia. The signs of acute transmural myocardial infarction of the anterior wall of the left ventricle were determined. Posthumously, SARS-CoV-2 RNA was detected in the lung tissue by nucleic acid amplification. In the described clinical case, a patient with concomitant cardiovascular diseases, such as arterial hypertension, coronary heart disease, developed complications against the background of COVID-19: hemorrhagic pneumonia and myocardial infarction with a fatal outcome.Copyright © Infectious Diseases: News, Opinions, Training.
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Objectives: Varicella is common infectious disease mainly in childhood, usually is a mild, self-limited illness and complications are usually rare. The incubation period for this disease is generally 14- 16 days but may vary from 7 to 21 days. Varicella in the adults with comorbidities or immunosuppressed children may be severe and prolonged with complications. Method(s): A case report of a 6-year-old girl hospitalized for new-onset manifestations of disseminated vesicular exanthema, the manifestations of which occurred mainly on the chest, back, capillitium, oral cavity, and genital area. The child was suffering from abdominal, knee and lumbosacral pain at that time. The patient's history revealed that 10 days prior to the cutaneous manifestations, she had influenza with bronchopneumonia requiring oxygen therapy, steroids and antibiotics. Result(s): The condition progressed within 48 h, complicated by the development of multi-organ failure, coagulopathy with the development of disseminated intravascular coagulopathy over the course of antiviral, antibiotic and antifungal therapy. Laboratory parameters included high elevation of C-reactive protein, il-6, leukocytosis, neutrophilia and highly elevated liver enzymes. Varicella infection was confirmed by detection of herpes zoster virus - polymerase chain reaction (PCR) from vesicles. The patient received intravenous immunoglobulin therapy at a dose of 2 g/L and fresh frozen plasma, thrombocyte concentrate. The girl was intubated with analogization. Laboratory parameters subsequently revealed high anti CoV-2 positivity, high CoV-2 IgG positivity and negative CoV-2 IgM. The patient's condition did not preclude the course of multisystem inflammatory syndrome in children (MIS-C) corticosteroids were added to the treatment at a dose of 1 mg/kg weight. Patient's condition stabilized after 1 month. Discussion(s): Our case report presents an example of fulminant complicated life-threatening course of varicella. Even in common respiratory infections, we must think about the risk and consequences of coinfections and post-infectious complications such as in our case especially influenza and COVID-19.
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Summary Introduction: The SARS-CoV-2 coronavirus, that causes the COVID-19 disease, has become a global public health problem that requires the implementation of rapid and sensitive diagnostic tests. Aim(s): To evaluate and compare the sensitivity of LAMP assay to a standard method and use RT-LAMP for the diagnosis of SARS-CoV-2 in clinical samples from Colombian patients. Method(s): A descriptive and cross-sectional study was conducted. A total of 25 nasopharyngeal swab samples including negative and positive samples for SARS-CoV-2 were analyzed, through the RT-LAMP method compared to the RT-qPCR assay. Result(s): LAMP method detected ~18 copies of the N gene, in 30 min, evidenced a detection limit similar to the standard method, in a shorter time and a concordance in RT-LAMP of 100% with the results. Conclusion(s): RT-LAMP is a sensitive, specific, and rapid method that can be used as a diagnostic aid of COVID-19 disease.Copyright © 2021. All Rights Reserved.
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Over the past century, synthetic polymers have had a transformative impact on human life, replacing nature-derived materials in many areas. Yet, despite their many advantages, the structure and function of synthetic polymers still appear rudimentary compared to biological matter: cells use dynamic self-assembly to construct complex materials and operate sophisticated macromolecular devices. The field of DNA nanotechnology has demonstrated that synthetic DNA molecules can be programmed to undergo predictable self-assembly, offering unparalleled control over the formation and dynamic properties of artificial nanostructures. Intriguingly, the principles of DNA nanotechnology can be applied to the engineering of soft programmable materials, bringing the abilities of synthetic polymers closer to their biological counterparts. In this perspective, we discuss the unique features of DNA-functionalized polymer materials. We describe design principles that allow researchers to build complex supramolecular architectures with predictable and dynamically adjustable material properties. Finally, we highlight two key application areas where this biologically inspired material class offers particularly promising opportunities: (1) as dynamic matrices for 3D cell and organoid culture and (2) as smart materials for nucleic acid sequencing and pathogen detection.
