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1.
Semin Respir Crit Care Med ; 42(6): 828-838, 2021 12.
Article in English | MEDLINE | ID: covidwho-1585701

ABSTRACT

The past two decades have witnessed the emergence of three zoonotic coronaviruses which have jumped species to cause lethal disease in humans: severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1), Middle East respiratory syndrome coronavirus (MERS-CoV), and SARS-CoV-2. MERS-CoV emerged in Saudi Arabia in 2012 and the origins of MERS-CoV are not fully understood. Genomic analysis indicates it originated in bats and transmitted to camels. Human-to-human transmission occurs in varying frequency, being highest in healthcare environment and to a lesser degree in the community and among family members. Several nosocomial outbreaks of human-to-human transmission have occurred, the largest in Riyadh and Jeddah in 2014 and South Korea in 2015. MERS-CoV remains a high-threat pathogen identified by World Health Organization as a priority pathogen because it causes severe disease that has a high mortality rate, epidemic potential, and no medical countermeasures. MERS-CoV has been identified in dromedaries in several countries in the Middle East, Africa, and South Asia. MERS-CoV-2 causes a wide range of clinical presentations, although the respiratory system is predominantly affected. There are no specific antiviral treatments, although recent trials indicate that combination antivirals may be useful in severely ill patients. Diagnosing MERS-CoV early and implementation infection control measures are critical to preventing hospital-associated outbreaks. Preventing MERS relies on avoiding unpasteurized or uncooked animal products, practicing safe hygiene habits in health care settings and around dromedaries, community education and awareness training for health workers, as well as implementing effective control measures. Effective vaccines for MERS-COV are urgently needed but still under development.


Subject(s)
Middle East Respiratory Syndrome Coronavirus , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/therapeutic use , Camelus/virology , Coronavirus Infections/diagnosis , Coronavirus Infections/drug therapy , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Disease Outbreaks/prevention & control , Humans , Infection Control/methods , Middle East Respiratory Syndrome Coronavirus/drug effects , Middle East Respiratory Syndrome Coronavirus/pathogenicity
2.
Int J Infect Dis ; 2021 Mar 10.
Article in English | MEDLINE | ID: covidwho-1574772

ABSTRACT

Despite slow reductions in the annual burden of active human tuberculosis (TB) cases, zoonotic TB (zTB) remains a poorly monitored and an important unaddressed global problem. There is a higher incidence in some regions and countries, especially where close association exists between growing numbers of cattle (the major source of Mycobacterium bovis) and people, many suffering from poverty, and where dairy products are consumed unpasteurised. More attention needs to be focused on possible increased zTB incidence resulting from growth in dairy production globally and increased demand in low income countries in particular. Evidence of new zoonotic mycobacterial strains in South Asia and Africa (e.g. M. orygis), warrants urgent assessment of prevalence, potential drivers and risk in order to develop appropriate interventions. Control of M. bovis infection in cattle through detect and cull policies remain the mainstay of reducing zTB risk, whilst in certain circumstances animal vaccination is proving beneficial. New point of care diagnostics will help to detect animal infections and human cases. Given the high burden of human tuberculosis (caused by M. tuberculosis) in endemic areas, animals are affected by reverse zoonosis, including multi-drug resistant strains. This, may create drug resistant reservoirs of infection in animals. Like COVID-19, zTB is evolving in an ever-changing global landscape.

