Taxonomical and functional changes in COVID-19 faecal microbiome are related to SARS-CoV-2 faecal load

Abstract Since the beginning of the pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) the gastro-intestinal (GI) tract has emerged as an important organ influencing the propensity to and potentially severity of the related COVID-19 disease. However, the contribution of the SARS-CoV-2 intestinal infection on COVID-19 pathogenesis remains to be clarified. In this exploratory study, we evidenced that alterations in the composition of the gut microbiota depends on the levels of SARS-CoV-2 RNA in the gastrointestinal tract but not on the presence of SARS-CoV-2 in the respiratory tract, COVID-19 severity and GI symptoms. Altered molecular functions in the microbiota profiles of high SARS-CoV-2 RNA level faeces as established by metaproteomics highlight mechanisms that may contribute to vicious cycles. Uncovering the role of this gut microbiota dysbiosis could drive the investigation of alternative therapeutic strategies to favour the clearance of the virus and potentially mitigate the effect of SARS-CoV-2 infection.