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During the COVID-19 pandemic, point-of-care genetic testing (POCT) devices were used for on-time and on-site detection of the virus, which helped to prevent and control the spread of the pandemic. Smartphones, which are widely used electronic devices with many functions, have the potential to be used as a molecular diagnostic platform for universal healthcare monitoring. Several integrated diagnostics platforms for the real-time and end-point detection of COVID-19 were developed using the functions of smartphones, such as the operating system, power, sound, camera, data storage, and display. These platforms use the 5V output power of smartphones, which can be amplified to power a micro-capillary electrophoresis system or a thin-film heater, and the CMOS camera of smartphones can capture the color change during a colorimetric loop-mediated isothermal amplification test and detect fluorescence signals. Smartphones can also be used with self-written web-based apps to enable automatic and remote pathogen analysis on POCT platforms. Our lab developed a handheld micro-capillary electrophoresis device for end-point detection of SARS-CoV-2, as well as an integrated smartphone-based genetic analyzer for the qualitative and quantitative colorimetric detection of foodborne pathogens with the help of a custom mobile app. © 2023 SPIE.
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Objective: Acute respiratory tract infections are one of the leading causes of morbidity and mortality in children. Although human bocavirus (HBoV) infections are not as common as other seasonal respiratory viruses, children who are infected with HBoV are more likely to suffer from a variety of respiratory conditions, including the common cold, acute otitis media, asthma exacerbations, bronchiolitis pneumonia, some of the affected children require pediatric intensive care unit stay. Here, we aimed to evaluate pediatric bocavirus (HBoV) cases presenting with severe respiratory tract symptoms during the coronavirus disease 2019 (COVID-19) pandemic. Method(s): This retrospective study evaluated the medical records of children diagnosed with respiratory infections, followed up at the Faculty of Medicine, Eskisehir Osmangazi University between September 2021 and March 2022. In this study, patients with HBoV identified using nasopharyngeal polymerase chain reaction (PCR) were considered positive. Cases were analyzed retrospectively for their clinical characteristics. Result(s): This study included 54 children (29 girls and 25 boys) with HBoV in nasopharyngeal PCR samples. The cases ranged in age from 1 month to 72 months (median 25 months). At the time of presentation, cough, fever, and respiratory distress were the most prevalent symptoms. Hyperinflation (48%), pneumonic consolidation (42%), and pneumothorax-pneumomediastinum (7%) were observed on the chest X-ray;54% of the children required intensive care unit stay. The median length of hospitalization was 6 days. Bacterial coinfection was detected in 7 (17%) children, while HBoV and other viruses were present in 20 (37%) children;57% of children received supplemental oxygen by mask, 24% high-flow nasal oxygen, 7% continuous positive airway pressure, and 9% invasive mechanical ventilation support. Antibiotics were given to 34 (63%) cases, and systemic steroid treatment was given to 41 (76%) cases. Chest tubes were inserted in three out of the four cases with pneumothorax-pneumomediastinum. All patients were recovered and were discharged from the hospital. Conclusion(s): The COVID-19 pandemic changed the epidemiology of seasonal respiratory viruses and the clinical course of the diseases. Although it usually causes mild symptoms, severe respiratory symptoms can lead to life-threatening illnesses requiring intensive care admission.Copyright © 2023. The Author(s).