3.
Pharmaceuticals (Basel) ; 14(12)2021 Nov 24.
Article in English | MEDLINE | ID: covidwho-1542704

ABSTRACT

Without effective antivirals, the COVID-19 pandemic will likely continue to substantially affect public health. Medicinal plants and phytochemicals are attractive therapeutic options, particularly those targeting viral proteins essential for replication cycle. Herein, a total 179 phytochemicals of licorice (Glycyrrhiza glabra) were screened and scrutinized against the SARS-CoV-2 main protease (Mpro) with considerable binding affinities in the range of -9.831 to -2.710 kcal/mol. The top 10 compounds with the best docking scores, licuraside, glucoliquiritin apioside, 7,3'-Dihydroxy-5'-methoxyisoflavone, licuroside, kanzonol R, neoisoliquiritin, licochalcone-A, formononetin, isomucronulatol, and licoricone, were redocked using AutoDock Vina, yielding -8.7 to -7.3 kcal/mol binding energy against Glycyrrhizin (-8.0 kcal/mol) as a reference ligand. Four compounds, licuraside, glucoliquiritin apioside, 7,3'-Dihydroxy-5'-methoxyisoflavone, and licuroside, with glycyrrhizin (reference ligand) were considered for the 100 ns MD simulation and post-simulation analysis which support the stability of docked bioactive compounds with viral protein. In vitro studies demonstrated robust anti-SARS-CoV-2 activity of licorice and glycyrrhizin under different treatment protocols (simulations treatment with viral infection, post-infection treatment, and pre-treatment), suggesting multiple mechanisms for action. Although both compounds inhibited SARS-CoV-2 replication, the half-maximal inhibitory concentration (IC50) of glycyrrhizin was substantially lower than licorice. This study supports proceeding with in vivo experimentation and clinical trials and highlights licorice and glycyrrhizin as potential therapeutics for COVID-19.

5.
Encyclopedia of Respiratory Medicine ; : 146-161, 2022.
Article in English | [Unspecified Source], Grey literature | ID: grc-750374

ABSTRACT

Three novel coronaviruses have emerged as new lethal zoonotic pathogens of humans during the past 17 years: The Severe Acute Respiratory Syndrome (SARS) coronavirus (SARS-CoV), the Middle East Respiratory Syndrome (MERS) coronavirus (MERS-CoV), and most recently SARS-CoV-2. SARS-CoV first surfaced as a human pathogen in Guangdong, China in November 2002 and rapidly spread worldwide with 8098 cases and 774 deaths before the end of the epidemic. SARS-like CoVs have been detected in horseshoe bats with high sequence homology with human or civet isolates, suggesting that bats could be a natural reservoir of a close ancestor of SARS-CoV. No cases of SARS have been reported since January 2004. MERS-CoV was first reported in September 2012, after it was isolated from respiratory samples from a patient in Jeddah, Saudi Arabia who died in June 2012. How humans acquire MERS-CoV infection is not yet known although bats and dromedary camels are intermediary reservoirs. MERS-CoV continues to circulate in the Middle East. As of May 22, 2019, 2428 cases of laboratory-confirmed MERS-CoV cases reported to the World Health Organization, including 838 deaths (34.5% mortality) have been reported from 27 countries. While the majority of MERS cases occur in the Middle East, travel related MERS cases have been reported from all continents. Large health care associated outbreaks of MERS-CoV have occurred in Saudi Arabia, United Arab Emirates, and the Republic of Korea. SARS-CoV-2 emerged from Wuhan, China in December 2019, and by March 2020 had established as a pandemic which has caused massive disruption in multiple countries. The eventual mortality caused by this virus remains to be seen. All three viruses cause a similar wide range of nonspecific clinical manifestations from mild upper respiratory tract illness to severe respiratory, gastrointestinal and other extra-pulmonary disease. Early recognition of cases, improved compliance with internationally recommended infection control protocols, and rapid implementation of infection control measures are required to prevent health care facility-associated outbreaks, and in the case of SARS-CoV-2 for control of community spread as well. Treatment is supportive and there are no specific antivirals or vaccines available for both SARS and MERS.

6.
Saudi Med J ; 42(7): 742-749, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1513260

ABSTRACT

OBJECTIVES: To identify the prevalence of COVID-19 antibodies among operating room and critical care staff. METHODS: In this cross-sectional study, we recruited 319 Healthcare workers employed in the operation theater and intensive care unit of King Abdulaziz University Hospital (KAUH), a tertiary teaching hospital in Jeddah, Saudi Arabia between August 9, 2020 and November 2, 2020. All participants completed a 20-item questionnaire on demographic data and COVID-19 risk factors and provided blood samples. Antibody testing was performed using an in-house enzyme immunoassay and microneutralization test. RESULTS: Of the 319 participants, 39 had detectable COVID-19 antibodies. Five of them had never experienced any symptoms suggestive of COVID-19, and only 19 were previously diagnosed with COVID-19. The odds of developing COVID-19 or having corresponding antibodies increased if participants experienced COVID-19 symptoms (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.2-7.5) or reported contact with an infected family member (OR, 5.3; 95% CI, 2.5-11.2). Disease acquisition was not associated with employment in the ICU and involvement in the intubation of or close contact with COVID-19 patients. Of the 19 previously diagnosed participants, 6 did not possess any detectable COVID-19 antibodies. CONCLUSIONS: Healthcare workers may have undiagnosed COVID-19, and those previously infected may not have long-lasting immunity. Therefore, hospitals must continue to uphold strict infection control during the COVID-19 pandemic.


