SARS-CoV-2 spike gene Sanger sequencing methodology to identify variants of concern

SARS-COV-2 causes significant abnormalities in the fibrinolysis system of patients: correlation between viral mutations, variants and thrombosis

Background

Coronavirus disease (COVID-19) is reported as a complex disorder affecting multiple systems and coagulopathy that can cause mortality. In this study, we investigated the correlation of SARS-CoV-2 mutations found in blood samples with various changes in the fibrinolysis system, as well as the severity of the disease based on outcome and whether or not these patients were admitted into the ICU.

Materials and methods

COVID-19 patients (n = 446) admitted to our institute between 2021 and 2022 were recruited. Blood samples were collected, and a sequence analysis of the SARS-CoV-2 spike gene was isolated from the blood. Measured several parameters of fibrinolysis and coagulation, including alpha-2-antiplasmin and plasminogen, thrombin activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), D-dimer, and fibrinogen levels.

Results

SARS-CoV-2 RNA was found in 123/446 (27.6%) of the blood samples. The N501Y, D614G, K417N, and P681R mutations among COVID-19 patients were associated with higher admissions to the ICU (P = 0.0057, P = 0.0068, P = 0.0193, and P = 0.018, respectively). Omicron (BA.1.1) variant variants are highly associated with thrombosis (P = 0.002) in hospitalized COVID-19 patients that are unvaccinated and have comorbidity conditions. The plasma levels of tPA, aPTT, and D-dimer were significantly higher in participants who had the N501Y mutation (P = 0.044, P = 0.024, and P = 0.027, respectively).

Conclusion

Thrombosis was the most prevalent condition among severe COVID-19 patients. The correlation between specific SARS-CoV-2 new variants and thrombosis warrants more investigation.

Targeted Sanger Sequencing of a Cluster of COVID-19 Cases in the Surgical ICU of a Non-COVID Hospital: Lessons Learned

Small clusters of infection due to SARS-CoV-2 in a non-COVID-19 healthcare facility can disrupt services. Here, we investigated a cluster of SARS-CoV-2 cases by targeted Sanger sequencing and clinical epidemiological methods in a non-COVID-19 super-specialty hospital. Epidemiological data were collected in a blinded manner using a proforma to find the risk factors associated with infection. Targeted Sanger sequencing of the spike protein receptor binding domain (RBD) coding region was performed on all the available real-time reverse transcription polymerase chain reaction (RT-PCR)-positive samples that included a patient, his mother, and 11 healthcare workers (HCWs) to determine any genomic variations in the samples from the cluster. All positive cases were due to the Delta variant. However, it detected a unique mutation, N501I, in the RBD region of the SARS-CoV-2 strains. The viral genome extracted from the mother's sample lacked the mutation, thus excluding her from the cluster and pointing out that the outbreak was nosocomial, leading to a focus on infection control measures. Though whole genome sequencing is more universally accepted, in this study, targeted sanger sequencing provided a rapid and cost-effective solution to correctly delineate between the actual cases that form the cluster and other community cases in a pandemic situation.