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Autoimmune haemolytic anaemia (AIHA) is rare but described after the SARS-CoV- 2 Pfizer-BioNTech vaccine. We present a case of severe refractory warm AIHA after this vaccine, managed with emergency splenectomy and complement inhibition with eculizumab. A male in his teens with a history of liver transplant for biliary atresia (aged 2 years) and AIHA (aged 6 years) presented to his district general hospital with jaundice, dark urine, fatigue and chest discomfort 48 h after the first dose of SARS-CoV- 2 Pfizer-BioNTech vaccine (BNT162b2 mRNA). Investigations revealed haemoglobin (Hb) of 70 g/L and bilirubin of 98 mumol/L, which was treated as AIHA. The patient initially responded to prednisolone (1 mg/kg, 60 mg) but subsequently deteriorated and failed to respond to second-line rituximab (375 mg/m2) and two units of packed red blood cells (PRBC). By day 29 the patient had developed life-threatening anaemia culminating in a Hb of 35 g/L (after transfusion), lactate dehydrogenase (LD) of 1293 units/L and bilirubin of 228 mumol/L. This necessitated an immediate transfer to our tertiary centre for specialist support. Further investigations revealed a haptoglobin <0.1 g/L and direct antiglobulin test (DAT) strongly positive for IgG (4+) and negative for C3d. The peripheral blood film showed severe anaemia, nucleated red cells, anisocytosis and spherocytes with no autoagglutination, schistocytes or platelet clumps. Thrombocytopaenia (platelets 49 +/- 109/L) was present. Differentials were ruled out, such as paroxysmal nocturnal haemoglobinuria and heparin-induced thrombocytopaenia. HIV and hepatitis serology were negative, as were adenovirus, cytomegalovirus and Epstein-Barr virus PCR assays. A CT showed splenomegaly of 15.5 cm. Urinalysis found urobilinogen and bilirubin at high concentrations and negative urinary haemosiderin. Together, the investigations were consistent with warm AIHA. On day 29, four units of PRBC were transfused alongside 100 mg methylprednisolone and 1 g/kg IVIG. On day 30 the patient deteriorated despite the escalated treatment: Hb had only increased to 54 g/L, bilirubin was 200 mumol/L and LD was rising. Considering this life-threatening fulminant haemolysis, an emergency splenectomy was performed. This slowed haemolysis but did not completely ameliorate it: by day 33 the patient had received 15 units of PRBC. Thus, eculizumab, a terminal complement pathway inhibitor, was trialled to arrest intravascular haemolysis, alongside rituximab, repeat IVIG 1 g/kg, prednisolone 40 mg and tacrolimus 2 mg. This showed a favourable response, requiring less frequent transfusions and settling haemolysis. This case highlights the rare complication of warm AIHA with the SARS-CoV- 2 Pfizer-BioNTech vaccine, the use of emergency splenectomy for disease control, and the potential of eculizumab for refractory cases.
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It is known that inflammatory cytokines exacerbate the persistence and severity of various disease states. Breast cancer is the most frequently detected cancer among women worldwide and our recent studies suggest that the inflammatory state of breast (BrCa) cancer, a byproduct of elevated cytokine expression, induces epigenetic modifications leading to increased recurrence. Ongoing NCI clinical trial data (ClinicalTrials.gov, CCC19, NCT04354701) indicates that among patients with cancer and COVID-19, the mortality is high, and the most prevalent malignancies are of breast [21%] and prostate [16%] origin. Due to the risk of cytokine storm during SARS-CoV-2 infection, it is crucial to identify potential mechanisms of hyperinflammation in BrCa patients. In this study, we have evaluated the level of copy number alteration (CNA) of different inflammatory cytokines including IL-8, IL-1b, IL6, IL-8, GM-CSF, TNF-alpha and many others using cBioportal platform which includes over sixty-nine thousand tumor samples (n>69,000 from 213 different studies) from over 33 different cancers. We found that IL-8 has the highest level of amplification in different breast cancers subtypes. Besides, we also analyzed serum samples from BrCa patients, both recurrent and non-recurrent, by different proteomics methods to identify serum cytokines involved in prognosis and recurrence. Comparative data analysis between non-recurrent BrCa against recurrent BrCa patients identified several proteins with very high significance, mostly proteins associated with epigenetic pathways including HDAC9 (P = 0.0035), HDAC5 (P = 0.013), and HDAC7 (P = 0.020). Besides, we identified differential expression of several pro-inflammatory cytokines and immune regulators (IL-8, IL-4, IL-18, IL-12p70) that were present only in recurrent BrCa patient serum. Our data indicate that inflammatory processes contribute to epigenetic modifications that ultimately play a critical role in breast cancer recurrence. In terms of COVID-19 associated co-morbidity, the already dysregulated inflammatory state of BrCa patients may increase their susceptibility to cytokine-storm, leading to increased severity of COVID-related complications and increased mortality rate. Specifically, we hypothesize that the identified elevated level of IL-8 in BrCa patients may lead to a higher basal level of inflammation and contribute to the risk of attaining cytokine-storm during SARS-CoV-2 infection, making it a valuable target for future studies.