Subject(s)
COVID-19 Serological Testing/statistics & numerical data , COVID-19/diagnosis , Health Personnel , SARS-CoV-2/isolation & purification , Adult , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/epidemiology , Critical Care , Cross-Sectional Studies , Enzyme-Linked Immunosorbent Assay , Female , Hospitals, Teaching , Humans , Infectious Disease Transmission, Patient-to-Professional , Male , Middle Aged , Operating Rooms , Pandemics , Prevalence , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , Saudi Arabia/epidemiology
7.
Int J Mol Sci ; 22(19)2021 Sep 28.
Article in English | MEDLINE | ID: covidwho-1444229

ABSTRACT

Extracellular vesicles (EVs) carry important biomolecules, including metabolites, and contribute to the spread and pathogenesis of some viruses. However, to date, limited data are available on EV metabolite content that might play a crucial role during infection with the SARS-CoV-2 virus. Therefore, this study aimed to perform untargeted metabolomics to identify key metabolites and associated pathways that are present in EVs, isolated from the serum of COVID-19 patients. The results showed the presence of antivirals and antibiotics such as Foscarnet, Indinavir, and lymecycline in EVs from patients treated with these drugs. Moreover, increased levels of anti-inflammatory metabolites such as LysoPS, 7-α,25-Dihydroxycholesterol, and 15-d-PGJ2 were detected in EVs from COVID-19 patients when compared with controls. Further, we found decreased levels of metabolites associated with coagulation, such as thromboxane and elaidic acid, in EVs from COVID-19 patients. These findings suggest that EVs not only carry active drug molecules but also anti-inflammatory metabolites, clearly suggesting that exosomes might play a crucial role in negotiating with heightened inflammation during COVID-19 infection. These preliminary results could also pave the way for the identification of novel metabolites that might act as critical regulators of inflammatory pathways during viral infections.


Subject(s)
COVID-19/metabolism , Extracellular Vesicles/metabolism , Metabolome , SARS-CoV-2/physiology , Adult , Anti-Inflammatory Agents/metabolism , COVID-19/pathology , Extracellular Vesicles/pathology , Female , Humans , Male , Metabolomics , Middle Aged
8.
Curr Pharm Des ; 27(32): 3444-3453, 2021.
Article in English | MEDLINE | ID: covidwho-1435740

ABSTRACT

BACKGROUND: Viruses are known as the major causative agents for infectious diseases globally. The coronaviruses are one of the serious pathogens to cause serious diseases in humans. Recently identified SARSCoV- 2 from Wuhan City, China, has emerged as a serious threat to human health and caused a global pandemic. Bats have been confirmed as a primary source of infection. The vaccination of the human population and animals serving as a potential reservoir is a straightforward strategy to control the transmission of any pathogen to humans. Natural products from many herbal plants are well known to have novel antiviral properties and evaluated against various viral diseases. There are many alkaloids that have shown to be effective against coronaviruses. METHODS: Recently, the antiviral efficacy of natural alkaloids known as Homoharringtonine (HTT) and Emetine has been evaluated and provided promising results against coronaviruses, including SARS-CoVs. These alkaloids may be very useful and can be used as antivirals against SARS-CoV-2 because they have already been reported to inhibit the replication of SASRS-CoV and other viruses in cell lines. CONCLUSION: This review specifically focuses on the recent findings of these alkaloids against coronaviruses and possible treatment options for SARS-CoV-2. It is expected that natural products as alkaloids from herbal plants could be considered as novel and valuable candidates for the new antiviral drugs against SARS-CoV-2.


