Accurate and reliable surface-enhanced Raman spectroscopy assay for early detection of SARS-CoV-2 RNA with exceptional sensitivity.

This research proposes a highly sensitive and simple surface-enhanced Raman spectroscopy (SERS) assay for the detection of SARS-CoV-2 RNA using suitably designed probes specific for RdRp and N viral genes attached to a Raman marker. The sensitivity of the assay was optimized through precise adjustments to the conditions of immobilization and hybridization processes of the target RNA, including modifications to factors such as time and temperature. The assay achieved a remarkable sensitivity down to 58.39 copies/mL, comparable to or lower than the sensitivities reported for commercial fluorescent polymerase chain reaction (PCR) based methods. It has good selectivity in discriminating SARS-CoV-2 RNA against other respiratory viruses, respiratory syncytial virus (RSV), and influenza A virus. The reliability of the assay was validated by testing 24 clinical samples, including 12 positive samples with varying cycle threshold (Ct) values and 12 negative samples previously tested using real-time PCR. The assay consistently predicted true results that were in line with the PCR results for all samples. Furthermore, the assay demonstrated a notable limit of detection (LOD) of Ct (38 for RdRp gene and 37.5 for N-gene), indicating its capability to detect low concentrations of the target analyte and potentially facilitating early detection of the pathogen.

Evaluation of diagnostic performance of SARS-CoV-2 detection kits: a comparative study.

Background: Coronavirus Disease 2019 (COVID-19) pandemic has hit many countries worldwide. Rapid and accurate diagnosis is crucial to reduce disease burden. Many commercial kits have become available, but their performance needs to be assessed. This study aimed at evaluation of the diagnostic performance of real-time polymerase chain reaction (RT-PCR) and Rapid Antigen detection (RAD) kits for detecting Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Five hundred sixty-four Nasopharyngeal swab specimens sent to Molecular Laboratory at Ain Shams University Specialized Hospital for SARS-CoV-2 PCR testing collected from 564 subjects who attended the outpatient clinic for sample collection were randomly selected. All samples were tested for SARS-CoV-2 PCR using Viasure. Each time a recent kit was introduced, 94 samples, previously tested using Viasure, were used to determine the performance characteristics of the recent kit in comparison with Viasure, including Fast Track Diagnostics (FTD), DNA Technology, QiaPrep, Xpress SARS-CoV-2, ID NOW COVID-19 assay and Artron COVID-19 Antigen test kit. Results: Upon comparison, FTD, DNA Technology, QiaPrep, Xpress SARS-CoV-2 and ID Now showed positive percent agreement, 100%, 100%, 97.7%, 100%, 100% negative percent agreement, 86%, 100%, 98.8%, 90%, 100%, respectively. The RAD kit results, when compared with RT-PCR, showed high sensitivity at cycle threshold (Ct) < 30, low sensitivity at Ct ≥ 30, while specificity was 100%. Conclusion: Fast track, DNA Technology, QiaPrep, Xpress SARS-CoV-2 and ID Now showed good diagnostic performance. Positive RAD rule in SARS-CoV-2 infection, however negative results should be correlated with clinical condition and molecular testing.

SARS-CoV-2 PCR positivity rate and seroprevalence of related antibodies among a sample of patients in Cairo: Pre-wave 2 results of a screening program in a university hospital.

BACKGROUND: Research has revealed that asymptomatic and pre-symptomatic infections are important contributors to the transmission of SARS-CoV-2 in populations. In Egypt, the true prevalence of infections is veiled due to the low number of screening tests. The aim of this study was to determine the SARS-CoV-2 PCR positivity rate as well the seroprevalence of the SARS-CoV-2 antibodies before the ultimate development of a second wave of the epidemic in Cairo, Egypt. METHODS: Our study was carried out between May 5 and the end of October 2020. It included all patients requiring admission to Ain Shams University hospitals. An interview questionnaire was used to collect demographic and clinical data. Laboratory tests for all participants included RT-PCR and total antibody assay for SARS-CoV-2. RESULTS: A total of 4,313 subjects were enrolled in our study, with females representing 56% of the sample. Adults and middle-aged individuals represented around 60% of the study sample. The positivity rate of SARS-CoV-2 PCR was 3.84% (95% CI 3.29-4.48), and the SARS-CoV-2 antibody seroprevalence was 29.82% (95% CI: 28.16-31.51). Males showed a higher risk for getting the COVID-19 infection, while middle-age group had significantly higher antibody seroprevalence rates. CONCLUSION: SARS-CoV-2 infection imposes a high burden on the community as detected by high seroprevalence rates.

COVID-19 in Children With Cancer: A Single Low-Middle Income Center Experience.

BACKGROUND: Coronavirus disease-2019 (COVID-19) could be associated with morbidity and mortality in immunocompromised children. OBJECTIVE: The objective of this study was to measure the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among hospitalized children with cancer and to detect the associated clinical manifestations and outcomes. METHODOLOGY: A prospective noninterventional study including all hospitalized children with cancer conducted between mid-April and mid-June 2020 in Ain Shams University Hospital, Egypt. Clinical, laboratory, and radiologic data were collected. SARS-CoV-2 infection was diagnosed by reverse transcription polymerase chain reaction tests in nasopharyngeal swabs. RESULTS: Fifteen of 61 hospitalized children with cancer were diagnosed with SARS-CoV-2. Their mean age was 8.3±3.5 years. Initially, 10 (66.7%) were asymptomatic and 5 (33.3%) were symptomatic with fever and/or cough. Baseline laboratory tests other than SARS-CoV-2 reverse transcription polymerase chain reaction were not diagnostic; the mean absolute lymphocyte count was 8.7±2.4×109/L. C-reactive protein was mildly elevated in most of the patients. Imaging was performed in 10 (66.7%) patients with significant radiologic findings detected in 4 (40%) patients. Treatment was mainly supportive with antibiotics as per the febrile neutropenia protocol and local Children Hospital guidance for management of COVID-19 in children. CONCLUSIONS: Pediatric cancer patients with COVID-19 were mainly asymptomatic or with mild symptoms. A high index of suspicion and regular screening with nasopharyngeal swab in asymptomatic hospitalized cancer patients is recommended.

Cord blood interleukin-6 and neonatal morbidities among preterm infants with PCR-positive Ureaplasma urealyticum.

OBJECTIVES: To evaluate the clinical significance of Ureaplasma urealyticum recovery from umbilical cord blood, using Polymerase Chain Reaction (PCR), and its association with umbilical cord interleukin-6 (IL-6) levels and neonatal morbidity in preterm infants. METHODS: Cord blood PCR for Ureaplasma urealyticum, and IL-6 were assessed in relation to neonatal outcomes of 30 preterm deliveries of less than 35 weeks' gestation. RESULTS: Ureaplasma urealyticum was present in 43.3% of the examined cord blood samples. Positive neonatal Ureaplasma urealyticum was more common in association with premature rupture of membranes, chorioamnionitis, antenatal maternal use of antibiotics, and earlier gestation. Ureaplasma urealyticum was also associated with an early pro-inflammatory immune response (i.e. elevated IL-6 and positive C-reactive protein). Cutoff level of interleukin-6 of 240 pg% predicts the occurrence of respiratory distress syndrome (RDS), in neonates with positive PCR for Ureaplasma urealyticum. CONCLUSIONS: Preterm patients with positive cord blood PCR for Ureaplasma urealyticum were more likely to have premature rupture of membrane, antenatal antibiotics, chorioamnionitis, earlier gestation, pro-inflammatory response, and RDS than those with a negative PCR. High IL-6 is more likely associated with RDS in Ureaplasma urealyticum positive neonates.