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Objectives: Clinical Practice Research Datalink (CPRD) Aurum captures primary care electronic healthcare records for ~28% of the population in England. From August 2020-;March 2022, all SARS-CoV-2 polymerase chain reaction (PCR) tests performed were reported back to the patient's general practitioner (GP), making the CPRD a closed system uniquely positioned to answer COVID research questions. Method(s): We defined persons with COVID as those recorded in primary care with a positive PCR test from August 1, 2020-March 31, 2021. We required continuous registration with their GP practice for >=365 days prior to diagnosis to establish comorbid conditions, and eligibility for linkage to Hospital Episode Statistics (HES) Admitted Patient Care data. Hospitalizations for COVID were defined as persons admitted with a primary diagnosis of COVID (ICD-10-CM U07.1) within 12 weeks of the initial primary care diagnosis record. Result(s): Our cohort included 535,453 persons diagnosed in primary care with COVID, with 2% later hospitalized. The hospitalized group was 57% male, 42% current/former smokers, 35% obese46% with a Charlson Comorbidity Index >1 and 98% had never received any COVID vaccine. Hospitalizations increased with age;<0.1% of patients aged 1-17, 1% aged 18-49, 4% aged 50-64, 9% aged 65-74, 13% aged 74-84, and 11% of COVID cases aged >=85 were hospitalized. Persons living in socially disadvantaged areas were overrepresented in the hospitalized cohort (25% in the Index of Multiple Deprivation's most deprived quintile). Conclusion(s): Consistent with other studies, hospitalized COVID patients were disproportionately those with male sex, smoking history, high body mass index, comorbidity and unvaccinated status. Hospitalizations were more common with age, and for individuals living in socially and economically deprived communities. Understanding the demographic and clinical characteristics of this cohort can help contextualize future work describing healthcare resource utilization and costs, as well as the impact of vaccines, associated with COVID in England.Copyright © 2023
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Background & Aim: The new UCOE models we have recently developed, tested on many cell groups (including mouse ES and human iPS cells) and human mAb recombinant production studies as well, shows a powerful resistance to DNA methylation- mediated silencing and provides a higher and stable transfection profile. By the urgent need of vaccine development for COVID-19 during the pandemic, in this study we aimed to produce a potential recombinant vaccine by using the new generation UCOEs models of our own design. Methods, Results & Conclusion(s): Existing new-generation UCOE models and standard plasmid vectors to be used as control group were provided. Then, the sequences related to the PCR method were amplified for sufficient stock generation and cloning experiments. Verification in the plasmid vector was carried out in gel electrophoresis. Transfection of 293T cells was performed with clone plasmids carrying antigen genes and plasmids carrying genetic information of lentivirus units for the production of lentiviral vectors. Afterwards, 293T cells produced lentiviral vectors carrying antigen genes. Harvesting of these vectors was carried out during 48th and 72nd hours. Afterwards, CHO cells were transduced with appropriate quantity of lentiviral vectors. Isolation and purification of targeted proteins from the relevant medium were performed by HPLC and Q-TOF methods. A part of the spike and nucleocapsid gene sequences of COVID-19 were firstly cloned into our UCOE models. These UCOEs plasmids were then transferred into 293T cells along with plasmids carrying the genes that will form the lentivirus vectors (LVs). After harvesting and calculation of LV vector titers, the cloned vectors were then transfected into the CHO cells which the targeted recombinant production of the antigen proteins will be carried out. Antigenic structures were then isolated from the culture medium of CHO cells in following days for confirmation. Using HPLC and qTOF mass spectrometer methods, these structures in the medium were confirmed to be the units of spike and nucleocapsid proteins of the COVID-19 virus. In order to produce large amount of the recombinant antigens, the culture was then carried out with bioreactors in liters. At the final stage, these recombinantly produced antigen proteins were tested on rats to measure their immunogenic responses, and the study recently been completed successfully as a potential recombinant vaccine against COVID-19.Copyright © 2023 International Society for Cell & Gene Therapy