Subject(s)
Alkaloids , Biological Products , COVID-19 , Alkaloids/pharmacology , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Biological Products/pharmacology , Emetine , Homoharringtonine , Humans , SARS-CoV-2
9.
Int J Infect Dis ; 108: 112-115, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1351691

ABSTRACT

BACKGROUND: Immunocompromised patients with coronavirus disease 2019 (COVID-19) have prolonged infectious viral shedding for more than 20 days. A test-based approach is suggested for de-isolation of these patients. METHODS: The strategy was evaluated by comparing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load (cycle threshold (Ct) values) and viral culture at the time of hospital discharge in a series of 13 COVID-19 patients: six immunocompetent and seven immunocompromised (five solid organ transplant patients, one lymphoma patient, and one hepatocellular carcinoma patient). RESULTS: Three of the 13 (23%) patients had positive viral cultures: one patient with lymphoma (on day 16) and two immunocompetent patients (on day 7 and day 11). Eighty percent of the patients had negative viral cultures and had a mean Ct value of 20.5. None of the solid organ transplant recipients had positive viral cultures. CONCLUSIONS: The mean Ct value for negative viral cultures was 20.5 in this case series of immunocompromised patients. Unlike those with hematological malignancies, none of the solid organ transplant patients had positive viral cultures. Adopting the test-based approach for all immunocompromised patients may lead to prolonged quarantine. Large-scale studies in disease-specific populations are needed to determine whether a test-based approach versus a symptom-based approach or a combination is applicable for the de-isolation of various immunocompromised patients.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Immunocompromised Host , Quarantine , Virus Shedding
10.
Vox Sang ; 116(6): 673-681, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1319364

ABSTRACT

BACKGROUND AND OBJECTIVES: During the ongoing pandemic of COVID-19, SARS-CoV-2 RNA was detected in plasma and platelet products from asymptomatic blood donors, raising concerns about potential risk of transfusion transmission, also in the context of the current therapeutic approach utilizing plasma from convalescent donors. The objective of this study was to assess the efficacy of amotosalen/UVA light treatment to inactivate SARS-CoV-2 in human plasma to reduce the risk of potential transmission through blood transfusion. METHODS: Pools of three whole-blood-derived human plasma units (630-650 ml) were inoculated with a clinical SARS-CoV-2 isolate. Spiked units were treated with amotosalen/UVA light (INTERCEPT Blood System™) to inactivate SARS-CoV-2. Infectious titres and genomic viral load were assessed by plaque assay and real-time quantitative PCR. Inactivated samples were subject to three successive passages on permissive tissue culture to exclude the presence of replication-competent viral particles. RESULTS: Inactivation of infectious viral particles in spiked plasma units below the limit of detection was achieved by amotosalen/UVA light treatment with a mean log reduction of >3·32 ± 0·2. Passaging of inactivated samples on permissive tissue showed no viral replication even after 9 days of incubation and three passages, confirming complete inactivation. The treatment also inhibited NAT detection by nucleic acid modification with a mean log reduction of 2·92 ± 0·87 PFU genomic equivalents. CONCLUSION: Amotosalen/UVA light treatment of SARS-CoV-2 spiked human plasma units efficiently and completely inactivated >3·32 ± 0·2 log of SARS-CoV-2 infectivity, showing that such treatment could minimize the risk of transfusion-related SARS-CoV-2 transmission.


Subject(s)
Furocoumarins/pharmacology , Plasma/virology , SARS-CoV-2/drug effects , SARS-CoV-2/radiation effects , Ultraviolet Therapy , Virus Inactivation , COVID-19/prevention & control , COVID-19/transmission , Humans , Transfusion Reaction/prevention & control , Treatment Outcome
11.
Int J Infect Dis ; 110: 267-271, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1313161

ABSTRACT

Immunocompromised patients who have a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection pose many clinical and public health challenges. We describe the case of a hematopoietic stem cell transplantation patient with lymphoma who had a protracted illness requiring three consecutive hospital admissions. Whole genome sequencing confirmed two different SARS-CoV-2 clades. Clinical management issues and the unanswered questions arising from this case are discussed.


