Background COVID-19 is an infectious disease characterized by multiple respiratory and extrapulmonary manifestations, including gastrointestinal symptoms. Although recent studies have linked gut microbiota to infectious diseases such as influenza, little is known about the role of the gut microbiota in COVID-19 pathophysiology. Methods To better understand the host-gut microbiota interactions in COVID-19, we characterized the gut microbial community and gut barrier function using metagenomic and metaproteomic approaches in 63 COVID-19 patients and 8 non-infected controls. Both immunohematological parameters and transcriptional profiles were measured to reflect the immune response in COVID-19 patients. Results Altered gut microbial composition was observed in COVID-19 patients, which was characterized by decreased commensal species and increased opportunistic pathogenic species. Severe illness was associated with higher abundance of four microbial species (i.e., Burkholderia contaminans , Bacteroides nordii , Bifidobacterium longum , and Blautia sp. CAG 257), six microbial pathways (e.g., glycolysis and fermentation), and 10 virulence genes. These severity-related microbial features were further associated with host immune response. For example, the abundance of Bu. contaminans was associated with higher levels of inflammation biomarkers and lower levels of immune cells. Furthermore, human-origin proteins identified from both blood and fecal samples suggested gut barrier dysfunction in COVID-19 patients. The circulating levels of lipopolysaccharide-binding protein increased in patients with severe illness and were associated with circulating inflammation biomarkers and immune cells. Besides, proteins of disease-related bacteria (e.g., B. longum ) were detectable in blood samples from patients. Conclusions Our results suggest that the dysbiosis of the gut microbiome and the dysfunction of the gut barrier might play a role in the pathophysiology of COVID-19 by affecting host immune homeostasis. Supplementary Information The online version contains supplementary material available at 10.1186/s12916-021-02212-0.
【저자키워드】 COVID-19, SARS-CoV-2, Microbiome, Metaproteomic, Gut barrier, Immune homeostasis, 【초록키워드】 Inflammation, immune response, Biomarker, Infectious diseases, Influenza, gut microbiome, Infectious disease, Protein, microbiota, Host immune response, pathophysiology, Patient, Fecal sample, pathway, Manifestations, immune cells, Bacteria, gut microbiota, respiratory, microbial community, Dysbiosis, patients, lipopolysaccharide, COVID-19 patients, Blood, Glycolysis, Interaction, gastrointestinal symptoms, COVID-19 patient, Gut, microbial, dysfunction, Bifidobacterium longum, supplementary material, Blood samples, blood sample, abundance, pathogenic, circulating, fecal samples, virulence genes, Bacteroides, fermentation, transcriptional profiles, parameter, Host, controls, feature, non-infected, Result, approach, example, detectable, characterized, suggested, affecting, were measured, Altered, Bacteroide, Burkholderia, CAG, metagenomic, transcriptional profile, 【제목키워드】 COVID-19 patient, Gut, alteration, Host,