Negative Pharyngeal Swab Research Articles

A Protein Microarray-Based Respiratory Viral Antigen Testing Platform for COVID-19 Surveillance.

High-throughput and rapid screening testing is highly desirable to effectively combat the rapidly evolving COVID-19 pandemic co-presents with influenza and seasonal common cold epidemics. Here, we present a general workflow for iterative development and validation of an antibody-based microarray assay for the detection of a respiratory viral panel: (a) antibody screening to quickly identify optimal reagents and assay conditions, (b) immunofluorescence assay design including signal amplification for low viral titers, (c) assay characterization with recombinant proteins, inactivated viral samples and clinical samples, and (d) multiplexing to detect a panel of common respiratory viruses. Using RT-PCR-confirmed SARS-CoV-2 positive and negative pharyngeal swab samples, we demonstrated that the antibody microarray assay exhibited a clinical sensitivity and specificity of 77.2% and 100%, respectively, which are comparable to existing FDA-authorized antigen tests. Moreover, the microarray assay is correlated with RT-PCR cycle threshold (Ct) values and is particularly effective in identifying high viral titers. The multiplexed assay can selectively detect SARS-CoV-2 and influenza virus, which can be used to discriminate these viral infections that share similar symptoms. Such protein microarray technology is amenable for scale-up and automation and can be broadly applied as a both diagnostic and research tool.

Management of a novel strain of Riemerella Anatipestifer isolated from mandarin ducks (Aix Galericulata) in Australia

AbstractSix clinically healthy, adult, captive‐reared mandarin ducks from a commercial mixed age, mixed species bird breeder grew positive cultures of Riemerella anatipestifer from pharyngeal swabs during admission into a zoological collection. Treatment with tetracycline 5 g/kg in feed for 14 days resulted in negative pharyngeal swabs at 30 and 100 days post‐treatment. R. anatipestifer has not previously been reported in mandarin ducks in Australia. The present detection suggests that commercially sourced mandarin ducks in Australia should be screened for R. anatipestifer prior to co‐housing with naïve Anseriformes.

Detection of SARS-CoV-2 pneumonia: two case reports\xa0

BackgroundDeveloping therapeutic strategies for a SARS-CoV-2 infection is challenging, but first the correct diagnosis has to be made. Unspecific upper and lower respiratory tract symptoms can be misleading; hence, a nasopharyngeal swab test with a real-time reverse-transcription-polymerase chain reaction is of great importance. However, early viral clearing jeopardizes a sound diagnosis of COVID-19.Case presentationWe report on two Caucasian patients who had negative pharyngeal swab tests at the onset of SARS-CoV-2 pneumonia. In one patient, the virus was not even detectable in bronchoalveolar lavage despite typical radiomorphologic changes.ConclusionsNegative PCR findings in both the pharynx and bronchoalveolar lavage do not exclude COVID-19 pneumonia. Computed tomography is a crucial diagnostic prerequisite in this context.

Negative viral nucleic acid test of induced sputum: an additional criteria for COVID-19 patient's discharge.

Concerns have been raised that patients with Coronavirus Disease 2019 (COVID-19) are still infectious with a re-positive nucleic acid test of the pharyngeal swab after hospital discharge. The aim of this study was to investigate the clinical relevance of induced sputum as an additional indicator for the current clinical discharge criteria of COVID-19 patients to prevent virus recurrence. Twenty-one COVID-19 patients who met the national clinical discharge criteria were discharged from the hospital and tested daily for the presence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) nucleic acid in their pharyngeal swabs and every other day for the presence of SARS-CoV-2 in their induced sputum. Once the patient's induced sputum was negative after two consecutive tests, testing was discontinued. Among 21 discharged patients from COVID-19, the first pharyngeal swab and induced sputum tests for viral nucleic acid were positive in 3 (14.3%) and 8 (38.1%) patients respectively. Induced sputum was significantly more positive than pharyngeal swab (p < 0.05). In our cohort, all pharyngeal swabs became negative at day 7, and all induced sputa turned negative at day 11 after discharge. Interestingly, patients with negative pharyngeal swabs experienced viral relapse, whereas patients with negative induced sputum did not revert to positivity. The detection rate of positive viral nucleic acid in induced sputum was high. Patients with negative induced sputum nucleic acid tests did not have a relapse of SARS-COV-2, indicating that viral nucleic acid testing of induced sputum should be used as an additional criterion for patients with national clinical discharge criteria COVID-19.