Subject(s)
COVID-19 , Hematopoietic Stem Cell Transplantation , Humans , Reinfection , SARS-CoV-2 , Virus Shedding
12.
Microb Ecol ; 82(2): 365-376, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1293356

ABSTRACT

The unprecedented COVID-19 pandemic has had major impact on human health worldwide. Whilst national and international COVID-19 lockdown and travel restriction measures have had widespread negative impact on economies and mental health, they may have beneficial effect on the environment, reducing air and water pollution. Mass bathing events (MBE) also known as Kumbh Mela are known to cause perturbations of the ecosystem affecting resilient bacterial populations within water of rivers in India. Lockdowns and travel restrictions provide a unique opportunity to evaluate the impact of minimum anthropogenic activity on the river water ecosystem and changes in bacterial populations including antibiotic-resistant strains. We performed a spatiotemporal meta-analysis of bacterial communities of the Godavari River, India. Targeted metagenomics revealed a 0.87-fold increase in the bacterial diversity during the restricted activity of lockdown. A significant increase in the resilient phyla, viz. Proteobacteria (70.6%), Bacteroidetes (22.5%), Verrucomicrobia (1.8%), Actinobacteria (1.2%) and Cyanobacteria (1.1%), was observed. There was minimal incorporation of allochthonous bacterial communities of human origin. Functional profiling using imputed metagenomics showed reduction in infection and drug resistance genes by - 0.71-fold and - 0.64-fold, respectively. These observations may collectively indicate the positive implications of COVID-19 lockdown measures which restrict MBE, allowing restoration of the river ecosystem and minimise the associated public health risk.


Subject(s)
Bacteria/isolation & purification , Communicable Disease Control/legislation & jurisprudence , Ecosystem , Rivers/microbiology , Bacteria/classification , COVID-19/epidemiology , COVID-19/prevention & control , Drug Resistance, Bacterial , Environmental Monitoring , Hinduism , Human Activities , India/epidemiology , Principal Component Analysis
13.
Diagnostics (Basel) ; 11(6)2021 May 30.
Article in English | MEDLINE | ID: covidwho-1256438

ABSTRACT

The unusual cases of pneumonia outbreak were reported from Wuhan city in late December 2019. Serological testing provides a powerful tool for the identification of prior infection and for epidemiological studies. Pseudotype virus neutralization assays are widely used for many viruses and applications in the fields of serology. The accuracy of pseudotype neutralizing assay allows for its use in low biosafety lab and provides a safe and effective alternative to the use of wild-type viruses. In this study, we evaluated the performance of this assay compared to the standard microneutralization assay as a reference. The lentiviral pseudotype particles were generated harboring the Spike gene of SARS-CoV-2. The generated pseudotype particles assay was used to evaluate the activity of neutralizing antibodies in 300 human serum samples from a COVID-19 sero-epidemiological study. Testing of these samples resulted in 55 positive samples and 245 negative samples by pseudotype viral particles assay while microneutralization assay resulted in 64 positive and 236 negative by MN assay. Compared to the MN, the pseudotyped viral particles assay showed a sensitivity of 85.94% and a specificity of 100%. Based on the data generated from this study, the pseudotype-based neutralization assay showed a reliable performance for the detection of neutralizing antibodies against SARS-CoV-2 and can be used safely and efficiently as a diagnostic tool in a biosafety level 2 laboratory.

14.
Molecules ; 26(9)2021 May 01.
Article in English | MEDLINE | ID: covidwho-1224074

ABSTRACT

SARS CoV-2 pandemic is still considered a global health disaster, and newly emerged variants keep growing. A number of promising vaccines have been recently developed as a protective measure; however, cost-effective treatments are also of great importance to support this critical situation. Previously, betulinic acid has shown promising antiviral activity against SARS CoV via targeting its main protease. Herein, we investigated the inhibitory potential of this compound together with three other triterpene congeners (i.e., ursolic acid, maslinic acid, and betulin) derived from olive leaves against the viral main protease (Mpro) of the currently widespread SARS CoV-2. Interestingly, betulinic, ursolic, and maslinic acids showed significant inhibitory activity (IC50 = 3.22-14.55 µM), while betulin was far less active (IC50 = 89.67 µM). A comprehensive in-silico analysis (i.e., ensemble docking, molecular dynamic simulation, and binding-free energy calculation) was then performed to describe the binding mode of these compounds with the enzyme catalytic active site and determine the main essential structural features required for their inhibitory activity. Results presented in this communication indicated that this class of compounds could be considered as a promising lead scaffold for developing cost-effective anti-SARS CoV-2 therapeutics.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus 3C Proteases/antagonists & inhibitors , Protease Inhibitors/pharmacology , SARS-CoV-2/enzymology , Triterpenes/pharmacology , Antiviral Agents/chemistry , COVID-19/virology , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/metabolism , Humans , Molecular Docking Simulation , Molecular Dynamics Simulation , Olea/chemistry , Pentacyclic Triterpenes/chemistry , Pentacyclic Triterpenes/pharmacology , Protease Inhibitors/chemistry , SARS-CoV-2/drug effects , SARS-CoV-2/metabolism , Triterpenes/chemistry
15.
Diagnostics (Basel) ; 11(5)2021 May 02.
Article in English | MEDLINE | ID: covidwho-1223965