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Introduction: TBX1 haploinsufficiency is an inborn error of immunity with the phenotype of DiGeorge Syndrome. DiGeorge Syndrome has variable immunodeficiency associated with grade of thymic hypoplasia ranging from mild with no infections to severe requiring thymus implant. Enterovirus is an example of an opportunistic infection that can be fatal in these patients. Case Presentation: A 1 year old girl with TBX1 haploinsufficiency complicated by Tetralogy of Fallot, pulmonary atresia, high arched palate, and vesicovaginal fistula presented for elective cardiac repair surgery from another country due to failure to thrive and cyanosis. She had no prior infectious history but was on sulfamethoxazole-trimethoprim for prophylaxis. She was asymptomatic with a negative COVID test but no other infectious studies performed. Immediately postoperatively, she was febrile and nasal respiratory viral panel was positive for rhinovirus/enterovirus with increased procalcitonin and leukocytosis with left shift. She decompensated with multi-organ failure and cardiac arrest on postoperative day two. She was cannulated to veno-arterial extracorporeal membrane oxygenation (ECMO). Pre-operatively, she had a normal absolute lymphocyte count. No thymus tissue was observed in surgery. She had profound CD3 lymphopenia to 130 cells/cmm when critically ill. Enteroviral meningitis was suspected as no infectious, cardiac, or other pathology could be identified causing decompensation. Enteroviral serum polymerase chain reaction (PCR) test was negative while lumbar puncture deferred due to clinical status. She was treated with immunoglobulin. Offlabel investigational drug pocapavir was considered but deferred to patient's irreversible neurological status. The patient was disconnected from ECMO and expired. Discussion(s): Though we cannot confirm that this patient had enteroviral meningitis, invasive enteroviral infections are associated with elevated transaminases, coagulopathy, and seizures all present in our patient. There has also been reported negative serum enteroviral PCR but positive CSF enteroviral PCR in an immunodeficient patient. Additionally, this case highlights the importance of immunologic evaluation in patients with DiGeorge Syndrome and questions if asymptomatic viral screening for viruses like enterovirus should be considered pre-operatively in patients with inborn errors of immunity. This case highlights potential treatment options for invasive enteroviral infections in patients with inborn errors of immunity: high dose immunoglobulin, fluoxetine, and pocapavir.Copyright © 2023 Elsevier Inc.
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Due to the high reproduction rate of COVID-19, it is important to identify and isolate infected patients at the early stages of infection. The limitations of current diagnostic methods are speed, cost, and accuracy. Furthermore, new viral variants have emerged with higher rates of infectivity and mortality, many with mutations at various primer binding sites, which may evade detection via conventional PCR kits. Therefore, a rapid method that is sensitive, specific, and cost-effective is needed for a point-of-care molecular test. Accordingly, we developed a rapid molecular SARS-CoV-2 detection kit with high specificity and sensitivity, RT-PCR, taking advantage of the loop-mediated isothermal amplification (LAMP) technique. Four sets of six primers were designed based on conserved regions of the SARS-CoV-2 genome: two outer, two inner and two loop primers. Using the optimized protocol, SARS-CoV-2 genes were detected as quickly as 10 min but were most sensitive at 30 min, detecting as little as 100 copies of template DNA. We then coupled the RT-LAMP with a lateral flow dipstick (LFD) for multiplex detection. The LFD could detect two genic amplifications on a single strip, making it suitable for multiplexed detection. The development of a multiplexed RT-LAMP-LFD reaction on crude VTM samples would be suitable for the point-of-care diagnosis of COVID-19 in diagnostic laboratories as well as in private homes.
