Dysbiosis: An Indicator of COVID-19 Severity in Critically Ill Patients

Abstract

Here, we examined the dynamics of the gut and respiratory microbiomes in severe COVID-19 patients in need of mechanical ventilation in the intensive care unit (ICU). We recruited 85 critically ill patients (53 with COVID-19 and 32 without COVID-19) and 17 healthy controls (HCs) and monitored them for up to 4 weeks. We analyzed the bacterial and fungal taxonomic profiles and loads of 232 gut and respiratory samples and we measured the blood levels of Interleukin 6, IgG, and IgM in COVID-19 patients. Upon ICU admission, the bacterial composition and load in the gut and respiratory samples were altered in critically ill patients compared with HCs. During their ICU stay, the patients experienced increased bacterial and fungal loads, drastic decreased bacterial richness, and progressive changes in bacterial and fungal taxonomic profiles. In the gut samples, six bacterial taxa could discriminate ICU-COV(+) from ICU-COV(−) cases upon ICU admission and the bacterial taxa were associated according to age, PaO2/FiO2, and CRP levels. In the respiratory samples of the ICU-COV(+) patients, bacterial signatures including Pseudomonas and Streptococcus were found to be correlated with the length of ICU stay. Our findings demonstrated that the gut and respiratory microbiome dysbiosis and bacterial signatures associated with critical illness emerged as biomarkers of COVID-19 severity and could be a potential predictor of ICU length of stay. We propose using a high-throughput sequencing approach as an alternative to traditional isolation techniques to monitor ICU patient infection.

Acetate-encapsulated Linolenic Acid Liposomes Reduce SARS-CoV-2 and RSV Infection

“…Interestingly, it has been estimated that 40–45% of CoV-2 cases are asymptomatic, which raises the question of which biological factors are present in the asymptomatic group that contribute to this limited symptomology and prevention of disease [ 8 ]. One of the host factors that is key to pathology from a viral infection is the correlation observed between gut dysbiosis and disease, which established a protective role of metabolic byproducts including the short-chain fatty acid (SCFA) acetate [ 9 , 10 ]. Recent work has shown that SCFAs produced from the gut microbiota significantly reduced the expression of ACE2 in airway epithelial cells in culture, which could also help, in part, explain the discrepancy in symptoms [ 11 ].…”