ABSTRACT

A few months ago, the availability of a reliable and cost-effective testing capacity for COVID-19 was a concern for many countries. With the emergence and circulation of new SARS-CoV-2 variants, another layer of challenge can be added for COVID-19 testing at both molecular and serological levels. This is particularly important for the available tests principally designed to target the S gene/protein where multiple mutations have been reported. Herein, the SARS-CoV-2 NP recombinant protein was utilized to develop a simple and reliable COVID-19 NP human IgG ELISA. The optimized protocol was validated against a micro-neutralization (MN) assay, in-house S-based ELISA, and commercial chemiluminescence immunoassay (CLIA). The developed assay provides 100% sensitivity, 98.9% specificity, 98.9% agreement, and high overall accuracy with an area under curve equal to 0.9998 ± 0.0002 with a 95% confidence interval of 0.99 to 1.00. The optical density values of positive samples significantly correlated with their corresponding MN titers. The assay specifically detects IgG antibodies to the SARS-CoV-2 NP protein and does not cross-detect IgG to the viral S protein. Moreover, it does not cross-react with antibodies related to other coronaviruses (e.g., the Middle East respiratory syndrome coronavirus or human coronavirus HKU1). The availability of this reliable COVID-19 NP IgG ELISA protocol is highly valuable for its diagnostic and epidemiological applications.

16.
Emerg Infect Dis ; 27(5)2021 05.
Article in English | MEDLINE | ID: covidwho-1200875

ABSTRACT

Understanding the immune response to Middle East respiratory syndrome coronavirus (MERS-CoV) is crucial for disease prevention and vaccine development. We studied the antibody responses in 48 human MERS-CoV infection survivors who had variable disease severity in Saudi Arabia. MERS-CoV-specific neutralizing antibodies were detected for 6 years postinfection.


Subject(s)
Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Animals , Antibody Formation , Camelus , Coronavirus Infections/epidemiology , Humans , Saudi Arabia/epidemiology
18.
Mikrochim Acta ; 188(4): 137, 2021 03 25.
Article in English | MEDLINE | ID: covidwho-1148895

ABSTRACT

The novel corona (SARS-CoV-2) virus causes a global pandemic, which motivates researchers to develop reliable and effective methods for screening and detection of SARS-CoV-2. Though there are several methods available for the diagnosis of SARS-CoV-2 such as RT-PCR and ELSIA, nevertheless, these methods are time-consuming and may not apply at the point of care. In this study, we have developed a specific, sensitive, quantitative and fast detection method for SARS-CoV-2 by fluorescence resonance energy transfer (FRET) assay. The total extracellular protease proteolytic activity from the virus has been used as the biomarker. The specific peptide sequences from the library of 115 dipeptides were identified via changes in the fluorescence signal. The fluorogenic dipeptide substrates have the fluorophore and a quencher at the N- and the C- terminals, respectively. When the protease hydrolyzes the peptide bond between the two specific amino acids, it leads to a significant increase in the fluorescence signals. The specific fluorogenic peptide (H-d) produces a high fluorescence signal. A calibration plot was obtained from the changes in the fluorescence intensity against the different concentrations of the viral protease. The lowest limit of detection of this method was 9.7 ± 3 pfu/mL. The cross-reactivity of the SARS-CoV-2-specific peptide was tested against the MERS-CoV which does not affect the fluorescence signal. A significant change in the fluorescence signal with patient samples indicates that this FRET-based assay might be applied for the diagnosis of SARS-CoV-2 patients. Graphical abstract.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Coronavirus 3C Proteases/metabolism , Fluorescent Dyes/metabolism , Peptides/metabolism , SARS-CoV-2 , Viral Proteins/metabolism , Animals , Biological Assay , COVID-19/microbiology , Chlorocebus aethiops , Fluorescence Resonance Energy Transfer , Humans , Peptide Library , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Vero Cells , Viral Plaque Assay
19.
Pathogens ; 10(3)2021 Mar 08.
Article in English | MEDLINE | ID: covidwho-1143550

