COVID-19 - gastrointestinal and gut microbiota-related aspects.

OBJECTIVE: The aim of this review paper was to discuss the gut microbiota-related aspects of COVID-19 patients. We presented the faecal-oral transmission of SARS-CoV-2, gut microbiota imbalance, and fecal microbiota transplantation as a hidden source of this virus.

MATERIALS AND METHODS: We analyzed the available literature (PubMed, Embase, Google Scholar databases) regarding COVID-19 and gut microbiota related aspects.

RESULTS: The gastrointestinal symptoms, such as nausea, vomiting, diarrhea, abdominal discomfort/pain, may occur in these patients. Notably, these symptoms may contribute to the severity of COVID-19. Recent several studies have revealed a new SARS-CoV-2 transmission possibility, opening a fresh view on COVID-19. It is observed the possibility of SARS-CoV-2 transmission via faecal-oral route. Fecal microbiota transplantation may be a hidden source of SARS-CoV-2. Additionally, the pharmacological treatment of COVID-19 and other factors may significantly alter the composition of gut microbiota. Among others, loss of bacterial diversity, the decrease of commensal microbes as well as the increase of opportunistic pathogens are observed.

CONCLUSIONS: The alterations of gut microbiota in COVID-19 patients consequently may lead to the development of gut dysbiosis-related diseases even after recovery from COVID-19. Therefore, it is recommended to screen stool samples taken from recovered patients at least 35 days after clearance of virus from respiratory tract. Before 35 days period, SARS-CoV-2 may still be detected in feces. It is also recommended to screen the composition as well as the activity of gut microbiota to assess its balance. In the case of gut dysbiosis, there should be introduced an appropriate method of its modulation. Additionally, all the fecal samples which are prepared for fecal microbiota transplantation should be tested for SARS-CoV-2 to provide protection for its recipients.