ABSTRACT
COVID-19 outbreak has caused over 3 million deaths worldwide. Understanding disease pathology and the factors that drive severe and fatal clinical outcomes is of special relevance. Studying the role of the respiratory microbiota in COVID-19 is particularly important since it’s known that the respiratory microbiota interacts with the host immune system, contributing to clinical outcomes in chronic and acute respiratory diseases. Here, we characterized the microbiota in the respiratory tract of patients with mild, severe, or fatal COVID-19, and compared with healthy controls and patients with non-COVID-19-pneumonia. We comparatively studied the microbial composition, diversity, and microbiota structure across study groups and correlated the results with clinical data. We found differences in diversity and abundance of bacteria between groups, higher levels of dysbiosis in the respiratory microbiota of COVID-19 patients (regardless of severity level), differences in diversity structure among mild, severe, and fatal COVID-19, and the presence of specific bacteria that correlated with clinical variables associated with increased mortality risk. Our data suggest that host-related and environmental factors could be affecting the respiratory microbiota before SARS-CoV-2 infection, potentially compromising the immunological response of the host against disease and promoting secondary bacterial infections. For instance, the high levels of dysbiosis coupled with low microbial structural complexity in the respiratory microbiota of COVID-19 patients, possibly resulted from antibiotic uptake and comorbidities, could have consequences for the host and microbial community level. Altogether, our findings identify the respiratory microbiota as a potential factor associated with COVID-19 severity.
Subject(s)
COVID-19 , Bacterial InfectionsABSTRACT
The COVID-19 pandemic caused by infection with the betacoronavirus SARS-CoV-2 is the greatest public health defiant on a global scale in the last 100 years. Governments and health Institutes face challenges during the pandemic, related to the diagnosis, mitigation, treatment, and timely detection after the epidemic peak for the prevention of new infections and the evaluation of the real impact of the COVID-19 disease in different geographic areas. To develop a valuable tool to study the seroprevalence of SARS-CoV-2 infection in Colombia, an in-house ELISA was achieved for the detection of IgG anti-SARS-CoV-2 antibodies in serum. The test was standardized using an antigenic epitopes Pool of the synthetic peptide as antigen derived from antigenic regions of the spike, nucleocapsid, envelope, and membrane structural proteins, which were designed, based on the genomic information of SARS-CoV-2 circulating in Colombia. In the ELISA standardization process, 34 positive sera were used, including sera from asymptomatic and symptomatic patients (mild and severe) and 68 negative sera, including pre-pandemic historical negatives originating from patients living in arbovirus endemic areas or patients with a history of respiratory diseases and sera from patients with a negative rRT-PCR test for SARS-CoV-2. The in-house peptide ELIPSE-COL test showed promising performance, being able to detect reactivity in sera from asymptomatic and symptomatic patients. The sensitivity and specificity of the assay were 91% for both parameters. The ELIPSE-COL assay was developed as an ELISA test using synthetic peptides for the study of the seroprevalence of SARS-CoV-2 infection in Colombia.