Analysis of the positive rate of anal swab nucleic acid test and clinical characteristics in patients with different severity of coronavirus disease 2019

To compared the positive rate of anal swab nucleic acid test and clinical characteristics of critical and general coronavirus disease 2019 (COVID-19) patients. Clinical data of 18 patients with COVID-19 admitted to the First People's Hospital of Lianyungang City from February to March 2020 were retrospectively analyzed. The patients were divided into general group (n = 11) and critical ill group (n = 7) according to the severity of the disease. The differences of gender, age, epidemiological characteristics, fever duration after admission, underlaying disease, positive rate of anal swab nucleic acid test at admission and two times of negative pharyngeal swab test were compared between the two groups. There were no significant differences in gender, age, fever duration after admission or underlaying disease between the two groups. The number of anorectal swab positive cases in critically ill group was significantly higher than that in general group (cases: 4 vs. 1, P = 0.047). After two negative pharyngeal swab nucleic acid test, the number of anal swab positive cases in critical illness group was still higher than that in general group (cases: 2 vs. 0), but the difference was not statistically significant (P = 0.137). The number of non-local infection in critical ill group was significantly higher than that in general group (cases: 4 vs. 0, P = 0.047). All of the 4 non-local infected patients had a history of living in Wuhan. The patients with anorectal swab nucleic acid positive may have a more serious condition. It may be a risk to transfer ill patients out of the isolation ward by the criteria of only two times of negative pharyngeal swab nucleic acid test. Patients returning to our city after infection in Wuhan may be more serious.

Are urologists in trouble with SARS-CoV-2? Reflections and recommendations for specific interventions.

ObjectiveTo assess the risk of viral infection during urological surgeries due to the possible hazards in tissue, blood, urine and aerosolised particles generated during surgery, and thus to understand the risks and make recommendations for clinical practice.Patients and MethodsWe reviewed the available literature on urological and other surgical procedures in patients with virus infections, such as human papillomavirus, human immunodeficiency virus and hepatitis B, and current publications on coronavirus disease 2019 (COVID‐19).ResultsSeveral possible pathways for viral transmission appear in the literature. Recently, groups have detected severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) in the urine and faeces, even after negative pharyngeal swabs. In addition, viral RNA can be detected in the blood and several tissues. During surgery, viral particles are released, aerosol‐borne and present a certain risk of transmission and infection. However, there is currently no evidence on the exact risk of infection from the agents mentioned above. It remains unclear whether or not viral particles in the urine, blood or faeces are infectious.ConclusionsWhether SARS‐CoV‐2 can be transmitted by aerosols remains controversial. Irrespective of this, standard surgical masks offer inadequate protection from SARS‐CoV‐2. Full personal protective equipment, including at least filtering facepiece‐2 masks and safety goggles should be used. Aerosolised particles might remain for a long time in the operating theatre and contaminate other surfaces, e.g. floors or computer input devices. Therefore, scrupulous hygiene and disinfection of surfaces must be carried out. To prevent aerosolisation during laparoscopic interventions, the pneumoperitoneum should be evacuated with suction devices. The use of virus‐proof high‐efficiency particulate air filters is recommended. Local separation of anaesthesia/intubation and the operating theatre can reduce the danger of viral transmission. Lumbar anaesthesia should be considered especially in endourology. Based on current knowledge, COVID‐19 is not a contraindication for acute urological surgery. However, if possible, as European guideline committees recommend, non‐emergency urological interventions should be postponed until negative SARS‐CoV‐2 tests become available.

Two cases of COVID-19 with positive salivary and negative pharyngeal or respiratory swabs at hospital discharge: A rising concern.