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Pediatric COVID-19 determines a mild clinical picture, but few data have been published about the correlation between disease severity and PCR amplification cycles of SARS-CoV-2 from respiratory samples. This correlation is clinically important because it permits the stratification of patients in relation to their risk of developing a serious disease. Therefore, the primary endpoint of this study was to establish whether disease severity at the onset, when evaluated with a LqSOFA score, correlated with the gene amplification of SARS-CoV-2. LqSOFA score, also named the Liverpool quick Sequential Organ Failure Assessment, is a pediatric score that indicates the severity of illness with a range from 0 to 4 that incorporates age-adjusted heart rate, respiratory rate, capillary refill and consciousness level (AVPU). The secondary endpoint was to determine if this score could predict the days of duration for symptoms and positive swabs. Our study included 124 patients aged between 0 and 18 years. The LqSOFA score was negatively correlated with the number of PCR amplification cycles, but this was not significant (Pearson's index -0.14, p-value 0.13). Instead, the correlation between the LqSOFA score and the duration of symptoms was positively related and statistically significant (Pearson's index 0.20, p-value 0.02), such as the correlation between the LqSOFA score and the duration of a positive swab (Pearson's index 0.40, p-value < 0.01). So, the LqSOFA score upon admission may predict the duration of symptoms and positive swabs; the PCR amplification of SARS-CoV-2 appears not to play a key role at onset in the prediction of disease severity.
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Sensitive and rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a vital goal in the ongoing COVID-19 pandemic. We present in this comprehensive work, for the first time, detailed fabrication and clinical validation of a point of care (PoC) device for rapid, onsite detection of SARS-CoV-2 using a real-time reverse-transcription loop-mediated isothermal amplification (RT-LAMP) reaction on a polymer cartridge. The PoC system, namely PATHPOD, consisting of a standalone device (weight less than 1.2 kg) and a cartridge, can perform the detection of 10 different samples and two controls in less than 50 min, which is much more rapid than the golden standard real-time reverse-transcription Polymerase Chain Reaction (RT-PCR), typically taking 16-48 h. The novel total internal reflection (TIR) scheme and the reactions inside the cartridge in the PoC device allow monitoring of the diagnostic results in real-time and onsite. The analytical sensitivity and specificity of the PoC test are comparable with the current RT-PCR, with a limit of detection (LOD) down to 30-50 viral genome copies. The robustness of the PATHPOD PoC system has been confirmed by analyzing 398 clinical samples initially examined in two hospitals in Denmark. The clinical sensitivity and specificity of these tests are discussed.
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In COVID-19 patients who are severe or immunocompromised, the duration of infectious viral shedding may be longer, and a longer isolation duration is recommended. In National Sagamihara hospital, a decline in the viral load to end the isolation of COVID-19 hospitalized patients is confirmed by loop mediated isothermal amplification (LAMP). However, a subset of patients persisted in displaying LAMP positivity for more than 20 days since symptom onset. Therefore, we conducted a retrospective observational study to investigate factors impacting the persistence of LAMP positivity. The study included 102 participants. The severity of COVID-19 was mild in 25.5%, moderate in 67.6%, and severe in 6.9% of patients. The median number (interquartile range) of days until negative LAMP since symptom onset was 16 (14-19) days. Multivariate logistic regression analysis showed that age ≥55 years and the delta variant were correlated with persistently LAMP positive for more than 20 days since symptom onset. This study identified that age, the delta variant, and oxygen requirement were factors contributing to persistently positive LAMP. Therefore, it is posited that in these patients, the implementation of LAMP for de-isolation would result in a prolonged duration of isolation.
