Improved gut microbiota features after the resolution of SARS‑CoV‑2 infection

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) has a tropism for the gastrointestinal tract and several studies have shown an alteration of the gut microbiota in hospitalized infected patients. However, long-term data on microbiota changes after recovery are lacking. METHODS: We enrolled 30 patients hospitalized for SARS‑CoV‑2-related pneumonia. Their gut microbiota was analyzed within 48 h from the admission and compared with (1) that of other patients admitted for suspected bacterial pneumonia (control group) (2) that obtained from the same subject 6 months after nasopharyngeal swab negativization. RESULTS: Gut microbiota alpha-diversity increased 6 months after the resolution of SARS-CoV-2 infection. Bacteroidetes relative abundance was higher (≈ 36.8%) in patients with SARS-CoV-2, and declined to 18.7% when SARS-CoV-2 infection resolved (p = 0.004). Conversely, Firmicutes were prevalent (≈ 75%) in controls and in samples collected after SARS-CoV-2 infection resolution (p = 0.001). Ruminococcaceae, Lachnospiraceae and Blautia increased after SARS-CoV-2 infection resolution, rebalancing the gut microbiota composition. CONCLUSION: SARS-CoV-2 infection is associated with changes in the gut microbiome, which tend to be reversed in long-term period. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13099-021-00459-9.