We report two cases of COVID‐19 showing negative respiratory swabs but positive salivary samples at the same time. These findings rise the concern about how to manage these patients before hospital discharging, thus avoiding contagion among their family members or a second coronavirus wave once the lockdown is over.

Manifestaciones gastrointestinales de la infección por el "Nuevo Coronavirus"

El 11 de marzo del 2020 la Organización Mundial de la Salud (OMS) declaró la pandemia por el brote de la enfermedad por coronavirus 2019 (COVID-19). Los primeros datos acerca de las manifestaciones clínicas provienen de estudios retrospectivos de Wuhan, China, epicentro de la pandemia; además del compromiso respiratorio, se ha descrito la afectación del sistema gastrointestinal. Aunque no está del todo claro el porqué del tropismo de COVID-19 por el tracto gastrointestinal, se ha demostrado que la enzima convertidora de angiotensina 2 (ECA2), la cual tiene una alta expresión en el sistema gastrointestinal, es empleada como receptor de entrada del virus. Se ha logrado documentar la posibilidad de trasmisión fecal-oral luego de demostrar la existencia del virus en las heces, incluso hasta dentro de 7-12 días después de la conversión negativa en la muestra faríngea, independientemente de la presencia o no de síntomas gastrointestinales. La afectación del sistema gastrointestinal en pacientes con infección por COVID-19 no es infrecuente; los datos reportan que los pacientes con síntomas gastrointestinales tienen un peor pronóstico. El conocimiento de estas manifestaciones nos permite aumentar la sospecha clínica y, de esta manera, establecer diagnósticos tempranos.

Umifenovir treatment is not associated with improved outcomes in patients with coronavirus disease 2019: a retrospective study

ObjectivesCoronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Umifenovir (Arbidol®) is an antiviral drug being used to treat influenza in Russia and China. This study aimed to investigate the effectiveness and safety of umifenovir for COVID-19. MethodsA retrospective study was performed in a non-intensive care unit (ICU) ward in Jinyintan Hospital from 2 February 2020 to 20 March 2020. COVID-19 was confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assay of pharyngeal swab specimens. The confirmed patients were divided into the umifenovir group and the control group according to the use of umifenovir. The main outcomes were the rate of negative pharyngeal swab tests for SARS-CoV-2 within 1 week after admission and the time for the virus to turn negative. The negativity time of SARS-CoV-2 was defined as the first day of a negative test if the nucleic acid of SARS-CoV-2 was negative for two consecutive tests. ResultsA total of 81 COVID-19 patients were included, with 45 in the umifenovir group and 36 in the control group. Baseline clinical and laboratory characteristics were comparable between the two groups. Thirty-three out of 45 (73%) patients in the umifenovir group tested negative for SARS-CoV-2 within 7 days after admission, the number was 28/36 (78%) in the control group (p 0.19). The median time from onset of symptoms to SARS-CoV-2 turning negative was 18 days (interquartile range (IQR) 12–21) in the umifenovir group and 16 days (IQR 11–21) in the control group (p 0.42). Patients in the umifenovir group had a longer hospital stay than patients in the control group (13 days (IQR 9–17) vs 11 days (IQR 9–14), p 0.04). No deaths or severe adverse reactions were found in both groups. DiscussionUmifenovir might not improve the prognosis or accelerate SARS-CoV-2 clearance in non-ICU patients. A randomized control clinical trial is needed to assess the efficacy of umifenovir.

AGA Rapid Recommendations for Gastrointestinal Procedures During the COVID-19 Pandemic

Abbreviations used in this paper AGAAmerican Gastroenterological AssociationCDCCenters for Disease Control and PreventionCIconfidence intervalCOVID-19coronavirus disease 2019GIgastrointestinalGRADEGrading of Recommendations Assessment, Development and EvaluationMERS-CoVMiddle East respiratory syndrome–related coronavirusORodds ratioPAPRpowered air-purifying respiratorPPEpersonal protective equipmentRRrisk ratioSARS-CoV-2severe acute respiratory syndrome coronavirus 2WHOWorld Health Organization

