In Vitro Evaluation of Leuconostoc mesenteroides Cell-Free-Supernatant GBUT-21 against SARS-CoV-2.

The unprecedented health catastrophe derived from the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2 infection) met with a phenomenal scientific response across the globe. Worldwide, the scientific community was focused on finding a cure for the deadly disease. A wide range of research studies has consistently revealed the link between SARS-CoV-2 infection severity and abnormal gut microbiomes, suggesting its potential in developing novel therapeutic approaches. Probiotics have been extensively studied to promote health in human hosts and reestablish a balance in the dysbiotic gut microbiome; however, there is strong skepticism about their safety and efficacy. Consequently, the metabolic signatures of probiotics, often referred to as "postbiotics", could prove of paramount importance for adjuvant cures in patients with SARS-CoV-2. Postbiotics exhibit safety, enhanced shelf-life, and stability and, therefore, could be implemented in SARS-CoV-2 prophylactic strategies with no undue adverse side effects. The current study is a preliminary investigation of the antiviral properties of postbiotic metabolites derived from Leuconostoc mesenteroides GBUT-21. The study focuses on the potential biological role in inactivating SARS-CoV-2 and reducing related inflammatory pathways.

Clinical and Serological Findings of COVID-19 Participants in the Region of Makkah, Saudi Arabia.

Makkah in Saudi Arabia hosts the largest annual religious event in the world. Despite the many strict rules enacted, including Hajj cancellation, city lockdowns, and social distancing, the region has the second highest number of new COVID-19 cases in Saudi Arabia. Public health interventions that identify, isolate, and manage new cases could slow the infection rate. While RT-PCR is the current gold standard in SARS-CoV-2 identification, it yields false positive and negative results, which mandates the use of complementary serological tests. Here, we report the utility of serological assays during the acute phase of individuals with moderate and severe clinical manifestations of SARS-CoV-2 (COVID19). Fifty participants with positive RT-PCR results for SARS-CoV-2 were enrolled in this study. Following RT-PCR diagnosis, serum samples from the same participants were analyzed using in-house ELISA (IgM, IgA, and IgG) and microneutralization test (MNT) for the presence of antibodies. Of the 50 individuals analyzed, 43 (86%) showed a neutralizing antibody titer of ≥20. Univariate analysis with neutralizing antibodies as a dependent variable and the degree of disease severity and underlying medical conditions as fixed factors revealed that patients with no previous history of non-communicable diseases and moderate clinical manifestation had the strongest neutralizing antibody response "Mean: 561.11". Participants with severe symptoms and other underlying disorders, including deceased individuals, demonstrated the lowest neutralizing antibody response. Anti-spike protein antibody responses, as measured by ELISA, showed a statistically significant correlation with neutralizing antibodies. This reinforces the speculation that serological assays complement molecular testing for diagnostics; however, patients' previous medical history (anamnesis) should be considered in interpreting serological results.