ABSTRACT

The aim of our study was to define the spectrum of viral infections in pilgrims with acute respiratory tract illnesses presenting to healthcare facilities around the holy places in Makkah, Saudi Arabia during the 2019 Hajj pilgrimage. During the five days of Hajj, a total of 185 pilgrims were enrolled in the study. Nasopharyngeal swabs (NPSs) of 126/185 patients (68.11%) tested positive for one or more respiratory viruses by PCR. Among the 126 pilgrims whose NPS were PCR positive: (a) there were 93/126 (74%) with a single virus infection, (b) 33/126 (26%) with coinfection with more than one virus (up to four viruses): of these, 25/33 cases had coinfection with two viruses; 6/33 were infected with three viruses, while the remaining 2/33 patients had infection with four viruses. Human rhinovirus (HRV) was the most common detected viruses with 53 cases (42.06%), followed by 27 (21.43%) cases of influenza A (H1N1), and 23 (18.25%) cases of influenza A other than H1N1. Twenty-five cases of CoV-229E (19.84%) were detected more than other coronavirus members (5 CoV-OC43 (3.97%), 4 CoV-HKU1 (3.17%), and 1 CoV-NL63 (0.79%)). PIV-3 was detected in 8 cases (6.35%). A single case (0.79%) of PIV-1 and PIV-4 were found. HMPV represented 5 (3.97%), RSV and influenza B 4 (3.17%) for each, and Parechovirus 1 (0.79%). Enterovirus, Bocavirus, and M. pneumoniae were not detected. Whether identification of viral nucleic acid represents nasopharyngeal carriage or specific causal etiology of RTI remains to be defined. Large controlled cohort studies (pre-Hajj, during Hajj, and post-Hajj) are required to define the carriage rates and the specific etiology and causal roles of specific individual viruses or combination of viruses in the pathogenesis of respiratory tract infections in pilgrims participating in the annual Hajj. Studies of the specific microbial etiology of respiratory track infections (RTIs) at mass gathering religious events remain a priority, especially in light of the novel SARS-CoV-2 pandemic.

20.
J King Saud Univ Sci ; 33(3): 101366, 2021 May.
Article in English | MEDLINE | ID: covidwho-1080393

ABSTRACT

Objective: The new coronavirus disease 2019 (COVID-19) is a major health problem worldwide. The surveillance of seropositive individuals serves as an indicator to the extent of infection spread and provides an estimation of herd immunity status among population. Reports from different countries investigated this issue among healthcare workers (HCWs) who are "at risk" and "sources of risk" for COVID-19. This study aims to investigate the seroprevalence of COVID-19 among HCWs in one of the COVID-19 referral centers in Makkah, Saudi Arabia using three different serological methods. Methods: In-house developed enzyme-linked immunoassay (ELISA), commercially available electro-chemiluminescence immunoassay (ECLIA), and microneutralization (MN) assay were utilized to determine the seroprevalence rate among the study population. 204 HCWs participated in the study. Both physicians and nurses working in the COVID-19 and non COVID-19 areas were included. Twelve out of 204 were confirmed cases of COVID-19 with variable disease severity. Samples from recovered HCWs were collected four weeks post diagnosis. Results: The overall seroprevalence rate was 6.3% (13 out of 204) using the in-house ELISA and MN assay and it was 5.8% (12 out of 204) using the commercial ECLIA. Among HCWs undiagnosed with COVID-19, the seroprevalence was 2% (4 out 192). Notably, neutralizing antibodies were not detected in 3 (25%) out 12 confirmed cases of COVID-19. Conclusions: Our study, similar to the recent national multi-center study, showed a low seroprevalence of SARS-Cov-2 antibodies among HCWs. Concordance of results between the commercial electro-chemiluminescence immunoassay (ECLIA), in-house ELISA and MN assay was observed. The in-house ELISA is a promising tool for the serological diagnosis of SARS-CoV-2 infection. However, seroprevalence studies may underestimate the extent of COVID-19 infection as some cases with mild disease did not have detectable antibody responses.

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