Application and Optimization of RT-PCR in Diagnosis of SARS-CoV-2 Infection

Background: Coronavirus Disease 2019 (COVID-19) caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global threat to public health. Aiming to construct an efficient screening pattern, we comprehensively evaluated the performances of RT-PCR and chest CT in diagnosing COVID-19. Methods: The records including demographics, RT-PCR, and CT from 87 confirmed COVID-19 cases and 481 exclusion cases were collected. The diagnostic accuracy of the pharyngeal swab RT-PCR, CT, combination with the second pharyngeal swab RT-PCR or with CT were evaluated individually. Besides, all the stool RT-PCR results were plotted by time to explore the value of stool RT-PCR. Findings: Combination of RT-PCR and CT has the higher sensitivity (91.9%,79/86) than RT-PCR alone (78.2%,68/87) or CT alone (66.7%, 54 of 81) or combination of two RT-PCR tests (86.2%,75/87). There was good agreement between RT-PCR and CT (kappa-value, 0.430). In 34 COVID-19 cases with inconsistent results, 94.1% (n=32) are mild infection, 62.5% of which (20/32) showed positive RT-PCR. 46.7% (35/75) COVID-19 patients had at least one positive stool during the course. Two cases had positive stool earlier than the pharyngeal swabs. Importantly, one patient had consecutive positive stool but negative pharyngeal swabs. Interpretation: Combination of RT-PCR and CT with the highest sensitivity is an optimal pattern to screen COVID-19. RT-PCR is superior to CT in diagnosing mild infections. Stool RT-PCR should be considered as an item for improving discovery rate and hospital discharge. This study shed light for optimizing scheme of screening and monitoring of SARS-CoV-2 infection. Funding Statement: This work was supported by the National Natural Science Foundation of China (No. 81502104), National Program on Key Basic Research Project (No. 2018YFC0910600), the Nature Science Foundation of Guangdong Province, China (Grant No: 2017A030313771 and 2020A151501001 ) and the Young Teachers Nurturing Program of Sun Yat-Sen University (Grant No:17ykpy62). Declaration of Interests: All authors declare no competing interests. Ethics Approval Statement: The study was approved by The Fifth Affiliated Hospital of Sun Yat-sen University Ethics Committee and written informed consent was obtained from patients involved before enrolment when data were collected retrospectively.

Status epilepticus associated with Mycoplasma pneumoniae encephalitis in children: good prognosis following early diagnosis and treatment.

Status epilepticus associated with Mycoplasma pneumoniae encephalitis in children: good prognosis following early diagnosis and treatment.

173 Upper respiratory tract colonization in infants with cystic fibrosis diagnosed by newborn screening

Cystic fibrosis, is characterised by production of abnormally thick and viscous mucus. It results in disturbances of mucociliary clearance, a basic defensive mechanism of the respiratory system, leading to increased susceptibility to recurrent and chronic respiratory infections in over 90% of patients. The aim of this study is to evaluate nasopharyngeal cavity colonization in infants with cystic fibrosis diagnosed by newborn screening. Material and Methods: Nasal and pharyngeal swabs were obtained from 26 infants aged 10−20 weeks, without any signs of infections, who were examined in the Cystic Fibrosis Outpatient Clinic. Isolates were identified by means of routine diagnostic methods. Results: Negative nasal swabs were obtained in 10 (40%) infants, negative pharyngeal swabs − in 6 (23%), and in 4 patients both nasal and pharyngeal swabs were negative. In the nasal swabs the most frequently observed growths were: Staphylococcus aureus MSSA(+) in 9 (34.5%), Corynebacterium sp. in 6 (23.5%), and b-lactamase(+) Moraxella catarrhalis in 2 (8%). Pharyngeal swabs revealed a-hemolytic Streptococcus in 20 (80%), Staphylococcus aureus MRSA(+) in 7 (27%), Neisseria sp. in 4 (15%), Escherichia coli ESBL(−) and Candida albicans in 3 (11.5%) examined infants. Conclusion: Nasopharyngeal cavity colonization by pathogenic bacteria in infants suffering from cystic fibrosis occurs during the first months of life, in the absence of noticeable signs of upper respiratory infection.