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Recombinase polymerase amplification (RPA) running at 37-42 °C is fast, efficient and less-implemented; however, the existing technologies of nucleic acid testing based on RPA have some limitations in specificity of single-base recognition and multiplexing capability. Herein, we report a highly specific and multiplex RPA-based nucleic acid detection platform by combining flap endonuclease 1 (FEN1)-catalysed invasive reactions with RPA, termed as FEN1-aided RPA (FARPA). The optimal conditions enable RPA and FEN1-based fluorescence detection to occur automatically and sequentially within a 25-min turnaround time and FARPA exhibits sensitivity to 5 target molecules. Due to the ability of invasive reactions in discriminating single-base variation, this one-pot FARPA is much more specific than the Exo probe-based or CRISPR-based RPA methods. Using a universal primer pair derived from tags in reverse transcription primers, multiplex FARPA was successfully demonstrated by the 3-plex assay for the detection of SARS-CoV-2 pathogen (the ORF1ab, the N gene, and the human RNase P gene as the internal control), the 2-plex assay for the discrimination of SARS-CoV-2 wild-type from variants (Alpha, Beta, Epsilon, Delta, or Omicrons), and the 4-plex assay for the screening of arboviruses (zika virus, tick-borne encephalitis virus, yellow fever virus, and chikungunya virus). We have validated multiplex FARPA with 103 nasopharyngeal swabs for SARS-CoV-2 detection. The results showed a 100% agreement with RT-qPCR assays. Moreover, a hand-held FARPA analyser was constructed for the visualized FARPA due to the switch-like endpoint read-out. This FARPA is very suitable for pathogen screening and discrimination of viral variants, greatly facilitating point-of-care diagnostics.
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Rapid and sensitive detection of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for early diagnosis and effective treatment. Nucleic acid testing has been considered the gold standard method for the diagnosis of COVID-19 for its high sensitivity and specificity. However, the polymerase chain reaction (PCR)-based method in the central lab requires expensive equipment and well-trained personnel, which makes it difficult to be used in resource-limited settings. It highlights the need for a sensitive and simple assay that allows potential patients to detect SARS-CoV-2 by themselves. Here, we developed an electricity-free self-testing system based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) that allows for rapid and accurate detection of SARS-CoV-2. Our system employs a heating bag as the heat source, and a 3D-printed box filled with phase change material (PCM) that successfully regulates the temperature for the RT-LAMP. The colorimetric method could be completed in 40 min and the results could be read out by the naked eye. A ratiometric measurement for exact readout was also incorporated to improve the detection accuracy of the system. This self-testing system is a promising tool for point-of-care testing (POCT) that enables rapid and sensitive diagnosis of SARS-CoV-2 in the real world and will improve the current COVID-19 screening efforts for control and mitigation of the pandemic.
Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Self-Testing , COVID-19 Testing , Clinical Laboratory Techniques/methods , Sensitivity and Specificity , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methodsABSTRACT
Tuberculosis, caused by Mycobacterium tuberculosis (MTB), is the second leading cause of death after COVID-19 pandemic. Here, we coupled multiple cross displacement amplification (MCDA) technique with CRISPR-Cas12a-based biosensing system to design a novel detection platform for tuberculosis diagnosis, termed MTB-MCDA-CRISPR. MTB-MCDA-CRISPR pre-amplified the specific sdaA gene of MTB by MCDA, and the MCDA results were then decoded by CRISPR-Cas12a-based detection, resulting in simple visual fluorescent signal readouts. A set of standard MCDA primers, an engineered CP1 primer, a quenched fluorescent ssDNA reporter, and a gRNA were designed targeting the sdaA gene of MTB. The optimal temperature for MCDA pre-amplification is 67°C. The whole experiment process can be completed within one hour, including sputum rapid genomic DNA extraction (15 minutes), MCDA reaction (40 minutes), and CRISPR-Cas12a-gRNA biosensing process (5 minutes). The limit of detection (LoD) of the MTB-MCDA-CRISPR assay is 40 fg per reaction. The MTB-MCDA-CRISPR assay does not cross reaction with non-tuberculosis mycobacterium (NTM) strains and other species, validating its specificity. The clinical performance of MTB-MCDA-CRISPR assay was higher than that of the sputum smear microscopy test and comparable to that of Xpert method. In summary, the MTB-MCDA-CRISPR assay is a promising and effective tool for tuberculosis infection diagnosis, surveillance and prevention, especially for point-of-care (POC) test and field deployment in source-limited regions.